A model for recovery-from-extinction effects in Pavlovian conditioning and exposure therapy

Exposure therapy is an effective intervention for anxiety-related problems. The mechanism of this intervention has been the extinction procedure in Pavlovian conditioning, and this application has provided many successful instances for the prevention of relapse. However, traditional associative theories cannot comprehensively explain many findings. In particular, it is difficult to explain the recovery-from-extinction effects, which is the reappearance of the conditioned response following extinction. In this paper, we propose an associative model that is a mathematical extension of Bouton's (1993, Psychological Bulletin, 114, 80-99) model for the extinction procedure. The core of our model is that the asymptotic strength of the inhibitory association depends on the degree of excitatory association retrieved in a context in which a conditioned stimulus (CS) is presented and that the retrieval is determined by the similarity between contexts during both reinforcement and non-reinforcement and the retrieval context. Our model provides an explanation of the recovery-from-extinction effects, and implications for exposure therapy.