German young man can change pupil size whenever he wants

Some people have curious abilities regarding their own bodies. Studies show that between 65% and 80% manage, for example, to bend the tongue in two parts, forming a U. This index decreases well when the challenge is to fold it in three. The Vulcan greeting “Long and prosper”, a gesture immortalized by Star Treck’s character Spock, is something that far fewer people can easily do. However, there is no report in the world of someone who can change the size of pupils voluntarily. At least there wasn’t.

Until DW, a psychology student at the University of Ulm, Germany, discovered that he had this “gift”. He is able to contract and dilate the tiny black spheres in his eyes at any time he wants. According to the young man, he can even feel the small muscles that control these movements.


His case, unpublished so far, was recently reported in the International Journal of Psychophysiology.

Scientific research has proven that the movement of contraction and dilation of the pupil of a young German can happen voluntarily. Image: sruilk – Shutterstock

Voluntary movement of the pupils requires concentration, says the young man

“Contracting the pupil is like grabbing, tensing something; making it bigger is like releasing it completely, relaxing the eye”, revealed DW to the team of scientists who investigated the case.

He says he discovered his strange ability when he was around 15 years old. According to the student, he only needs to concentrate on his eye and on his movements. “I showed a friend that I can ‘tremble’ my eyes, and he noticed that my pupils got small,” DW told Christoph Strauch, assistant professor of experimental psychology in the department at the University of Utrecht, Netherlands, the case investigator.

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Scientists applied various tests in DW

According to the researchers involved in DW’s case, the boy was subjected to many tests to determine whether there was, in fact, voluntary control over his movements or whether the young man was using some known indirect method.

Using pupillometry and optometry techniques, one of the tests performed consisted of measuring the body’s electrodermal activity, a term used to define autonomic and continuous variations in the electrical properties of the skin.

These tests were intended to try to understand if DW made intense mental effort when controlling the action of his pupils, concluding that this was not the case.

In this way, the boy’s ability is drawing the attention of investigators. Strauch told the Live Science website that this ability “is surprising, as it was thought to be impossible.”

After several analyzes and observations, it was concluded that DW really has the ability to contract and dilate the pupils whenever he wants, proving that voluntary control of the pupils’ muscles is possible.

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