One Weird Visual Illusion Explained

One Weird Visual Illusion Explained


This is an image of a young woman with a feathered
hat looking over her shoulder. Or… is it? Her chin also makes out the nose of an old
woman, looking down. And take this image of a vase. Is it a vase? It’s also the outline
of two faces. These perceptual illusions are called ambiguous
figures, because they cause you to switch between more than one way of viewing an object. And there’s one type of visual phenomena
that’s a lot weirder – personally it’s my favourite. And to experience it, I’m going to show
you how to see through a hole in your hand, just by using a piece of paper. It’s really,
really simple! Start with a piece of paper or even a bank
note and roll it up into a tube– it’s important to keep the tube narrow. Put that
tube right up to your eye and look through it. Then place your other hand right against the
piece of paper, about 2 inches or 5 centimetres away from your face. Keep your hand there
and look into the distance, through the tube and don’t focus on your other hand. Give it a little bit of time, like at least
10 seconds of looking down the tube. What you can see seems like your field of vision
merging; so you can see a hole in your hand, the hole being the middle of that tube you’re
holding. It’s weird, right? So what’s going on? Well, two different images are being shown
to each of your eyes. If your brain can’t combine these two images, it just suppresses
the image in one eye, and your other eye becomes more dominant. In this case, your hand will
generally stay suppressed from your awareness because it’s the weaker stimulus. This phenomenon is known as binocular rivalry. And A number of brain areas and operations
are involved in binocular rivalry, including what’s going on in your visual pathway. The brain cells or neurons in the early stages
of your visual processing respond to the physical stimulus of each eye, but then neurons in
later stages of visual processing can be switched on and off and cause the alternations. Researchers
think the signals with one of the stimuli are suppressed somewhere between these stages,
as if there’s a gate to visual consciousness that some signals open first. You don’t normally notice this dominance
and suppression in your eyes because they rarely stay fixed on one thing for more than
a few hundred milliseconds. For me, what makes binocular rivalry so amazing
is that your perceptual experience changes while the physical stimulus you’re seeing
remains the same. The input from your eyes is constant – the difference takes place
in your brain. Of all the ways you can trick your brain,
this is an awesome one to show people because you can turn your hand into anything at the
dinner table. Velociraptor hand! See you next week.

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  1. Could someone explain why the brain is wired so inefficiently? The right eye is connected to the left hemisphere and the left eye is connected to the right hemisphere… What makes matter worst is that the eyes are connected all the way in the back to the visual cortex.

  2. Hei ! 🙂

    I bet it should be nice, to see that. But also it is nice to see 3D effects, objects getting out of screen, right? But, could you also explain why me for example and a lot of other guys, cannot see this effect with the tube and neither the 3D effects ?

    I could figure that one of the reasons is because i cannot focus with both eyes in the same time. It would be nice to have an explanation about that, what happens, and if this can be corrected :).

  3. I thought my hand had become a fleshlight and I smacked the tip of my penis really hard now…please help 🙁

  4. Here is another fun ambiguous figure: point each of your index fingers towards one another horizontally to your point of view. Place your index fingers on the top of your nose and then slowly move them away from your face. If done correctly you should see a floating finger sausage mid air that isn't connected to either hand!

  5. What if i always see both, for example is see the vase and the faces i dont have to switch or look at another point.
    I always did, not only after i ve seen them before.
    Can this be related to autism because of the alternative way of processing information?

  6. OMG Vanessa! I'm in the Youtube Women's Program too! (London) I almost died of happiness when I saw u were there too! ?? The video I did for the program will come out on Saturday. I'm so excited! Bravo Vanessa! I'm a huge admirer!

  7. our vision is amazing at how much stuff it makes up.
    and how imperfect our eyes are is pretty weird.
    if you cover one eye, then look at a spot on the wall you can hold up your finger, move out away from the spot on the wall you are looking at and at some point the top of your finger will disappear.
    there's literally a hole in your eyes and the brain is constantly inventing images to fill it up.

