Scientists have long believed that our eyes can give us insights into how our minds work. They use a method called “pupillometry” to measure changes in the size of the pupil in response to mental activities (Laeng et al., 2012). By using special eye-tracking systems, researchers can precisely and discreetly measure how our pupils dilate, which is the scientific term for getting bigger.
Pupil dilation is interesting to cognitive researchers because it can show how much mental effort or attention we are using (Kahneman, 1973). For example, if you have to do a difficult math problem in your head, like multiplying 36 by 49, your pupils might dilate more than if you were multiplying 6 by 9, which is easier. This dilation is a sign of how much mental energy we are using (Kahneman, 2011).
Recent studies have also shown that pupil dilation can predict brain activity related to attention and focus (Murphy et al., 2014). It reflects how our brains allocate resources to help us concentrate on a task. In sports psychology, researchers have used pupillometry to study how athletes’ attention changes over time. They found that pupil dilation can reveal the levels of focus and effort exerted by equestrian athletes of different skill levels (Moran et al, 2016).
Kahneman, D. (1973). Attention and effort. New York: Prentice-Hall.
Kahneman, D. (2011). Thinking, fast and slow. London: Macmillan.
Laeng, B., Sirois, S., & Gredeba ̈ck, G. (2012). Pupillometry: A window to the preconscious? Perspectives on Psychological Science, 7, 18 27.
Moran, A., Quinn, A., Campbell, M., Rooney, B., Brady, N., & Burke, C. (2016). Using pupillometry to evaluate atten- tional effort in quiet eye: A preliminary investigation. Sport, Exercise, and Performance Psychology, 5, 365 376.
Murphy, P. R., O’Connell, R. G., O’Sullivan, M., Robertson, I. H., & Balsters, J. H. (2014). Pupil diameter covaries with BOLD activity in human locus coeruleus. Human Brain Mapping, 35, 4140 4154.