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You want to know something about how bullshit insane our brains are? OK, so there's a physical problem with our eyes: We move them in short fast bursts called "saccades", right? very quick, synchronized movements. The only problem is: they go all blurry and useless during this
1,439 replies and sub-replies as of Jul 04 2018

having your vision turn into a blurry mess every time you move your eyes is obviously not a good idea, so our brains hide it from us. Now, imagine you're an engineer and you have this problem.
You've got some obvious solutions you could do. 1. make the vision go black during movement. (Some VR games do this!) 2. just keep showing the last thing we saw prior to movement
both are good options with different downsides, but OH NO. this is assuming everything makes sense and is chronological and (regular) logical. Your brain does neither of these options, really.
first, it basically puts your visual system on "pause". You're not seeing blackness or even nothing, you're just not seeing period. then when you finish your saccade, it shows you what you now see at the new position. and then it pretends it can time travel.
it seriously shows you the image at the new point, but time-shifts it backwards so that it seems like you were seeing it the whole time your eyes were moving. And because your brain is not a computer with a consistent clock, this shit works.
you can see this effect happen if you watch an analog clock with a second hand. Look away (with just your eyes, not your head), then look back to the second hand. It'll seem like it takes longer than a second to move, then resumes moving as normal.
that's because your freaking visual system just lied to you about HOW LONG TIME IS in order to cover up the physical limitations of those chemical camera orbs you have on the front of your face.
we've known about this effect for over 100 years, it's called "Saccadic masking" and more specifically Chronostasis. Your visual system lies to you about WHEN things happen by up to half a second(!) just to avoid saccades blurring everything.
So while I firmly believe we're basically just overgrown biological computers, we're apparently computers programmed by batshit insane drunkards in Visual Basic 5.
and you might think "hey wait, wouldn't my vision 'pausing' for half a second have all kinds of weird effects on moving objects? why don't they appear to stutter when moving?" and the answer is simple! your brain has EVEN MORE UGLY HACKS on top of this to avoid you seeing that
if you've got a clock where the second hand doesn't "tick" but instead smoothly rotates, you won't see this. Because your brain recognizes it's moving and adjusts what you see to make sure it sees the "right" thing.
it's only really obvious with periodically moving things like a clock hand, because it's not moving (so not triggering the movement-during-chronostatis hack) but it moves at a set rate, so you can notice that rate appearing to change.
It's tempting to think of your eyes and visual system as a camera just dumping a video feed into your conscious brain but that's so very, very not the case. What you think you see and what your eyes can actually see are two exceptionally different things.
The big obvious one being the blind spot. Vertebrate eyes are wired backwards so we've got a blind spot in each eye were the nerves enter into the eye. About 6 degrees of your vision in each eye is just not there, as there's no light sensitive cells there.
do you see a blind spot, right now? no, you probably don't. Close one eye! there's now no way for the other eye to fill in the gaps. Still, no blind spot... Your visual system is lying, and making up content it thinks is there. You literally cannot see what you think you see.
Here's another one: You can see in color, right? (well, some of you can't. Sorry) You can see in color all throughout your vision, it's color everywhere? Well, most of your cone cells (Which are sensitive to color) are in the fovea, a little spot in the center of your vision
So outside of that center-of-vision spot, you have very little color perception. There's some but it's very limited compared to your main color vision. But I bet if you shift your attention to your peripheral vision right now, it's in color.
your vision system is lying. it's remembering what colors things are and guessing and filling in the gaps. It's basically doing a Ted Turner colorization process on your non-central vision.
There's even weird effects like what's called "Action-specific perception". If you get a bunch of white balls of various sizes and toss them at people then ask them to estimate the size of the balls thrown at them, they'll have a certain size estimate, right?
now repeat the experiment but ask them to try to hit the balls back with a bat, and suddenly all the estimates shift larger. They actually see the ball as bigger because they need to hit it. their vision is exaggerating it to make it easier to see!
which just goes to show, like I said, your vision is not a camera. perfect accuracy is not one of its goals. it does not give any shits about "objective reality", that's not important.
what's important to the evolution of the visual system is any trick that helps you survive, no matter how "dumb" or "weird" it is. So if you want an accurate visual representation of what things look like? Use a camera. Not your eyes.
in any case the original point was that while you might know this about your eyes being poor cameras that lie to you, you might still think that at least they're consistent, time-wise. they don't screw with your sense of time passing, just to make up for visual defects. NOPE!
if you can't get it done in time, turn back the clock and pretend you did. That's a perfectly good solution when you're the visual system.
BTW @hierarchon reminded me of a neat trick with saccadic masking: go look in a hand mirror. no matter how close you bring it to your eyes, and how much you look around, you will never see your eyes move. You're blind during those moments. But you still think you are seeing.
she additionally pointed out that your phone's selfie-mode is NOT a mirror, and it has a slight delay, so you can see your eyes moving in it.
And for fun, here's wikipedia's example of the blindspot. Stare at L with only your left eye, adjust the distance, and the R will disappear. You don't see "nothing" or "black", you see the background, because you expect to.
This is why laser damage your retina can be so insidious. Your visual system already can hide "holes" in your vision, what's one more to hide? So you damage a small spot of your retina and your visual system covers it up.
but since you didn't go "WELL THAT WAS TERRIBLE I BETTER TAKE BETTER CARE OF MY EYES" and stop fucking with lasers, you keep doing it eventually you accumulate so much damage that your visual system simply cannot manage hiding it all and your vision rapidly degrades.
the other reason lasers are so dangerous is that they don't necessarily trigger the same responses as regular incoherent light. your pupil reflex is only triggered by some special cells in the center of your eye, so an off-center laser might not cause your iris to contract
and infrared laser light is just as dangerous as visible laser light, but can't trigger your blink reflex. Your eyes automatically close when exposed to bright light, but they can't detect infrared light. Despite not seeing it, it still causes damage.
Anyway, back on how amazing and crazy your vision is: There was an experiment back in 1890 where someone wore glasses made with mirrors in them to flip their vision. After about 8 days, they could see just fine with them on. Their vision system had started "flipping" the image.
(I say flipping in quotes because it's not as simple as it started showing the pixels at the top row on the bottom row, cause our vision doesn't work like that) It only took them a few hours to get back to normal after taking these glasses off, though.
The last really fun part about this flipping experiment: your eyes already do it. Based on how our vision is wired, we should be seeing everything upside down. We don't, but only because our visual system has had our whole life to adapt to this.
BTW, since a few people have brought it up: There's a great sci-fi novel by Peter Watts called Blindsight. In it humans encounter an alien race they call Scramblers, who can move very fast and precisely, and they exploit saccades.
because if they only move during saccades, we never see them moving. and since so much of our vision is based on just filling in what we think is there, if they stay out of the direct center of our vision, we'll just visually fill them in, like they were never there.
Check it out if you're into hard SF stories of first contact. It's got some really neat ideas about human vision, very unique aliens, the nature of conciousness, the future of humanity in the face of perfect VR, and vampires. (Really, it has "vampires", while still being hard-SF)
BTW, remember how I said "vertebrate eyes" up there? Guess who has eyes which are wired forwards instead of backwards (no have no blindspot), have an internal lens, and can even see polarization of light? our good friends the Cephalopods!
Where do I buy that upgrade?
That's a good question. It's still an open issue as to if this is just a crazy case of parallel evolution or just convergent evolution for a similar result, but I'm betting there's some CRISPR biohacker looking into how to grow octopus eyes that can be transplanted into humans
fun fact with cephalopod eyes: if they're damaged, they can just grow them back, by turning the regeneration genes back on. cephalopods are /slightly/ scary.
That seems like a useful ability. Is DARPA already on it?
oh, I'm sure the military will be one of the first industries in line to hack all kinds of neat animal advantages into humans to make them Better. They'd be pretty foolish at this point to at least not have considered this sort of thing.
So, like I mentioned in the other tweet somewhere, cephalopod eyes evolved from skin tissue invaginating inward, instead of nerve tissue expanding outward, and thus it's probably more plausible in squid than it'd be to hack it into humans
Wow, I never knew that. I've only ever encountered the light-sensitive skin tissue invaginating inward explanation.
Which can only mean one thing - freaking nanosuit like in Crysis!
The best emulation right now is just growing new organs over existing synthetic "frameworks". Looking for source on this but iirc we've grown lungs, hearts, and skin in this way
Out of curiosity, does octopus vision ever deteriorate with age? Can they regenerate back to their equivalent of 20/20 vision?
There should be a downside with this super eye, right?
The answer here to your question about whether it's parallel or convergent evolution is that it's convergent. We know this because Lizard & Mammal (and everything else with a skull) eyes are outgrowths of the brain. But cephalic eyes are outgrowths of their skin & nerves.
so what i'm getting out of this is that there's an extremely popular post-apocalyptic shooter featuring creatures almost impossible to distinguish from humans they can shapeshift, they have superior eyesight and regenerative abilities AND IT'S A GODDAMN NINTENDO GAME
Vertebrate eyes in inverts, and vice versa, has been done with PAX6 RNA transfer. Evolution might even be divergent, as last common ancestor likely had machinery for both, and examples of rhabdomeric and ciliary crossover exist
Google 'ectopic eyes' 😉
Holy shit this explains all the weird little visual things and disconnect between sight and reality (like the analog clock) that I have experienced in my life!
fascinating, thanks! i knew about blind spots and peripheral color vision but not the rest. here’s a fun vision/brains are f***ked up anecdote:
i briefly (3mo) took topamax and had a rare side effect, pallinopsia, aka seeing staggered after-image slices of moving objects. but possibly due to my TBI, i only see it when i move my head, & only in the morning. 1 mo off the drug, still got it 🤷🏻‍♀️
weird to stumble to the bathroom and see 15 slices of toilet
oh wow, that's amazing! I can only imagine what kind of strange effects could happen in your brain to get that kind of sliced after-image. Thanks for the info!
sure!! very strange things are afoot up there, haha. wikipedia has some facts. i have the discontinuous type but not the thing where i can’t see motion:…
That actually sounds fun for a few minutes but not much more. Makes me curious how that would mix with marijuana. Even if it becomes legal where I live, to me it's not worth any sort of addiction (if it exists with legal products) or especially how it would mow down my wallet.
sincere it only lasts about 15 minutes, it’s not that bothersome, but it doesn’t have any fun elements really. seeing 6 copies of the door jamb isn’t all that interesting.
I see. I feel like being more than just a bit loopy when experiencing it could be entertaining. I had to get a cracked tooth removed in middle school and after the gas wore off I felt like I understood a bit of why people like it. As for how I managed to crack it...
I'm notoriously nicknamed The Owl for reasons like this. One time I had a Tootsie Pop in my mouth only just long enough to wet the whole thing before crunching and it came clean off. Not a shard of candy or Tootsie Roll on the stick.
I had a baby tooth inching its way out when I broke it, and there was a small gap between the gum and part of the tooth. I crunched a Tootsie Pop and a sliver wedged itself into the gap. It cracked and broke away. It was damaged so badly it broke into shards while being removed.
I know what you mean, weed ‘zaps' and Kepra starbursts are kinda similar, the zaps are much more predictable and fun, however. Like, oh, my brain just took in way too much info for a second.
This is why I follow u bro
You mean the aliens! One neat way to use some of this to your advantage, as I'd not seen you cover it yet: If you are trying to see something in the dark, don't look directly at it. While those rods are bad for color, they're great for dark vision.…
oh yeah, I remember seeing that effect as a kid looking at the stars. there were some fainter objects you could only see by looking indirectly at them.
yess! some stars wouldn't be visible when stared directly at. Wow, your thread has given explanations to several phenomena I had always noticed but never gave much importance to, thanks!
Heck thanks for this, this helps me understand better so many optical illusions I have sometimes (and that I start thinking "am I going insane"). Also is there any similar stuff that explains schizophrenic delusions? My cousin has it and I would like to know more ;/
sorry, I'm not sure. it's certainly possible.
no probs! if you have any book on this kind of thing please let me know!
It's only mildly related, but I remember reading that when those "deep dreams" images created by inverting Google's neural networks came out, some people said those were similar to hallucinations experienced under LSD.
So I guess some delusions might work like that - the part of the visual cortex that elaborates symbols and stuff being fed backwards and making us "see" things that aren't there but we think of/imagine.
They're even cooler. They have no colour receptors, but we know they can see colour. How? Current theory is they use their strange-shaped pupils to set up diffraction edges. They they USE chromatic aberration - they can SEE the rainbows at edges. That lets them see colours.
And not just our rubbish red/green/blue triplet - oh no, they literally see a barcode of ALL the frequencies. They can tell the difference between red+green and yellow (we can't). Cephalopod eyes are NUTS.
Man. And at this point all I wanted was the ability to shoot ink at people that annoyed me, now I want Octopus eyes as well??
So I got this thing where my right eye slips in and out of focus post accident. Ever since I fail all the dots depth perception tests. But I see and catch fine. Until twilight when it falls apart. Sup with that?
We're also as stupid as evolution. Originally all CMOS and CCD image sensors were wired backwards too, we just ran the wires out the sides instead to avoid a blind spot. It wasn't until backside illumination sensors that we went the cephalopod way.
Fascinating, thanks!
Here’s one: because our eyes are wired backwards there a ton of vasculature crossing our vision. But you don’t see it, because when your eyes move, the blood vessels do too, and your brain detects stationary “eye bits” from the moving “outside bits” and patches over the gaps.
Your eyes involuntary twitch periodically to get this data, but you see none of this. To see it, make a small pinhole with your fingers, hold it directly in front of one eye (w/ other closed) and jiggle the pinhole horizontally rapidly (1/4 inch motion) while looking at a light.
This causes the angle of incident light to shift across the blood vessels, and your eye will start to pick them up because they’re now registered as moving. Looks like a map or a craggily spider’s web.
I see these all the time. Frustrating as all hell.
Wow. It worked!!
You can also see it by looking at a very blue sky
that was cool!!
Wow. Question - is this related to why if I stare at a spinning hubcap and then jerk my eyes away it seems to freeze - to the point I can actually see the shape of the hubcap even though it blurs when spinning?
yup. Same phenomenon.
are there any phenomena like this thread talks about but for hearing?
Yep! Check out wikipedia's "Auditory Illusions" page:…
I read somewhere that eyes get 'lazy' and will patch in info it has seen before, which is why drivers hit bicyclists on the road or other objects around their driveway, because the eyes literally did not tell you about them.
have you ever looked at a segmented LED display (being dimmed by PWM?) while brushing your teeth with an electric toothbrush? my alarm clock's digits become "wavy" while everything else looks normal when I do it.
Humans can also see polarization of light, but it is a very subtle effect. See Haidinger’s brush.
Thanks for the fascinating and interesting thread.
I want octopus eyes, now.
Nat Geo WILD has a programme about some kind of lobster that has lighting fast and extremely destructive melee attacks and how their eyes are insanely good at seeing colour (and have two pupils as well if I am not mistaken)
Great thread - entertaining *and* informative! I read / heard that veterbrae eyes are just aquatic eyes only slightly altered -barely evolved- for land living, since we crawld outta the water however many epochs ago...
Also, I can detect analog TV framerates when they're away from the center of my sight. Don't we have faster movement detection on the borders ? Thanks
We also see in different "frames per second" form the focus (high) to peripheral vision (low). That's why you sometimes see flickering lights/monitor only with the corner of your eye.
I have this thing where I can 'switch' between eyes. So, I can see through both eyes, but I can give prominence to one eye and see mostly through that. What is that called, and how does it work?
I have that too!
(Apologies for self-promotion) I wrote 3 novels based on Chronostasis (the 3rd actually using that as its title, the first being The Long Second)…
I imagine you know that for sound, if you suddenly hear something loud your brain bypasses the normal processing, it jumps the loud noise to the front of the queue and dumps what you heard just before. It's called temporal masking, it's a survival reflex. FIFO with queue jumping?
The day octopi with their delocalised arm-brains and superior eyes manage to get a longer lifespan and begin to accumulate knowledge is the day humans lose their place at the top of the food pyramid 😀.
I really enjoyed all these eye facts. I learned a lot. I know that eyes have special immunity where they’re separate from our bodies immune system else our body would destroy our eyes.
It’s coming home 🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁥󠁮󠁧󠁿 (But seriously this is an amazingly interesting thread and should be read by any inquisitive mind)
What an incredible thread. Thank you.
I knew about most of this, but I'll be eternally grateful to you for that explanation of the "slow first second" when you look at a clock! I've noticed that all my life and always wondered about it!
This is an amazing thread. I have a question. I used to play with a scanner we had as a kid. Whenever the bar of white light was scanning something, I could see three different bands of color (R/G/B) if I moved my eyes while the bar itself was moving.
If I just started straight into the white light, it just appeared white, but if I moved my eyes then I could see three different colors. Why is that?
Does this all have anything to do with me seeing things like in a video game when I get moderately drunk? Noticed that when I look at my hands do things while drunk, it really does look like I'm playing a video game IRL, difficult to explain exactly
Awesomely interesting! Do you think this saccadic phenomenon could have any connection with the feeling of deja vu? Basically the brain confusing a lag in perception with experience?
Ever read Dr. Terry Bahill's work on saccades and baseball? This weird eye system has some profound effects in baseball.
I have an issue/question with the data as presented. It seems to assume time is “real”, perhaps the “hack” is the perception time is constant and contiguous. Get in a car wreck you can see every nanosecond in slowmo. Perception and awareness are not the same.
Have you read Magic Leap's theory on how filtered information is sent from the eye to the brain? If accurate it's kinda spooky.
This was freaking amazing. Thank you. And it made me feel so much better about some weirdness I noticed back around high school, but never told anyone because I thought my eyes were broken. 😄
Loved this thread. I’ve always thought that about the second hand of a clock, but had no idea that it was real what what was causing it. Awesome thread!
I'm guessing this is also a good explanation for the feeling of deja vu.
Wauw. Just wauw. Thank you. Do you have similar explanation in an article with a link, so I can share it with people who are not on Twitter?
If someone loses an eye, does the brain do anything to simulate binocular vision. Closing one eye seems to make things flatter, but not completely flat. Any other interesting hacks involving depth perception?
