Although past experience may operate to produce an initial increase in undesired behaviors during behavior modification procedures, the data of the present study demonstrate that these behaviors will decrease if the model is not abandoned at the point when the behavior appears to be getting worse rather than better. (Authors)

Argues that a better understanding of developmental processes is provided by three types of operant research -- laboratory behavioral descriptions, descriptions of naturalistic behavior-environment interdependencies, and predictive naturalistic studies. The usefulness of these processes are examined in light of the goals of life span developmental…