This thread went viral because it’s fascinating and you’ll never see in quite the same way again

Someone called @foone posted this thread about our eyes and the way our brain enables us to see and it’s seriously gripping stuff.

It’s the leap from 7 to 8 that enthralled us most – we’d always noticed this but never knew why (or bothered to ask) and the reveal from 28 to 29 is pretty good too.

Take your time, it’s worth it.

1.

https://twitter.com/Foone/status/1014267515696922624

2.

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.

— foone (@Foone) July 3, 2018

3.

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

— foone (@Foone) July 3, 2018

4.

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.

— foone (@Foone) July 3, 2018

5.

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.

— foone (@Foone) July 3, 2018

6.

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.

— foone (@Foone) July 3, 2018

7.

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.

— foone (@Foone) July 3, 2018

8.

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.

— foone (@Foone) July 3, 2018

9.

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.

— foone (@Foone) July 3, 2018

10.

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.

— foone (@Foone) July 3, 2018

11.

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

— foone (@Foone) July 3, 2018

12.

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.

— foone (@Foone) July 3, 2018

13.

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.

— foone (@Foone) July 3, 2018

14.

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.

— foone (@Foone) July 3, 2018

15.

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.

— foone (@Foone) July 3, 2018

16.

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.

— foone (@Foone) July 3, 2018

17.

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 pic.twitter.com/Xf7sGgtdtx

— foone (@Foone) July 3, 2018

18.

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.

— foone (@Foone) July 3, 2018

19.

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. pic.twitter.com/3rV3uTZypf

— foone (@Foone) July 3, 2018