Introduction (Psychology and Mental Health)
Learning has been of central interest to psychologists since the beginning of the field in the late 1800’s. Learning refers to changes in behavior that result from experiences. The term “behavior” includes all actions of an organism, both those that are directly observable, such as typing at a keyboard, and those that are unobservable, such as thinking about how to solve a problem. Psychologists studying learning work with a variety of species, including humans, rodents, and birds. Nonhuman species are studied for a variety of reasons. First, scientists are interested in fundamental principles of learning that have cross-species generality. Second, the degree of experimental control that can be obtained with nonhumans is much higher than with humans. These controlled conditions make it more likely that any effect that is found is due to the experimental manipulations rather than to some uncontrolled variable. Third, studying the learning of nonhumans can be helpful to animals. For example, a scientist might need to know the best way to raise an endangered giant condor so it is more likely to survive when introduced to the wild.
There are two major types of learning. Classical conditioning (also called Pavlovian `conditioning, after Russian physiologist Ivan Petrovich Pavlov) involves the transfer of control of reflexes to new environmental stimuli. For example, when a person gets a glaucoma test at an optometrist’s...
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Classical Conditioning (Psychology and Mental Health)
Classical conditioning was first systematically investigated by Pavlov beginning in the late 1800’s and into the 1900’s. Classical conditioning involves the transfer of control of an elicited response from one stimulus to another, previously neutral, stimulus. Pavlov discovered classical conditioning accidentally while investigating digestion in dogs. A dog was given meat powder in its mouth to elicit salivation. After this process had been repeated a number of times, the dog would start salivating before the meat powder was put in its mouth. When it saw the laboratory assistant, it would start to salivate, although it had not initially salivated at the sight. Pavlov devoted the rest of his long career to the phenomenon of classical conditioning.
In classical conditioning, a response is initially elicited by an unconditioned stimulus (US). The US is a stimulus that elicits a response without any prior experience. For example, the loud sound of a balloon bursting naturally causes people to blink their eyes and withdraw from the noise. The response that is naturally elicited is called the unconditioned response (UR). If some stimulus reliably precedes the US, then over time it, too, will come to elicit a response. For example, the sight of an overfull balloon initially does not elicit blinking of the eyes. Because the sight of the balloon predicts the loud noise to come when it bursts, however, eventually people...
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Operant Conditioning (Psychology and Mental Health)
Operant conditioning (also called instrumental conditioning) involves the regulation of voluntary behavior by its consequences. Thorndike first systemically studied operant conditioning in the late 1800’s. He placed cats in puzzle boxes and measured the amount of time they took to escape to a waiting bowl of food. He found that with increasing experience, the cats escaped more quickly. Movements that resulted in being released from the box, such as stepping on a panel or clawing a loop in a string, became more frequent, whereas movements that were not followed by release became less frequent. This type of operant learning is called trial-and-error learning, because there is no system to teach the behavior. Instead, the organism makes many mistakes, which become less likely over time, and sometimes hits on the solution, which then becomes more likely over time.
Beginning in the 1930’s, Skinner greatly extended and systematized the study of operant conditioning. One of his major contributions was to invent an apparatus called the operant chamber, which provided a controlled environment in which behavior was automatically recorded. In the operant chamber, an animal, such as a rat, would be able to make an arbitrary response, such as pressing a small lever on the side of the chamber with its paws. The apparatus could be programmed to record the response automatically and provide a consequence, such as a bit of food, to...
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Reinforcers and Punishers (Psychology and Mental Health)
In operant conditioning, there are four basic contingencies that can be used to modify the frequency of occurrence of nonreflexive behavior. A contingency refers to the relation between the situation, a behavior, and the consequence of the behavior. A reinforcement is a consequence that makes a behavior more likely in the future, whereas a punishment is a consequence that makes a behavior less likely in the future. Reinforcements and punishments come in positive and negative forms. A positive consequence is the presentation of a stimulus or event as a result of the behavior, and a negative consequence is the removal of a stimulus or event as a result of the behavior. Correctly used, the terms positive and negative refer only to whether the event is presented or removed, not whether the action is judged good or bad.
A positive reinforcment is a consequence that increases the future likelihood of the behavior that produced it. For example, if a parent were to praise a child at dinner for eating properly with a fork, and as a result the child used the fork properly more often, then praise would have served as a positive reinforcement. The vast majority of scientists studying learning recommend positive reinforcement as the best technique to promote learning. One can attempt to increase the desired appropriate behavior through positive reinforcement, rather than focusing on the undesired or inappropriate behavior. If...
