Behavior modification is a term that applies both to an orientation to clinical problems that is conceptually consistent with experimental psychology and to a number of different behavior change techniques that have the goal of changing human behavior in a beneficial manner. The learning concepts that provide the basis for most of the behavior modification work with the mentally retarded are those derived from the operant conditioning model of Skinner and colleagues. The focus of the educational or rehabilitation program is on the overt behavior which is causing difficulty or concern to the environment in which the retarded reside. The concept of low intelligence is frequently used as an explanation for much of the behavioral inadequacies of the retarded. Education and rehabilitation personnel, however, have the alternative of viewing behavior in terms of environmental requirements and of attempting to provide those programs that will in fact influence the behavior.