442 upvotes, 13 direct replies (showing 13)
Our brain is always filling in blanks. Most of what you think you see right now is your brain filling in blanks. The only area where we have decent resolution vision at all is in the fovea; the rest is the brain filling in details from memory, other senses, and guesses. Blinking, blind spots, peripheral vision color, saccades, and more are all places where the brain just... makes stuff up, even if you have perfect vision and a neurotypical brain.
Comment by meostro at 04/02/2025 at 22:48 UTC
220 upvotes, 8 direct replies
/u/untempered knows what's up - it's way more ridiculous than you can imagine.
Your optic systems (eyes plus visual processing bits of your brain) are so good at lying to the rest of your brain that you time travel[1] all the time. You can see while your eye is sitting still, but when your eyes move (it's called a saccade) it's like a video feed with a pause button - you get the last image from before the movement, then the camera moves, then once everything is squared away the feed continues. If the new video frame is too far out of sync with the last frame your optic system kinda says "eh... it was probably moving" and *just does it* so the rest of your brain just gets the smooth fill-in-the-blank version.
1: https://www.cell.com/current-biology/fulltext/S0960-9822%2802%2900707-8
This isn't even starting on the part where your eyes are cameras with all of the electronics and such sitting directly between the lens and the sensor... it's incredible that we can "see" at all!
tl;dr: "Seeing" things is incredibly overgenerous. You are blind maybe half the time you're seeing things, and most of your perception of what you see is either faked or old. And because your eyes/brain are such good liars, you have absolutely no idea just how bad things are.
Fun fact: VR developers want to take advantage of this weird eye system to lie to you even more to make games better. If you're walking in a straight line in a headset you're going to run into stuff like walls or furniture. If they take advantage of all those fractions of a second where you're blind to scootch everything a little to the left you would never notice, but you would turn a tiny bit left to compensate and would now be walking in circles.
Comment by NickDouglas at 04/02/2025 at 22:12 UTC
70 upvotes, 2 direct replies
Every few days, I re-read some word that I could *swear* said something different a second ago. My brain is just trying to patch up my vision with spit and duct tape.
Comment by Hazel_nut1992 at 04/02/2025 at 22:30 UTC
29 upvotes, 1 direct replies
I have a very small blind spot that I am only ever aware of when I do a visual field test at the Ophthalmologist. The rest of the time I have no idea it’s there. The brain and the eyes can do some neat stuff
Comment by ChocolatChipLemonade at 05/02/2025 at 00:09 UTC
12 upvotes, 2 direct replies
After a brain injury, my brain went wild with this. You know the childhood game where you can look up at the sky and sometimes see a rough outline of some animal? My brain sees what your brain sees, and then adds in all these specific, minute details. I see the most interesting things when I look at objects/patterns like granite countertops or window reflections. I figured I should one day create art with the things I see
Comment by ashtarout at 04/02/2025 at 22:46 UTC
20 upvotes, 3 direct replies
It also means when you're missing a chunk big enough for it to be noticeable, it's pretty disconcerting. Twice in my life I've had migraines bad enough that I couldn't see my thumb (on one occasion) and couldn't read (on the other). Aura migraines are no joke. Thankfully resolved after only 30 - 45 minutes. Too bad they're excruciating. I can only be thankful they're rare for me.
Comment by Suspicious_Plantain4 at 04/02/2025 at 22:53 UTC
8 upvotes, 1 direct replies
When I meditate, my vision often gets blurry and my peripheral vision seems to lessen. I can also see the shadow of a vein pulsing in my eye that apparently my brain usually edits out.
Comment by PM_ME_YOUR_PRIORS at 05/02/2025 at 00:51 UTC
8 upvotes, 0 direct replies
This is a big cause of people pulling out in front of motorcycles and causing horrific accidents. They see a spot of clear road, saccade over the motorcycle into clear road, and fill in the blanks in between with clear road that is actually motorcycle-occupied.
Comment by Shebazz at 05/02/2025 at 00:31 UTC
6 upvotes, 1 direct replies
it's not always filling in the blanks, sometimes it's blanking out stuff that should be there too. For example you can always see your nose, but your brain ignores it
Comment by FatPenguin42 at 04/02/2025 at 23:59 UTC
3 upvotes, 1 direct replies
So humans have DLSS ai upscaling…
Comment by Willing_Refuse_2543 at 05/02/2025 at 00:51 UTC
1 upvotes, 0 direct replies
I have a few issues with my eyes. My eyesight has just recently hit the amount of bad where I am starting to notice visual hallucinations fairly regularly. Freaks me out every time because my brain is 100% sure it's seen something that logically I know isn't there.
Comment by HEBushido at 05/02/2025 at 04:22 UTC
1 upvotes, 0 direct replies
My brain has frame gen.
Comment by user_bits at 05/02/2025 at 08:53 UTC
1 upvotes, 0 direct replies
The Ames window illusion is a great example of our brains actively showing us something different from what we know is there.
Comment by antwan_benjamin at 04/02/2025 at 22:36 UTC
1 upvotes, 0 direct replies
Such a cool concept to think about. Its like the way AI is working nowadays with image processing, especially when you remove objects from pictures.