Semester

Fall

Date of Graduation

2021

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Psychology

Committee Chair

Kennon Lattal

Committee Member

Barry Edelstein

Committee Member

Genae Hall

Committee Member

Kathryn Kestner

Committee Member

Michael Perone

Abstract

Reinforcer magnitude is one of several parameters of reinforcement. In the present study, it referred to the quantitative value of the reinforcer in terms of duration of access to a finite supply of grain pellets. Pigeons responded on concurrent-chain schedules earning one of several reinforcer durations depending on response allocation and experimental conditions. Experiment 1 consisted of relatively long reinforcer durations available for completing one chain compared to relatively short durations available on the other. Response allocation in the initial link determined the reinforcer duration, but responses in the terminal link produced no change in the upcoming reinforcer. This arrangement allowed for the comparison of response-correlated and experimenter-controlled changes in reinforcer magnitude in terms of the control by reinforcer magnitude they produced. Additional changes in reinforcer durations were programmed between experimental conditions to allow for comparisons of within-sessions and between-conditions changes in magnitude as well. Experiment 2 was procedurally similar to the first, but the total reinforcer duration was identical for each chan. Instead, reinforcer durations were segmented into bins on one chain and kept continuous on the other (e.g., two 4-s reinforcers separated by a brief blackout period compared to one, continuous 8-s reinforcer). Control by reinforcer magnitude was most apparent when changes were response correlated and within-sessions, but behavior change was also observed on the between-conditions scale. No magnitude effects were observed in changes in magnitude were experimenter controlled (i.e., not correlated to behavior). Further, the observed effects seemed to be mediated by eating efficiency. It is recommended that future research on reinforcer magnitude include thorough measurement of the consummatory chain to fully describe the role of eating efficiency in control by reinforcer magnitude.

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