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A 23-year-old student in Germany can scale down and expand his pupils on demand, according to a new case report – a feat previously thought impossible.
Two opposing small muscles in the eye act as puppeteers of each pupil (the dark center of the eye), dilating or enlarging them in a dark environment to let in more light and squeezing them in a bright environment to limit the amount of light entering . This process has been designed to be completely automatic; When you walk into a dark room, you don’t have to consciously tell your pupils to change size. Pupils may also change in height in response to other factors, such as increased arousal.
It was previously known that some people can change their pupil size at will, but using indirect methods.
For example, researchers already knew that just thinking about the sun could make pupils constrict and thinking of a dark room or mentally calculating something could dilate them, said Christoph Strauch, lead author of the new case report and professor. assistant in experimental psychology. department of the University of Utrecht in the Netherlands.
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But no one believed that it was possible to change the size of the pupil by controlling it directly like a muscle – that is, until a psychology student at the University of Ulm in Germany contacts Strauch after taking one of his classes. (Strauch was previously a doctoral student at the University of Ulm).
Around the age of 15 or 16, the young man – identified in the case report by his initials, DW – realized he could change the size of his pupils. “I showed a friend that I could ‘shake’ with my eyeballs, and he noticed my pupils got small,” DW told Strauch and colleagues at Ulm University. But DW didn’t notice he had this ability until he played computer games for long periods of time.
“Controlling the pupil is like grabbing, straining something; enlarging it is like completely releasing, relaxing the eye,” DW told the researchers. At first he would change his pupil size by focusing in front of or behind an object, but with practice he learned to do so without focusing on objects. He explained to the researchers that to change the size of his pupil all he had to do was focus on the eye; he does not need to imagine a bright or dark environment.
This makes DW different from other people who have demonstrated the ability to change their pupil size, Strauch told Live Science. Moreover, that he could directly feel the muscles of the pupils “is astonishing, because we thought it was impossible”.
Is it rare?
Through a series of tests, the researchers confirmed that DW did indeed have this ability – and they found no indication that he was indirectly changing the size of his pupils. In one test, the researchers measured the electrical properties of the skin by applying voltage to test if it was aroused by increased mental strain, which could also have indirectly increased the size of its pupil. (He wasn’t.)
Without using an indirect method, DW could dilate her pupils up to 0.09 inch (2.4 millimeters) in diameter and constrict them to 0.03 inch (0.88 mm) in diameter. Moreover, even at the closest point of an object can be so that the eye can always see it at the point, in which the pupil is already “to the maximum” constricted (imagine holding a pencil in front of the eyes and bringing it closer to the face and stopping at the point before it got out of focus), DW could voluntarily tighten his pupil even more. By doing this, DW improved his focus and was able to clearly see objects nearly twice as close to his face as he could if he didn’t control the size of his pupil.
Using a type of brain imaging known as functional magnetic resonance imaging (fMRI), researchers found increased activation of parts of the brain involved in will power, or the ability to decide and do something. willingly.
The researchers can’t say for sure that DW directly controlled his students, but based on their numerous tests, they found no evidence that he was using indirect strategies.
Can other people learn to do this? Maybe, says Strauch. Finding and researching more people who have this ability could help the team understand if there is a strategy to train people to control their pupil size at will. (Readers who believe they have this ability can contact researchers at [email protected].)
Studies of more people who might have this ability can help researchers describe and understand the phenomenon, such as where it came from, Strauch added. “A lot of people have reached out and think they might be able to do the same – it’s really cool,” he said.
The results were published online Aug. 12 in the International Journal of Psychophysiology.
Originally posted on Live Science.
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