Context and ambiguity in the extinction of emotional learning: Implications for exposure therapy

Abstract

The effect of exposure therapy on anxiety disorders is often attributed to the Pavlovian extinction of fear. The present article reviews some recent animal research that suggests a role for environmental context in fear extinction and conditioning. Although extinction exposure to a conditioned stimulus (CS) clearly reduces fear of the CS, even prolonged exposure typically leaves the CS with fear-evoking power that can relapse under certain conditions. It is argued that the CS after extinction is analogous to an ambiguous word: the response it evokes is unusually dependent on its context. Empirical support for this view is presented and discussed. When an extinguished fear stimulus is presented in a context that itself arouses fear, fear can be ‘reinstated’ to the CS. In addition, removing the CS from the context in which extinction has occurred can cause a ‘renewal’ of fear; fear extinction can be specific to its context. Fear of a CS that has never been extinguished is not as sensitive to these effects of context; for example, fear conditioning itself is not usually context-specific. Instead of causing an ‘unlearning’ of fear, extinction gives the CS a mixed, ambiguous meaning that is strongly affected by context. This view, and other empirical findings, suggest an important role for context in the extinction process and have a number of novel implications for exposure therapy and relapse after treatment.