Positive Reinforcement

Description of the Strategy

A positive reinforcer is a stimulus (e.g., item, event, experience) the presentation of which, or contact with [Page 962]which, increases the probability of (i.e., strengthens) responses that produce the presentation or contact. Positive reinforcement (PR) is the descriptive label for the relationship between the stimulus, the presentation or contact, and the change in probability. The increase in probability (or strengthening) that defines reinforcement refers to measurable changes in the dimensions of behavior (e.g., rate, duration, magnitude). PR is a ubiquitous phenomenon, and examples of positively reinforced behavior abound on every scale of human (and infrahuman) existence. Some small-scale examples include button pressing that produces desired results (e.g., elevator arrives), work that produces wages, study that produces high grades, comportment that produces praise, exercise that produces improved health and appearance, dressing that produces admiring glances, and gardening that produces attractive landscaping. Large-scale examples include higher education, theft, selling, investing, and capitalism itself. Relatedly, the range of events that can exert a PR influence is extraordinarily broad. Colloquially, any events that have even a remote possibility of being preferred over other available events have the potential to be positive reinforcers, and behavior whose purpose is the production of, or contact with, these events is said to be positively reinforced.

Despite a fairly straightforward definition that is widely available in textbooks and research literature, PR is often misunderstood and the word reinforce and its cognates misused. A common misunderstanding is that the words reinforce and reward are interchangeable. Colloquially, they may be, but technically, they are not. A reward is a reinforcer only if its presentation strengthens the behavior that produces the reward. That rewards do not always have such an effect is often used to criticize the concept of reinforcement and, indeed, operant theory itself (more on it below). This criticism is misplaced, however, because reinforcers, by definition, are consequential events that increase the probability of (i.e., strengthen) the behaviors that produce them. If events do not have a strengthening effect on behavior, they may still be rewards, but they are not reinforcers. Another common misunderstanding is that the word positive in PR refers to a quality of the reinforcing event, meaning pleasant or something preferred. Although reinforcers are often pleasant or preferred, the word positive refers to something that has been added (e.g., presented, obtained, contacted) and not to a quality. A common misuse of the term positive reinforcement involves statements that pertain to reinforcing persons (e.g., “I reinforced him for doing his chore”). PR refers to the strengthening of behavior, not persons. Persons can be rewarded, but they cannot be reinforced.

Historically, PR emerged from and was actually a primary predicate of the operant learning tradition and the work of B. F. Skinner, arguably the most influential psychologist of the 20th century. Although facts pertaining to PR were available long before Skinner, he organized the most pertinent ones, incorporated them with new facts generated by his own experiments, and developed what has come to be known as operant learning theory.

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