Conditioned enhancement as a function of the percentage of CS-US pairings and CS duration

Abstract

Eighteen rats were trained to barpress on a variable interval 90-sec schedule of sucrose-solution reinforcement. Ss were then divided into three groups (N = 6) and exposed to a classical conditioning contingency while barpressing, in which a 2-min light CS preceded the delivery of a food pellet US on either 100%, 66%, or 33% of the CS presentations. When the response rate during the CS was compared to response rate prior to the CS, it was found that the CS response rate was directly related to the percentage of US presentation. When the CS duration was changed to 8 sec, the highest CS response rates were associated with the partial pairing of CS and US. © 1974, The Psychonomic Society, Inc.. All rights reserved.