Operant conditioning

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Operant conditioning, also called instrumental conditioning, is a learning process where voluntary behaviors are modified by association with the addition (or removal) of reward or aversive stimuli. The frequency or duration of the behavior may increase through reinforcement or decrease through punishment or extinction.

Operant conditioning originated in the work of Edward Thorndike, whose law of effect theorised that behaviors arise as a result of whether their consequences are satisfying or discomforting. In the 20th century, operant conditioning was studied by behavioral psychologists, who believed that much, if not all, of mind and behaviour can be explained as a result of environmental conditioning. Reinforcements are environmental stimuli that increase behaviors, whereas punishments are stimuli that decrease behaviors. Both kinds of stimuli can be further categorised into positive and negative stimuli, which respectively involve the addition or removal of environmental stimuli.

Operant conditioning differs from classical conditioning, which is a process where stimuli are paired with biologically significant events to produce involuntary and reflexive behaviors. In contrast, operant conditioning is voluntary and depends on the consequences of a behavior.

The study of animal learning in the 20th century was dominated by the analysis of these two sorts of learning,[1] and they are still at the core of behavior analysis. They have also been applied to the study of social psychology, helping to clarify certain phenomena such as the false consensus effect.[2]

Operant conditioningExtinction
Reinforcement
Increase behavior
Punishment
Decrease behavior
Positive reinforcement
Add appetitive stimulus
following correct behavior
Negative reinforcementPositive punishment
Add noxious stimulus
following behavior
Negative punishment
Remove appetitive stimulus
following behavior
Escape
Remove noxious stimulus
following correct behavior
Active avoidance
Behavior avoids noxious stimulus

History

Edward Lee Thorndike in 1912

Thorndike's law of effect

Operant conditioning, sometimes called instrumental learning, was first extensively studied by

Edward L. Thorndike (1874–1949), who observed the behavior of cats trying to escape from home-made puzzle boxes.[3] A cat could escape from the box by a simple response such as pulling a cord or pushing a pole, but when first constrained, the cats took a long time to get out. With repeated trials ineffective responses occurred less frequently and successful responses occurred more frequently, so the cats escaped more and more quickly.[3] Thorndike generalized this finding in his law of effect, which states that behaviors followed by satisfying consequences tend to be repeated and those that produce unpleasant consequences are less likely to be repeated. In short, some consequences strengthen behavior and some consequences weaken behavior. By plotting escape time against trial number Thorndike produced the first known animal learning curves through this procedure.[4]

Humans appear to learn many simple behaviors through the sort of process studied by Thorndike, now called operant conditioning. That is, responses are retained when they lead to a successful outcome and discarded when they do not, or when they produce aversive effects. This usually happens without being planned by any "teacher", but operant conditioning has been used by parents in teaching their children for thousands of years.[5]

B. F. Skinner

B.F. Skinner at the Harvard Psychology Department, circa 1950