Pupil Size, Information Overload, and Performance Differences

As a test of the hypothesis that pupil dilation during performance is partially due to a task related anxiety component, pupillary patterns were measured while subjects ( S s) processed digit strings of various lengths for immediate recall. Information overload resulted in a leveling of the dilation pattern which suggested a momentary suspension of processing effort. In addition, significant correlations were observed between individual differences in pupil size and recall performance.