This is the best thread I have ever read on twitter.
This entire thread is flipping fantastic. This fun fact about cephalopod eye anatomy just blew my mind.
My left eye is 1/2 blind. Closest to my nose. I literally cannot get a blind spot to show in my vision. And that’s half my eye! Your brain is a crazy machine.
Cephalopods can also see colour in spite of seeing the world in gray scale! However, our eyes fare much better having their back to front set up, even though everyone thinks it is a glitch.
The Extraordinary Secret of Cephalopod Vision
Cephalopod vision has always been a mystery to scientists. In spite of being colourblind, their behaviour shows they are able to distinguish colour, and this...
But back to the matter at hand, can you see why kids love the taste of Cinnamon Toast Crunch?
As an utter SWAG I wonder whether the amount of light exposure is the key here? Cephalopods would need higher % of avail light than we do; perhaps our optical structure is a protective design. But I know nothing of other possible comparison animal groups.
I once read that when running our brain sees ahead of us by projecting what is coming slightly before we actually get there.
Hey, thanks for the interesting morning read!
I think this is one of the best threads l've ever read on Twitter. Congratulations!
Finding this fascinating as I have an adult son with Lowe Syndrome. Born with bilateral cataracts, taken out, occasionally uses +25 contact lenses, has pendulum nystagmus, microphthalmia and CVI. How does nystagmus affect saccades, how does his brain "see?"
yeah, that's a good question. there's not a lot of info on that sort of issue, sadly.
I know he has some functional vision, though registered blind, he's nonverbal so he doesn't test at all well & has to be sedated for eye exams. He's also at risk for glaucoma. He has an enduring obsession with lights, esp sunlight.
Hugely grateful that his operations were done so early @ 1 week old and fitted with +36 lenses shortly after. What brilliant technology! Helped build his visual pathways whatever they are.
Yeah! I've read about cases where people have had basically no vision in their early years and then had the physical parts of their blindness fixed later on. Even though there's nothing functionally wrong with their eyes now, they just don't see. you need it develop early.
Many boys with his syndrome wait months or years to get their cataracts dx & removed. Our surgeon later told us that Joff was the youngest bilateral cataract patient in Scotland at the time! #lucky
wtf foone, why do you have these tweet threads that make me wonder what the heck is up with brains
sorry. something the other day reminded me of this so I wanted to rant about how my mental model of how brains work is so obviously very, very wrong.
Never apologize, between your weird retrotechtacular stuff and these rants, I know why I follow you. Keep these kinds of things going
And he's made it available for free on his website, for those who want to read it that way:…
It's funny how you can surprise your brain by making it understand things it's already been doing since your very birth. Oh, brains, you complicated fellows.
Eye see what you did there. (sorry)
I had a patient with Charles-Bonnet Syndrome. That shit’s nuts. He had end stage macular degeneration so his brain just filled his vision with hot ladies.
I've noticed that clock hand shit, it made me start thinking that we exist in a sort of frozen landscape where time doesn't progress until we interact with it in some way for about a solid month of my life in fifth grade.
I did a ton of research into deja vu, because it happens to me a lot. Turns out, scientists think deja vu is related to how our vision and brain interact. By the time we're mentally processing an image, we've already seen it.
Most of the time our brain time stamps it as "happening right now" but on occasion it accidentally time stamps it as "been there done that"
ooh, very interesting! Thanks!
thank you for this extremely good thread
it should be a movie
Links to your scifi?
And why some people don't see cyclists, because their brain filled in without us there. And why you should always look twice at a junction.
How has this not been made into a Doctor Who villain yet?
Weeping angels intermingled with the silence. Well, i had no intention of sleeping tonight.
Why do I read this shit right before bed. Fuck.
Imagine if the Weeping Angels knew how to exploit this!
In related news, be seriously SERIOUSLY sceptical of eye-witness testimony, especially of some time ago. Our memory system is similarly weirdwired. Police have only just been learning this.
For this reason we constantly lose sight of the flies when we blink, right?
The Weeping Angels of Dr. Who explained.
*bumps this up the reading list, it was already on there*
now that you mention it, I've been wondering how even the super-low-latency VR setups we're starting to get could *ever* keep up with eye movements for the sake of faking depth-of-field, etc… but they've got a built-in buffer period that we won't see to get ready in…!
Experiments in the 70s demonstrated as long as you can track the fovea as someone reads, you can show only a fraction of the text and the reader won’t notice. Foveated rendering is expected to revolutionize VR by drastically cutting GPU requirements.
Right, but I figured that just masking text was a simple enough task that rendering time wouldn't be a significant strain on the latency although, I actually didn't realise that those experiments were done in the 70s, which means it might have been after all!
It may have been the 80s. I don’t have specific citations handy. It was definitely multiple decades ago, though. Long enough ago that related technology was integrated into high-end SLR cameras in the 90s (gaze-tracking autofocus point selection hit the EOS 5 in 1992).
Scrambler: ok so this trick is frame-perfect
exactly. an entire race of speedrunners run into some slow apes and are like "THIS IS VERY EXPLOITABLE"
Further proof the universe is a simulation and human life just a bug
This reminds me of the Weeping Angels in Doctor Who...but that’s much more soft sci fi (the angels are “quantum locked” so they can’t move while being observed, yeesh)
Reminds me of the Silence, especially the part where your brain just edits them out.
wtf that sounds terrifying?? I'm buying it immediately
There's actually an SCP that does this too, pretty interesting.
yup. And the comments for it explicitly call out Blindsight as being one of the inspirations for it.
The concept is pretty uniquely horrifying in a primal way. a direct exploitation of our most trusted sense not using supernatural abilities or technology far outside our understanding, just... being better evolved.
Echopraxia (the sequel) is no less creepy
So, I can't reproduce the second-hand ticking clock phenomenon you described. Does this mean I am the Chosen One who is destined to defend mankind against the Scrambler aliens?
But seriously, I can't seem to reproduce the discrete second hand ticking phenomenon.
Is it a real physical clock? It makes noise, which is for me more difficult to get. But on a silent clock on a computer screen it's easier.
This is an awesome thread. I was going to mention Blindsight but you beat me to it.
One other neat thing about saccades is that you have to emulate them when you animate people or the avatars are very creepy. Flipping on saccades made our avatars significantly less creepy when we first started experimenting with VR avatars.
I was surprised that the VR headsets have low even latency (and eye tracking) good enough to detect the saccades and act on them. That's pretty neat on its own!
lol damnit I’d already forwarded this thread to multiple people having only read the top half of it, commenting “…and there’s this great novel called Blindsight where this is a key plot point!”
Hooray! I'm glad others mentioned it. I was going to, too.
I'm also here to say 'not first' re: Blindsight.
There's an old 1000 Series SCP that does this too! The Perephiral Jumper.
Yup! And if you check the comments, it was specifically inspired by Blindsight
So glad you brought this up. I was screaming BLINDSIGHT at my phone while reading the thread!
Yup! Blindsight is one of the things that got me into this whole subject.
It’s where I learned about saccades too!
Well then, we’re all doomed
The Weeping Angels in Doctor Who as well...
Is this where Doctor Who got the concept of Weeping Angels from? They move during blinks though.
‘Blink’ was the first thing I thought of too! 😬
Thank you (for this thread and the book recommendation). I think I've just found my holiday reading material for next week 😃
Are saccades synchronized cause i would think 5 or more people looking in the same directions would be hard to avoid?
Also a great sci-fi short story by Greg Egan called Seeing, in which someone's vision switches to a fake bird's-eye view.
do they have pale skin and look like marble statues?
I do believe we’ve just uncovered the science to Doctor Who’s weeping angels. Time to finally fight back
wow, now I want to build a prototype with a high frequency eye tracker and a 120hz display...
Blindsight is one of my favorite novels, mostly because it's a research dump of weird corners in neuroscience and biology like this
- since we were talking about Sci Fi the other day, thought this may interest you
Sleight-of-hand artists too
There was an X-File episode dealing with same subject (though ironically not alien)
I had a squint op as a child, and when doing a prismatic correction test you can put the largest prism in and my vision still won't line up. But because my brain has been doing it for 25 years, there's no appreciable impact on my vision. (Except 3D glasses - no helping there.)
yah! I had the same sort of single-eye vision for a long while. because of an injury around 7, my left eye was basically useless, and until I got glasses around 14, I basically just used my right eye for everything. It's amazing how quickly you stop noticing that.
My earliest memory of of doing eye exercises, but other than that you just stop thinking about it and your brain somehow adds depth perception even when your weak eye is closed. "You need binocular vision for depth perception" ignores the brain being a truly weird computer.
yup. binocular vision is just another trick that helps with depth perception, but your visual system will happily use shading clues and head movements and just plain guess.
I had a cataract in my left eye for a few years. When I had the op to remove it and my left improved I suddenly had trouble with basic hand-eye coordination - say putting a object in a hole - I would miss the hole by an inch. It improved very quickly but it was weird.
huh. Presumably your brain was coping with only having one eye but then when your other eye started working again, you were now over-compensating! very interesting, I've not heard of that happening before.
All of this might help explain why people report such crazy visuals while on psychedelics, it's hard to believe if it were just a camera, much easier to believe if it's actually effecting the plumbing of these hacks instead. Maybe akin to a timing attack of some sort.
mmm, yes! I've actually read that one theory for how LSD (and related drugs) work is that it basically "overclocks" the visual perception system. It starts trying extra hard to see things where there's nothing to see
and also the information it's trying to send to the rest of the brain is now somewhat corrupted by the fact that it's now running at a different rate, so it gets misinterpreted. like playing a 33 record at 78.
He has the paper implementation and then a much simpler python implementation:…. Best part is the sample output is a bunch of gabor filters, which is what you typically find in all modern neural networks trained from reward on image data.
BasicV1 - A simple model of V1 receptive field learning in 25 lines of Python
so that explains it. everyone in australia is right-side up. we're all upside-down. now I know why upsidedownternet doesn't work in Australia :^)
The single thing that both intrigued and terrified me about human vision was triggering the McCollough effect on myself which lasted about 15 minutes, then reading that if you stare at the patterns for long enough it can last for months.
hence the death cab lyrics: “And when I see you I really see you upside down But my brain knows better It picks you up and turns you around”
Most of your thread is in line with the evidence, but this tidbit is not. What is your visual system "flipping" the image relative to? Where is the sub-modality to give the image a frame and tell the brain "this is up-side-down"? Old wives tale, neither logical nor empirical.
As someone with glaucoma vision loss who's lost some extra sight from a cataract this is SUPER fascinating and jives (I think?) with my experience of my brain filling in content in familiar settings but suddenly feeling blinder than usual in new contexys. Would this be similar?
Yeah! we actually see a lot less than we think we do, so in familiar settings your visual system is probably able to easily fill in the parts you can't actually see, but go into a new area and it has nothing to base it on.
That is so wild and I love it.
Upside down in relation to what? The retina is a sensor array. Inputs to neural cascade can be arbitrary as long as they're consistently reporting on the same stimuli
That is, what difference would it make to VC neurology if photoreceptors were randomly located on the retina. Not upside down, but scrambled?
Granted, evolution wouldn't likely arrive at such an array. But the point is, no picture exists on the retina that needs to be righted
Im not quite sure why this happens. Is there a reason why our brain prefers things falling down rather than up?
Is it true that babies spend their first moments seeing upside down, until their brain corrects it
I'm really curious if there is anyone out there who, due to some damage or deficiency, can't flip the image and therefore sees the whole world upside down
Why does the brain feel the need to flip the image if we could likely cope with just seeing things upside down?
1b) as elsewhere, the brain or visual system is doing the flipping, not the eyes.
What would “seeing upside down” even mean in this context? We have no other visual reference than our eyes, so whatever they show as “up” is by definition up. It’s only when you switch do something like wear mirror glasses that the brain has to compensate.
Great thread! We had some prism glasses in the psychology dept where I studied. I remember those being left/right rather than up/down, but my memory may be failing. A very striking effect, and disorientation on removal / eventual tolerance of both states was fascinating :)
i believe some people got sick afterwards headaches etc that did not go away easily
After playing BeatMania or Dance Dance Revolution or any game where you concentrate hard (for a sustained period) on patterns perpetually falling down the screen, everything appears to drift the opposite way (upwards) for a while. Perhaps related to vision system hacks?
Yeah, I think so. Your vision system is always trying to compensate for movement to try to get a clearer image, so it can be tricked by these kind of "after-images".
I remember this from watching Mr Wizard
Well...there's a considerable literature about attempts to repeat Stratton's 1897 experiment. It works better in theory than practice.
ooh, that's good to know. Thanks!
Love this story. Bicycles and all
Have you heard of the the McCollough effect? With just a few minutes of looking at a couple of pictures, you can train your brain to see a different color when looking at horizontal stripes than when looking at vertical stripes. The effect can last for several weeks.
I think natgeo recreated this in one of their series a couple years ago
Similarly, I have nystagmus, which makes my eyes wobble, but unless I'm *really* tired I don't see any wobble in my vision at all because my brain cancels it out.
I have heard of some brain injury therapies using modified glasses, I'm having Vestibular Physio at moment which is very much eye/brain connection. and having ones head wobbled by some young woman.
There is a ton of stuff like this in “The Mind is Flat: The Illusion of Mental Depth and The Improvised Mind” by @NickJChater. I think you’d enjoy reading it.
Adaptation & deprivation experiments by vision scientists have a long history as you point out. My fave (maybe? Probably!) The visual system, even primary visual cortex, isn’t only visual. 5 days of deprivation can “unmask” tactile processing ability.
Rapid and Reversible Recruitment of Early Visual Cortex for Touch
Background The loss of vision has been associated with enhanced performance in non-visual tasks such as tactile discrimination and sound localization. Current evidence suggests that these functional gains are linked to the recruitment of the occipital visual cortex for non-visual processing, but the neurophysiological mechanisms underlying these crossmodal changes remain uncertain. One possible explanation is that visual deprivation is associated with an unmasking of non-visual input into visual cortex. Methodology/Principal Findings We investigated the effect of sudden, complete and prolonged visual deprivation (five days) in normally sighted adult individuals while they were immersed in an intensive tactile training program. Following the five-day period, blindfolded subjects performed better on a Braille character discrimination task. In the blindfold group, serial fMRI scans revealed an increase in BOLD signal within the occipital cortex in response to tactile stimulation after five days of complete visual deprivation. This increase in signal was no longer present 24 hours after blindfold removal. Finally, reversible disruption of occipital cortex function on the fifth day (by repetitive transcranial magnetic stimulation; rTMS) impaired Braille character recognition ability in the blindfold group but not in non-blindfolded controls. This disruptive effect was no longer evident once the blindfold had been removed for 24 hours. Conclusions/Significance Overall, our findings suggest that sudden and complete visual deprivation in normally sighted individuals can lead to profound, but rapidly reversible, neuroplastic changes by which the occipital cortex becomes engaged in processing of non-visual information. The speed and dynamic nature of the observed changes suggests that normally inhibited or masked functions in the sighted are revealed by visual loss. The unmasking of pre-existing connections and shifts in connectivity represent rapid, early plastic changes, which presumably can lead, if sustained and reinforced, to slower developing, but more permanent structural changes, such as the establishment of new neural connections in the blind.
Even though Pascual-Leone and group don’t cite Hughlings-Jackson’s 1880s theorizing in that study, the concept of unmasking goes back to him and a quick check of my Twitter history shows I’ve tweeted about this... 7 times since 2012. #myfavoriteneurologist
I use this effect as a metaphor for cultural hegemonic collapse. Neoliberal cultural hegemony has worked like a lens, slowly flipping USians perception over years without them knowing. Now it's collapsing, it's like taking the glasses off suddenly and being unable to see.
I work in neuroscience - this particular experiment is one that gets *way* exaggerated in pop culture.
I assume lying on your side watching tv or a movie and your brain allowing you to watch it without issue is also your brain adjusting what we see so it just works.
Some green lasers are really bad. Most of the power is in the IR range, but your eyes only trigger a blink based on the weaker green output.
Wait, so what about the IR projector on the iPhone X spraying your face with IR light every time you pick up your phone? Is that dangerous?
You should add in the experiment where they injected special rods/comes into monkey eyes so that they could see infrared light 🤯
Loads of info on those with hallucinations having tracking problems too! Veeeeeeery interesting!
Is this the reason why sometimes things that are spinning, such as car wheels, appear to spin backwards at a lower speed than the wheel is actually turning?
Hi - I may have the answer to this. I bet you see this effect under LED street lights but not with incandescent bulbs - some LEDs flicker very fast, cause a streboscopic effect and 'freeze' the wheel motion. I've noticed it more in the past ten years or so.
it was there 30 years ago it was there forever
Interesting! Where have you seen this, and what were the lighting conditions?
...and looking at what? A wheel hub?
at a car you know it's called a wagon wheel effect? as in, the horse powered wagons?
Okay - I've seen the effect in films where the 25 frames per second causes a streboscopic effect, but I've not seen it in broad daylight with my own eyes.
Oh this is fantastic, I didn't know about this effect under full illumination at all! Thank you, I'm going to watch out for this!
capitol city streets and dumb cars are probably humm enough for humming effect
Do not look at laser with remaining eye
try looking directly at the sun for once a year for a seconded or two, it overwork your eyes greatly, causing temporally blindness in some cases but it will help your eyes work faster and provide them with a high target to work safely under (eventually we will evolve night vision
By laser, you mean laser treatment?
As someone who works with lasers, I suppose I should have realized this danger. Thank you for removing the blind spot.
T1 diabetic here. I've twice had laser treatment for retinopathy. Straight after, my vision is affected, where parts of my retina have been intentionally burned. After about a day my brain fills in the gaps.
there's a bunch of bad spots on this quickly rotating metal disk, what's one more to hide? but it eventually piles up and results in massive failure
Ok I'm this far down and I've already forgotten what the original point was. Really interesting stuff though.
