Introduction (Psychology and Mental Health)
The casual, everyday use of the word “reinforcement” generally refers to the granting of a reward for some behavior. While the use of this term by psychologists is more formal, a great deal of research has been dedicated to studying the effects of rewards on behavior. The most influential of the early studies were those done in the 1890’s by American psychologist Edward L. Thorndike. Thorndike created a problem box from which a hungry cat could escape by performing a specific action, such as pulling on a wire, stepping on a pedal, or some similar behavior, thereby gaining access to food. From these studies Thorndike proposed his famous law of effect; that is, actions that are followed by satisfying events are more likely to recur while actions that are followed by discomfort will become less likely. The more satisfying or the more discomfort, the greater the effect on subsequent behavior.
Not all psychologists have used the word “reinforcement” to describe the same processes. In research where he conditioned dogs to salivate to tones, the Russian physiologist Ivan Petrovich Pavlov called pairing a stimulus (food) that automatically elicits a response (salivation) to a new stimulus (a tone) reinforcing; that is, the food reinforced the ability of the tone to generate the same response. This process has come to be known as Pavlovian conditioning. Unlike Thorndike, who was referring to consequences after the organism...
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Modern Definitions (Psychology and Mental Health)
To maintain a reasonable degree of consistency, most psychologists use the term “reinforcement” exclusively for a process of using rewards to increase voluntary behavior. The field of study most associated with this technique is instrumental conditioning. In this context, the formal definition states that a reinforcer is any consequence to a behavior that is emitted in a specified situation that has the effect of increasing that behavior in the future. It must be emphasized that the behavior itself is not sufficient for the consequence to be delivered. The circumstances in which the behavior occurs are also important. Thus, standing and cheering at a basketball game will likely lead to approval (social reinforcement), whereas this same response is not likely to yield acceptance if it occurs at a funeral.
A punisher is likewise defined as any consequence that reduces the probability of a behavior, with the same qualifications as for reinforcers. A behavior that occurs in response to a specified situation may receive a consequence that reduces the likelihood that it will occur in that situation in the future, but the same behavior in another situation would not generate the same consequence. For example, drawing on the walls of a freshly painted room would usually result in an unpleasant consequence, whereas the same behavior (drawing) in one’s coloring book would not.
The terms “positive” and “negative”...
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Types of Reinforcers (Psychology and Mental Health)
The range of possible consequences that can function as reinforcers is enormous. To make sense of this assortment, psychologists tend to place them into two main categories: primary reinforcers and secondary reinforcers. Primary reinforcers are those that require little, if any, experience to be effective. Food, drink, and sex are common examples. While it is true that experience will influence what would be considered desirable for food, drink, or an appropriate sex partner, there is little argument that these items, themselves, are natural reinforcers. Another kind of reinforcer that does not require experience is called a social reinforcer. Examples are social contact and social approval. Even newborns show a desire for social reinforcers. Psychologists have discovered that newborns prefer to look at pictures of human faces more than practically any other stimulus pattern, and this preference is stronger if that face is smiling. Like the other primary reinforcers, experience will modify the type of social recognition that is desired. Still, it is clear that most people will go to great lengths to be noticed by others or to gain their acceptance and approval.
Though these reinforcers are likely to be effective, most human behavior is not motivated directly by primary reinforcers. Money, entertainment, clothes, cars, and computer games are all effective rewards, yet none of these would qualify as natural or primary...
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Why Reinforcers Work (Psychology and Mental Health)
Reinforcers (and punishers) are effective at influencing an organism’s willingness to respond because they influence the way in which an organism acquires something that is desired, or avoids something that is not desired. For primary reinforcers, this concerns health and survival. Secondary reinforcers are learned through experience and do not directly affect one’s health or survival, yet they are adaptive because they are relevant to those situations that are related to well-being and an improved quality of life. Certainly learning where food, drink, receptive sex partners, or social acceptance can be located is useful for an organism. Coming to enjoy being in such situations is very useful, too.
An American psychologist, David Premack, has argued that it is the opportunity to engage in activity, and not the reinforcer itself, that is important; that is, it is not the food, but the opportunity to eat that matters. For example, he has shown that rats will work very hard to gain access to a running wheel. The activity of running in the wheel is apparently reinforcing. Other researchers have demonstrated that monkeys will perform numerous boring, repetitive tasks to open a window just to see into another room. This phenomenon has come to be known as the Premack principle. Premack explains that any high-probability activity can be used to reinforce a lower-probability behavior. This approach works for secondary...
