Resurgence, behavioral contrast, and stimuli correlated with the absence of reinforcement

Behavioral contrast and resurgence emerge following worsening of conditions of alternative reinforcement. In this experiment, the effects of stimuli correlated with nonreinforcement during extinction were compared with respect to their effects in generating resurgence and contrast within individual pigeons. Four pigeons were exposed to a two-key concurrent schedule in which a target response arranged a variable-interval (VI) 60-s schedule and an alternative response key arranged a two-component multiple VI 60-s VI 60-s schedule. In the resurgence preparation, target responding was extinguished after training before extinguishing the alternative. In the contrast preparation, both components of the multiple schedule were associated with extinction, whereas target responding was still reinforced. In both, one of the two multiple schedule stimuli was replaced by a darkened keylight. When the key associated with the alternative component was on during extinction, there was less resurgence and the magnitude of contrast was less than when the key was dark. The results replicated earlier findings of the effects of the presence or absence of stimuli on resurgence and contrast but under conditions allowing direct comparisons within individual subjects. The results both suggest a functional similarity between behavioral phenomena labeled resurgence and contrast and invite a search for other similarities.