However by the 1960s, Behaviorism was slipping out of favor, both among academic researchers and among applied psychologists who looked to the lab for guidance in developing new therapeutic tools. Valuable as they had been, respondent and operant conditioning didn't go far enough in explaining human behavior. As a result, Behavioral Therapy couldn't go far enough either. Too much was missing and unaccounted for, and most of what was missing was the role of cognitive processes such as thoughts, beliefs, assumptions, attitudes, memories, mental imagery and fantasies. As time went both in research settings and in the therapeutic trenches behaviorism gave way to the cognitive revolution in psychology.
Early Behavioral Therapy was often understood to be based on the stimulus-response model of classical behaviorism. Focusing on observable events had the advantage of discouraging speculation about inner, hidden processes that need to be inferred because they can't be directly observed. It thus avoided the kind of rampant guesswork that had led psychoanalysis so far astray. However in the end, it became accepted that the S-R approach was leaving too many important thi