This ability is both a neat party trick and a scientific breakthrough. A student in Germany can resize his pupils at will!
Initially thought to be impossible, the enlargement or dilation of pupils was thought to be completely automatic and in response to certain environmental conditions. However, according to a new case report, a 23-year-old man just blew up the status quo.
What’s different about this new case report is that the man can change his pupil size by directly controlling it as a muscle. Christoph Strautch, the senior author of the report, was approached by the man, who was a student of psychology at Ulm University in Germany.
The man, identified in the case report as D.W., told researchers that "Constricting the pupil feels like gripping, tensing something; making it larger feels like fully releasing, relaxing the eye." D.W. was able to learn how to change his pupil size without focusing on objects after a long time of practice. All he has to do now is to concentrate on the eye instead of imagining a bright or dark environment.
Image credit: Eberhardt et al., IJP, 2021,