Transfer of learning across reinforcers: Appetitive discrimination learning between stimuli previously associated with shock

In each of two experiments rats learned a food-rewarded discrete-trial discrimination in which the correct response in a two-lever Skinner box was signalled by an external stimulus. For one (experimental) group of subjects, one of the stimuli had previously been associated with electric shock while the other had been used to signal the absence of shock. A control group had previously experienced the stimuli uncorrelated with shock. In both experiments its was found that the control subjects learned the discrimination more rapidly than experimental subjects. The relevance of these findings to theories of the acquired distinctiveness of cues and to accounts of interaction between appetitive and aversive motivational systems is discussed.