Yeah. I laser welded a retina during an eclipse in the 80s. I was aware of a spot in my vision for several years. They even took pics of it. Eventually my brain edited it out. Doc says scar still there, but I cant tell.
this thread & this comment particularly gave me major Optic Nerve Blocking vibes
Oh fuck. That explains why I think my right eye has a bigger blind spot. I used to stare at the sun as a kid. I was an idiot.
great so for all I know i could be blind Brilliant lol
The same with modern hard discs. They map out bad sectors and just go on working, just a little slower. Or cats: they have to be very ill before you notice they're ill.
I’m curious about this one (as an airline pilot, I’ve been subject to a few cases of what is euphemistically called “laser illumination”). I assumed that I hadn’t suffered any damage because I hadn’t noticed… but if I wanted to “find” damage, is there a way to test?
I love this illustration of the same physical limitations
Another fun trick is to stare at a tile floor long enough - at a certain point your brain starts filling in details wrong, like merging two neighboring tiles together.
I have done this do many times, never realized what was going on
An old job had this wallpaper that the way the pattern was, if you stared at it long enough it started to go 3-d. The pattern would start to merge and the lines would actually pop out in front of the background. I used to love staring at that wallpaper...
Me: *closes eye* "Ok so I need to get OH NOPE, IT'S GONE. Back...gone...back..gone......that's fucked up."
This test didn’t work for me. I saw both L and R no matter which eye I used. They just got really blurry at some point.
hmm, that's odd. Are you part octopus by any chance? :)
Wouldn't that be nice. ^_^ I have excellent peripheral vision, despite everything else rapidly deteriorating.
I'm pretty sure my astigmatism caused the same issue. The test image with the 12 dots I can "see" the example.
Oh. Just saw this. And yes obvs.
Try doing this while moving the phone slowly away/closer to you. At some distance that letter will disappear I just tired it
I tried this and I think I can tell where it is meant to be blind but I still see the letter! I notice a blur then refocus as I slowly bring it in
I've done this before, but it's still hella weird
I'll have to see if I can find it, but I saw a fun illustration of this kind of thing where you put a dot in your blind spot and a line grows through it. You see the line reach the blind spot, pause, and then backfill once it reaches the other end.
oh yeah, that sounds neat. I was thinking it'd be fun to make a version of the blind-spot display test where you could push a key and switch the background to a pattern, like a grid. See how well your visual system can fill in.
Ooooh that'd be amazing!
I would have a version where the pattern is different just at the R. So the whole of the background is parallel lines except there are dots around the R. Then you’d see parallel lines around the R and not dots when you look at the L
it didn't disapear, but stayed the same absolute size as the l got bigger and smaller apparently my eyes have enough ram to remember an R
Oh wait you were supposed to close the other oops I didn't read the directions right
im blind in one eye. Soooo..... i can see both in one eye and nothing in the other OTL
Yerrr... fucking lying eyes
"holy crap" i sez
Tried it and could see the R disappear, then pop back into existence as soon as I looked over That's trippy as hell
dosnt wrk with me, i can still see both letters
really tripy thing about that, if you cover your eye and leave both open, once you focus on it you will see the letter in the covered eye. surrounded by blackness, like your looking through a pin-hole or keyhole.
Eh I see both letters regardless of which eye I use. What's that mean lol!
It means your eyes are too close to or far from the screen to position the letter for your closed eye in the blind spot, or that your head is tilted slightly relative to the image, which also moves the letter away from the blind spot.
Now place your fingertip in the blind spot. The visual system can't fill in your fingertip so you get the sensation of your finger like a tall building extending into the clouds, except the clouds are invisible. Mostly it feels like it's saying "don't think too much about it".
But, but I still saw it
The best thing actually is that the brain fills in with the background PATTERN, not just color. The brain tries to understand it and fills in with what it thinks would go there. It's interesting to try to this one out yourself to see what the brain fills in in complex patterns :D
I love things like this! 😊
It's so awesome!
I remember playing in an online pool and when i was focused on one spot i noticed that some balls would disappear.
Mostly, the other letter disappears when my nose gets in the way. Am I doing it wrong?
Your nose cannot get in the way because you closed the eye on the other side of your nose!
I’m meant to close both eyes? Can’t see anything like that…
Close your right eye and look at the L with your left eye. L for left. R for right 😂
It's not clear that you do see the background, and it's easier to believe that's what you do when the background is plain white rather than a pattern.
This one’s not true
HOOOOLY CRAP this whole thread 👀
Yeah so that didn't work.
Heres a fun thing, get the distance right and everything.. then move a finger or hand across the R... MAGIC
I can still see though no matter how hard I try
another way to “see” your blind spot is to close your left eye and hold your right thumb straight in front of your face, then slowly move it out towards your side, keeping your arm straight. when you get to your blind spot, your thumb will “disappear”
(you gotta keep your right eye facing straight the entire time. don’t follow your thumb with your eye!)
I laughed way too hard while doing this
This wasn’t working for me for a hot minute, and then it just like >clicked< when I tried it with the R, almost dropped my fucking phone lol
Being born blind in my right eye because the optical nerve is there but not connected, this does not work for me. Also I can always see my nose. Which I hear two eyed people do not see.
Brilliant thread. Except I tried this with each eye & respective letters, multiple times. I see both letters; the opposite letter doesn’t disappear. What do you make of that?
Equipped with some theory, this time I finally managed to experience my blind spot! It's pretty cool.
Holy smokes!
(I know you wouldn't do otherwise, but seeing myself referred to as 'she' always makes me happy)
of course! my general default is "they" but I try to always check profiles, and if you've got pronouns, I'm using 'em. it's just basic politeness, you know?
OMG!! That is freaky. I thought - “a mirror must do the same thing.” Nope! Mind blown.
OHHH FUCK. SO THAT'S HOW THAT WORKS. Man, I spent countless hours growing up trying to see my eyes move in the mirror and being baffled at my inability to do so and knew their was some funky shit going on. Tysm for this enlightening af thread. Mind = bologna
Which makes me wonder how on Earth could comedian Marujita Díaz practice her "moving eyes" gag
I had a biopsych textbook use that example to demonstrate how motion blindness works. It was really crazy to think about at the time.
Weird, if you move your eyes, nothing, but if you turn your head and look straight they move around nice and smooth. The muscles still have to move your eyes to keep them focused on the same spot...
Fun addition to this that if you can make one of your eyes move independently of the other you can see it move in a mirror hahaha. I actually learned how to do that trying to see my eyes move in a mirror.
My left eye turned in as a kid, but after corrective surgery I learned how to do it on command. When hearing about this first I tested it that way. Cool as hell innit?
How about when the brain lies so much a dude tells himself he's a girl
you can do this with your phone's camera: look at different sides of your phone. fucking freaky
How could you see your eyes move in any case? You need to be looking at your eyes in the mirror to see your eyes; when you move your eyes you can't see your eyes until they're pointed at your eyes, ie finished moving
Interesting thread, just to add though, I have a condition called Nystagmus which means my eyes constantly move. With the mirror example I can actually see my eyes move in the mirror when looking around.
Also you mentioned a "flipping" experiment which made me think of rotation, I don't know if this is normal but I can consciously rotate my vision +/- 30 degrees or so.
No you can't.
Just did that and watched me eyes move.
Yeah except not.
What about seeing other people’s eyes move during saccadic?
So does this mean that there’s basically no where to go but up for cybernetic eyes?
There's a theory I read somewhere that cybernetic eyes will need to be from-brith in order to improve on sight because of just how much of a mess our existing processing is.
I can believe that. OTOH our “hardware” is also crazy adaptable, so hopefully not.
Yeah! there's a fun experiment you can do: get a pair of glasses with a set of mirrors in them to turn your vision upside down. Wear them all the time. In under two weeks, you'll start seeing everything rightside up again, even with them on.
brain plasticity is amazing but I feel that there are probably limits
That’s what graphene is for😁
Exactly the experiment I was thinking about. I also like the one where the subject’s braille scores improved dramatically after wearing blackout goggles for a couple weeks.
If you like sci-fi, look into a book called Blindsight by Peter Watts. It's free and this is a whole thing in it
Yeah, I read that a while back! that's one of the things that got me into this subject. I need to read the follow up, it somehow slipped through the cracks on my to-read list.
I knew saccades are crazy, but I didn't realize they were time travel. There is some recent VR research I've heard of where they're doing "redirected walking" (turning the virtual world out of match with real, so you walk in circles without knowing) not by changing rotational
Gain (like is a more common technique) but instead using eye tracking to detect saccades, and moving the world on you during saccades so you can't detect it. As long as the brain is going to paper over some gaps, may as well use it to keep you from walking away...
sounds like the solution being used in most science right now lol
Excellent thread 👏
Is this why my driving instructor told me to always turn my head when checking my mirrors and blind spots? Reduce the number of tricks my visual system can play on my conscious mind?
This also applies to tardy contributors and editors who don't realize there is a time stamp on their Word documents.😒
our wetware is amazing, taking hundreds of thousands of years to perfect. And it only takes 9 months to make a new one!
sounds to me like you have lost a few days somewhere lol
1a) as elsewhere, the brain or visual system is lying, not the eyes.
I can't keep living with al these bugs in my eyes help
My camera doesn't shoot accurate purple ☹️ blue looks blue and purple looks blue, no matter the setting. My brother has a better camera with graph thingies and color values and whatnots. Purple looks purpler. But if you really want accuracy, ask an 8-year-old child how you look
Except cameras *also* distort
I disagree with this 'use a camera' point. cameras do all sorts of things to match the 'accurate' visual representation with the perceptual. White balance, HDR, etc. Exhibit A: "The Dress" Some of these dirty hacks that our eyes do are worth replicating apparently.
Cameras struggle to replicate reality much of the time. But they do provide another viewpoint.
But you use your eyes to determine that the camera is an accurate visual representation, so...
*slight* problem with this: you still have to look at the photo you just took....With your eyes. Womp womp.
I think I might be missing something. It seems clear to me that "chronostasis" and saccades were developed biologically to prevent blurry vision or blackness when switching from one point of your vision to another, but I don't understand how being behind time aids our survival.
Lol. Each of them. Then use your untrustworthy eyes to decide which photo is most authentic.
So I should not believe the image I see in the mirror, but only my photos are real? That sucks
Cameras are not an accurate visual representation of what things look like, they have flaws too
So why do people look fatter in photos?
I'll to disagree there. Cameras are no better than our eyes at representing reality. Our visual cortex is replaced by a visual processing unit in them. That's what turns raw pixel data into JPEGs and PNGs. Lookup why the Pixel line is better than dual camera brands to see this.
Is that why pictures make us fat? The eyes lie to keep is happy, cameras don't?
The whole thing about the time hacks is, in fact, fantastic!! It makes sure we get a fluent experience, even in lieu of actual information. These aren't ugly hacks, imho, it's like a reality-augmentation-layer that improves our perception of reality!
Yep. It’s probably a good thing, too, since the visual system takes time to process input, and the world keeps changing while that happens. Damn it, world, why won’t you just wait for the brain?
Wait is that why people say “The camera adds * pounds”? It’s just our brain telling us we’re thinner than we actually are?
Actually that applies pretty much unedited for the rest of the brain too. Read Kahneman, 'Thinking, fast and slow'. Reality, for the brain, is a construction, and only as good as it needs to be.
This statement is true about so much things though 🧐
Yep, this is also why I find eye witness testimony suspect 😜
I didn't know about this, neat! This reminded me of the Moon Illusion, which I learned about while trying to do lunar photography:…
This does explain the large variation in hand-eye co-ordination in sports that you see in the population. People with brains that do really good interpolations would have the edge.
That explains why I always look bigger in pictures. My brain lies to me and makes me thinner!
I wonder if this is the same mechanism that causes the moon illusion!
Maybe their vision is reducing the balls size in the first case, instead of exaggerating in the second.
There is this phrase cricket commentators use where once the batsman has been in for a while and is hitting the ball well they will say "he is seeing the ball like a football now". I guess thats not a metaphor!
So, this is related to an effect I've never heard people talk about, but have experienced it enough to be sure it's the brain doing a trick. After Driving or Biking for a length of time, then stopping, and looking up. The Clouds seem to be zooming away from you
Is this related to looking at the moon? It always looks enormous by eye compared to in photographs(even bigger at horizon), I read somewhere, and I don't remember where I'm afraid, that we're great at exaggerating differences in a plain-ish scene (moon in sky, fin in ocean, etc.)
I did research on this. Perceived size of objects is also affected by skill and physiology. A better batter perceives the ball as bigger than a less skilled batter.
Have you ever read the book blindsight by Peter Watts? It talks about saccades and other brain hacks in a sci-if setting. A bit difficult to ready but conceptually fascinating.
Yup! that's one of the things that got me interested in all this. I still need to read the follow up, for some reason it fell through the cracks.
Echopraxia is good, but even more difficult to parse at times. Still quite fascinating. Did you have trouble with his prose? Maybe it’s just me.
Not really, I don't think? I just have too much ADHD to read novels anymore, so they tend to be far back on the list. Don't get me wrong, I love reading, I just can't handle it most of the time.
And you used Jimmy Stewart from "It's a Wonderful Life" to make your point. You rock.
Visual artist cheat the brain on purpose by putting more saturated colors where you're supposed to look and dimming and blurring the colors elsewhere. It gives the illusion of depth and interest.
Another fun thing is most of your peripheral vision is triggered not by light level but a change in light level, which is one reason your eyes are constantly moving, if they stop the image fades. You can simulate this by staring hard at something distinctive for a few minutes...
Ideally at distance so your eyes don't tire and where there is no movement to distract you. If you switch your attention to your peripheral vision (but don't look there!) you will see the colour slowly wash out and then the image leading to tunnel like vision.
By actively fixing on a target consciously you are limiting the amount of unconscious movement your eyes make, and it slowly deprives them of fresh triggers. Fun to do in boring meetings, just don't stare at a person as that kind of focus is creepy...
Is this why if I do a relaxation exercise with my eyes open the colour of my surroundings starts to go weird after a few minutes?
What if a person has one eye? A family member does, and This is fascinating 🌞
Does this mean that if you were looking at something for the first time that the colors in your peripheral vision could be wrong since you wouldn’t have memory to pull from?
Good point. I questioned this claim as well. It seems an amplification process for cones in the periphery would eliminate this and explain the perception of color in the periphery. After all, color is a perception.
Is it? Or ar the signals from comes in the periphery “amplified” in some way? An research on this?
This explains the sight in my right eye perfectly. My visual system is completely fucked in my right eye, it perceives barely anything. But I can still sense a general shape, location and colour of what things are to my right side. Must be mostly guess work
Well then how come when something in your peripheral vision changes color you can see it change?
Is this noticable? I tried staring at the picture while my tv was on in peripheral vision, where scene changes would "break" color memory, and it seemed like some things (but not skin tones) went grey on big cuts. But maybe I was imagining it?
This feels like the extended eye-based version of "you are now thinking about yourself breathing." At the same time thank you very much and fuck you very much because this was both very interesting and very disturbing at the same time and I will never be able to unlearn it.
Yeah, sorry about that second half. This stuff can definitely knock you out of being able to ignore your visions weird quirks.
Not sure how common this is but I have this weird thing where sometimes, despite having looked at something with a distinct colour it goes a completely different one when it goes into mid-to-deep peripheral region (like, e.g. a child's red hat going green as the kid walks away).
Interesting. I suppose that could be a form of colorblindness? Most types are partial, rather than complete. Maybe you have less cones outside your fovea, so you have a lessened ability to color in your peripheral vision? but I really don't know, that's just a guess.
Curious question, and I feel like I've seen (?) this demonstrated when I'm looking at our dog when it's dark out-- I can't really tell which way he's oriented when looking directly at him, but when I focus a little distance away, I can see him just fine. Is this the reason?
Yes, there is a reason. Peripheral vision (outside of your direct line of foveal sight) is very good at detecting movement and shading. It works as a mesh. If you want to see what’s around you in very low light try not looking directly at things but slightly to the side.
With my MS relapse that screwed my right eye up, I've noticed this one
I always see my eyes as two telephoto lenses with some motion detectors around them. My view is just a collage of things i've seen and the motion detection controls my eye movements to recapture areas that might have changed. The temporal hacks are just weird.
Is this why I can see faint stars in the sky more clearly when I look around them than when I look directly at them?
I can see a little bit of color on the edges of my periphery. Don’t think my brain is lying. It is just doing what it does.
When I hold my phone in my outer periphery and have it display a random colour that I'm not consciously aware of, my brain still sees the right colour. Maybe it could be interpreting the lighting it causes or something
Sometimes you can notice this whilst soldering. If you focus on a small feature and bring it close it's hard to tell the difference between shiny solder (silver) and light reflecting off of flux (brown or yellow) when it's not the exact thing you're focussing on. Both look bright
So, I’m totally with you on saccadic suppression and visual stability, but the no color in the periphery bit really isn’t what the anatomy looks like. You’re going from ~200k cones/mm^2 in the retina down to 2-4k cones/mm^2 in the periphery. That’s still plenty for color percept.
Ahh, I may have overstated it how much a difference it is. My understanding was that if you only have periphery-density of cones you'd qualify as quite color blind, so your vision was overstating colors to make up for that.
The cone dropoff is huge, and the usual plot sure looks like no cones > 5º eccentricity, but 2-4k cones/mm^2 is still a lot of resolution. Here’s a good paper (ok, by my postdoc advisor) talking about myths about peripheral vision, including this one:…
Ok take a barmy at this, Space "the night sky" isn't actually black, Its see through - your mind tells you its black cause you can't see all the way through it, same principle as being underwater if you can't see all the way through its black, Even though we know water is clear
While this whole wired backwards thing is indeed ridiculous, having full resolution and color depth over the entire field of vision would require an optic nerve as thick as a twig.
One thing I'm amazed by is that we don't notice that the eye suffers from chromatic aberration. So red light is focused to a point behind the retina, green just in front, and blue further in front still, but brain compensates so we don't notice.…
Figure taken for illustrative and educational purposes only from publicly accessible thesis… by Maria Vinas
Also of note is longitudinal chromatic aberration is compensated in some species by multifocal lenses (in some fish), while others like the jumping spider and firefly squids have different receptors at different depths. (From…)
I sometimes have an extremely upsetting weird eye behaviour where I actually have a blind spot of sorts but it is both eyes, and it is more like a blurred spot right in the centre of my vision Makes me unable to read normally (I have to read by rapidly shifting eyes to the side)
huh, interesting. that could be that you've got some retinal damage that your vision normally covers up, or it might be related to migraines. they often have visual effects like blurred strobing sections of vision.
