30.01.2012

Pupil size "gives an indication of concentration levels"

Pupil size "gives an indication of concentration levels"

By Adrian Galbreth

Many times we have had a conversation with another person and wondered if they were paying attention to us, but never known the truth - until now.

That is after experts in Europe conducted a new study which shows that the size of a person"s pupil is an indicator of how much they are concentrating on someone or something.

According to the study, published in Perspectives on Psychological Science, a journal of the Association for Psychological Science, measuring the diameter of the pupil, which is known as pupillometry, has successfully been used in social and clinical psychology in adults, children and animals, and should be used even more.

Bruno Laeng of the University of Oslo, who co-wrote the paper with Sylvain Sirois of Universite du Quebec a Trois-Rivieres and Gustaf Gredeback of Uppsala University in Sweden, explained that the pupil is best known for changing size in reaction to light.

He noted that in a dark room people"s pupils open wide to let in more light, but as soon as they step outside into the sunlight, the pupils shrink to pinpricks, which keeps the retina at the back of the eye from being overwhelmed by bright light.

The expert noted that something similar happens in response to psychological stimuli, as when someone sees something they want to pay closer attention to, the pupil enlarges, though it is not clear why this happens.

One idea is that enlarging the field of the visual input is beneficial to visual exploration, he says, adding that it proves psychological scientists can use the fact that people"s pupils widen when they see something they"re interested in when conducting future studies.

Certain pupillometry technology already exists for measuring pupils, with many modern psychology studies using eye-tracking technology, to see what a subject is looking at, and Dr Laeng hopes it will to convince other psychological scientists to use this method.

by Emily Tait


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