However, the cognitive revolution did not kill behaviorism as a research program; in fact, research on operant conditioning actually grew at a rapid pace during the cognitive revolution.[1] In 1994, scholar Terry L. Smith surveyed the history of radical behaviorism and concluded that "even though radical behaviorism may have been a failure, the operant program of research has been a success. Furthermore, operant psychology and cognitive psychology complement one another, each having its own domain within which it contributes something valuable to, but beyond the reach of, the other."[1]:xii