Efecto de recuperacion de la respuesta extinta

Bouton, M.E. (1988). Context and ambiguity in the extinction of emotional learning: Implications for exposure therapy. Behaviour Research & Therapy, 26(2), 137-149.

CONTEXT AND AMBIGUITY IN THE EXTINCTION OF EMOTIONAL LEARNING: IMPLICATIONS FOR EXPOSURE THERAPY
MARK E. BOUTON
Summary—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 isanalogous 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 canbe 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 forcontext in the extinction process and have a number of novel implications for exposure therapy and relapse after treatment.

In most therapies used in the treatment of anxiety disorders, the client or patient receives extensive exposure to the fear-evoking stimulus as a part of the clinical treatment (e.g. Foa and Kozak, 1986; Marks, 1978). Exposure appears to be an important component of therapy;by itself it may account for a large part of the efficacy of many interventions (e.g. Marks, 1978). Because Pavlovian fear conditioning is often assumed to be involved in the acquisition of anxiety disorders (e.g. Wolpe, 1958), the effect of exposure is often linked to the process of extinction. That is, if fear of the evoking stimulus (a conditioned stimulus, or CS) is due to an experience inwhich it was associated with a traumatic event or experience (an unconditioned stimulus, or US), then exposure to the stimulus by itself should extinguish the conditioned fear. Other mechanisms besides simple conditioning and extinction are no doubt also involved in the etiology and treatment of anxiety disorders (e.g. Bandura, 1977; Beck and Emery, 1985; Jacobs and Nadel, 1985; Mineka, 1985a,b). Butrecent research on the extinction of conditioned emotional responding in animals may have some heuristic value to clinicians. Much of the research to be described was concerned with how contexts, or the places or environments in which conditioned stimuli are encountered, can influence fear of conditioned fear Stimuli. In the animal learning laboratory, the question can be approached byinvestigating how a rat's fear of a tone that has been associated with a mildly aversive footshock can be affected by what the rat 'knows' about the experimental box (i.e. context) in which the tone is presented during a test. We discovered an unusual and interesting thing about contexts over the course of experimentation in my own laboratory. Namely, what the subject knew about the context often hadsurprisingly little effect on its fear of the tone. But when fear of the tone had undergone extinction prior to testing, the context was important indeed; fear of an extinguished tone could easily return depending on what the rat knew about the test context. The extinction procedure eliminated signs of fear, but not its underlying basis. As much as anything, it created a stimulus whose fear was...