Publication Date


Advisor(s) - Committee Chair

James Craig, Leroy Metze, Sam McFarland

Degree Program

Department of Psychology

Degree Type

Master of Arts


Eighteen rats were divided into equal groups which received three different food deprivation procedures: 23 hour deprivation, maintenance at 80% of pre-experimental weights, or fixed daily food allotments of 10 grams. The rats were then given two training sessions with an unearned food source and 15 training sessions earning an identical food source by pressing a lever. Training was followed by three days of choice testing. There were no significant differences between groups in preference for earned rewards during choice testing in degrees of weight loss. However, a correlation comparing propensity to work for pellets with body weight deficit over the last eight training days was significant (p < .05). Group correlations of weight loss with propensity to barpress resulted in significance only for the fixed intake animals (p .05). The significant relationship between weight loss and operant performance is consistent with the earlier findings of Bolles (1965). The timed deprivation group had the greatest range in level of weight deficit and the percentage body weight group had the least. These findings indicate that maintaining animals at a designated percentage of their normal body weight produces less within group variance in the level of weight deficit than the more popular method of timed deprivation.


Experimental Analysis of Behavior | Psychology | Social and Behavioral Sciences