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Patterns of Reinforcer Delivery (Psychology and Mental Health)
It is not necessary to deliver a reinforcer on every occurrence of a behavior to have the desired effect. In fact, intermittent reinforcement has a stronger effect on the stability of the response rate than reinforcing every response. If the organism expects every response to be reinforced, suspending reinforcement will cause the response to disappear very quickly. If, however, the organism is familiar with occasions of responding without reinforcement, responding will continue for much longer on the termination of reinforcers.
There are two basic patterns of intermittent reinforcement: ratio and interval. Ratio schedules are based on the number of responses required to receive the reinforcer. Interval schedules are based on the amount of time that must pass before a reinforcer is available. Both schedules have fixed and variable types. On fixed schedules, whatever the rule is, it stays that way. If five responses are required to earn a reinforcer (a fixed ratio 5, or FR 5), every fifth response is reinforced. A fixed interval ten seconds (FI 10) means that the first response after ten seconds has elapsed is reinforced, and this is true every time (responding during the interval is irrelevant). Variable schedules change the rule in unpredictable ways. A VR 5 (variable ratio 5) is one in which, on the average, the fifth response is reinforced, but it would vary over a series of trials. A variable interval ten...
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Sources for Further Study (Psychology and Mental Health)
Flora, Stephen Ray. The Power of Reinforcement. Albany: State University of New York Press, 2004. Emphasizes the use of reinforcement for improving behavior.
Hilgard, Ernest Ropiequet. Psychology in America: A Historical Review. San Diego, Calif.: Harcourt Brace Jovanovich, 1987. An excellent text describing the history and development of all facets of psychology. Chapters 3, 6, and portions of 10 are especially relevant to reinforcement.
Kimble, Gregory A. Hilgard and Marquis’ Conditioning and Learning. 2d ed. New York: Appelton-Century-Crofts, 1968. Though somewhat dated and fairly advanced, this text gives an excellent and thorough review of the field of learning theory.
Kimble, Gregory A., Michael Wertheimer, and Charlotte L. White, eds. Portraits of Pioneers in Psychology. Washington, D.C.: America Psychological Association, 1991. This is an edited text with various authors describing the lives and contributions of the most important theorists from the early days of psychology. Most of the authors were personally familiar with their subjects, giving an interesting personal view. Especially relevant are the essays on Pavlov and Thorndike.
Lieberman, David A. Learning: Behavior and Cognition. 3d ed. Belmont, Calif.: Wadsworth, 2000. This is a college-level text for advanced psychology students, but it gives a very strong review of modern learning...
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Reinforcement (Encyclopedia of Mental Disorders)
A reinforcer is a stimulus that follows some behavior and increases the probability that the behavior will occur. For example, when a dog's owner is trying to teach the dog to sit on command, the owner may give the dog a treat every time the dog sits when commanded to do so. The treat reinforces the desired behavior.
In operant conditioning (as developed by B. F. Skinner), positive reinforcers are rewards that strengthen a conditioned response after it has occurred, such as feeding a hungry pigeon after it has pecked a key. Negative reinforcers are stimuli that are removed when the desired response has been obtained. For example, when a rat is receiving an electric shock and presses a bar that stops the shock, the shock is a negative reinforcerit is an aversive stimulus that reinforces the bar-pressing behavior. The application of negative reinforcement may be divided into two types: escape and avoidance conditioning. In escape conditioning, the subject learns to escape an unpleasant or aversive stimulus (a dog jumps over a barrier to escape electric shock). In avoidance conditioning, the subject is presented with a warning stimulus, such as a buzzer, just before the aversive stimulus occurs and learns to act on it in order to avoid...
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Reinforcement (Encyclopedia of Psychology)
In either classical or operant conditioning, a stimulus that increases the probability that a particular behavior will occur.
In classical (Pavlovian) conditioning, where the response has no effect on whether the stimulus will occur, reinforcement produces an immediate response without any training or conditioning. When meat is offered to a hungry dog, it does not learn to salivate, the behavior occurs spontaneously. Similarly, a negative reinforcer, such as an electric shock, produces an immediate, unconditioned escape response. To produce a classically-conditioned response, the positive or negative reinforcer is paired with a neutral stimulus until the two become associated with each other. Thus, if the sound of a bell accompanies a negative stimulus such as an electric shock, the experimental subject will eventually be conditioned to produce an escape or avoidance response to the sound of the bell alone. Once conditioning has created an association between a certain behavior and a neutral stimulus, such as the bell, this stimulus itself may serve as a reinforcer to condition future behavior. When this happens, the formerly neutral stimulus is called a conditioned reinforcer, as opposed to a naturally positive or negative reinforcer, such as food or an electric shock.
In operant conditioning (as developed by...
