In psychology, ‘extinction’ is said to occur if a conditioned response gradually weakens so as to lead to the decrease or disappearing of a behaviour. In terms of classical conditioning, extinction occurs when the unconditioned stimulus is discontinued such that the conditioned stimulus is no longer paired with it. In terms of operant conditioning, extinction occurs when a response is no longer reinforced following a discriminative stimulus.Some recent research indicates that extinction may also occur due to habituation, subject to attentiveness.
A related phenomenon, called extinction burst, is likewise out of scope of reinforcement theory but is explained by control theory. The eventual decrease of the behaviour getting extinguished may exhibit, in the short term, a sudden spike of an increase in frequency, before continuing to steadily decrease. It provides an evolutionary advantage that is otherwise not conferred on creatures that ‘give up’ too easily.
The phenomenon of extinction is often leveraged in anxiety treatment programs and related therapies (such as those for PTSD).