Behavioral cusp

A behavioral cusp is any behavior change that brings an organism's behavior into contact with new contingencies that have far-reaching consequences. A behavioral cusp is a special type of behavior change because it provides the learner with opportunities to access new reinforcers, new contingencies, new environments, new related behaviors (generativeness) and competition with archaic or problem behaviors. It affects the people around the learner, and these people agree to the behavior change and support its development after the intervention is removed.

The concept has far reaching implications for every individual, and for the field of developmental psychology, because it provides a behavioral alternative to the concept of maturation and change due to the simple passage of time, such as developmental milestones. The cusp is a behavior change that presents special features when compared to other behavior changes.

The concept was first proposed by Sidney W. Bijou, an American developmental psychologist. The idea of the cusp was to link behavioral principles to rapid spurts in development (see Behavior analysis of child development).

A behavioral cusp as conceptualized by Jesus Rosales-Ruiz & Donald Baer in 1997 is an important behavior change that affects future behavior changes. The behavioral cusp, like the reinforcer, is apprehended by its effects. Whereas a reinforcer acts on a single response or a group of related responses, the effects of a behavioral cusp regulate a large number of responses in a more distant future.

The concept has been compared to a developmental milestone, however, not all cusps are milestones. For example, learning to play soccer is not a milestone, but it was life-changing for Pelé. As a result of learning to kick grapefruits (the initial important change or cusp), Pelé accessed (1) new environments, (2) new reinforcers, (3) new soccer moves, (4) dropped competing behaviors (smoking), and (5) gained international acclaims for his skill. Soccer is not a developmental milestone because it is not a necessary skill in most environments.

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