Pupil Size Predicts Your Next Move

Your eye size may actually show if you're about to make an important decision, according to recent findings published in the journal PLOS Computational Biology.

By monitoring the moment-to-moment fluctuation of pupil size in laboratory participants, researchers found that larger pupil size is typically indicative of poorer upcoming task performance. Furthermore, people with the largest pupils overall also tended to be the least consistent when making decisions.

The latest findings actually suggest that our pupils may reflect our state of responsiveness. For instance, size could be used to help determine the variability of decisions we make in the world. Furthermore, studies reveal that decision-making appears to be less sharp and more likely to lead to undesirable outcomes during hyper-responsiveness.

Researchers measured 26 participants' pupil sizes before each segment of an experiment in order to reveal decision precision. They were asked to perform visual choice-based tasks that mimic the kinds of challenging perceptual decisions frequently faced in everyday life.

"We are constantly required to make decisions about the world we live in. Researchers have long known that the accuracy and reliability of such everyday decision making can be tremendously variable for different people at different times, but we understand quite little about where this variability comes from. In this study, we show that how precise and reliable a person is in making a straightforward decision about motion can be predicted by simply measuring their pupil size. This finding suggests that the reliability with which an individual will make an upcoming decision is at least partly determined by pupil-linked 'arousal' or alertness, and furthermore, can potentially be deciphered on the fly. This new information could prove valuable for future research aimed at enhancing the precision of decision making in real time," concluded lead study author Peter Murphy at Leiden University, in a news release.

More information regarding the findings can be seen via the journal PLOS Computational Biology.