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Reinforcement (Encyclopedia of Drugs, Alcohol, and Addictive Behavior)
Although the term reinforcement has many common uses and associated meanings, its meaning is precise when used by behavior analysts and behavior therapists. The act or process of making a reinforcer contingent on behavior is termed positive reinforcement, and a reinforcer is any object or event that, when delivered following some behavior, increases the probability that the behavior will occur again. A typical example might evolve from a laboratory experiment with rats. A rat is placed in a small plastic chamber. The rat can press a lever located on one wall of the chamber. When the rat presses the lever, a small food pellet drops into a dish. If the rat returns to the lever and continues to press it would be said that the food pellet functions as a reinforcer that the behavior is maintained by positive reinforcement.
There is often confusion between positive reinforcement and negative reinforcement. Negative reinforcement occurs when a behavior results in terminating an aversive stimulus. In the case of the rat, the negative stimulus might be a loud noise. A lever press turns off the stimulus. If the rat continues to press the lever, it would be said that loud noise functions as a negative reinforcer and the behavior is maintained by negative reinforcement. Thus, both positive and negative reinforcement refer to increases in behavior, but differ in whether a pleasant stimulus is presented as the result of some behavior (positive reinforcement). Negative reinforcement is also referred to as escape (if the response turns off the stimulus each time it appears) or avoidance (if the response can postpone presentation of the stimulus).
It is important to note that reinforcement is a concept that refers to the relationship between behavior and its consequences. Stimuli or events are not assumed to have inherent reinforcing effects. For example, although most people like money and will continue to exhibit behavior that results in obtaining money, it cannot be assumed that money functions as a reinforcer for everyone. For example, money might not serve as a reinforcer for a monk devoted to an ascetic lifestyle. The defining characteristic of reinforcement depends on how a behavior is changed and not on the types of things that serve as reinforcing events (Morse & Kelleher, 1977). Factors that help determine whether a given object or event is reinforcing or punishing for a given individual include that individual's previous experiences and other features of the environment that coexist and are associated with the object or event. The upshot is that different things may function as reinforcers for different people.
DRUGS can serve as reinforcers that maintain drug-seeking and drug-taking behaviors. This can be observed in the prevalence of drug use among humans and has also been shown in laboratory research with animals. In a typical laboratory experiment, the animal such as a rat or monkey has a catheter placed in a vein and connected to a pump-driven syringe. The animal can press a lever to activate the pump, and this results in a dose of a drug such as COCAINE, HEROIN, NICOTINE, or ALCOHOL being infused into the vein. If the animal continues to press the lever to obtain the drug, then the drug is said to serve as a reinforcer. Interestingly, those drugs which lead to ADDICTION in humans also serve as reinforcers in animals. The only exception is MARIJUANA (THC), which is used fairly extensively by humans but does not function as a reinforcer in animals. It should be noted that drugs that serve as reinforcers under one condition may not serve as reinforcers under other conditions. For example, nicotine serves as a reinforcer only at low doses and when doses are properly spaced. Nevertheless, the observation that drugs of abuse generally function as reinforcers in experimental animals has brought the study of drug-seeking behavior and drug abuse into a framework that allows carefully controlled behavioral analyses and the application of well-established and objective behavioral principles (Schuster & Johanson, 1981).
The acquisition of drug use in humans predominantly involves positive reinforcement, whereas the maintenance of drug use can involve both positive and negative reinforcement. The ability of a drug to serve as a positive reinforcer is usually associated with its pleasurable subjective effects (e.g. a "rush", a "high", or other feelings of intoxication). But again, given the definition of reinforcement, it is not necessary for a drug to be subjectively reinforcing or pleasurable in order for it to maintain behavior. Many drugs are also associated with symptoms of WITHDRAWAL when abstinence is initiated following a period of regular use. In this case, taking the drug again may terminate the aversive state of withdrawal; in this way, drug use is maintained by negative reinforcement. Drug use can also be influenced by sources of reinforcement other than the direct effects of the drug. For example, social encouragement and praise from a peer group can play an important role in the development of drug use by teenagers. Biological factors may also come into play. For example, some individuals may be more or less susceptible than others to feeling and recognizing the pleasurable effects of drugs. When drug use is viewed as a behavior maintained by the reinforcing effects of drugs, it suggests that this behavior is not amoral or uncontrolled but rather that it is the result of normal behavioral processes.
(SEE ALSO: ; ; Wikler's Pharmacologic Theory of Drug Addiction)
MORSE, W. H., & KELLEHER, R. T. (1977). Determinants of reinforcement and punishment. In W. K. Honig & J. E. R. Staddon (Eds.), Handbook of operant behavior. Englewood Cliffs, NJ: Prentice Hall.
SCHUSTER, S. R., & JOHANSON, C. E. (1981). An analysis of drug-seeking behavior in animals. Neuroscience and Biobehavioral Reviews, 5, 315-323.