Classical conditioning was first studied by physiologist Ivan Pavlov. In classical conditioning, a person or animal learns to associate a neutral stimulus (the conditioned stimulus, or CS) with a stimulus (the unconditioned stimulus, or US) that naturally produces a behaviour (the unconditioned response, or UR). As a result of this association, the previously neutral stimulus comes to elicit the same or similar response (the conditioned response, or CR).
Classically conditioned responses show extinction if the CS is repeatedly presented without the US. The CR may reappear later in a process known as spontaneous recovery.
Organisms may show stimulus generalization, in which stimuli similar to the CS may produce similar behaviours, or stimulus discrimination, in which the organism learns to differentiate between the CS and other similar stimuli.
Second-order conditioning occurs when a second CS is conditioned to a previously established CS.
Psychologist Edward Thorndike developed the law of effect: the idea that responses that are reinforced are “stamped in” by experience and thus occur more frequently, whereas responses that are punished are “stamped out” and subsequently occur less frequently.
B. F. Skinner expanded on Thorndike’s ideas to develop a set of principles to explain operant conditioning.
Positive reinforcement strengthens a response by presenting something pleasant after the response, and negative reinforcement strengthens a response by reducing or removing something unpleasant. Positive punishment weakens a response by presenting something unpleasant after the response, whereas negative punishment weakens a response by reducing or removing something pleasant.
Shaping is the process of guiding an organism’s behaviour to the desired outcome through the use of reinforcers.
Reinforcement may be either partial or continuous. Partial-reinforcement schedules are determined by whether the reward is presented on the basis of the time that elapses between rewards (interval) or on the basis of the number of responses that the organism engages in (ratio), and by whether the reinforcement occurs on a regular (fixed) or unpredictable (variable) schedule.
Not all learning can be explained through the principles of classical and operant conditioning. Insight is the sudden understanding of the components of a problem that makes the solution apparent, and latent learning refers to learning that is not reinforced and not demonstrated until there is motivation to do so.
Learning by observing the behaviour of others and the consequences of those behaviours is known as observational learning. Aggression, altruism, and many other behaviours are learned through observation.
Learning theories can be and have been applied to change behaviours in many areas of everyday life. Some advertising uses classical conditioning to associate a pleasant response with a product.
Rewards are frequently and effectively used in education but must be carefully designed to be contingent on performance and to avoid undermining interest in the activity.
Social dilemmas, such as the prisoner’s dilemma, can be understood in terms of a desire to maximize one’s outcomes in a competitive relationship.