Skinner has assigned the persistence of cognitive explanations to the literature of freedom and dignity. This view is challenged especially as it applies to behavioral scientists. It is argued that cognitive explanations persist because current behaviorism does not challenge cognitive epistomology; because behavior analysts have failed to provide research evidence at the level of human behavior, and finally because a science of behavior based solely on operant principles is necessarily incomplete. The implications of these problems for behavior analysis are addressed.

Activity anorexia illustrates selection of behavior at the biological, behavioral, and neural levels. Based on evolutionary history, food depletion increases the reinforcement value of physical activity that, in turn, decreases the reinforcement effectiveness of eating – resulting in activity anorexia. Neural opiates participate in the selection of physical activity during periods of food depletion.

Activity anorexia illustrates selection of behavior at the biological, behavioral, and neural levels. Based on evolutionary history, food depletion increases the reinforcement value of physical activity that, in turn, decreases the reinforcement effectiveness of eating – resulting in activity anorexia. Neural opiates participate in the selection of physical activity during periods of food depletion.