Date of Award

12-1991

Degree Name

Doctor of Philosophy

Department

Psychology

First Advisor

Dr. Alan Poling

Second Advisor

Dr. Alyce M. Dickinson

Third Advisor

Dr. Jack L. Michael

Fourth Advisor

Dr. Rollin G. Douma

Abstract

The present study used a discrete-trials procedure to examine choice in pigeons presented with various three-component sequences of fixed-ratio schedules of reinforcement. An experimenter-controlled stimulus was correlated with each sequence and pigeons were presented with a specified number of forced-exposure and choice trials. Three phases were implemented in an effort to investigate the conditions under which fixed-ratios other than the first in a sequence of three affect choice. In Phase 1, pigeons were given a choice between a fixed-ratio X fixed-ratio 1 fixed-ratio 25 and a fixed-ratio X fixed-ratio 25 fixed-ratio 1 sequence of food delivery. Across conditions, X was 1, 5, 20, 35, and 50; food delivery followed completion of each fixed-ratio. Results indicated that fixed-ratios other than the first had little effect on choice. Because it was possible that the food presentations following the initial fixed-ratio in both sequences were disrupting control by the shorter second fixedratio, Phases 2 and 3 were implemented. Results of Phases 2 and 3 indicated that the food presentations following the initial fixed-ratios were disrupting sensitivity to the fixed-ratios that followed. During Phase 3, when hopper light presentations rather than food followed the initial fixed-ratios, all subjects were sensitive to fixed-ratios other than the first, and the majority of choice responses was allocated to the sequence with the shorter second fixed-ratio. Moreover, the effects of fixed-ratios other than the first depended on the size of the initial fixed-ratio. Preference for the sequence with the shorter second fixed-ratio schedule increased as the size of the initial fixed ratio decreased. These findings complement previous results with concurrent chain procedures.

Access Setting

Dissertation-Open Access

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