Some Data on the Discriminative Stimulus Hypothesis of Secondary Reinforcement

Pigeons pecked at either of two response keys on variable-interval (VI) schedules to produce a secondary reinforcer associated with that key. The secondary reinforcer was a discriminative stimulus for responding to obtain food on fixed-ratio (FR) schedules. The discriminative stimulus value of the stimulus was weakened by extinction (Experiment I) or by “ratio strain” (Experiment II). Although the stimulus was no longer a discriminative stimulus for responding in its presence, it continued to reinforce responding to obtain it.