It seems like physical stress-induced as the bright spot usually slowly travels in a spiral until it disappears completely, and affects both eyes at once. It is very weird.
Whoops Gboard replaced and with as, completely changing the narrative
So actually, I always thought that the reason I see almost-blackness when I close my eye was because, you know, that's what my eyelids show. I can make it darker and lighter by putting my hand in front and stuff :P
there's a fun fact about the whole "hand in front of the face" thing. That effect, where you can see where your hand is in darkness? it works even in very deep caves, with your flashlight off. There is literally NO LIGHT to be seen in there. But you still "see" your hand.
There's evidence that the standard human eye can detect a single photon**
Hah! That's how I ended up hiding a detached retina for a very long time. The defect would have presented itself along the ridge of my nose, but the other eye covered so strongly. Get your eyes checked regularly, peeps!
Blind spots are weird - I first found out about them in college during an eye exam that used thumbtacks in a board to track what I could/couldn't see. Is saccade-handling related to LEDs on car taillights blinking when you move your head?(besides the LEDs PWM-blinking)
What content? The visual system doesn't think, or make anything up exactly. It just takes no notice of the blind spot whatsoever so in normal circumstances we're unaware of it
Occasionally when I get a migraine exactly 50% of my vision, divided vertically in the centre, becomes a blind spot. Anything I look at is cut off where I focus. One time, I was reading during this and had to specifically look at the last letter of each word to see the whole word
And now we're at "WHAT"
something like this happened to me at an eye test, one eye was looking down a corridor an one eye was blocked by the wall, i could still see the wall but it was also "see through" as in my other eye was making up the image and merging the two causing it to seem see through,
Experienced this with a detached retina. Didn't know it wasn't there but my hand disappeared unexpectedly when sweeping across my view. I could hide my entire hand in the gap in my vision and it wasn't a big black zone of nothing to me it just looked like the beige wall continued
With a book open to a new chapter close one eye and dance your single-eyed vision around until the chapter # disappears. This happened inadvertently while reading with one eye closed once.
you'll find a sweet spot where it seems like you see a clear page where the chapter # is but is landing in the blind spot
Like interpolation?
I have this in the (dead) center of my left eye. I just "don't see". It's not like a black spot, it's more like things were "not there" until I move my eye a bit (or just open the right eye and see perfectly Kkkk)
What about the nose?! Brain why are you hiding this information?!
you actually can see your nose, it’s just that your brain is so good at tuning out constant stimuli (if it couldn’t, every tiny thing would become so distracting that it would be hard for us to survive in the wild) that it can seem like your nose isn’t there
That's what I'm saying; your brain filters out the nose! It's a deception that's as plaon as rhe nose on your face!!!
some people with disorders like ADHD struggle with tuning out constant stimuli, so things like the feeling of clothing against the skin or the sound of chatter in a public place become extremely distracting
Oh man let me tell you about that, I've been known to take earplugs out when I know it's goig to be particularly overwhelming.
oh man, i guess you know exactly what i’m talkin about then 😅
Fun fact: this is because our eyes (unlike those of squid) developed from a nerve that grew outward, instead of skin growning inward (as squid did)
2) wired “backward” is not very clear here or in the later cephalopod tweet. And, the blind spot exists because the optic nerve has to leave the eye, not enter it. Again, though, a nice science outreach set of tweets about how the visual system is not like a camera.
So we're, like, watching a slideshow of reality with a lot of what we suppose happens between the frames that actually get delivered to us? That's neat. Or incredibly ugly.
Kinda? but weirder. it's like your visual system can stuff extra slides in before the "now" one, so you think you saw it but didn't. and it does this in real time, without delaying your vision. it's some weird time-travel-esque shit.
Here's a fun related experiment I just tried. If I get real close to a mirror and look back and forth between my eyes, I don't see my eyes move because of masking. But I *can* see my eyes move if I use my phone's front camera as a mirror because there's a delay!
(Afterwards, I recorded myself looking into the mirror with my phone just to make sure that the mirror-gaze saccades were externally visible.)
ooh, that's a good one. very neat.
You'd think it'd just be easier to fix the eyes instead of just making so many patches you no longer have anything left of the original. Then again, I remember your thread on Jenkins and scripts...
yeah. evolution isn't great at "throw everything out and start fresh with a better solution". It's more likely to just pile fix upon fix upon fix until you run out of options and go extinct.
Some of the crazier things happen when the conscious parts of visual processing (V4, if I remember from my neuroscience days?)get disconnected from all the subconscious preprocessing and preconscious responses
When I was a kid, I was in a store and noticed that on just one of the many fluorescent light fixtures, there were rings of light slowly running down the length of the tube, which is impossible. I'm guessing this is due to the effect you're discussing?
indirect perception: never doubted it for even a second. or half second.
Thanks to your brain being amazing, this wont work if you can hear the clock
Another good illustration: spitting on an ant bed. When your head moves in, the ants all seem to freeze
Dear Lord! Whoever made our brain's programming is worse than the devs who made Windows Vista's Aero bullshit.
Pretty sure I'd have been tossed out of introductory Java for trying solutions this hacky.
And then immediately get hired by some big-name software company because of those hacky solutions.
So, in a way, ocular medicine (and kinda all other too) is basically the equivalent of a newly hired junior dev, tasked to solo keep up an ages old legacy system that had a multitude of devs doing their stuff, and absolutely no documentation. But worse.
We've done pretty darn well for ourselves with all those ugly hacks. They get our genes passed on and the universe doesn't give a fuck whether you think its wire and duct tape are elegant.
yeah, that's the thing. I'm trying to mentally model how humans work by approaching it like an engineer, when in reality evolution cares not one bit for "elegance" and is just going to throw duct tape fixes upon duct taped fixes. if it works, it works.
Remember, premature optimization is the root of all evil :)
More seriously though, disorder and entropy as such are not surprising. What's astonishing is the instances where sophisticated, elegant solutions emerge as a result of this very dumb, simple, brute-force evolutionary process.
E.g when you train convolutional neural networks on object recognition tasks in images, you do it through a very dumb process of optimization via gradient descent (not unlike the evolutionary search, albeit not parallelized). ....
... amazingly, through this simple procedure alone "neurons" in various layers of the network learn to activate on visual features in a way extremely similar to biological systems -- and to distinguish very sophisticated patterns. If that's not magic, I don't know what is.
I recently had implantable lens surgery. Since, my night vision has been crap because my pupils keep dilating wider than the lens, letting in excess light & turning my life in to the Rainbow Road level from Mario Kart. However, my surgeon says my eyes will soon start lying to me!
Yeah, the adaptability of the visual system is amazing. If you want a fun experiment, try to find an ultraviolet light source (like a black light) and see if you can see the light it puts off when your eyes do that!
because supposedly our cones are somewhat sensitive to UV light, but normally it gets filtered out by the lens, so we don't have any noticeable UV vision. With your implanted lens + too much dilation, you might be able to see it.
There's a theory that this affected Monet's work, as he'd had cataract surgery that may have given him some UV vision.
I'm going to interpret this as me being as talented as Monet.
definitely. Get out the canvas and start painting some waterlillies, quick! before your vision finishes healing :)
Hmmm 🤔. Not quite the same. But I'm guessing Monet wasn't scrawling during meetings...
Ohhh. I work at a university, so this shouldn't be too hard to find.
I'm gonna have to disagree with you here, evolution is *miraculously* stupider than a bunch of drunks writing VB5 - evolution is mostly just the equivalent of smashing the keyboard
It’s not an ugly hack unless the code looks like shit lol
Our vision system was written by Bethesda?
Oh, I'd have gone for an even numbered release. They seemed to have been just that much more wonky.
There goes the "intelligent design" hypothesis. ;)
That was my favorite line in the entire awesome thread.
You're clearly a "cup half full" type. ;)
But we're not programmed, at least not in a traditional computer science way. It's all random stuff that happened to work "good enough" or slightly better than some other random stuff, where "good" and "better" are measured solely by whether those genes were passed on or not...
And it's not just mutation/sexual selection randomness. There could have been an animal with a logical visual system that would have passed it on to us if it had been standing two feet to the left and hadn't been killed by the avalanche.
This is a good representation of the phrase "survival of the fittest" meaning "the fit enough" and not "the most fit possible"
yeah, and often "the most fit" is too expensive. better to do a crappy hack that sorta works than waste energy on The Best Solution
thank you for this thread. I remember being absolutely blown away the first time someone demonstrated the blind-spot effect for me in computer vision class...
Reaction one: hey, don't badmouth Visual Basic, it's great! One saccade later: Oh, right VB5. Yes, that was crap.
I enjoyed the thread, but we're definitely not biological computers. "Biological analogous self adjusting multi-resonators", maybe.
O mankind, worship your Lord, who created you and those before you, that you may become righteous -
[He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him].
And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful.
But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.
And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before."
Indeed, Allah is not timid to present an example - that of a mosquito or what is smaller than it. And those who have believed know that it is the truth from their Lord. But as for those who disbelieve, they say, "What did Allah intend by this as an example?"
It is He who created for you all of that which is on the earth. Then He directed Himself to the heaven, [His being above all creation], and made them seven heavens, and He is Knowing of all things.
And when your Lord said to the angels, I will make upon the earth a successive authority." They said, "Will You place upon it one who causes corruption therein and sheds blood, while we declare Your praise and sanctify You?" Allah said, "Indeed, I know that which you do not know
And He taught Adam the names - all of them. Then He showed them to the angels and said, "Inform Me of the names of these, if you are truthful."
They said, "Exalted are You; we have no knowledge except what You have taught us. Indeed, it is You who is the Knowing, the Wise."
He said, "O Adam, inform them of their names." And when he had informed them of their names, He said, "Did I not tell you that I know the unseen [aspects] of the heavens and the earth? And I know what you reveal and what you have concealed."
And [mention] when We said to the angels, "Prostrate before Adam"; so they prostrated, except for Iblees. He refused and was arrogant and became of the disbelievers.
And We said, "O Adam, dwell, you and your wife, in Paradise and eat therefrom in [ease and] abundance from wherever you will. But do not approach this tree, lest you be among the wrongdoers."
But Satan caused them to slip out of it and removed them from that [condition] in which they had been. And We said, "Go down, [all of you], as enemies to one another, and you will have upon the earth a place of settlement and provision for a time."
Then Adam received from his Lord [some] words, and He accepted his repentance. Indeed, it is He who is the Accepting of repentance, the Merciful.
We said, "Go down from it, all of you. And when guidance comes to you from Me, whoever follows My guidance - there will be no fear concerning them, nor will they grieve. 2:39
And those who disbelieve and deny Our signs - those will be companions of the Fire; they will abide therein eternally."
we are literally computers programmed by accreting randomly-introduced bugs and propagating the ones that seem useful
so my point is @Foone we are not computers..we are the Greatest Creation GOD has Made ..and Put Us above all the Creation He created before Us...He gave us Knowledge which no other Creation beholds....everything we Have Created on this Earth is only By His Command..nothing else
what’s the Quran or Bible say about online nudes? #albumcoming #godwilling 😂😂😂😂😂 #definitionofafuckboy
I imagine we're programmed in whatever language was cool at the time, so yeah there's some VB, but someone wanted to try Lisp, so that's in there, there's some core Java and some Perl that noone wants to debug and a couple of JS franeworsks for good measure.
Intelligent design confirmed.
I think you mean assembler. I'm pretty sure VB5 doesn't have access to low level OS details.
sorry, can't help imagining some ancient Greek inventor saying "well, it's obvious that human body is, essentially, a very elaborate system of pipes with different fluids running through them"
Damn, this stuff got me tripping no psychodelics needed.
It’s just that the migration from sea to land was more difficult for the whole tech stack than anticipated. The requirements for the eye were formulated in water, not on land/air. Maybe programmers were not drunk, just maybe didn’t have enough foresight.
Worse, programmed in C++. Dementia is just the memory leaks piling up.
Yeah, God. Evolution was a series of updates and patchwork jobs. Some features had to get cut to make way for new ones. Still miss the tail feature.
Y’all (dumb): evolution Me (enlightened): batshit insane drunkards in Visual Basic 5 evolution
This kind of stuff is why eyewitness testimony is mostly useless.
that's why gamers must be fixated at their screens and not move their eyeballs, not even close the lid
Yeah! When you look at pro esports players they don’t ever move their eyes. They’re always fixed dead on the screen, and using peripheral vision for the hud
Your auditory system does this too, btw. Nothing is real-time.
oh yeah, it's just like latency in LCDs, where your screen is very "slow" but you don't notice it in movies/TV because it delays the audio the same way.
yeah, but the audio delay isn't the same delay as the visual delay.. it's yet another hack on top of hacks that any audio syncs to motion.
Is there a link between this and dyslexia?
I don't believe so. dyslexia happens in the language processing parts of the brain, rather than the visual system parts.
Inreresting! I "noticed" this just because I pay too much attention to myself but I always thought it was "Brain is too slow to keep up with the sudden change, so it's like 50% or less of a visual feed until it stabilizes". Good to know better now.
Use a highly convex or the opposite camera lens (with a skirt shape to pick up the missed light energy) As in forwarding human evolution and applying it to technology.
do our eyelashes also playing apart in covering this up ? ;)
When I have very low blood sugar (Type I diabetic), when my eyes saccade, I consciously see nothing. Seriously, the world just goes away and then comes back when my eyes stop moving.
Does Chronostasis have anything in common with the relative slowness of time during an adrenaline rush?
Chronostasis has to be the coolest word I've ever read.
When I get drunk I can see this blurriness when I just more my eyes rapidly. Interesting how alcohol changes this behavior of eyes and brain.
Holy shit, is this why the second part of a digital clock seems to stay still for longer than a second when looking at it?
This is used constantly in magic - the magician 'throws' everyones eyes to a something and then has half a second to, for instance, take the melon that is in their bumbag and put it under the hat on the tressle table (watched - but didn't see - one doing that once)
This is why when you look at the wheel of a moving car on the road, then quickly shift your vision to the other wheel, you briefly see the shape of that wheel as if it weren't moving
Interesting. They say if you die 'instantly' in a car accident it takes about 300ms, so you don't even have time see, yet alone realise, you're about to die
This explains my irrational screaming at a basketball game clock when it seems slower than it should? START THE CLOCK!
I've noticed this sort of 'sticky' effect! What can I say, I'm a clockwatcher. So much of what reaches our brain is total lies
Did you see the amazing VR trick where they move stuff during your saccades to make you walk in circles so a small room feels infinitely big?
That's so awesome! Thanks for sharing.
Have you heard about David Eagleman’s experiment with time dilation due to fear? He and others flung themselves 15 stories to test how long the fall felt like and whether falling increased time “resolution”
I've been thinking this effect was me just overthinking things O_o
Chemical Camera Orbs. Genius.
Absolutely fascinating
this thread is incredibly fascinating but this is also just extremely unsettling. i'm trying to wrap my head around how that sort of timeshifting of seemingly live perception is possible, and there's no answer that isn't distressing
yeah, that's the thing. You'd think at least your brain would have some kind of consistent "clock" in it, but it turns out we just don't. or if we do, it's one that the visual system is winding back ALL THE TIME.
I have literally panicked slightly thinking I'd lost my ssh connection when I glance away from an htop screen or anything else that periodically updates all at once because of this
See also: I've been watching #DoctorWho for hours but it's also the best show made so of course time runs differently. Also, Time Lord technology.
See also: Weeping Angels. Don't Blink.
What is the speed of time? How different would it be if not using technological devices & means as comparisons & reference points? Familiar with Buddhist notion of eye-consciousness, ear-consciousness, etc? If our vision is mostly inefficient erring why are we so dominate?
Some of the most interesting neurological disorders happen when these hacks start breaking, like akinetopsia (one of my favorite) where you lose the ability to perceive motion
Since we really can't directly perceive motion - for the same reasons - our brains do the work of putting two and two together
Akinetopsia means basic tasks like crossing the street become really hard, since you (e.g.) only see a bunch of cars *standing still* at the moment you're looking at them
Or simultanagnosia, where you can only be aware of one thing at a time (since your brain isn't filling in the things you're not looking at)
wouldn't this actually prove the human construct of time is incorrect ? if our mentally processes an ability to trick us into unnoticeable time lengths, how do we actually know it will take 13 billion LY's to travel somewhere, it might just take a month and seem longer
We'll know cos relative time supports the longer time length. If it only takes a month then we'll still be alive, 13 billion years means we're not only dead and decayed but probably that we've been chemically recycled into so much other stuff we couldn't even be detected.
That.. and the maths supports the theory. Math after all is the language of reality. Computers and brains are just advanced computers stimulating, predicting,, and learning from reality or whatever data fed into them. That's why computers work so well. And why we have AI.
It's not just your visual system that does this. This is how our brain works when building up our reality- it will layer the data up as it comes along and rewrite history when needed. Here's the kicker though, we can't know if we ever saw the original unedited footage!
this one right here is where i got a knowledge boner
I always wondered why that was.
Oh, so THAT'S what that is
ooooh, so that's why that happens!
Holy shit I actually noticed this before
So THAT's what it is! I was sure that this happened sometimes but thought it was my imagination (which... well, it really is) - how amazing to read an explanation of it.
Straight up Solipsism was easier for me to contemplate for the reason for this lol I'm not just imagining this!? Holy crap, I never expected to just stumble upon the reason for this randomly on Twitter today.
okay this happens to me with digital clocks that show the seconds too, pls tell me this is the same phenomenon
Yeah, it's the same thing. It's just usually easier to notice it when it's an analog clock ticking, but your visual system is doing it every time you move your eyes.
okay cool, thank you!
So... I'm not batshit insane.
Nope! it's just a weird corner case that makes it possible to see one of the weird ways our vision system works. Your visual system tries very hard to pretend it's a lot better than it is, and it's frankly amazing it works as well as it does.
holy shit it's true i never knew why this happens
OMG! I've noticed that!!
