Acquisition of the Token-Reward Habit in the Rat

Abstract

Apparatus and procedure for establishing tokens as conditioned reinforcers in laboratory rats are described. Five rats were initially trained to deposit tokens (marbles) into a receptacle with each deposit response producing primary reinforcement. The rats then underwent discrimination training during which deposit responses were reinforced only in the presence of a clicker and localized illumination of the receptacle. Errorless performance was obtained within one to three sessions. The rats were next trained to press a lever in order to obtain the tokens from a dispenser. Initially, each lever-press response produced token delivery, and each token was immediately exchangeable for food. The schedules of token delivery were gradually increased to fixed-ratio and variable-interval schedules. Performance under these schedules was comparable to performance under similar schedules of primary reinforcement.