Sep 02, 2021 12:00:00

Surprise scientists with the discovery of a man with the ability to freely change the size of his pupils

The human

pupil is a hole that allows light to reach the retina, contracting in bright places to reduce the amount of light it takes in, and expanding in dark places to take in more light. In general, the pupils are contracted and expanded unconsciously, but it turned out that a 23-year-old man living in Germany has the ability to 'reduce and expand the pupils freely', and scientists I'm surprised.

Direct voluntary control of pupil constriction and dilation: Exploratory evidence from pupillometry, optometry, skin conductance, perception, and functional MRI --ScienceDirect
https://www.sciencedirect.com/science/article/pii/S0167876021008448

Man can change his pupil size on command, once thought an impossible feat | Live Science
https://www.livescience.com/man-can-control-pupil-dilation.html

The iris that surrounds the pupil contains two types of muscles: the dilator muscle , which is controlled by the sympathetic nerve , and the iris sphincter muscle, which is controlled by the parasympathetic nerve. When the dilator muscle contracts, the iris is pulled outward and the pupil expands, and when the iris sphincter contracts, the iris is pulled inward and the pupil contracts.

Until now, it has been thought that the process of contracting and expanding the pupil is completely unconscious. For example, a person who steps from a bright place to a dark place does not have to think 'let's enlarge the pupil', but the sympathetic nerve is automatically excited and the pupil becomes larger, and more light is emitted than when it was in a bright place. It is possible to incorporate. It is also known that the size of the pupil changes automatically when the mind becomes agitated or tired.

It seems that some cases have been confirmed in which the size of the pupil can be indirectly changed by 'imagining the bright sunlight or imagining a dark room'. However, as with the muscles of the arms and legs, it was thought that it was impossible for humans to 'change the size directly while being aware of the pupil.'

However, Christoph Strauch , an assistant professor of experimental psychology at Utrecht University in the Netherlands, said when he was enrolled in a doctoral program at Ulm University in Germany, a male student said, 'I have the ability to freely change the size of my pupils. I was contacted. The man, who is called 'DW' in the treatise, said he had devised a unique way to shake his eyes and relax after playing computer games for a long time when he was 15 to 16 years old. Then, one day, when he showed this relaxation method to a friend, he was pointed out that his pupils were getting smaller.

Initially, Mr. DW seems to have changed the size of the pupil by shifting the focus according to the object, but as he practiced, he became able to shrink and enlarge the pupil without being aware of the focus. .. 'When you contract your pupils, you feel like you're grabbing or taut. When you expand your pupils, you feel like you're completely free and relaxed.' He claims that all that is needed to change the size of the pupil is to 'focus on the eyes.'

Strauch thought that although it was possible to indirectly change the size of the pupil, such as by imagining a bright place, it was impossible to move the muscles of the pupil directly. Therefore, in order to confirm Mr. DW's claim, the electrical characteristics are measured with a device attached to the skin to check whether there is any mental effort, or the activity of the part related to intention is measured by performing a brain scan with fMRI. I did an experiment to do it.

Experiments did not convince DW that he was directly controlling his pupils, but found no evidence of indirect efforts. Mr. DW said that the pupil can be reduced and expanded in the range of 0.88 mm to 2.4 mm without using an indirect method, and it seems that it was possible to focus on an object close to the face by reducing the pupil. is.

The image below shows Mr. DW's pupils arranged in restricted, normal, and dilated. You can see that the pupil sizes are different.

Strauch suspects that there may be others with similar abilities to DW, and by conducting a survey of more people, he understands how to freely control pupil size. I insisted that I might be able to do it.