Thank you, I always wondered what that was about!
I noticed this many years ago (staring at classroom clocks), but just figured the clocks were jerky!
I noticed this as a kid, thanks for verification
if you catch it at the right time, you can even see the second hand go BACK, then forward again when your vision resumes.
Fuck! I always wondered why it seemed that way. Now I know 😁
I've noticed this for years and never knew why!
Sometimes this blindness doesn’t work fully. Look at a digital clock like the one on your oven when it’s dark. You may see it trace around.
This is called chronostasis. If you stare at a second hand for long enough it appears to slow
I see this effect when I'm working on the command line, the cursor seems to go to the next line before I press enter
Holy shit so THIS is why this happens. I’ve been wondering about the slow second hand effect since I was a kid!
Oh. My. God! I have always thought that but assumed it was just me. This is so cool to find out
I'VE SEEN THIS. @DarkShamashAran I couldn't work out the root cause.
Ohhhhhhh! I always wondered what that was 😁
I’ve noticed that and always wondered why. That’s crazy.
...been seeing this for years...**BRAIN EXPLODES**
What the fuck I honestly thought I was just a little insane
Thank you! I observed this many times during my childhood and always thought something strange is happening with clocks when you just start watching. This explains a lot. Only thing more explained :)
Holy shit, I used to notice this in elementary school, thought I was just imagining it
I’ve done this a thousand times in hs and had no idea how it worked. That’s wild
What a wonderful read. This piece in particular strikes at heart. I've noticed this before in traffic where I shift my eye to the orange light. We all know approx. how long they last but for some reason they last longer than usual. Same with car's indicators. Now I know why.
Is the "stopped clock illusion" the same as when you look at a passing car's wheels and for a fraction of a second you see a non-blurred version of the wheel?
I have always wondered why the hell this happens!
Wait, wait, wait! Is this why LED numbers on clocks seem to POP into existence for me? Same principle?
I have noticed this a few times before but never knew if this was real or just an illusion. Thanks for this thread.
OMG I’ve noticed that! I repair watches for a living and I always get worried for a split second thinking that the watch isn’t working.
I'd noticed that if I was looking at my watch and got distracted but pulled myself back to finish the task in hand then the second hand always seemed to take longer to move. Thanks for clearing up a mystery! I'd stare at it for a few seconds after just to check it was working.
Noticed this when I was a kid but never would have guessed this was the reason
Omfg I’ve always wondered about this!
I have wondered why this is as long as I can remember wondering things.
I was about to chip in with this example. Nice!
This is the point where I said "what the fuck?!"
Makes me wonder, how does this affect people in activities that need to rely on very quick reflexes? Such as boxers or martial artists during matches? Do they need to learn about these effects and compensate for them with muscle memory? Can an opponent exploit them?
There's a study that shows that properly timed small shocks to the brain can make you store stimuli as something that happened before it actually did So yeah Who gives a shit about proper perception anyway right 😅
There is a very similar auditory illusion.
How can any physical (causal) system time shift backwards? I must misunderstand you here. You can’t see the image before the light hits your eye.
So it’s like blindness? Is there a way to artificially prolong that effect?
yeah, it's closer to blindness rather than simply not seeing, if that distinction makes any sense. I don't think you can really prolong it.
Shows who? This stuff is interesting but this is conceptually confused. There are no pictures in the brain to "show"
yeah, "Show" is probably an confusing metaphor here. I'm kinda pretending like it's a little movie theater inside your head, in order to explain how that doesn't make sense, because of the tricks it's playing.
It's still interesting that we see just fine despite saccades and the blind spot. But the bad metaphor is what makes it seem like tricks. The real trick is that the VC just utterly ignores those things
I know you are trying to simplify this but I feel like the tiny humongous analogy is creeping in and it just kind of tints the whole thing weirder than it really is.
Sooo, if I move my eyes around contantly, like rolling my eyes, I would experience temporary blindness whilst moving my eyes?
Please explain the difference between “not seeing” and “seeing nothing”
(Extremely roughly): trying to take a picture with the camera switched off vs. trying to take a picture with the lens cap on.
So it's like position interpolation in video games?
Assisted a research prof if college. Also during the saccade some information processing and language centers shut down until the saccade ends. The eyes don’t just play the tricks, the rest of the plumbing plays (or is dragged) along.
Excellent thread! ‘People from primitive cultures who have never seen photographs cannot distinguish between images - the complex system necessary for the recognition of visual representations in 2D has to be specifically constructed by the brain’. Oliver Sacks, neurologist.
Did you know there's some neat VR R&D taking advantage of saccades to "shrink" the physical footprint of virtual spaces? By fudging the view during saccades, the VR software can cheat the user into occupying far less physical space without breaking immersion.
I need something to turn my TL into a blurry mess when pseudoscience arrives
We notice the blurry mess when we pay attention to it, but it passes so quickly that most of us never bother. We just take it for granted. It isn't hidden from us, it is negligible.
If I'm casually remembering my days in England, my brain mirrors the driving memories. It's much easier for him to drive on the right side, but I actually drove happily for 1 year on the left side. But if I dive deep into the memories, everything is corrected.
OMG! You’re right. My memory is driving on the right side, but being in the right hand seat of the car! I have to think about it to remember being in the left lane.
I lived and drove in Japan, and holy shit, this. Never realized until now. Memory is crazy.
Oh! me too!! At home we drive on the left hand side. My initial, first millisecond of memory of traveling in Europe, Canada, US, I'm on the left hand side of the road. Freaky!
So it's like putting a camera on those old propeller planes that interrupt shooting anytime the blade is in the way - but with pretend time travel to make us forget the blades were ever in the way. Neat.
THIS IS AWESOME STUFF I read about some of this years ago, but forgot about it til now!
Yes it's parallel blue lines . Brain - wake up !
I can see parallel lines if I „vibrate“ my eyes (concentrating on eye movement so heavily they start to vibrate)
But then everything is sadly blurred
sad thing is, I understood what you meant and 'vibrated' too for straight lines
Easier way is to rotate your screen and the more of an angle it is your eyes the more strait they look.
I can see the parallel lines anywhere by focusing on it, and only the darker blue lines ever look non-parallel. But, well, dyslexic. And the way OUR brains process stuff is just different in some ways to neurotypical...
I had to photoshop that image and double its length to see what my brain would make of the paradox that they did never meet. It resolved it by telling me that although they were still angled, they were bending... in some vague unspecified way <grin>
Look at this from enough distance to see both ends of the horizontal lines, but only focus at the centre of them and you can see that they are parallel and horizontal.
related: someone figured out how to use saccades to subtly change VR scenes so that humans think they're going straight when they're actually walking in circles (to prevent collision with walls in real-reality)
Using saccade-tracking to trick VR users into walking in circles, giving the illusion of "infinite walking"
Using saccade-tracking to trick VR users into walking in circles, giving the illusion of "infinite walking"
It's similar to the second hand thing -- our brains aren't wired well for discrete timed motion like that, so the abstraction is leaky there. Similarly, our brains aren't wired for the scene just shifting slightly, so they treat it like a miscalculation.
"Hmm our brains are good at fooling ourselves. Let's ... co-opt this for VR!"
Holy shit that is so cool. I wonder if this would work if the person is walking at a variable speed. The video showed people walking pretty carefully.
Make this sorcery stop, I got motion sickness just reading all of this. My brains basically a big fat liar and the next time I drink a lot of alcohol i'm going to tell my wife "its ok honey i'm just checking out the Saccades".
More fun: we see straight lines as straight even though they should appear curved based upon optical geometry. If you look at the center of a door and use your peripheral vision to see the edges you can perceive the curvature.
WOW @Foone !!! Thanks so much for sharing this!
This is a great thread to explain what a hack job our bodies and minds are. That's evolution for you: trying every quick fix until something works, then keeps them around until they become a problem and it needs a quick fix for that too
I think understand and appreciating all these absurd little details of how our brains barely work it really good for respecting people whose brains work differently somehow or may appear to be acting irrational. Our minds are a fucking mess and our ideas of normal are way off
You can't know what sort of weird brain stuff if going on in another person's body or how much of it seems weird only because of how much weird brain stuff you don't realize in yourself. Give people the benefit of the doubt more and accept they may just work differently
Is there a similar issue with movie frame rates or TV refresh rates? For many movies I play at home, it appears that there is a periodic stutter in some frames. Others in my family don’t see it. Is this a nascent super power?
I think you have to be perceptually aware of that stuttering, otherwise you wouldn't notice it. For instance, some people can't hear a difference between lossless and 64kbps MP3s, so those are "transparent" enough for them.
I mean, if you are used to hearing compression artifacts, you will notice the degraded quality more prominently.
Probably what you are seeing in your home playback is that your LCD is running at 60hz and you're watching films recorded at 24hz, which isn't an nice multiple of 60. So periodically it has to repeat one frame (since it's not interlaced) to sync up.
I dunno why you'd be able to see it but not your family members, though.
Some people just notice this sort of thing more, like a flickering lamp that other people perceive as normal. The stutter can also be due to a dodgy telecine job, where the frame rate is converted and it's awful because there's no way to nicely convert 24fps to 29.97fps
My roommate in college used to do visual editing and could see frame skips that I was completely oblivious to when watching movies together. He was used to watching films one-frame-at-a-time and to this day, watching HD gives him a headache. Dunno if that might explain it.
Perhaps some people are just more frame-sensitive? We know there are varying degrees of visual sensitivity, so it seems to make sense to me, but then again, this thread taught me a lot, so I'm no expert. Thank you for this, @Foone, very enlightening and interesting.
could be, yeah. it might also be that different activities train your brain to notice single-frame skips and such better. like playing action videogames vs only watching films.
but on the subject of editing, for a few recent projects I've been basically watching films in the video editor, and it's a really neat experience. you notice a lot of things, a lot of tricks they use and a lot of things that happen too fast to normally notice.
I have an abnormality in my visual system: bad LEDs, some fluorescents and other flickering light sources leave strobe-like trails in my vision. Yes, the ones at 60+ Hz, which is well above the threshold of visual fusion. Happens only during saccades or with fast-moving objects.
MRI: nothing wrong, EEG: no epilepsy. Consulted with neurologist: never seen this before. We do know, it's intensified by the effects of lithium carbonate. And my dad has it too, but not as much as I do.
My friends confirm this all the time: phone screens on low power, shitty Christmas lights, backlights on keyboards, they all leave flickery trails in my vision that nobody else can see.
It can be quite debilitating at times (I can't stay in fluorescent lighting for long before developing an intense headache and nausea), but it is very interesting.
Oh, also VR setups are THE. WORST. I tried one and instantly got a splitting headache from the entire world flickering and strobing around me. I'd be fascinated to know if you have any insight into this condition—nobody else seems to!
Huh. That's very interesting, I've never heard of that. My guess would be that it's a chemical issue, as the cones & rods sense light with a chemical process, and if those chemicals aren't properly decaying/converting, they might leave trails like an afterimage.
but that's just a guess, I'm certainly no eye doctor. Another possibility is that it's some kind of neural mis-wiring, which is causing some signals to get repeated. That's not really the kind of thing any test could diagnose.
Oh, I have the same. I HATE those flickering LEDs. I "see"/sense they're not ok, way upwards of the usual 30Hz, including the 800Hz Neopixel. 50Hz roomlights I actively flee. For me, it's triggering motion sickness. the eyes move fast and everything "is dotted", blinks, jumps :-/
LED Christmas lights drive me nuts - I have thought about rewiring them with a DC power supply to stay on steady. LED car taillights are another problem. They must use a PWM driver to modilate the brightness. I see dotted trails when I move my eyes, especially Cadillacs.
Yes, this. So very this. They could easily smooth the PWM, or jack the frequency but that'd probably cost $0.05. Drives me nutty.
I'm a ME designer, but even I know that there is a better way to drive LEDs on a DC vehicle... DC/DC converter perhaps?
Exactly! LEDs need current control anyway, so build in low and high set-points, (ensure smooth controller output) et voilà!
only high power leds need constant current. the (still bright) 20mA ones are driven through resistors. afaik leds tend to change color with current, so less useable for RGB mixing. (voltage control is even worse, not useable)
I guess car taillights use PWM to increase the perceived brightness (higher voltage = brighter led, even if it cancels out on average)
unfortunately not. Driving LEDs with PWM is cheapest, simplest and also best way (for dimming / color mixing). I'd always prefer to do it that way myself. So only option is to increase the frequency into the khz range. which also has drawbacks :-/
Same! Not all LED taillights, but I can often "strobe" them by moving my eyes back & forth. …other people can't? O_O
✋drives me freaking crazy. Don’t use most LED Christmas lights for this exact reason.
It used to be very bad. it's gone to "bad" - and crept into the interior. *all* new cars have dashboard lights with LEDs, all I'm aware of use not-high-enough PWM-f The reason I can't buy a new car :(
OH MY GOD THOSE CHRISTMAS LIGHTS ARE THE WORST. I have to change the ways I drive around the neighborhood because they make my brain hurt so much.
I modded christmas lights. You need to add a capacitor AND adapt the resistor, as the average voltage will increase. otherwise this reduces the lifespan considerably. (most already have diodes, just no smoothing)
Something that you might be seeing is the on/off cycle on the LEDs. To dim an LED you turn it off and on rapidly. Unlike a filiment bulb where you lower the power for less heating and the wire is dimmer. So for 50% brightness the LED is on half the time. This is called /1
Pulse code modulation, and has many other uses. So if the LED is not on full 'bright', then it is flickering. If you can twitch your eyes rapidly you can see the flickering. Otherwise, you vision masks it out.
Look up LiFi (or Li-Fi) in Wikipedia: this modulates the flicker to carry data. The presence of pre-existing flicker might be perceivable under the right circumstances, but not the subtle modulation which is v.high rate indeed. (Unless your name's Neo & you're seeing the Matrix)
sometimes I feel like that, involuntarily :) (for things below 1kHz)
yes, that's the thing. PWM = Pulse Width Modulation. LEDs are hard on/off, so this averages the brightness. Incasendent bulbs are "hot" and the ripple of "off" is unnoticably tiny. CCFL ripple more, still not that hard as LED (phosphor delayed)
I only see the multiple LED flicker trails on car's taul lights. Seems that at night saccades are not inventing time travel stories as much. Also, if I want, I can move my eyes around keeping the vision blurry. That shows very nicely the dotted flicker LED lines.
I get this too (although interestingly not so much with the neopixels). I've been able to point it out to others. The newer Audi indicators and brake lights are the worst while driving. I can see a 120Hz 4K TV flicker in my peripheral vision.
It's more pronounced in my peripheral vision. I honestly though it was to do with photophobia or sensory issues from ADHD.
That's actually your eye working exactly how it's intended: give high-detailed, colorful vision in the front and highly sensitive motion detection to the sides. could be lions or snakes moving there :)
What about the strobing LED lighting? That I notice no matter what area of visual field.
the whole @Volkswagen group seems to use the same horrible low LED frequency, from the cheap Skoda up to their Phaeton. Some years back I wrote to several big car manufatorers inquiring about it. Most had no idea what I was talking about.
Me too! Glad to know I'm not crazy. No one I've described it to believes me. Furthermore, these certainly are not all LEDs that might conceivably actually be flickering. But the sampling rate seems to be much faster than individual saccades. I'd like to know how/why!
Flicker at very high rates becomes much more obvious when the light is moving in your visual field. The on and off periods get smeared across some distance and persistence of vision makes them more obvious instead of less.
CRTs actually relied on this to create a coherent picture with a moving beam. Take a photo with a high speed shutter of a CRT and most of it will be blank.
Quite a few people see this on DLP projectors, particularly cheap ones, occasionally cinema ones. Also LED lights like modern brake lights, or LED road studs ("cats' eyes" in UK) Accentuated by dark environment, or eye scanning past the flickering source, or the motion of source.
You can train yourself to see it, and you can also train yourself to recognise it and ignore it. It's a super power of a limited sort: you're hacking your visual system to expose the hacks in your visual system!
It's nice to voluntarily see it. you can quickly flick your fingers and compare "smooth blurred line" vs "strobe-lighted several fingers" It's really bad if you can't not see it and it gives you headache :-(
DLP (esp v1) w/ color wheel is so bad, many ppl see it. It's dubbed "the rainbow effect". most can ignore it, though. Some of us just can't stand it, to dizzyness level (the worst leds I worry about migraine level headache inducing)
and I have the same thing with the LED lights. It's made way worse when there's more than one of the bulbs (chandelier or vanity). The soap opera effect or smoothing makes us sick as hell, too. Can't do 60hz+ in HD/UHD.
what smoothing / soap opera? is this about ambience illumination or TV display?
A friend of mine experience a similar thing, and suggests these effects are the real reasons to the "allergy to electricity" that some claim to have.
Interesting take. it has some similarities: it's proveably there, though impact on humans incl "ability to detect" is considered non-existant. and you get labeled an idiot / esoteric if you speak about it.
Not sure it’s the same, but people with Autism tend to be sensitive to lights that flicker (LED/fluorescent/etc). Will be interesting to see if LED lights work better if running off a clean DC power source, rather than a cheap (per bulb) AC-DC converter.
in many cases you do want to dim the light (incl all RGB color mixing). Then you have to do PWM, regardless of power source, and can't smoothen it with a cap either
And yet it's something that led monitors call a feature. Backlight blanking to avoid blur and replace it with horrid flicker.
Whoa. I thought that was normal. I mean, I don't have it as severe as you people do, but I certainly do see strobe-like patterns of fluorescent stuff when I move my eyes quickly. Never happened to the degree that would bether me though.
Also, back in the days of CRT displays, I was the one to complain the most about too low frequency, as I could see even 70Hz flickering in my side vision and 60Hz in central vision. Was glad that I could pump up 100Hz out of a Matrox graphic card and a Trinitron display. ;)
Also, some pro-gamers claim that they can see difference between 100Hz and 144Hz screen refresh rates (no flickering, just fast motion). I'm not sure if that could be proven true by a double blind (!) test though. :)
could be tested the same way audiophiles test: ABX-Tests.
