Your eyes deceive you: how optical illusions work

Your eyes deceive you: how optical illusions work


Have you ever wondered why your eyes show you things that are not there? We tell you about the science of optical illusions.

In 350 BC, Aristotle noted that If you looked at a waterfall and then enfocabas your view on the rocks, static, rocks They seemed to move in the opposite direction to the flow of water . This effect, now known as “motion sequel” or waterfall illusion, made Aristotle noted that “we can trust our senses, but they can be easily deceived.”

On Why is it so easy in appearance fool our senses to perceive a circle as if greater than one that is the same size, or seeing movement where it does not exist? In the nineteenth century, optical illusions began to be studied and analyzed in greater depth, and These studies revealed, among other things, that our brain tends to quickly jump to conclusions given the amount of information it receives for second.

In the case of the cascade, for example, certain neurons brain adapt to the motion , and when you change your focus to the rocks, other neurons overcompensate this adaptation and cause the illusion of opposite movement.

These studies carried out in the nineteenth century were the beginning of the early theories about how our eyes will play tricks on your mind.
For example, one of the most famous optical illusions is to Ebbinghaus, that reveals how in which our brains draw conclusions regarding the size of things in relation to adjacent objects , making it easy to manipulate the results:

 optical illusions

Ebbinghaus illusion by Fibonacci in the public domain.

Our sense of size and perspective can be confused by the context, because our minds are prepared to relate certain visual events with concepts of distance and depth; eg diagonal lines make us create the illusion of perspective because that’s how our brain is oriented in three-dimensional space.

Even during this period, several attempts to create a unified theory of illusions resulted in errors and confusion yes some interesting findings about perception were made. David Hubel and Torsten Wiesel discovered that certain neurons in the visual cortex of the brain were activated only when we saw objects oriented to specific angles: that is, that there are certain neurons in your brain that are activated when you see a triangle . This is interesting and has to do with our perception of the angles and the significance they have in our understanding of space and proportion of things.

Other illusions could point out the way in which our brain tries “fill in the blanks” and predict the immediate future. One theory is that some illusions show that our brain tries to predict the future as a way to compensate for the slightest delay between the occurrence of an event the time the signal reaches the brain perception.

Mark Changizi, a theoretical neurobiologist, and Shinsuke Shimogo, an experimental psychologist, wrote about a series of illusions, including the illusion Hering, that would fit with this theory is. Hering illusion, we see below, shows a series of radial lines that give the illusion of movement. Since this resembles the scenes we see as we move forward in the real world, our brains have evolved to deal with these lines as a representation of movement .

 optical illusions

Necker cube by Fibonacci under license CC BY SA 2.0

In more recent research, appliances resonancia Magnetic allow researchers to analyze how neurons in our brains respond to these illusions , extending the possibilities to understand how they work. For example, a study with people watching the Necker Cube (right) showed how the brain can switch between two different interpretations of an image, as it tries to turn a two-dimensional drawing into a three-dimensional cube .

As a result, what we know so far is that the brain handles perceptions of color, shape, texture and movement through different areas , and the process by which combines this information to generate a cohesive interpretation is not yet understood. We know, however, that our brain does not have enough capacity to handle all the information that is perceived by our eyes, and thus our mind is the need to take shortcuts, to choose the interpretation that seems most logical. And that is the reason why your eyes deceive you .


Hypertext

Your eyes deceive you: how optical illusions work
Source: english  
July 20, 2015


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