Fears conditioned by association tend to be short-lived. Most conditioned reflexes will weaken and disappear after a few exposures to the fear-provoking event, quite unlike the more persistent fear and avoidance behavior that we call a phobia. One important finding may, however, help to resolve this problem and explain how a conditioned fear response could persist and become a phobia. Avoidance of a feared situation blocks the normal process of unlearning the fear response.
