An examination of relations between baseline pupil measures and cognitive abilities

Examining individual differences in pupil size and pupillary dynamics have revealed important insights into the nature of individual differences in cognitive abilities like working memory capacity, long‐term memory, attention control, and fluid intelligence. These findings are often tied to the locus coeruleus‐norepinephrine (LC‐NE) system, as this system has a tight temporal correlation with pupil diameter. Some recent research has demonstrated positive correlations between resting pupil size and cognitive ability, specifically fluid intelligence. The present study attempted to replicate such relations. Across three studies, a large sample of participants (N = 845) completed batteries of cognitive ability measures and measures of resting pupil size and pupillary hippus (fluctuations in pupil diameter). The cognitive measures comprised tasks previously used to measure attention control, visual short‐term memory capacity, fluid intelligence, working memory capacity, and visuospatial ability. At the factor level, cognitive ability and pupil size correlated near zero. We did observe some limited evidence for a negative correlation between resting pupillary hippus and cognitive ability. Given the null findings in the present data, we encourage further replication of relations between resting pupil measures and cognitive abilities before making any strong theoretical conclusions about such relations. Recently, it has been proposed that the locus coeruleus‐norepinephrine (LC‐NE) brain system may be a crucial source of individual differences in cognitive ability and age‐related cognitive decline. LC‐NE functioning can be indirectly measured via pupil diameter. Indeed, some have proposed that one's resting pupil diameter correlates with their and intelligence. However, we find no evidence for these claims, casting doubt that resting pupil diameter can be used as a correlate of general cognitive abilities.