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Learned Helplessness (Psychology and Mental Health)
As Seligman, Maier, and Overmier discovered, exposure to uncontrollable aversive events can have profound impacts on future learning, a phenomenon called learned helplessness. In learned helplessness, an organism that has been exposed to uncontrollable aversive events later has an impaired ability to learn to escape from aversive situations and even to learn new, unrelated behaviors. The phenomenon was accidentally discovered in laboratory research with dogs. Seligman and his colleagues found that dogs that were exposed to electrical shocks in a harness, with no possibility of escape, later could not learn to escape shocks in a shuttle box in which they had only to jump to the other side. Disturbingly, they would lie down and whimper, not even trying to get away from the completely avoidable shocks. Dogs that had not been exposed to the uncontrollable shocks learned to escape in the shuttle box rapidly. More important, dogs exposed to the same number and pattern of shocks, but with the ability to turn them off, also had no trouble learning to escape in the shuttle box. In other words, it was the exposure to uncontrollable shocks, not just shocks, that produced the later deficit in escape learning. Moreover, the dogs that had been exposed to uncontrollable aversive events also had difficulties learning other, unrelated, tasks. This basic result has since been found many times with many different types of situations, species, and...
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Learned Creativity and Variability (Psychology and Mental Health)
Beginning in the 1970’s, some psychologists began to criticize the use of rewards to promote learning. Tangible rewards as well as praise and attention, they argued, could interfere with creativity, problem-solving ability, motivation, and enjoyment. Fortunately, these concerns were allayed in the 1990’s by careful research and examination of previous research, most notably that of Eisenberger and Cameron. Together, they analyzed the results of more than one hundred published studies on the effects of rewards and found that, in general, rewards increase interest, motivation, and performance. The only situation in which rewards had detrimental effects was when they were offered independently of performance. In other words, giving “rewards” regardless of how the person does is bad for morale and interest.
Furthermore, several aspects of performance previously thought to be beyond the domain of learning, such as creativity and even randomlike behavior, have been demonstrated to be sensitive to consequences. Children can learn to be creative in their drawing, in terms of the number of novel pictures drawn, using rewards for novelty. Similarly, as shown by the work of American psychologist Allen Neuringer and his colleagues, people and animals alike can learn to engage in strings of unpredictable behavior that cannot be distinguished from the random sort of outcomes generated by a random number...
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Biological Bases of Learning (Psychology and Mental Health)
The features of learning do not occur in a vacuum: They often produce lasting, physiological changes in the organism. The search for the physical underpinnings of learning has progressed from relatively basic reflexes in relatively simple organisms to more complex behaviors in mammals. Beginning in the 1960’s, Kandel and his colleagues started to examine simple learning in the large sea snail Aplysia. This snail was chosen as a model to study physiological changes in learning because its nervous system is relatively simple, containing several thousand neurons (nerve cells) compared to the billions of neurons in mammals. The neurons are large, so researchers can identify individual cells and monitor them for changes as learning progresses. In this Nobel Prize-winning work, Kandel and his colleagues outlined many of the changes in the degree of responsiveness in connections between neurons that underlie classical conditioning processes. The same processes have been observed in other species, including mammals, and the work continues to expand to more complex behavior. This research shows the commonality in learning processes across species and emphasizes the progress in understanding the physical basis that underlies learning.
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Sources for Further Study (Psychology and Mental Health)
Branch, Marc N., and Timothy D. Hackenberg. “Humans Are Animals, Too: Connecting Animal Research to Human Behavior and Cognition.” In Learning and Behavior Therapy, edited by William O’Donohue. Boston, Mass.: Allyn & Bacon, 1998. The authors explain the relevance of work with nonhumans to humans. Includes a discussion of the effects of explicit rewards on motivation and the phenomenon of learning without awareness. This book chapter is clearly written and understandable to the interested nonprofessional reader.
Carroll, Marilyn E., and J. Bruce Overmier, eds. Animal Research and Human Health: Advancing Human Welfare Through Behavioral Science. Washington, D.C.: American Psychological Association, 2001. This comprehensive book contains descriptions of the application of research with animals to a variety of human conditions, including anxiety, stress, depression, drug abuse, aggression, and a variety of areas of learning. Also contains a section on the ethics of using animals in behavioral research and a list of additional readings.
Eisenberger, Robert, and Judy Cameron. “The Detrimental Effects of Reward: Myth or Reality?” American Psychologist 51, no. 11 (1996): 1153-1166. This journal article in the premier publication of the American Psychological Association provides an analysis of more than one hundred studies and finds that rewards generally are not detrimental,...
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