Psychology ETDs

Publication Date

7-23-1974

Abstract

The experiment was designed to demonstrate the transfer of a discrimination along an interoceptive stimulus continuum associated with changes in dose of Δ 9-tetrahydrocannabinol (Δ 9-THC), the major active ingredient in marihuana.

Two groups of ten male albino rats were trained on a two-bar, simultaneous choice discrimination. The prior administration of a high or a low dose of Δ 9-thcc indicated reinforcement availability on the right or left bar respectively. All drug injections were given by the I. P. route two hours before the discrimination session. Each daily session began with a variable period of extinction followed by a period of variable interval 30 sec. reinforcement on the correct bar and extinction on the incorrect bar. The experimental and control groups differed in the number and difficulty of the discriminations on which they were trained. The control group was trained exclusively on the "difficult" (3 mg/kg versus 4 mg/kg) discrimination. The experimental group was trained to a criterion of four successive sessions of responding at 70% correct or better on first an "easy" (1 mg/kg versus 6 mg/kg), then on an "intermediate" (2 mg/kg versus 5 mg/kg), and finally on the "difficult" (3 mg/kg versus 4 mg/kg) discrimination.

None of the rats in the control group learned the difficult two-dose drug discrimination. The experimental group readily learned the easy discrimination, and when finally transferred to the difficult discrimination, this group performed at well above chance levels. Thus, it was concluded that the phenomenon of transfer of a discrimination, in which pretraining on an easy discrimination facilitates performance on a subsequent difficult discrimination, was demonstrated.

The fact that similar phenomena can be demonstrated with drugs and exteroceptive stimuli supports the contention that drugs act as stimuli in stimulus control situations.

Degree Name

Psychology

Level of Degree

Masters

Department Name

Psychology

First Committee Member (Chair)

Douglas Peter Ferraro

Second Committee Member

Frank Anderson Logan

Third Committee Member

John Paul Gluck Jr.

Fourth Committee Member

Karl Peter Koenig

Sponsors

Research for this study was supported by NIMH Grant DA00355.

Language

English

Document Type

Thesis

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