Masters Theses

Date of Award

8-2025

Degree Type

Thesis

Degree Name

Master of Arts

Major

Experimental Psychology

Major Professor

Shannon Ross-Sheehy

Committee Members

Greg Reynolds, Jessica Hay, Caglar Tas

Abstract

Environments have an overwhelming amount of visual input, therefore requiring a system that works diligently to select and filter the most relevant, or salient, information. Posner and colleagues posited a spatial “attentional spotlight” that is shifted by the viewer to new locations either accompanied by an eye movement, overtly, or while eyes are fixated elsewhere, covertly. These covert attentional shifts typically precede an eye movement facilitating efficient visual scanning. This critical component of pre-verbal learning develops around 4-months in infants. Adult research pairs behavioral responses with verbal or button box responses to determine the speed and capabilities of covert orienting. The purpose of this study was to pair traditional reaction time and accuracy measures with pupillometry to further inspect developmental and conditional differences of covert orienting across infancy. A linear mixed effect (LME) model revealed that pupil dynamics were reflective of developmental differences, with older infants showing significantly greater dilation than younger infants across multiple conditions. Further, conditions that required inhibition and re-orienting showed significantly greater dilations when compared to both the baseline (no visual cue condition) and the valid cue conditions. Taken together, results from this study suggest pupillometry may bea sensitive marker of attentional orienting, though dilation may be more reflective of saccade inhibition and attention re-orienting.

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