REINFORCEMENT CONTINGENCY SHAPES EXTINCTION DYNAMICS IN PIGEONS (<EM>COLUMBA LIVIA</EM>)

Previously extinguished reactions can reappear in the form of the renewal effect. For that, extinction must have occurred in a different context. These contexts are usually reliable and highly contingent, signalling food during acquisition and no food during extinction. In this experiment, we manipulated the contingency during extinction by rarely (5%, 10%, 15% and 20%) rewarding pigeons for a correct response in an ABA extinction working memory task. Results indicate that even under the lowest contingency violation, in one out of 20 trials, pigeons did not extinguish their response anymore. Nevertheless, other behavioral markers (the reaction time and number of pecks on a stimulus) transformed throughout the extinction period. For the 5%, 10% and 15% group, those measures significantly changed, reaction times increased and number of stimulus pecks dropped, compared to the beginning of extinction. Similar results were found for the 20% group. Here, however, the behavior returned fast to pre-extinction levels. This indicates that a 20% contingency violation is surprising at first but gets re-encoded similarly to the acquisition context. Lower levels, however, are encoded differently and produce markedly different behavior, as demonstrated in the reaction times and stimulus pecks. Thus, contingency is a salient and perceivable dimension of contexts. A previously extinguished conditioned behavior can reappear, when cues in the environment change from the extinction context back to the acquisition setting. A phenomenon called the renewal effect. Further research could elucidate the effects of violated contingencies on other aspects of extinction like the renewal effect.