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Sensitivity of preference to reinforcement amount depends upon the method used to manipulate amount

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
David R. Maguire (Creator)
The University of North Carolina Wilmington (UNCW )
Web Site:
Raymond Pitts

Abstract: Four pigeons were trained on concurrent variable-interval 30-s schedules. Relative reinforcer amounts arranged across the two alternatives was varied. During Experiment 1, sessions consisted of a mixed concurrent schedule with different ratios of reinforcer amounts arranged for the two alternatives across components. Sessions consisted of 5 components that differed only with respect to the relative reinforcer amounts arranged for each alternative. Reinforcer amount was manipulated by presenting an arranged number of brief (1.2-s) hopper presentations. The amounts presented ranged from one to five presentations and the ratios used were 1/5, 2/4, 3/3, 4/2, and 5/1 (L/R). The order of ratios within each session was randomly determined, and there were no exteroceptive stimuli signaling the particular ratio in effect. After 60 sessions of training, responding for all subjects remained insensitive to reinforcer amount ratios. During Experiment 2, relative reinforcer was held constant within and across sessions until responding became stable, at which point, the absolute amounts arranged for each alternative were switched. The ratios used were 1/7 and 7/1 hopper presentations. After six sessions in each condition, all subjects showed an appreciable shift in preference toward the alternative providing the larger amount, and asymptotic sensitivity was comparable to previous reports using a similar procedure. During Experiment 3, sessions were identical to those used during Experiment 2, except that the amount ratio (either 1/7 or 7/1) presented during each session changed from session to session according to a pseudorandom binary sequence (cf., Hunter & Davison, 1985). After 30 sessions, response ratios within each session for all subjects began to shift in the direction of the amount ratio in effect for that session (i.e., subjects’ responding showed a moderate increase in sensitivity to reinforcer amount). Characteristics of responding under this procedure were quite similar to responding procedures under which reinforcer rate and delay were manipulated in much the same fashion. The procedure used in Experiment 3 may serve as a method for studying the effects of certain environmental manipulations (e.g., drug administration) on sensitivity to reinforcer amount.

Additional Information

A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Arts
Language: English
Date: 2009
Animal experimentation, Pigeons--Experiments, Reinforcement (Psychology)
Reinforcement (Psychology)
Pigeons -- Experiments
Animal experimentation