"Limits of sensitivity to delayed timeout from avoidance" by Chad Michael Galuska

Semester

Fall

Date of Graduation

2000

Document Type

Thesis

Degree Type

MA

College

Eberly College of Arts and Sciences

Department

Psychology

Committee Chair

Michael Perone.

Committee Co-Chair

Kennon A. Lattal

Committee Member

Stanley H. Cohen

Abstract

Session-reduction procedures have been employed to assess molar control of avoidance responding. By conceptualizing session reduction as a delayed timeout from avoidance, the present study investigated the limits of molar control while minimizing several methodological limitations inherent in such procedures. Six times during each session, a two-link chain schedule was superimposed on a baseline schedule of variable-cycle shock avoidance. Completion of the initial link (fixed-ratio 10 schedule) produced a timeout following a signaled delay during which the avoidance schedule remained operative. For most rats, the delay was manipulated across conditions from 0 s to 60 s. Control by the delayed timeout was indicated by elevated initial-link responding relative to baseline avoidance responding. Reliable initial-link elevations were obtained only when the timeout was presented immediately upon the completion of the initial link. These findings cast doubt on previous interpretations of session-reduction as molar reinforcement, and underscore the importance of response-reinforcer contiguity.

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