Evocative and repertoire-altering effects of an environmental event.

The behavioral effects of environmental events can be classified as evocative when we refer to an immediate but momentary change in behavior, and as repertoire-altering when we refer to a lasting effect that can only be observed when the situation that preceded the event is again present. The stimulus between two responses in an operant chain has an evocative effect in evoking the next response (its effect as a discriminative stimulus) and a repertoire-altering effect in increasing the future frequency of the response that preceded it (its effect as a conditioned reinforcer). New terms are introduced to permit a similar dichotomy of respondent functional relations as well as hybrid relations involving the respondent pairing procedure to develop conditioned reinforcers and punishers, and conditioned establishing operations. The resulting arrangement permits the assignment of a different term to each different behavioral function, and a classification of effects that is mutually exclusive and collectively exhaustive.