The Pupils Are the Windows to the Mind

 

The eyes are the window into the soul -- or at least the mind, according to a new paper published in Perspectives on Psychological Science,   a journal of the Association for Psychological Science. Measuring the   diameter of the Pupil, the part of the eye that changes size to let in   more light, can show what a person is paying attention to. Pupillometry,   as it's called, has been used in social psychology, clinical   psychology, humans, animals, children, infants -- and it should be used   even more, the authors say.

  The Pupil is best known for changing size in reaction to light. In a   dark room, your Pupils open wide to let in more light; as soon as you   step outside into the sunlight, the Pupils shrink to pinpricks. This   keeps the retina at the back of the eye from being overwhelmed by bright   light. Something similar happens in response to psychological stimuli,   says Bruno Laeng of the University of Oslo, who cowrote the paper with   Sylvain Sirois of Université du Québec à Trois-Rivières and Gustaf   Gredebäck of Uppsala University in Sweden. When someone sees something   they want to pay closer attention to, the Pupil enlarges. It's not clear   why this happens, Laeng says. "One idea is that, by essentially   enlarging the field of the visual input, it's beneficial to visual   exploration," he says.

  However it works, psychological scientists can use the fact that   people's Pupils widen when they see something they're interested in.

  Laeng has used Pupil size to study people who had damage to the   hippocampus, which usually causes very severe amnesia. Normally, if you   show one of these patients a series of pictures, then take a short   break, then show them another series of pictures, they don't know which   ones they've seen before and which ones are new. But Laeng measured   patients' Pupils while they did this test and found that the patients   did actually respond differently to the pictures they had seen before.   "In a way, this is good news, because it shows that some of the brains   of these patients, unknown to themselves, is actually capable of making   the distinction," he says.

  Pupil measurement might also be useful for studying babies. Tiny   infants can't tell you what they're paying attention to. "Developmental   psychologists have used all kinds of methods to get this information   without using language," Laeng says. Seeing what babies are interested   in can give clues to what they're able to recognize -- different shapes   or sounds, for example. A researcher might show a child two images side   by side and see which one they look at for longer. Measuring the size of   a baby's Pupils could do the same without needing a comparison.

  The technology already exists for measuring Pupils -- many modern   psychology studies use eye-tracking technology, for example, to see what   a subject is looking at, and Laeng and his coauthors hope to convince   other psychological scientists to use this method.
         

  http://www.sciencedaily.com/releases/2012/01/120127162800.htm

 

   

The above story is reprinted from materials provided by Association for Psychological Science.