Conditioned Reinforcement: the Effectiveness of Stimulus—Stimulus Pairing and Operant Discrimination Procedures

Abstract

The purpose of the present experiment was to evaluate which method, stimulus–stimulus pairing or operant discrimination training, establishes neutral stimuli as more effective conditioned reinforcers, and to explore ways to maintain effects of the stimuli established as conditioned reinforcers. Four rats were exposed to an operant discrimination training procedure to establish a left-situated light as a conditioned reinforcer and to a stimulus–stimulus pairing procedure to establish a right-situated light as a conditioned reinforcer. Acquisition of new responses was then arranged to determine how formerly neutral stimuli could maintain responding when the unconditioned reinforcer (water) was presented intermittently in an experimental design similar to a concurrent-chain procedure. During this acquisition, two levers were concurrently available and presses on the left lever produced an operant discrimination trial (left light–response–water), whereas presses on the right lever produced a stimulus–stimulus pairing trial (right light–water). The results suggest that the operant discrimination training procedure was more effective in establishing a neutral stimulus as a conditioned reinforcer and also maintained a higher rate of responding over time.