Eyes Wide Open – Pupil Dilation and Important Information
Christopher Philip

In a study by researchers Robert Ariel and Alan Castel, it was found that pupil dilation was greater when people studied high-value information over low-value information.

The study was designed to measure how people react to and encode information of varying importance.

In the research, participants were tracked as they viewed certain words of different point values – high and low value words. The participants were told to maximize their scores after studying word lists.

“Consistent with the differential resource allocation hypothesis, participants’ pupils dilated more when studying high-valued words than when studying low-valued words and recall was also greater for high- than low-valued words,” say the researchers.

“The results suggest that learners allocate attention differently to items as a function of their value, and that multiple processes and operations contribute to value-directed remembering.”

For our purpose, what is interesting to note is that pupils opened up when viewing important information. Many other studies have found similar results indicating that pupil dilation is an important element in tracking visual attention and can be used to nonverbally track a persons interest.


Ariel, Robert and Alan D. Castel. Eyes wide open: enhanced pupil dilation when selectively studying important information. Exp Brain Res. 2014. 232 :337–344
DOI 10.1007/s00221-013-3744-5