I used to watch many years at 50Hz PAL. Got worse when I grew older. It's mostly motion sickness in my case, and those led flickering triggering it.
60Hz on TFT was never an issue for me, though - as that was the "refresh rate for new image", while the pixel illumination stayed on the whole time
I have similar issues with a smaller group of items. Modern cell phone screens in the dark and LED tailights on cars give me the tracing effect. The phone screen one is a minor inconvenience and can be worked around, but the LED tailights give me all sorts of issues driving.
Wait...not everyone has that? Thank you though, this explains a lot!
same here, my husband and I both get those trailing LEDs when moving our eyes around. Cadillac taillights are notorious! but our mutual friend sees none of this whatsoever. 🤔🤔
what you are most likely seeing is PWM brightness control (not sure about what the "800Hz" neopixel claim actually means). that is a dirt-cheap, rational engineering solution for basically EVERYTHING, that turned out to be absolutely atrocious in lighting or visual applications
the "threshold of visual fusion" seems to apply to information intake, not "crazy strobed light" that disrupts or vision in some way. thankfully in recent years this has been noticed and we've finally got "flicker-free", current-controlled brightness (instead of PWM) monitors
pulsing is still a common problem with cheapo LED light bulbs that don't even try to filter the 50Hz mains, and LEDs have no delay and inertia and will truthfully show any power oscillation.
Proper light diffusion is also frequently neglected. nature has no insane pinpoint light sources, so RAZOR SHADOWS from single-led lights make everything look horrendous, and FLICKERING RAZOR BACLAVA SHADOWS from economy un-diffused public space LED array lights are the worst
yes, the smaller the point light source, the more obvious it's PWM is. e.g. car dashboards with the illuminated key symbols, in a night dark environment.
brain frequency is around 16Hz, so things above that aren't seen as individual images. I don't "see blinking". I do perceive it as "hurting" light, and as dotted line when moving - the source, or my head, or my eyes alone.
if it's room illumination, this means that I perceive *all* motion as in strobing lights - e.g. my own arm movements. I have to slow down in the very worst areas. In better ones it's less often noticeably.
Neopixel is a fancy name for the WS2812 LED controller, hugely popular with Makers/Arduino. It has 800kHz oscillator internally which results in around 800Hz PWM (confirmed with phototransitor and scope)
I have that too, but to a lesser degree. I don't get the motion sickness, but it does sometimes gives me a headache. I was under the impression that everyone saw it that way so I never really thought about it or asked anyone about it.
I got it too. No headache though. I found some good leds, which does not cause the flickering, but when sitting by them and doing smth starring intensive, like painting figures, dot patterns starts to appear after 30-45 minutes and I have to stop.
One of the graphics professors at my old school was trying out new VR tech that involved flickering images with lots of thin lines. People managed to notice that up to like 1500 Hz, so the usual thing about 24 Hz being "fast enough" is far from universal.
I always cringe when games use full-screen flashing for an effect, cause there are so many people out there that are bothered by it, even besides people with epilepsy.
When fast moving those flickering LED light are even splitter in red, green and blue for me.
My guess with mine is that it's a timing issue with various neural sub-processing.
Could always see it too, thus can tell capacitor-smoothed lights from directly wired one. Not debilitating though, but noticeable.
My understanding is that this is very common in autistic people and similar folks. Anecdata suggests correlation with visual snow and migraine with scotomas, so it may somehow be related to some sort of system in the visual wiring that fires more easily than usual.
how much time does it last?
Are your lenses dislocated? Mine were and I had something similar.
What about office projectors? I often see rainbow flashes in my peripheral vision when moving my eyes. I can make myself see it, but it happens many times over the course of an hour.
Do you happen to have been diagnosed with ADHD?
I get something might be similar that I *think* comes from taking SSRIs: objects moving across my visual field (like a fly or my hand reaching for something) will leave a trail of images behind, like the attached photo. I deduce there's timing issues with syncing various bits.
I HAVE THIS. I kill time making shapes with the LED trails. It’s best when the LED is faking a colour by oscillating because then the trail is dotted in each colour in sequence.
I have a family member that took a common medication that resulted in what has been diagnosed as a brain injury, and he experiences similar issues with his vision.
LED tail lights on cars do the same thing, flickering like that. Very irritating.
I refuse to try VR, I can’t handle 3D films lol
Sterling Moss could see the refresh of lightbulbs. Meaning he could see beyond 25Hz. This is not uncommon with F1 drivers and fighter pilots. It’s a neural processing feature.
I have a similar issue, tho not nearly as extreme
I find flickering lights (especially old style 50Hz fluorescents when they're dying) are a reliable trigger for migraines (intense forehead or one sided headache with nausea).
Maybe you're just particularly sensitive?
When I was on Effexor I got really high blood pressure and couldn’t keep my eyes open because of a similar issue. Moving people made me nauseous n I was walking in Walmart so lots of movement and instead I closed my eyes because too much to see.
I don’t get visual effects but I am extremely sensitive to motion in games and fluorescent lighting makes me sick AF feeling after about a half hour. Bodies are weird
I also see this, but only if I focus on it. I'd imagine it's a cognition thing (if that's the right word) not a chemical thing. But what do I know! 🤷‍♂️
I hope this doesn't offend you, but have you ever done ecstasy? Even if not, I'd imagine it's the same thing, only it occurs naturally in you.
Have you ever looked into Akinetopsia/Motion Blindness? It can have trailing after images.… "The akinetopsia often occurs with visual trailing (palinopsia), with afterimages being left at each frame of the motion."
A colleague has a similar light sensitivity issue with flourescent and led lighting. Needs darker space or lots of natural light.
I can detect a neon light going wrong about six months before the rest of the world notices it has started flickering. Some subtle thing tells me the light 'is wrong'. So yeah, there must be some people with extra sensitivity to these things.
I also have a super-flexible eye lens. Meaning I can focus things normal people can't (better eyesight at long ranges)... and I will get tired eyesight pretty young, too, since I am unconsciously over-stretching the lens. These things have pros and cons, evolution trying shit out
If you mean fluorescent lamps they flicker, when good, at 2x the supply frequency, so 120Hz in USA, 100Hz in Europe etc. As a failing fluorescent lamp acts as a partial rectifier, alternate peaks are smaller, so effectively the visual flicker drops to the supply i.e 60Hz etc
Yup, same-same.
That thing where you dart your eyes for half a second while driving, and see a line of 30 separate impressions of the taillights in front of you because they're turning on and off at 60Hz? Doesn't everyone see that?
My partner sees the 60+ Hz flickering all the time. I only notice it when the thing moves fast enough in my vision that the impressions don't overlap, so I can tell it's not continuous, it has gaps.
Bad leds like new xmas tree lights flicker to me when i move my eyes or scan across a room theyre in. Its pretty annoying. And leds out on cars and traffic lights seem so bright have a halo. I cant imagine trailing from those things. Goodluck hope you find a good coping mechanism
Look into Visual Snow Syndrome, maybe some of the other issues line up? It may be easy to quickly dismiss as people talk about an apparent tv snow type of effect but many who experience it also experience bad trailing and afterimages and find no explanations from medical sources
LED's and fluorescent lamps do not flicker at the supply frequency, they flicker at twice the supply frequency. So 60hz supply equals 120hz flicker because there's two output peaks per full cycle. True movie frame rate is 24 per second and to some very obvious.
I notice the same a lot with LEDs (especially on cars) and while it's not an outright flicker I find OLED screens uncomfortable to look at because they're often 240hz. The peripheral vision is more sensitive to motion so that could be part of the reason
fight club. classic.
i wonder if these technological advances will cause an evolution in human eyesight?
Bad case of sensitivity, I'm sure. With CRTs I was unable to work with "flickerfree" 75+Hz for longer times, the flickering usually stopped for me somewhere around 85Hz-90Hz on bad days, 100Hz was okay. 75+Hz flicker was only noticeable in peripheral vision, but caused headaches
After a ton of time spent in VR I can definitely see a variety of frame skip/tracking issues/ latency problems that people ignore
I used to rip DVDs and check my rips very carefully. I've unwittingly trained myself to be hyper sensitive to frame skips and bad lipsync 😩 @__BRH__ see if your TV and player can do "24p" playback it'll help!
Certainly anybody who’s watched Fight Club or otherwise become sensitized to “cigarette burn” cue marks has something similar when watching films. Though that is a disappearing phenomenon courtesy of digital projection.
I’m a filmmaker, and it’s actually training. If you watch/edit a lot of film you see individual frames better. But it requires practice- if you stop working on films it degrades over time and you have to train it back up!
I think it's this, gamers have varied refresh rate sensitivities. In fact, I know that even YOU can increase your frame-sensitivity by putting something towards your peripheral vision. (Peripheral is also better for low contrast viewing)
What Is It With Mona Lisa's Smile? It's You!
Dr Margaret Livingstone, Harvard neuroscientist, says smile of the Mona Lisa appears to come and go because as the observer's eye moves from her eyes to her mouth two different regions of the eye come into play; photo (M)
Depends on what you normally do. I used to play a lot of FPS games and you can see a lot better after a while. If i had a break for a few weeks I couldnt keep up at first, would take me a day or two to get back to normal.
I'm a video editor and that happens to all of us. HD television is unbearable to me, because of the blending of the 24 frames per second of film to suit whatever frame ratio TV works at. There's an potion to turn that feature, I don't understand why people don't do it.
It's like the feature on newer TVs where it can artificially increase the frame rate, filling in extra frames (say, from 30fps to 60fps) to make the video "smoother." To me, it is the most unnatural looking thing and hurts to watch for any extended period of time.
When I watch movies in 3D, I see -- every frame. I don't see it in the continuous stream that we get tricked into seeing with most video. Something about looking at it with "depth" makes me perceive individual frames go by. Splitting headache in minutes.
certain colours in HD i dont see as a solid but as radio noise! its like i see each colour variant its made up of all scattering around....i dunno if its my eyes directly or just the way i handle viewing hd screens?
once you've edited videos, you gain super powers you wish you didn't have. brain please,let us go back to being oblivious so we can enjoy things!
Whenever I watch Blu-ray or ultra HD quality videos / movies I also get a headache. I also seem to notice most frame skips but not all. Could this somehow be related?
You can learn to not see skipped frames
I hate Cadillac taillights on the highway. I am the only person I’ve talked to that can see it, but the refresh rate of their LEDs is just low enough that I can spot them a mile away (maybe literally?). They strobe for me, just at the edge of perception.
I get the same thing watching films, but the rest of my family claim to have never noticed it,
This is one of the main benefits of displays with 120Hz refresh rates; the video processor can multiply 24, 30, and 60fps into 120 cleanly.
On some displays, if I move my eyes across the screen it splits into red green and blue channels
I heard that we apprehend visually at 13 frames per second.
Oh wise eye-ball person. Can you explain why if I look at certain lights or CRT screens directly on it appears smooth but if I see them in my peripheral vision the flickering is there. Does peripheral vision have a different refresh rate??
Different people have different abilities to pick up refresh rates. Some people with autism are particularly good at this...
...for such people flourescent light flicker and/or standard screen refresh rates (50 Hz or 60Hz) can be painful. Your eyes might have milder version.
Sounds like the Cinescope effect, where an old school television camera (at 60 half frames a second) is trying to create a copy of a film-based original (at 24 frames a second). Every so often, a duplicate half-frame gets captured...
This may also be results of 24fps movie being upconverted to redic 120fps or 240fps, a “feature” most modern TVs have, which is actly the TV looking at two beautiful frames of original movie & making crap up and shoving in between to make it seem “smoother”. This ruins movies IMO
The stuttering happens when huge action scenes with lots of crazy crap happens and the TV can’t possibly interpolate what nine made-up frames are supposed to be. So it barfs algorithmic visual trash at you.
This could be the result of frame rate conversion. When you convert a movie from one frame rate to another, one way is to just double print one frame which causes a stutter. Some people don't notice it but the people we called "golden eyeballs" could always see it.
And once you've seen it, you can't go back to not seeing it. Like timing dots back when movies came in 20-minute reels that had to be overlapped just right to hide the switchover...
On refresh rates but not film, as I understand it our brains have a visual refresh rate, for example it’s what makes wheels appear to be spinning backwards. I’ve always wondered, does everyone have a different rate/see the wheel effect in different speeds? What does it depend on?
It sounds like you have a TV with “motion smoothing” on. It’s supposed to be a feature but for people like us that can see it, it’s absolutely awful. Thankfully for most TV’s you can turn this “feature” off.
Do you get optical migranes as well from time to time? I see LED blinking too and every now and then get optical migraines, but no headache. Just a big flashing blind spot!
I have to say, I’ve always thought that chronostasis and the stopped clock illusion would make a pretty good name for a band or something
definitely! maybe "stopped clock illusion" as an album name, by Chronostatis. put in an a song called Saccade and you've got the full hat-trick
Oh my god this is why the second hand always seems to move irregularly
"Chronostasis" is my new band name
Why don't I believe you?
dunno. I'm just rambling about weird stuff I read. Feel free to confirm any of this on wikipedia or elsewhere, it's certainly possible I'm wrong or misunderstood something!
Is there anything similar for our auditory perception? Could you watch a second hand, listen to a one second metronome, look away and back and they might jar?
Ninjas only move during these blurred moments:)
I've noticed sometimes I seem to tune into a conversation at the exact time something is said, and I've long suspected my brain heard it and processed it already, and is sort of replaying it and lying to me that it's currently happening. Do our auditory systems work this way too?
I don't know about that specific example, but in general yes, our auditory system is similarly playing a bunch of tricks to get around its limitations. That wouldn't at all surprise me.
Very interesting tricks on how we sync vision, touch, and sound. (Somebody link to them, please?) I notice how one of my music/game programs is (barely) in sync [touch,visual,sound], but switching to bluetooth speakers introduces such a delay it becomes unplayable.
i'm hyper sensitive to when audio is out of sync, even if there's only a fractional delay, but i haven't noticed any lag from the wireless earbuds i have. i also notice right away if the picture on a tv is squished by even a couple of pixels, and get a headache from it.
My car & my wife’s car both have factory Bluetooth interfaces for the audio system. If you turn on a video, there’s a few seconds of lag between what’s seen vs what’s heard. This is Bluetooth tech in cars which are 6+ years old, so your speakers might have a similar issue.
Also—it takes a few seconds from the time I play/pause/skip an audio track to the time that change can be heard.
There's a distinct threshold effect for audio sync. Below a certain amount our brain fixes it for us. Above that amount our brain suddenly stops fixing it. So it may be the small delay in the Bluetooth system puts it over the line for you.
Our auditory processing takes longer than our visual processing, as left/right signals are compared to extract timing information to give us directional cues. A reason for the 0.5s delay in our conscious perception is our visual input has to wait for the audio to make it's model.
MP3 encoding relies on quirks of our auditory system - for instance if there's a quiet sound then a loud sound within the delay period, the brain spends its resources making sure the loud one isn't dangerous, and the quiet one"wasn't heard".…
Wow, that's true! I don't remember ever noticing a conversation while someone was mid-sentence.
Sounds like the so-called 'cocktail party effect', if @Foone feels like putting together another thread about auditory weirdnesses...
Something not quite similar but related is how you don’t have something memorized but it’s in your memory. I stopped reading a page and in my dream, read the next page I saw but didn’t really focus on. Next day I swore I read it but knew I didn’t.
It sounds like you're describing the 'phonological loop':…
Is this the explanation for the (I assume, typical) phenomenon of not "listening" to something you just heard someone say because you're distracted, and then playing it back to yourself a moment later to understand what was said? Like it's waiting in a queue for processing.
I believe so, but undergrad psych was a LONG time ago now.
The other explanation would be that you discard the tail end of whatever came right before the new sentence, which on its own would have been meaningless
I know there was at least one study that determined that people had a memory of sound they weren't focusing on, but certain keywords would make them retroactively pay attention. (Their name was the biggest one, but other words could trigger same response.)
Same happens with dreams - we may incorporate a noise we heard during sleep into the end of our dream, even if the whole “story” has to be retrofitted. Time perception is also completely false in dreams.
That’s exactly why sometimes I will say “huh?” And then respond to exactly what was said. Like there’s an auditory buffer that wasn’t getting fully processed until something made me know it was relevant.
Brain Games had an episode about a similar effect where you can here through distortion just fine… but only if you knew what the message was beforehand.
*hear, not here Fragging autoincorrect
I feel like this is sometimes why I wake up just before I hear loud noises. It's so clever.
I tend to think of myself as having an “audio buffer” of several seconds so that if I wasn’t paying attention but I’m asked a question or startled into focus I can “replay” the last few moments and often recover enough context. 1/2
I can’t fool myself into thinking I was listening all along, though—there’s usually a jolt of adrenaline involved! 2/2
This is exactly the same reason why pilots are taught how to scan the sky around them for other aircraft: stop and focus on each different area one at a time, because when moving your head or eyes you’re not actually able to notice anything.
that makes sense, yeah! I'd not heard of that before, very interesting.
There’s also something called “averted vision” - in low light conditions, you can sometimes see things off to the side that you can’t when looking straight at them because the rod cells around the fovea are much more light sensitive.
This is the only way for near sighted people without glasses on to get around in the dark.
Holy crap....I've noticed this....This is me!
And me. I always walk into dark rooms looking slightly away from where I'm headed/intending to focus. I see soooo much better that way. (and yes to the near-sighted and yes it's when not wearing glasses in particular).
Noticeable when there was a visible comet a few years ago - it was visible only in peripheral vision by looking away from its position in the sky. Look directly at it and the low-light sensitivity of the fovea wasn't sufficient.
I can only see the Pleiades out of the corner of my eye. I know they're there, but I can't see them if I look directly at them.
I've never asked if that was normal, lol.
I always wondered if there was something up with my eyes because whenever I looked directly at any particular star it got dimmer (and vanished if it wasn't bright enough to start with). Nice to know it's normal.
Wait what? I’m near sighted, please explain. I don’t know what this means
This is basically the only thing I actually learned at science camp as a kid. We learned about stars a little and were told always to look juuuuust a little to the side of them to see them better. Works especially well for the more faint constellations.
