Cognitivism has dominated mainstream psychology for decades, but lately its position has been weakened. It has been criticized not only by behavior analysts but also by social and evolutionary psychologists, neuroscientists, and authors who are or used to be cognitivists themselves. At the same time, psychologists and neuroscientists in several fields are now rediscovering the necessity of understanding behavior in light of its functional relations. Hence a need for relevant knowledge is felt. Cognitive psychology has little to offer in this regard. Behavior analysis, on the other hand, possesses a wealth of relevant facts and theory. Though chances seem slight that mainstream psychology will return to behaviorism, a window of opportunity now exists for the reintegration of behavior-analytic research into the mainstream.