Date of Award

Spring 1975

Document Type



Life & Environmental Sciences

First Advisor

John Christenson

Second Advisor

James Manion

Third Advisor

Alfred Murray


Swiss-Webster male, albino mice were used in either a habituation or positive reinforcement experiment to test Carlton’s (1969) suppression of behavior theory. Twenty-six mice were habituated to a beam of light presented for 5 sec with a 25 sec inter-trial period during two 10 sin sessions. Scopolamine hydrobromide (1ag/kg) or physiological saline was injected 50 min before testing 5 days later. Scopolamine reversed habituation to the light so that Session #2 differed significantly from the test session by Student’s t and Mann-Whitney 0 analysis. The test session was similiar to Session #1 suggesting scopolamine reversed habituation to the light. Thirty mice were trained on a simple approach, positive reinforcement contingency to respond to a similar beam of light during the 5 sec, 25 sec schedule in two 10 min sessions. Scopolamine caused a decrease in performance of the learned response. The effect of scopolamine on habituation and positive reinforcement could not be attributed to reduced fluid consumption, reduced motor activity or dissociation. Carlton’s suppression of behavior was supported by the habituation experiment but not by the positive reinforcement schedule.