Yes. This is a well known star gazing technique. Also spending longer at the eyepiece means that your eyes/brain bring out more details in the small area of sky that is being focused on.
Now that's interesting. When I take the cat and dog for an evening walk I look at the stars. I can spot the Pleiades slightly off to the side but if I look directly at them I can't see them. I've always blamed my multifocals but this really is a Thing.
Related: in dim light conditions, with your eyes fully adjusted, everything is in black-and-white. Unless you know what colour things are - then you see that colour.
And I suddenly realize this is why I teach my kids to **really** look both ways, not just to habitually sway their heads when crossing the road
We do this in search and rescue too, and are also taught to scan from right to left because it’s the opposite direction to reading (for English speakers) so we notice more details.
Good motorcycle training teaches this, too!
if we're lucky we will never encounter an alien species 7 light months away from the sun that is capable of moving between saccades after reading the EM bursts in our nerves and figuring out how stupid our shit is
heh. I mention that book later on. Reading Blindspot was one of the things that got me interested in all this!
Blindspot helps me cope by pitching the idea that self awareness is an evolutionary trap
I learned some of this stuff from a book series called WWW: Wake/Watch/Wonder, which is about a girl who gets an implant to give her sight. They spend a lot of time discussing sight and conciousness, before it gets very sci-fi. Recommend it as a fun read.
HAHAHAHAHAHAHAHAHAHAHAHAHA. Smart fuckers aren’t they. What did they do when they figured out some of us CAN see them?
amazing thread
I feel like there are huge advances to be made in VR by reverse engineering the eyes and the brain's visual processing on a deeper level. Can probably get better, more realistic experience at less than 10% of current rendering cost.
Yup! And Some forms of it are being worked on. Foveated rendering, for example, is a trick where you put an eye-tracker in the headset, and only render at max quality where the user is looking. Everywhere else can be low quality.
there's a neat one too where the VR repositions during saccade. You think you're walking in a straight line but it's keeping you confined in a circle in the room.
Is THAT how the holodeck does it? ^_^
nah, according to the next generation tech manual *pushes up nerd glasses*, the floor of the holodeck is a kinda of omni-treadmill, so when you walk forward it just slides you back so you don't hit a wall.
I suppose if it's generating a fake floor to start with, it can add slidey treadmill aspects just under the users, that's true.
Except you feel acceleration or lack thereof.
Except your body has already adjusted to that because you're on a moving ship
but the inertial dampeners correct for the ship's movement (my favourite Star Trek quote is when @MikeOkuda was asked how the Heisenberg Compensators work: "They work just fine, thank you.")
The inertial dampeners balance out the forward movement but don't cancel it entirely. If you've ever been on a cruise ship, I imagine the effect is similar; you don't feel velocity, but you are still aware of motion.
That is a great response. 😄
Is that a similar thing they do that stops a laser in LASIK?
What kind of latency requirement is there for delivering the hq version?
I'm not sure! VR isn't really my thing, but it's gotta be pretty low latency to start with just to keep the VR from getting dizzy, I think.
There's a company doing a simple version of this right now, without the eye tracking. It's two screens blended together. The center of each eye view is high pixel density, the outer second screen is lower pixel density. Super cool
That's got to be comparably nauseating to low-abbe eyeglasses.
90 FPS is what we have to aim for on Occulus and Vive. Both feature a motion smoothing effect for when it dips below this, but if you're wanting to keep things in sync with the eyes biological function, I'd imagine that's probably something to be avoided.
I imagine similar latency for head tracking to not be nauseating
That's very likely several times too high if ppl are reporting need for 90fps. But it could be even worse if eye movement is faster.
Overall you've got a latency budget of ~ 20 milliseconds. But since there are many points in a VR or AR system where latency is introduced, anything that adds it needs to aim for low single digits.
Back in the 90s, I worked on a cutting edge flight trainer that had a helmet mounted position tracker, and a 70lb projector, inside a 22’ sphere. The projector followed your head motion, the center 50deg or so was high resolution, the rest of the 178deg was low.
The kicker was that the servos were so powerful that they could accelerate the projector, move it, and stop it, faster than you could move your head. When they went haywire, it was a sight to behold, and get the hell away from.
for real, good point, huge advances in audio compression were made with better understanding of auditory perception.
Yeah. That's basically the big idea behind MP3! You basically simulate what parts of the sound data humans can hear (called "perceptual coding") and then toss out the rest.
MP3 psychoacoustics turned out to be junk (likely thrown in just for patent purposes). At tolerable bitrates, just disabling them gives better quality.
I am a snob anyway and use FLAC. but the point still stands.
Oh, interesting! I hadn't heard that.
I'm not familiar with any published work on it, but that was my experience using LAME and seemed to agree with others'. Also matched my experience with similar pre-encode tricks on video - ...
That is, perceptually half-decent at really low bitrates but worse/noticeably artifacted at good ones.
Redirected walking is already being done taking advantage of saccadic masking to reorient the world.
Yes! I mean the stitching our vision does in real time sounds like an incredible unexploited potential for real time rendering optimization. Nvidia already uses our pheripheral vision to lower the resolution around. This topic is so much fun!
Certainly the techniques used in compression of video take advantage of the characteristics of human vision. E.g. Almost all the video you see on the Web has 1/4 the resolution for the colour information compared to the brigtness. Humans aren't as sensitive to colour.
During research on helmet displays where non-visible spectra or time lagged remote images are being processed, the processing & rendering time lag induces severe nausea when the operator turns his head. The brain's saccade hack can't cope with the VR response delay.
This makes me think of how we hear ourselves differently on audio/video recordings than how we think we Sound
Yup! Supposedly a lot of that is because we're not even hearing with our ears, we're hearing through bone conduction up our jaw. Because of the different frequencies transmitted through bone vs. air, we tend to sound bassier and "fuller" to ourselves.
Another important thing to mention are the limitations in audio equipment. Everything has a preference to certain frequencies, hence is why you have vocal mics vs instrument mics. You also have cross-talk in the wiring no matter what
So, confirmed, Trump has VERY THICK head bone. #MakesSense
this shit deep
This is a fantastic thread. I was born with idiopathic nystagmus and no matter how fast my eyes move (it changes based on circumstances) I never see blurry. People can get nystagmus from a brain injury and they’re not so lucky. The adult brain can’t adapt as well.
So friggin’ informative. Yow!
I have read this entire tweet thread. I wasn't aware of how wide-spectrum this saccade stuff is. Humoungously Wild.
This is going to seem like a strange comparison but it reminds me of a physics thing. If planet A is orbiting planet B, Newton says that there is gravitational pull on B towards A. But we know gravity can't travel faster than the speed of light so surely B is pulled towards...
...where A was, not where it is. Bizarrely the universe conspires to hide the delay. In general relativity the field from A contains enough information about the motion of planet A to extrapolate where it's going to be. When the field "arrives" at B...
...the resulting force points towards A. It's not just brains playing these games. Spacetime does too!
yeah, I mentioned something about this in a reply, something like how this "no internal absolute time" thing meshes up with Einstein's "no absolute timeframe" and you start to think that time is just a flexible mess no matter what scale you're looking at
As Einstein said, time is merely what clocks measure. And sometimes the clock under consideration is a squishy brain.
I hope you do realize that this theory that you're talking about (no matter how advanced) it's ultimately just a descriptive model. Just because the model can't accurately describe everything it doesn't mean spacetime behaves like the model says it does.
How would you test this theory? Has it been done? What were the results?
It's a consequence of General Relativity. It's been well tested, especially in the recent gravitational wave observations where its predictions have been seen to hold up well even under extreme conditions.
Yes. I've read about the tests, fascinating work. Thanks. My question was addressed to @razcore_art to better understand what he has in mind.
Yeah, but the fact that the predictions are consistent within the model doesn't mean that space-time is the model itself. Math & thus physics is an abstraction, a language to describe what we observe. You can't really say "space-time behaves weird", what's weird is the model
Example that amazes me about brain messing with the timeline is when you are dreaming and some loud noise in the real world wakes you. Somehow your brain incorporates it into the dream eg you got shot and this includes the circumstances leading up to getting shot
Or when someone draws your attention to a sound and suddenly you're aware of the sound just before they did this as if you anticipated they were going to do this.
Wow, that's something new that I learned today, thank you
wasn't it where it was? they stay within the curve and they're falling around each other
At each moment in time, A's acceleration is (roughly) towards where B is now, not where B was in the past. But no signal about where B is can travel faster than light, so most people expect that A accelerates to where B was, not where it is now.
This is really interesting. It's so convoluted that I kind of thing we might not yet have the true model. Gravity is not exact and pulls to where an object was last seen... Sounds like a bad science explanation from decades back, doesn't it?
But it's no kludge. It follows automatically from Einstein's very elegant field equations. It also pretty much has to happen in order to conserve angular momentum. You can read a bit more here:…
Oh, sorry, didn't mean to imply it was wrong, I have very little understanding of the field! I still think in 100 years there will be new insights into a lot of things, just like now we know the magic sickness rocks are really radioactive. Thx for the link!
Well, we all know General relativity will be replaced one day :-)
it better be. I want to go check out Alpha Centauri and that stupid "speed of light" limitations is really cramping my style
I am liking these tweets because they are good jokes and I'm too far out of my depth here... 😬 G'Day to both of you!
(wow, that article is tough to follow for me... Not a native speaker and I was never good at physics... Still, what I could grasp was very interesting to read!)
gravity doesn't travel, surely? It's a field
It's a (possibly) time varying field and if you suddenly move the source (eg. some mass), the resulting change in the field is limited by the speed of light.
You don't need to consider gravity. The same effect occurs with electromagnetic fields:…
True. Although gravity does higher quality extrapolation :-)
Also, more importantly, people tend not to notice the effects of EM attraction on a scale large enough for the delay to be significant if it existed :-)
Excuse me but shouldn't gravity be able to travel instantly since it's a force and not matter ? I learnt that the speed constraint to lightspeed only applies to matter, am I mistaken ?
If forces could travel instantly you could take a mass or charge at A, jiggle it about, see the effect of the force at B instantaneously, and you'd have faster-than-light communication. Now you could get very rich with a communication system faster than anyone else's!
Except it's applicable only on really short distance because of the noise caused by every other mass in the universe and the precision that decays by square of distance, which would need tremendous energy to make the wobble noticeable on a massive object
We use radios all the time. Signal intensity falls off as inverse square of distance. They work fine.
I'm curious, has the theoretical application you stated been tested ?
Also, good point on the radio comparison.
Second faster than light communication is already theoretically possible with quantum entanglement
Thanks, this link has been informative.
Third discussing possible application does not give information on theories, only actual tests that allow to help confirm or outright reject a theory do.
I think you are thinking of advanced and retarded electromagnetic potentials (…), since planets do not usually travel at relativistic speeds.
Well, this just answered my question about the second hand on clocks in elementary school...
No. Those are actually moving backwards. Especially, during last class of the day.
My brain has been lying to me since I had a stroke last year, lost my right visual field in both eyes (hemianopia) The whole right side of my vision is like one big blind spot but my visual system fills in that side with what it 'knows' is there or a plausible hallucination.
So... if I could credibly tell you I'm standing next to you, would you forever see a vague figure in your periphery? You're welcome :)
My granddad suffered from this after getting macular degeneration in his eyes (where retina cells die off). It's very common in old people but often goes undiagnosed because they don't want to tell their Doctor about the vivid hallucinations (in case its confused with dementia!)
Apparently the hallucinations were incredibly clear even while he knew they weren't real. He hadn't said anything until I told him about an article I had read in Fortean Times (of all places) then was so relieved there was an explanation!
Love this thread. Makes me think of the moon illusion. I was shocked to learn that even when the moon is nowhere near the horizon we still see it as much larger than it really is
? Because it stands out in the visual field? Curious, not heard of this, any links?
There's a wikipedia entry about it… It seems like it's a combination of things...when it's near the horizon that definitely makes it look larger, but even if it's overhead people will greatly overestimate how much of the sky it takes up. Super weird.
Take a picture of the moon with your cell phone camera. The moon looks WAY smaller in the picture than what you see in real life.
A lot of this came up in my Designing Interfaces classes in college and it blew my mind then. Still does now! Thanks for the refresher :)
This information just blew my buggy hacked brain.
I’ve often observed a thing that seems similar to chronostasis: if you suddenly start observing a cyclical phenom (traffic signal, digital timer) the first state (green, 005) can seem to last much longer than you know it should. I’d always thot it ...
yeah, that's the same phenomenon. the second hand illusion is just the oldest one documented, but anything periodic is a good place to spot it.
Very cool. Thanks for the neat info dump. (And people actually trust eyewitnesses!)
And that is not even going into the malleability of *memory*.
So next time you run a red light and get pulled over, make sure you tell the officer why you saw a green light when they saw a red!
....was a squishy-brain-clock phenom because you didn’t observe the *start* of green or the shift from 004 to 005. Like the brain assumes it’s going to be shorter, so is surprised if it’s close to a full cycle. But now I wonder if 1/2 sec of it is compounded by chronostasis.
Oh, THAT'S what that's called?! My eyes have done that for as long as I can remember.
No... only one of my eyes does this at a time. Hmm...
This is awesome. Can you write it up in a blog or something. I would like more “brain dumps” from you!!
I like the Pulfrich effect. A dark-adapted eye sends fewer impulses to the brain. If only one eye is dark-adapted, its impulses are late getting to the brain compared to the other eye. Hence those fake "3D" glasses for watching the Rose Bowl Parade.
Brilliant! Grateful for this.
ooh, the connection makes a lot of sense. I've got both ADHD and vision problems, and I'm definitely noticing the chronostatis effect more often recently now that I've gone on medication for the ADHD.
wow this has been so enlightening because i feel like my brain sometimes doesn't fill in the gaps... when i used to play competitive sports there would be moments when i felt that i couldn't see (not dark, just, a blur. as you can imagine, this made it very hard to find the ball.
and while on some level, duh, it seemed that other people could see what was going on and react in a predictable way while i was just making wild guesses. I have ADD also, not sure but maybe this was actually an ADD-related vision problem?
Suffer it also! Specially during 'important' points in the game.
Exactly! the more important the moment the more my vision would seem to shut off! I'd run towards the ball and then just blindly guess. it was a terrible system. meanwhile most other people seemed to be able to get the ball and then see what they were doing.
I have MS and optic nerve damage in my right eye. For a long time whenever I looked out of my right eye I would get this weird ‘horror movie’ effect where the hallway would recede. I also have optic neuritis, so things appear super saturated in my left and grayish in my right.
Your post caught my eye because I have a saccade in my horizontal movement of my right eye. I also have nystagmus, which is an action tremor of the eye muscles. Now THAT’s weird. The whole room looks like it’s rotating.
I get this weird sort of unease when I look out of my right eye because the signal is delayed. My left eye gets it first. So my brain tells me there’s something wrong because the right eye input and left aren’t synced up.
Oh wow... I'm going to be thinking about this thread all tomorow!! Thank you!!
Fascinating stuff, thank you
I’m sorry but no amount of evolution theory can convince me that our eyes didn’t have an intelligent designer.
I'm making no points here about if our eyes did or didn't have an designer, just that however they were designed (by evolution or a god), they were designed in a very weird backwards hacky way.
As a computer programmer I know the value of a well performing consistent hack. ☺️
A designer with oppressive bosses, awful deadlines and bad project management, and a nutcase sales team maybe
Evolution or Creation still ongoing.
If this is intelligent design, then squid are the pinnacle of creation. At least their eyes aren't wired backwards. Ours were thrown together by the new apprentice.
Semi-intelligent design. Intelligent but inexperienced design.
The theory of the adjacent possible and natural selection has so much more appeal. It explains garbage like our eyes so much more acceptably than wanting to think the whole world was built by a bumbling incompetent.
Not attempting to make yt work tonight - can you summarise?
A nerve has to get a few inches from brain to larynx. It loops down the neck, turns near the heart, and goes back up the neck instead. In giraffes it extends many unnecessary *yards* as a result. Because we’re descended from fish who basically have no neck.
Bit of an oopsie. that would create significant delays in getting signals from the brain to the larynx or back - does he go into how it affects breathing and swallowing?
Or the bored kid on work experience.
Certainly not a project prioritised to be done by a master craftsman, anyway. And not connected to the skilled technician who put cephalopod eyes together. Actually the whole design is crummy.
The windows vista of eyes....
I wouldn't call it hacky, unless you've designed a vision system comparable to our own. Only after we may understand the true for all of these. IOW I wouldn't be presumptuous :)
Once you look at the greater picture and compare it with today's computer-vision/AI systems, it feels less weird/backward. It's an elegant, massively parallel and modular machine driven by memory, there is more feedback from memory involved in perception than forward processing
The fact that the mammallian retina is completely inside-out and backwards should convince you your eyes didn’t have an intelligent designer.
Or at least that any designer we did have possessed one weird sense of humor.
Oh really, how so?
Maybe you and I mean something else by “intelligent”, but that shows a lack of intentionality. Ergo it’s not the product of intention.
What unequivocally proves that it wasn’t intentional? I remember reading this explains why we see colors in the day more vividly and more light sensitivity at night. Many things seem unintentional until we learn the reason behind it.
Well, but it doesnt mean that. It means the opposite of that - everything we see is attenuated because the light passes through several non-responsive layers before impacting the rods and cones from the back. That’s why it shows a lack of intentionality - theres no upside.
whoever designed our eyes was an incompetent hack. it would have made so much more sense to put the nerve on the OTHER side of the retina, but nooo. ask an atheist and a theist 'what would convince you that you were wrong?" the atheist says "proof." the theist says "nothing."
But how did they see to make our eyes?
The other way round for me. This is not intelligent design but a pile of battle proven shitty hacks. (Trust me, I'm a software developer)
The designer of the designer would have to be even more advanced. Adding a layer of complexity doesn't reduce complexity.
Why is that?
Then quite frankly you're a fool. Everything in the OP thread shows the complete opposite of an intelligent designer.
