PT  - JOURNAL ARTICLE
AU  - Kirsten Ziman
AU  - Jeremy R. Manning
TI  - Unexpected false feelings of familiarity about faces are associated with increased pupil dilations
AID  - 10.1101/2021.02.22.432360
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.02.22.432360
4099  - http://biorxiv.org/content/early/2021/02/23/2021.02.22.432360.short
4100  - http://biorxiv.org/content/early/2021/02/23/2021.02.22.432360.full
AB  - Our subjective sense that something we encounter is familiar to us is reflected by changes in pupil size. Although pupil dilation effects of familiarity have been well documented, familiarity is not the only, or even the strongest, contributing factor to pupil dilation. Changes in pupil dilation also reflect changes in brightness, affective or emotional responses, hormonal release, expected value or utility, and surprise, among others. Because many factors can affect pupil dilation, important questions remain about how pupil dilation changes reflect high-order cognitive processes, like attention and memory. For example, because surprise and familiarity are often difficult to fully distinguish (since new experiences can be surprising or unexpected), it can be difficult to tease apart pupil dilation effects of surprise versus familiarity. To better understand the effects of surprise and familiarity on pupil dilation, we examined pupil responses during a recognition memory task involving photographs of faces and outdoor scenes. When participants rated novel face images as “familiar,” we observed a robust pupil dilation response.Competing Interest StatementThe authors have declared no competing interest.