Context, Ambiguity, and Unlearning: Sources of Relapse after Behavioral Extinction

Extinction is one of the most fundamental of all learning processes, and it is presumably involved in many therapies designed to reduce the pathological cognitions, emotions, or behaviors that can result from traumatic experiences. This presentation will review some basic behavioral research on classical fear conditioning and its extinction in animals with a goal of understanding how extinction actually serves to reduce anxiety or fear. Although it is tempting to assume that extinction simply destroys the original learning, even Pavlov knew this isn't true. Instead, extinction generates new learning. One implication is that it leaves fear cues with two available "meanings" in the memory store. Therefore, like responding to an ambiguous word, fear after extinction depends crucially on the current context, whether context is defined as physical background, interoceptive state, or time. Several phenomena (reinstatement, renewal, spontaneous recovery, and rapid reacquisition) follow directly from this perspective and provide important potential mechanisms for lapse and relapse. We will consider those mechanisms and their possible implications for building better behavior therapies.