Priming Younger and Older Adults’ Sentence Comprehension: Insights from Dynamic Emotional Facial Expressions and Pupil Size Measures

Abstract

Background: Prior visual-world research has demonstrated that emotional priming of spoken sentence processing is rapidly modulated by age. Older and younger participants saw two photographs of a positive and of a negative event side-by-side and listened to a spoken sentence about one of these events. Older adults’ fixations to the mentioned (positive) event were enhanced when the still photograph of a previously-inspected positive-valence speaker face was (vs. wasn’t) emotionally congruent with the event/sentence. By contrast, the younger adults exhibited such an enhancement with negative stimuli only. Objective: The first aim of the current study was to assess the replicability of these findings with dynamic face stimuli (unfolding from neutral to happy or sad). A second goal was to assess a key prediction made by socio-emotional selectivity theory, viz. that the positivity effect (a preference for positive information) displayed by older adults involves cognitive effort. Method: We conducted an eye-tracking visual-world experiment. Results: Most priming and age effects, including the positivity effects, replicated. However, against our expectations, the positive gaze preference in older adults did not co-vary with a standard measure of cognitive effort - increased pupil dilation. Instead, pupil size was significantly bigger when (both younger and older) adults processed negative than positive stimuli. Conclusion: These findings are in line with previous research on the relationship between positive gaze preferences and pupil dilation. We discuss both theoretical and methodological implications of these results.