ORCID Identifier(s)

0000-0002-9938-3851

Graduation Semester and Year

Spring 2025

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Psychology

Department

Psychology

First Advisor

Hunter Ball

Second Advisor

Tracy Greer

Third Advisor

Crystal Cooper

Fourth Advisor

Jared Kenworthy

Fifth Advisor

Amandeep Dhaliwal

Abstract

The current study examined whether pupil dilations at encoding reflect cognitive effort participants engage in a task. According to the cognitive effort hypothesis of pupil dilations, increases in cognitive effort cause activation of the locus coeruleus–norepinephrine (LC-NE) system, which is reflected in larger pupil dilations. While task-evoked pupillary responses (TEPRs) have been used as a marker of cognitive effort, it remains unclear whether changes in pupil size reflect encoding success. We proposed that the reason for conflicting findings on the topic is a lack of nuance in examining cognitive effort. Specifically, we suggested that cognitive effort consists of two separate processes: quantity and quality. While quantity refers to the amount of mental processing devoted to a task, quality reflects the effectiveness and thoughtfulness of the processing utilized. Across two experiments, we utilized levels of processing (quality) and forward and backward spelling (quantity) to investigate how the quality and quantity of cognitive effort affect pupil dilations at encoding and their relationship to subsequent memory. Our results showed that a) quality and quantity are two separate processes of cognitive effort, b) pupil dilations are sensitive to the quantity, but not quality of encoding effort, and c) pupillary responses do not track subsequent memory differences between varying levels of quantity and quality of cognitive effort. The results of this study suggest that while pupil dilations reflect the amount of cognitive effort, they may not fully capture the effectiveness of encoding processes. Additionally, our findings highlight the complexity of encoding processes and suggest the need for further research into the dissociation between quantity and quality of cognitive effort in memory formation.

Keywords

memory, cognitive effort, pupillometry, levels of processing, pupillary subsequent memory effect, effort ratings, recognition

Disciplines

Cognitive Psychology | Cognitive Science

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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