Operant Conditioning

Conceptual Overview

Edward L. Thorndike initiated the study of instrumental conditioning, a variant of OC, at the end of the 19th century. To investigate how animals learn new behaviors, Thorndike placed a cat in a locked puzzle box. If the cat performed the correct response (e.g., pulling a rope), the door opened and the cat would get access to food located outside the cage. In initial trials, it took a long time for the cat to emit the correct response, and the response seemed to occur by chance. However, as the cat gained experience, it would make the correct response more quickly; eventually, the correct response was emitted in a matter of seconds when the animal was placed in the cage. Based on these observations, Thorndike developed the principle of the law of effect. This law states that a behavior that is followed by pleasant consequences will be associated with the situation and will thus be more likely to occur in the future when the animal is again located in the same situation. The law of effect has a second part, that behaviors that are followed by unpleasant consequences will be weakened.

Thorndike's law of effect focused on the assumed pleasure or displeasure to explain how behavioral consequences affect future behavior. In the 1930s, B. F. Skinner reformulated this understanding; he also coined the term operant conditioning. Skinner pointed out that Thorndike's interpretation of the cat's learning was mentalistic in that it referred to assumed feelings on the part of the cat, and Skinner insisted that studies of OC should focus on functional relationships between behavior and its consequences. Also, in contrast to Thorndike, Skinner based his studies on responding in situations that allowed for free repetition of the required response (free-operant). For example, a rat could press a bar and receive food pellets for pressing. In this way, operant responding could be studied as a continuous process, without the intervention of the experimenter during sessions. Thus, Skinner focused on the flow of behavior in interaction with environmental events. He formulated a number of principles to describe such behaviorenvironment relationships, all of which have been supported by later research.

Critical Commentary and Future Directions