  8. For those of you confused about the old woman looking down (took me 10 minutes), the whole cheek is the old woman's nose and that horizontal line is her mouth, the black part under the feather is her hair and the young woman's ear is a wrinkle under her eye

  9. This is cool but annoying because this happens to me all the time for example I watched this video through my fingers (didn't use anything to cover either eye, either)

  10. I can somehow turn one of my eyes into a wall eye that can look in another direction. I do this by focusing on one object, for example, my face in a mirror, and defocuse my other eye to look someplace else. I can see my other eye moving elsewhere in the mirror with the focused one. Is this normal? I've been able to do it since I was little. My eyes feel fine afterward, as long as I don't do it too often. I do wear glasses, but I don't know if that has anything to do with it.

  11. Cool, Ive always wondered what that phenomenon was called. I expierence it when looking through a monocular with both eyes open.

  12. cara eu fiquei bugado primeiro eu percibir q era uma imagem com uma figura na mão depois q eu li e re li oq tava escrito na page do face( ecliquei no linke depois) e q eu percibir q era pra ser uma ilusão, n tive essa ilusao no primeiro momento eu so tive depois q eu me concentrei pra ver, eu vi sobre isso no site fato desconhecidos

  13. this video kinda reminded me about how you can see through wooden fences as you drive by them, I think that's pretty cool too

  14. Opticalusions that worked/didnt work in this video:
    1. Old woman? Where?
    2. We all know that one, so I guess yes.
    3. Hole in hand – Nah, doesn't work. I either forget about the hand or I see the hand and the hole combined, but no hole in my hand. It's like the UFO thing made by pointing two fingers together and relaxing your eye on the background. I get the point but I'm too concious of it to believe it is true

  15. Talk Nerdy brought me here. Good work Vanessa. My daughter and I watched this one and she is super excited to try it out.

  16. I like doing this when it's dark and there is a light in the distance, I close one eye and block the light with one hand and then the same with the other eye and then I open both, moving either hand reveals the light and it seems weird for the light to be behind both hands at the same item

  17. My favorite is drawing a 3D object and then alternate seeing it from the front and then seeing it from underground ???

  18. When you have strabismus, you don't have binocular vision, so my vision doesn't merge, and my eyes are not straight

  19. There are more than one type of illusion: There is the Stereo-optic illusion which is demonstrated here as the "hole through the hand trick", then there is the cognitive -optical illusion which is the old-lady versus the young woman, or the rabbit-duck image contrast, which uses your education or cultural norms, then the neurochemical illusions which give you persistence of vision, allowing you to see animation, and the strange warping effects caused by certain contrasting colors.

    Each type is capable of diagnosing conditions within their respective categories, but I have found very little research in the area. I hope your team can elaborate more on this subject in the near future.

  20. The tunnel vision at first didn't work, but I tried it again and the second time I focused more to the center then further towards the other eye vision and it viola I had a hole in my hand.

  21. I've seen the young/old lady picture so many times and people explained it to me every time, but I just can't see the old one.
    I wonder what that says about me lol

  22. Interesting to see how this video explains how the brain can change what we perceive in the real world. I remember when I was much younger (old fart) and sometimes still do it now, where I used to stare at the train tracks at the train station and force my mind to wipe away the track lines leaving the sleepers (I think thats what they call them). it works for a split second before you get excited and reality bounces back. I also used to do easier ones like a small picture on a bare white wall 3 meters away and I'd force to remove the picture and make it dissappear.. freakin fun stuff but really hard to do. might just it now to see if I can still do it.oh btw, the trick is to not stare at the object you're trying to wipe out but use your peripheral vision to look at it.

  23. I am new with "vase" pronouncing as /vas/….because I am used to hear it as /veys/ or /veis/ and not /vas/ from where I live. Such like that "base" is not pronounced the same as "bass", or a "case" is not "cass". English and various accents of it are really confusing….they don't have straightforward spelling-pronunciation relationship like other languages….Like the "-ough" is pronounced differently in "through", "though", "ought", "tough", and "thought".

  24. I have an eye problem, and my brain ALWAYS suppresses my left eye! It's cool that you explained that!

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