But the fact that it's backwards proves evolution to me. Cuz evolution doesn't aim for the best design, just the one that works
It’s good that you’re sorry about it though
Rule #1 of Design: Don't put in more than you need to, because extra complexity is extra points of failure. Humans--and other animals--are riddled with holdovers. Humans have tails in early development, and tailbones even now. Manatees have fingernails.
So the designer may have been intelligent, but he wasn't very good at it.
Yeah, just like the fact that we can painfully choke on our own saliva or ruin our backs for life bending over to pick up a pencil is also evidence of some great design.
Your eyes assist your desires🌸
It's the Grand Illusion. I try not to think to much I can't sleep and going mad.
I love it when you talk nerdy.
I've got a floppy disk for my icon, when do I NOT talk dirty? :)
Oh baby. Something something double-density. I’ll nibble a write protect notch in your jacket any day.
(may have dated myself a bit with this tweet)
Made me go all floppy.
Surely the image we see (pre-brain magic) is flipped horizontally as well as vertically? I don't see how it could be flipped on only one axis
That's a good point! I'm not sure. It's above my paygrade, but I'll have to see if I can find more details on that.
Yes - check this out and compare the four quarters of the visual field with where they appear on the retina
Lookup YouTube video on the subject by physicsgirl. There is no flipping going on at all 🤯
It's actually common for optical systems to flip only one axis. Think of a mirror, for example, which flips left to right but not up and down.
For some reason I see computer monitors flicker if I look at them while I am chewing gum.
hmm. That's probably your eyes trying to stabilize your vision during the chewing, so you're constantly adjusting your vision with lots of mini-saccades.
I worked at a company back in the crt day where we replaced a very expensive monitor many times because it was "jittery" but we could never see it. Turns out the head engineer liked peanuts but didnt eat them around IT because one of ours was alergic.
This is definitely a thing although I haven't experienced it on computer monitors, just old style number displays. There was an old pinball machine when I was a kid and if I looked around a lot or was chewing something the score displays would be jittery
But you can walk while chewing gum? 😆 (No offense meant, that joke just had to be made.)
Don't blink. Don't even saccade.
yes amazing lmao
That's EXACTLY what I thought about while reading this superlative thread!
Have you heard the one about how dreams are basically a C64 game fast-loader for short term memory -> long term memory? Ie, misusing the framebuffer etc etc
hmm. i wonder how all this relates to diplopia??
My new favorite thread on the internet. Thanks.
Awesome thread. Do you know anything about visual noise? I have constant colored noise in front of everything. Like if I was looking at a white wall i wouldn't really see white. Fuzz, dots, blobs. Also way overactive after-images. Doesn't obscure vision, it's pretty transparent.
I have the same thing, it could be migraine symptoms. Not all migraines are painful headaches, for some folks it just causes visual effects.
I see that too. I was tested and my eyes don't read white correctly. It has a name, somotrophic-something. Apparently it's common with Autism.
This sounds like the visual analog of tinnitus in hearing. Perceived noise (of different character for different people) introduced over a normally "quiet" background level. I wonder if the physiological mechanisms are similar...
I doubt it, because tinnitus is usually due to an injury
Could that be the veins that formed your eyes when you were a fetus? Everybody has them and if you watch anything for a moment you noticed them but the brain normally corrects it and we don't see them.
My mind is blown. Thank you for this; it’s fascinating!
Woah that's super weird but cool
Nice thread. Just one thing: when following a moving object, our eyes don't saccade, but move smoothly.
How do you think this relates to an athlete "in the zone" when the cup or hoop or ball looks bigger? And conversely when struggling and it looks smaller or they "aren't seeing it as well?"
Interesting you mention “in the zone”, as this was recently mentioned in an episode of the Australian TV show @bodyhackau in relation to Qi (from traditional Chinese Culture).
Andddddd I just kept looking around like a maniac in front of my family while reading. Lol. Cool thread.
This is interesting af
Wow I really just sat and read through all of that
Great posts! I already knew about our blind spots, but I've never heard of saccades before. I'll definitely learn more about this. Thanks for sharing all this great information! 🤔
you know...its not illegal to have your eyes fixed.
Anyone who has done a few tours with MDMA knows about this in spades 😂
Thanks for this thread. Fascinating, and just a little bit frightening.
I love science shit 😁
this thread is so good. brains are wild as hell
Most of the replis are from my dude!!!!
Well that’s my tiny mind blown!
Maybe thats how you see ghosts.
Webster’s won’t accept that long of a description for “sight”
That's a long.... Long tweet.
This thread = another reason for driver-less cars. Bring on our robotic overlords!
I was at an intersection, I looked right, saw a lady standing there, I looked left then right again, she was no longer there, I missed her right in front of me I nearly drove over her. I did not understand what had happend, bothered me for days. Thanks for this @Foone
During saccades in front of a screen projector I tend to see the RGB colors separated.
I see the colours separated on some LED lights (first noticed with the bread ovens in the nearby store - they usually glow orange around the knobs, but I can see red and green when I move my eyes).
That happens with the lights on the dashboard; when I look directly at them, they’re red, green or whatever, but peripherally (looking out of the screen) they’re a vague light yellow.
This rainbow effect during saccades happens with DLP projectors. These have a spinning colour wheel - it's how it colours the light. Your eyes normally fuse the flickering together. Thinking about it, this seems to contradict the claim that the brain blanks/fills saccades out.
You should have turned this into a YouTube segment.
This was amazing. Thank you.
So you're saying we need digital eyes, got it.
Loved the thread. Recently read (and loved) Andy Clark's 'Surfing Uncertainty' on how the brain doesn't use our sensory info to correct the errors in a model in our brain, not build a view of the world directly. Explains so much.
mine don't, I am short sighted though so maybe I'Ve learned to concentrate on the closer things more
(No comment)
some cool biology in this thread #tbt
Great thread! Takes me back to college. I remember learning how the eye is hard wired to be sensitive to objects entering our field of vision from either side, but objects leaving the opposite way can be next to invisible thanks to neuronal fatigue/recovery, yes?
Our brains have such terrible design. :-)
One of the reasons why people get knocked out.
My fav bit of optic system weirdness is blindsight. Basically, if the primary visual cortex gets damaged, you can lose conscious sight, but may still react to stimuli in surprisingly sophisticated ways. People with blindsight may catch balls and navigate around objects.
This immediately suggests the idea that there are a whole range of actions that we think of as conscious behaviours that occur due to some part of the nervous system acting automatically. The conscious mind then says "I did that because of X" after the action has occured.
Should we condemn a man who is sitting at a bar and gets bumped on the head by a dancer and proceeds to swing the bottle in his hand (killing the dancer)? Did he commit murder or is part of his brain wired to respond more quickly to pain than is optimal in modern society?
You can test the color by pulling up a random color ( while your phone is on the far side of your vision. Guess what it is. Then look at it and move it back. I couldn't really see a color at first, but when I moved it back after, the color was clear.
Random colour
A random colour, nothing more.
I'm very confused by this one. I had it all the way off to the right so I could barely see it and while I always saw when the colour changed (obviously), I managed to get the shade right about half the time before checking. Weird.
I thought it might have been the light reflecting off my glasses but taking them off didn't make a difference. I guess I just have a really wide range of colour vision?
apparently for this one I was mistaken about how complete the effect was. like, there's only 1/100th as many color-sensitive cones in your periphery, but that's still enough for significant amounts of color vision.
Where are the ‘tweet thread of the year’ awards?
Noe explain how that evolved?
Maybe they're resetting?
Evolution is a bunch of tech debt
Never doubt the brain. It's the only thing in the universe that named itself. #dumbass
Wow, this is awesome and crazy
We've had a bug problem a while ago and whenever I'd see a black spot of dust I would see it "move" only to see it actually wasn't a bug and the motion was nullified. I call this my idiot-proxy-brain effect and it's another prime example to your excellent piece.
This is because my brain would predict it would have to be bug. I love this stuff and this guy uses it as an argument to explain why we could all be living in this giant simulation because all we see is 'in the eye of the beholder':
You are a Simulation & Physics Can Prove It: George Smoot at TEDxSalford
Astrophysicist, cosmologist and Nobel Prize winner George Smoot studies the cosmic microwave background radiation — the afterglow of the Big Bang. His pionee...
Fun experiment : those saccades are also necessary for us to see. Block these (by pressing fingers firmly on the eyeball, but keeping the eye open), a black spot will grow from the center of vision field. Eyes perfectly opened, you can't see anymore.
Brains are weird AF. How can I not remember what I was doing last night at this time, but I CAN remember the exact and specific layout of Doom level E1M1, which I haven’t played in probably 15 years?
E1M1 probably has better level design.
I like science and humor and science with humor is my favorite thing. That is why I made screen shots of all of this
Everything you have ever experienced has been in the past by the time you realize it has happened. You eyes are compensating for that. #gotit.?
ist ziemlich interessant :)
If our eyes and brain functioned the way you proposed. Time would effectively stop. There would nothing to react to. @elonmusk should incorporate that into the "thinking"aspect of that self driving stuff.
Everything would be a blur. You would be perpetually time travelling in a space.
If your your eyes and brain worked as you proposed. As a ball throw at you approaches and you continually track it like you saying. There would be no reaction time in the equation. You mind would not be able to calculate where it we be at next. Then have time to check next frame.
What happens with 'saccade masking' when watching something synced to audio, but i am moving my eyes? wouldn't I notice some sounds and visual sequences don't match up? How does my brain cover that up?
May I ask what inspired you to share this informational, dare I say rant?
I can't exactly recall. something reminded me of saccades and chronostasis so I'd been meaning to talk about it
Well the thread was entertaining and I appreciate you sharing your knowledge. Thank you.
Also could explain the 'i watched this movie before but never noticed those details' effect.
Anyone who reads neuroscience knows that the brain basically "makes up" our vision. Our eyes have a blind spot but the brain fills in the gaps. Also look into blindsight. That's some vision we are unaware of consciously
Then calculate when to position your hands to catch. Then put the body in action. Effecting the catch. There would be zero response time built into the equation. The math would break down.
Your eyes aren't blurring. Your brain is calculating every possible future event according to what the last from revealed then checks that hypothesis.with another frame.
Also animators (of old) had noticed that people subconsciously blink when we turn our heads.
Dude, this thread is blowing up!!
the saccades allow us to see. You can hold your eye still through your eyelid and you'll experience temporary blindness.
it's a harmless experiment that helps us understand how our 👀 work! Focus ur sight on a single point & hold ur eye still
So one time at a track meet I fell asleep waiting for an event and when I woke up the shade had moved and I had lost my color vision lasted about an hour. Another time sunlight was just hitting my left eye and for a while I couldn’t see blue in that eye. What’s happening?
Now do a thread on why walking birds focus on something when they move and how come their heads bop back and forth and why this is so strangely entertaining to watch. Kthxbye. :)
"Storm in a teacup: The physics of everyday life" talks about this a bit, complete with birds falling over on a treadmill.
This should be mandatory fun in schools from grade one upwards. And thank you!
I'd love to know the tricks in avian vision. Especially given all the optical illusions that plague human pilots. Also, if you really want entertaining look up videos of people holding birds and rotating them. Birds stabilise vision with head movements. They have Steadicam heads.
You should write a book
Fantastic information! I had a mini stroke a few years back and when i look into a mirror I can’t see my slightly lopsided mouth, if I take a selfie, it’s very evident! My brain actually doesn’t want to see my small imperfection!
I'd say that your brain is filling in information that's not being received, cuz stroke, perhaps it's referring to memory, or knowing your face is symmetrical, just produces a mirror of the other side
Add to this your limbic brain filtering what your neocortex becomes aware of.. normal waking consciousness is 5Hz... Limbic brain is operating at 400 Hz.. see Richard Cytowics The Man who could taste shapes and Synaesthesia 2.0
Worse news. The lenses of our eyes build up more layers from the inside. But the outside can’t slough off, so the lenses grow less flexible over time, so acuity degrades and blurry vision ensues. Don’t even get me started on cataracts....
This is all good stuff
This thread made my day<3
This thread was amazing and now I'm gonna spend the next few hours experimenting 🤓
Interesting thread, your eyes create a time travel illusion for you! @jdepaor @sineadw @EyeyeSheffield
Good thread. If you haven't already look into Dr Julia Shaw's Memory Hackers.
Is is saccades that illusionists are exploiting? The quickness of the hand deceives the eye?
So many thanks for this. I remember reading a discussion (argument) about phone cameras, where 1 dude said “I guess human eyes really are the best cameras after all”. I near choked—wish I’d had this thread to link to then! Think I muttered something about brains and Photoshop.
It occurs to me that blurry may be good. When I take off my (strong) glasses, my non-colour vision (rod cells) works even better, detecting subtle patterns and movement out to the periphery of my vision.
Woah. That shit just actually blew my mind
Wow. Incredible. What a miracle of engineering...
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I have read this thread and I loved it. Please do post an article about it! I want to keep a reference to it and it is difficult through twitter. Kudos!
Awesome info! How about hearing? Isn’t mp3 compression about leaving out sound/info that the brain will fill in just like the blind spot in your eye?
I remember when only stoners had conversations like this. This has been mind blowing in the best way!
so if you want to use tech to feed the brain video from a camera, would you have to replicate all these weaknesses for a good experience or would it adapt to whatever
Depends on where in the brain you fed it in.
From what I've read of this (reading is slow), it is an interesting reminder that our eyes are imperfect and our brains' interpretation is often wrong. This is, of course, not news to someone with no central vision. I hope you help spread understanding. Thank you. :-)
great read.. are my anamorphic drawings not anamorphic 'by eye' due to brain trickery.. or is it just a 2d vs 3d image representation thing?
now re-think and re-write, taking into account that most people don't have equal quality eyes. One is usually slightly (at least) better than the other, causing your brain to do even more insane shit to compensate for i.e. depth perception
I fucking love Biology.
That book sounds like it’s about Weeping Angels
Incredibly interesting thread but I wouldn’t say that it’s bullshit our brains are like this. The body evolves as it did and needed to. Just like it isn’t bs that we can’t see in infrared, it’s not bs that there are gaps like this.
This sort of retroactive construction happens at higher levels of consciousness too. See famous split-brain experiments.…
Not sure what it is or why, but when I start the path to a migraine headache, the vision on the right side of my eyes starts to go blurry, and works from right to left. After it covers 1/3 of my vision, migraine is in full affect. Wonder what in my brain is being affect?
Not just vision, ALL of our senses of reality – see this:…
Very interesting read, thank you!
You can turn it off by unfocusing your eyes and looking round but u feel sick really quickly.
Love this thread
That was absolutely fascinating! Thank you.
The trouble here is the assumption that time exists. It doesn’t. It’s just a perception - an explanation of things given to us by our brains. ‘Time’ is different at every place in the universe and passes at different rates depending on proximity to mass and relative speeds...
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Have you read about #Biocentrism? Essentially our brains are VR machines projecting the world outwards through our senses. Time and space are creations of the brain.
This was genuinely facinating
I enjoyed this thread very much
The whole "your eyes fill in the blanks" thing explains so much about how my eyes compensate for my RP
Like how I will SWEAR there is nothing happening in my peripherals or when I turn my head and then something will just APPEAR a millisecond later in my central field of vision
this is amazing
Microsaccades are even cooler x
Cool trick I use to do. In pitch black room stand in front of mirror with arm raised look at self in mirror. Flick light switch on/off. Room brightens and see ur self in mirror. Drop arm, u still see ur self with arm raised. Spooky.
This is magical. Thank you so much.
so, given it's july. A line judge at #wimbledon musn't follow the path of the ball, but must focus on the line, without any eye movement. Otherwise their brain is synthesising what actually happened?
Mine won’t never cause I’m nearsighted and they be blurry all the time HA
Have you asked any old school video performers or realtime VJs their experience? Were used to multiple frame rates, strobing and frame by frame lifestyles, now with VR running at 90fps+ there's a lot of things you think you see.
Very interesting! I just read about this technique that's using saccades to shift a VR image (while you're not noticing) and trick you into thinking you're walking in a different direction…
I'm linking this thread and showing this to every flattard that insists because they see no curve that the world is flat.
Why are you hating on eyeballs?
You have too much time on your hands. Good read though!
So it's like when you turn in Unreal Tournament 3😂
Now this is what i call knowledge!!! Wow!!! This thread is insane!
So that is why I see the notification light on my phone blinking out of the corner of my eye, but when I move my eyes to look at it, it seems to be off for a very long time before blinking again?
Well now I know why when I suddenly look at the clock second hand it will often move backwards one tick before moving forward.
this is a brilliant thread. The kind of thing that keeps me on Twitter. Thank you.
Hey! This was a great thread! Do you mind if I translate it to portuguese and link it to your original tweet?
Really interesting. And so well written. Thank you for the lesson. You’d make a great teacher (if you aren't one already!)
I have to admit that I don't "get" some of the science in this thread but I love it anyway. This is what twitter is FOR. Thanks for the enlightenment.
Didn't @dallascampbell do a test on @bbcbang where he said when our eyes move they basically shutdown for milliseconds? Hence 'live' spot the difference (where images have ojects added or removed as you view them) are so hard to see the changes. That freaked me out at the time 😉
On plus side they are super quick to re-focus that we hardly notice any blur. Thank goodness for slow gradual evolutionary improvements.
Here's one more crazy thing: we can't move our eyes in a continuous motion (because then it would be blurry all the time). Try it yourself: try to follow a line with your eyes and you'll notice that you cannot smoothly follow it, but only "jump" between spots. However, ...
following the line with a finger and following your finger with your eyes results in smooth motion. The background will be all blurry, but your eyes don't care now. I imagine that's what we don't see during saccades.
Awesome thread, thanks for sharing! I don't know if you've heard of @AkiyoshiKitaoka? A Japanese researcher who works on optical illusions, keeps posting mind-blowing stuff, you should have a look!
Wow this is freaking awesome !!
So I guess even after all those years, when we'd be able to design and build insane simulations, we'd still be lazy? Sigh.
Peripheral vision.. no blinking.. you will be amazed at what else you can see if you can maintain awareness without going back to automatic focusing which is what generally happens as soon as we notice something different.
Awesome thread. Amazing how the human body covers up the eyes deficiencies.