Semester

Fall

Date of Graduation

2023

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Psychology

Committee Chair

Karen G. Anderson

Committee Co-Chair

Michael Perone

Committee Member

Claire St. Peter

Committee Member

Kathleen Morrison

Committee Member

Stanley M. Hileman

Committee Member

Oliver Wirth

Abstract

Shift-work conditions are a necessity for the constant provision of certain medical, industrial, and commercial services in modern society. Shift work is associated with the increased risk of many negative health outcomes, including type 2 diabetes, heart disease, reproductive issues, and cancer. Shift workers experience multiple levels of circadian-rhythm disruption, which may increase maladaptive decision making, and this may mediate the relation between shift work and negative health outcomes. Circadian-rhythm disruptions can be systematically investigated in the basic laboratory, and one type of procedure involves changing the light/dark cycle in the animal vivarium. The current study investigated effects of light/dark cycle shifts on impulsive choice under a delay-discounting procedure using male Sprague-Dawley rats as subjects. The delay- discounting task involved discrete-trial choices between a small, immediate reinforcer and a larger, delayed reinforcer. The delay to larger-reinforcer delivery increased across blocks within each session. Larger-reinforcer choice reliably decreased as delay to delivery increased during all conditions. Overall, delay discounting was relatively stable across different light/dark cycle shifts, and there were no changes in impulsive choice during the transition from one shift to another. Any shift effects were mediated by the delay series in place for each rat. The results indicate that the current conditions may not isolate the relevant variables associated with shift work and maladaptive decision making, and future research directions to identify circadian- disruption variables that may affect impulsive choice are discussed.

Embargo Reason

Publication Pending

Download

Share

COinS