1) A procedure in which the reinforcement of a previously reinforced behavior is discontinued. Also may be used to describe the "process" by which a previously learned behavior disappears as a result of nonreinforcement.

2) Withholding the reinforcers that maintain a target behavior.

3) In operant behavior, discontinuing the reinforcement of a response (or the reduction in responding that follows this operation). In negative reinforcement (escape and avoidance), extinction has often referred to the discontinuation of aversive stimuli, although the term applies more appropriately to discontinuing the consequences of responding. Aversive stimuli are presented but responses no longer prevent them. The discontinuation of punishment (see RECOVERY) is rarely referred to as a variety of extinction. In respondent conditioning, extinction is presenting the CS without, or no longer in a contingent relation to, the US (or the discontinuation in conditioned responding that follows this operation).

4) The procedure of extinction involves the breaking of the contingency between an operant and its consequence. For example, a bar press that was followed by food reinforcement no longer produces food. As a behavioral process, extinction refers to a decline in the frequency of the operant when an extinction procedure is in effect. In both instances, the term extinction is used correctly.

5) Stopping the reinforcement or escape contingency for a previously reinforced response causes the response rate to decrease.

6) Extinction refers to a procedure in which reinforcement of a previously reinforced operant performance is discontinued. Thus, if a performance has previously occurred with a certain frequency because it has produced food, we describe the situation as extinction when the performance is no longer followed by food. The use of the term here is specifically limited to the procedure of discontinuing reinforcement. The usual and most prominent effect of extinction is to decrease the frequency of a performance. Thus the effect of extinction on the organism's performance occurs as a result of each unreinforced emission of the performance. If the animal has no opportunity to engage in the behavior, then the term extinction is inappropriate. When a previously conditioned performance is extinguished (no longer reinforced), it generally occurs initially with a high frequency and then falls continuously until its rate reaches near zero. Occasionally, the rate of a performance may actually increase (although temporarily) when the performance is no longer reinforced. Such cases make it even more important to use the term extinction to describe the procedure of discontinuing reinforcement rather than as a description of a change in the animal's performance. Otherwise, we would be in the unfortunate position of saying, "The performance was extinguished, but it did not extinguish."

7) The procedure by which an event that followed a behavior in the past is not reinforced and the probability (or rate) of the behavior decreases.

8) A process in which a response is repeated without reinforcement. When we extinguish a behavior, we withhold the reinforcement that has maintained that behavior in the past so that responses go unreinforced. Note that extinguish is not the same as eliminate. There are many ways of eliminating a behavior besides extinction.

9) There is no definition currently available.