There has been considerable interest lately in cases where instrumental conditionability appears to depend on the reinforcer used. Here the effects of Pavlovian conditioned stimuli (CSs)on golden hamster behaviors was observed. The intent was to see whether previously reported differences among the behaviors produced by food reinforcement and…

Three experiments carried out second-order Pavlovian conditioning using either similar or dissimilar first-and second-order stimuli. All three experiments were designed to identify the effects of similarity upon conditioning as distinct from its effects upon sensitization or stimulus generalization. (Editor/RK)