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“Your vision lies to you”: a Twitter user conducted an educational program on how the brain hides the faults of the eyes

It turned out that nature carefully conceals its defects.

The human eye is a complex organ working in close connection with the brain. When a person looks at something, it is in the brain that the incoming information is processed.

However, the eyes are imperfect, therefore, a kind of “photoshop” is built into the human brain, due to which we see the world not as it actually is “seen” by the eyes. For example, it has long been known that they create an inverted image of the world, and the brain in the process of processing “turns” it back.

The Twitter user and the engineer under the pseudonym Foone remembered the tricks of the brain, about which many users did not seem to know. He published over 30 tweets explaining such “tricks”. For example, Foone spoke about the effect of saccades – fast synchronized eye movements.

“Do you want to know something about how crazy our brains are? Well, there is a physical problem with our eyes: the fact that we move them fast is called “saccades”, right? Very fast, synchronized movements. There is one problem: during them everything becomes blurry and useless ”

Saccades can occur when the environment is constantly moving: for example, when driving a car, the eyes are fixed at one point or another. Or while reading a book, when the view “jumps” from word to word.

However with saccades there is a problem: during such “jumps” the eyes move so fast that the image is blurred, and vision becomes useless. Foone decided to reflect on this in terms of engineering.

“Turning your eyes into a blurred mess every time you move your eyes is obviously not a good idea, so our brains hide it from us. Now imagine that you are an engineer with such a problem “

Foone came to the conclusion that there are two ways to solve the problem: you can darken your eyesight while moving your eyes or show the last seen image before you start moving. However, the human brain does not use any of them.<blockquote class=”twitter-tweet” data-lang=”en-gb”><p lang=”en” dir=”ltr”>first, it basically puts your visual system on &quot;pause&quot;. You&#39;re not seeing blackness or even nothing, you&#39;re just not seeing period.<br>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.

“First of all, in fact the brain simply puts your eyesight on a” pause. ” You do not see either darkness or anything else, just skip part of the time. After this, when you finish the saccade, it shows you what you see in the new position. And pretends to be able to travel in time “

According to Foone, the brain shows the image from a new point, but “shifts” it back in time so that it seems as if the person saw the whole picture all the time while the eyes moved. And it works, because the brain is not a computer with a constant clock.

Foone suggested checking the effect on the analog clock. If you quickly look away (but not head) from the arrow, and then look at it again, it will seem that the arrow has moved too slowly and in fact it has been less time.

You can also check the “stop time” on a regular mirror of any size: it’s enough to move your eyes and try to catch the moments of this “movement” (in self-mode on a smartphone this will not work).

“It’s because your fucking visual system has just lied to you about how long it took to hide the physical limitations of these chemical chambers on the front of your face”

This phenomenon is called chronostasis and was described in detail 100 years ago. It is believed that the eyes are in this movement about 10% of the total time. During the saccade, the human brain can “stop time” up to half a second.

Foone also noted that the brain has a separate way of hiding the movement of objects during “pauses”, so that it does not seem like they are teleporting. For example, the effect of a saccade is not so obvious if you check it on a clock with a smoothly moving arrow: the brain realizes that it constantly moves and adjusts the image.

“It’s tempting to think that your eyes and visual system are just dropping the video stream right into your brain, but that’s not the case. What you think you see and what your eyes can actually see are two completely different things “

Foone also talked about how the brain hides blind spots – a field of view that is not sensitive to light. Blind spots are in each eye and when using both eyes are imperceptible. But even closing one eye, it’s just not possible to see a blind spot – the brain will place an image there, taken in advance from the other eye.

“Just for fun: this is an example of a blind spot from Wikipedia. Look at the letter L with the right eye closed, changing the distance and at some point R disappears. You will not see “nothing” or “blackness”, you will see the background color, because you expect this “

In addition, the engineer recalled the peculiarities of color perception. In the human eye, only a small area of ​​cells is susceptible to color and they are all concentrated in the center of the glance. However, people see colors and peripheral vision, despite the fact that, in theory, they should not.

“Your visual system lies. She remembers the colors of things, and then guesses and fills in the blanks. In fact, the brain makes the Ted Turner colorization process on your peripheral vision ”
Also Foone recalled the effect of “special perception”. Its essence lies in the fact that if you take a bunch of white balls of different sizes and throw them into people, they will give one estimate of their size. And if after that do the same, but the balls will need to be repulsed, then in the eyes of the participants they will become much more. They deliberately exaggerate the size of the balls, so that it would be easier to get on them.

“What is really important for the evolution of vision is any trick that helps to survive, no matter how” stupid “or” strange “. So if you want to get an accurate idea of ​​how things look, use the camera, not your eyes. “

Lasers are so dangerous, including because the visual system can hide “blunders” in vision. Thus, when the retina hits a small point, the brain masks it. However, after some time, the laser will cause such damage to the eye, that it will not be possible to conceal it, then the vision sharply degrades.

In addition, Foone remembered about the experiment in 1890, when scientists put on glasses that turned the image upside down and carried them for 8 days. The brain adapted, and they did not feel the effect of the inverted image.

Finally, Foone invited interested users to read the science fiction novel of Peter Watts called “Blindness” (Blindsight). According to his story, people are faced with an alien race that enjoys shortcomings in human vision.

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