This image does not move but it can cause changes in your pupil

The top image does not move.

The hole doesn't get bigger, it doesn't expand, nor is it suddenly darker.

It is an optical illusion, and it is one of the protagonists of a study recently published in the journal

The experiment has consisted of showing this image and others of the same style, but with different colors, and the reactions to these stimuli show that, although they are not real images, but rather illusory images, the human body reacts to them .

In this case, and through an eye tracker, scientists have shown how the pupils change when looking at these illusory images.

When the hole is black, which evokes greater darkness, the pupils dilate, just like walking into a dark room.

In contrast, when the central hole is colored, including white, suggesting an expansion of light, people's pupils constricted.

In the first case, the dilation occurred monotonically,

while with the colored holes the pupils initially contracted on contact with the image, but later showed less change.

Also, the subjective expansions were weaker compared to black holes.

Bruno Laeng, professor of Cognitive Neuropsychology at the University of Oslo and one of the authors of the research, defends that this adaptation is something "useful", as a form of preparation for something that is going to happen very soon.

In this way it is “ready to act in the world”.

Another of the conclusions that these scientists have obtained is that the reality of people is not identical to the physical world.

“We have to realize that we don't know what's out there.

We do not have a perfect picture of the physical world.

Our mind gives us a version of it.

And he goes to great lengths to make a version that works, that is successful in interacting with the world,” he explains.

The experiment on which this research is based consisted of showing 26 static patterns with an elliptical central region on a dotted background, created by Akiyoshi Kitaoka, another of the researchers.

The sample consisted of 50 participants with normal vision from the University of Oslo.

But not the entire population experiences these illusory movements.

It was also reflected in the work: 20% of the participants hardly saw expansion or saw very little.

Laeng explains that this happens all the time in illusions because not everyone interprets, in this case, the images in the same way.

"One possibility is that for the illusions to affect you and the pupil to dilate, you have to see this two-dimensional image as if it were a rendered three-dimensional image."

To explain it, he uses the example of video calls in which, despite seeing a two-dimensional image, it is known that there is actually a three-dimensional image behind it.

“If people do the same thing with our illusions, then it creates this movement, this animation effect.

I suspect that people who don't experience that interpret it as a two-dimensional image and therefore there is no reason to be alarmed and change something."

Patterns used in the experiment.AKIYOSHI KITAOKA

Ignacio Morgado Bernal, Professor Emeritus of Psychobiology at the Institute of Neurosciences and at the Faculty of Psychology of the Autonomous University of Barcelona, ​​goes further and defends that even the same person, depending on the moment or the lighting, can see these illusions or not .

"Probably, a certain position of the eye is needed to see it and, above all, a predisposition is needed," he details.

Laeng explains that a very clear example of the different ways of interpreting an image was the photo of a dress that went viral in early 2015. Society was divided between those who believed that it was blue and black, while the rest insisted on which was white and gold.

“This is another example showing that it depends on how you start to interpret an image: you discover the characteristics of the scene and based on that you conclude something.

Even though everyone looks at the same thing, the brain will build completely different things.”

This image was analyzed and the results published in

The authors suggest that these differences in color perception may be caused by the action of visual mechanisms used to stabilize colors.

Optical illusions have been trying to be deciphered by scientists for years.

This term is defined as illusions characterized by visually perceived images that differ from objective reality, explains 2011 research published in the Japanese journal

"The problem with optical illusions, of which there are many, is that we rarely know the neuroscientific mechanism that makes them possible," explains Morgado Bernal.

These can be based, as he details, on phenomena that occur in the retina itself, that is, inside the eye or in the brain, where there is much more complication.

But not only humans are capable of seeing these optical illusions.

Animals such as rhesus macaques, cats, or lions, among others, also have the perception of illusions in movement, according to a study published in

a few months ago.

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