• diverging
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    1 day ago

    Because of this we have blind spots, one for each eye. They are not usually noticeable because 1) the blind spot of one eye can usually be seen by the other, and 2) the brain fills in the gap.

    So with this I will perform a magic trick, I will make your thumb disappear: Close your left eye and with your right look at a spot in the background, make a thumbs up gesture and place the tip of your thumb on that spot, move your thumb to the the right continuing to look at the spot in the background, when your thumb moves about 15 cm your thumb should disappear.

    You can use your left eye too, just switch the directions.

    • @Carrot@lemmy.today
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      715 hours ago

      Woah, i didn’t know that the effect would be so drastic. I want to point out to those struggling to get it to work that, as diverging mentioned, your arm needs to be fully extended. Also, the blind spot is about a thumb’s width, at least for me, and is only visible at a specific x/y axis location. Any deviation from that single spot will cause it to stop working. I could tell I was close to the spot when parts of my thumb would disappear, and just had to slowly move it around until I found the spot that looked like the thumb was gone completely.

      • 0ops
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        312 hours ago

        Thanks you helped me see it (or not see it I guess)

    • cally [he/they]
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      514 hours ago

      It looks like there’s just a gap in spacetime or something.

      By the way, your eyes are not meant to track your thumb when doing this, you have to keep still and move only your thumb for it to work, so don’t move your eyes.

    • Dr. Moose
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      15 hours ago

      the brain fills in the gap

      To expand on this, current leading theory (predictive processing) says that brain first generates a visual image then confirms it with inputs and if there’s no input to confirm/deny the halucination it’s just accepted as is. So we can have a whole load of blind spots in all of our sensors and continue functioning rather well with an ocassional artifact.

      • @Whats_your_reasoning@lemmy.world
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        1220 hours ago

        I think about this at night when my eyes are forced to attempt to make sense of the low light levels in a dark room. I know my room isn’t grainy and grey-scale - that’s just the best my eyes and brain can do at night. It’s interesting to look around and try to imagine the proper colors and shapes of things, reckoning the difference between what I know and what I see in the moment.

        With our brains constantly making things up to explain gaps in information, it’s no wonder kids think they see “monsters” in the dark. It’s also no wonder that nightlights work well to keep said “monsters” away.

      • Owl
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        317 hours ago

        AI witchhunting crowd hates this one simple trick !

    • @InvalidName2@lemmy.zip
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      401 day ago

      It’s way too late at night for all those directions, somehow ended up creating my own blind spot by sticking my thumb in my bum.

      • diverging
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        161 day ago

        Well, I guess your thumb disappeared.

        I can try another way the blind spot is about 15 cm at arms length to the right of the right eyes center of vision. So put your thumb there and it should disappear

    • @Modern_medicine_isnt@lemmy.world
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      51 day ago

      I couldn’t make it work. But I did notice that the spot in the background changed focus a tiny bit at one point. I suspect my brain was tracking the thumb and simply refused to continue to truely focus on the background spot. I tried and tried, but just couldn’t make it happen. Neither eye. :(

    • Clot
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      31 day ago

      What is a “spot in the background”? Like where exactly

      • @Todd_cross@lemmy.dbzer0.com
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        1 day ago

        Anywhere. It makes it easier, if you have a dot or a feature to look at, but really it’s anywhere in the distance. I guess generally straight ahead.