Learning

I

Introduction

Learning, acquiring knowledge or developing the ability to perform new behaviors. It is common to think of learning as something that takes place in school, but much of human learning occurs outside the classroom, and people continue to learn throughout their lives.

Even before they enter school, young children learn to walk, to talk, and to use their hands to manipulate toys, food, and other objects. They use all of their senses to learn about the sights, sounds, tastes, and smells in their environments. They learn how to interact with their parents, siblings, friends, and other people important to their world. When they enter school, children learn basic academic subjects such as reading, writing, and mathematics. They also continue to learn a great deal outside the classroom. They learn which behaviors are likely to be rewarded and which are likely to be punished. They learn social skills for interacting with other children. After they finish school, people must learn to adapt to the many major changes that affect their lives, such as getting married, raising children, and finding and keeping a job.

Because learning continues throughout our lives and affects almost everything we do, the study of learning is important in many different fields. Teachers need to understand the best ways to educate children. Psychologists, social workers, criminologists, and other human-service workers need to understand how certain experiences change people’s behaviors. Employers, politicians, and advertisers make use of the principles of learning to influence the behavior of workers, voters, and consumers.

Learning is closely related to memory, which is the storage of information in the brain. Psychologists who study memory are interested in how the brain stores knowledge, where this storage takes place, and how the brain later retrieves knowledge when we need it. In contrast, psychologists who study learning are more interested in behavior and how behavior changes as a result of a person’s experiences.

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There are many forms of learning, ranging from simple to complex. Simple forms of learning involve a single stimulus. A stimulus is anything perceptible to the senses, such as a sight, sound, smell, touch, or taste. In a form of learning known as classical conditioning, people learn to associate two stimuli that occur in sequence, such as lightning followed by thunder. In operant conditioning, people learn by forming an association between a behavior and its consequences (reward or punishment). People and animals can also learn by observation—that is, by watching others perform behaviors. More complex forms of learning include learning languages, concepts, and motor skills.

This article discusses general principles of learning. For information about the application of learning principles to formal education, see Educational Psychology.

II

Simple Forms Of Learning

Habituation, one of the simplest types of learning, is the tendency to become familiar with a stimulus after repeated exposure to it. A common example of habituation occurs in the orienting response, in which a person’s attention is captured by a loud or sudden stimulus. For example, a person who moves to a house on a busy street may initially be distracted (an orienting response) every time a loud vehicle drives by. After living in the house for some time, however, the person will no longer be distracted by the street noise—the person becomes habituated to it and the orienting response disappears.

Despite its simplicity, habituation is a very useful type of learning. Because our environments are full of sights and sounds, we would waste a tremendous amount of time and energy if we paid attention to every stimulus each time we encountered it. Habituation allows us to ignore repetitive, unimportant stimuli. Habituation occurs in nearly all organisms, from human beings to animals with very simple nervous systems. Even some one-celled organisms will habituate to a light, sound, or chemical stimulus that is presented repeatedly.

Sensitization, another simple form of learning, is the increase that occurs in an organism’s responsiveness to stimuli following an especially intense or irritating stimulus. For example, a sea snail that receives a strong electric shock will afterward withdraw its gill more strongly than usual in response to a simple touch. Depending on the intensity and duration of the original stimulus, the period of increased responsiveness can last from several seconds to several days.

III

Classical Conditioning

Another form of learning is classical conditioning, in which a reflexive or automatic response transfers from one stimulus to another. For instance, a person who has had painful experiences at the dentist’s office may become fearful at just the sight of the dentist’s office building. Fear, a natural response to a painful stimulus, has transferred to a different stimulus, the sight of a building. Most psychologists believe that classical conditioning occurs when a person forms a mental association between two stimuli, so that encountering one stimulus makes the person think of the other. People tend to form these mental associations between events or stimuli that occur closely together in space or time.

A

Pavlov’s Experiments

Classical conditioning was discovered by accident in the early 1900s by Russian physiologist Ivan Pavlov. Pavlov was studying how saliva aids the digestive process. He would give a dog some food and measure the amount of saliva the dog produced while it ate the meal. After the dog had gone through this procedure a few times, however, it would begin to salivate before receiving any food. Pavlov reasoned that some new stimulus, such as the experimenter in his white coat, had become associated with the food and produced the response of salivation in the dog. Pavlov spent the rest of his life studying this basic type of associative learning, which is now called classical conditioning or Pavlovian conditioning.

The conditioning process usually follows the same general procedure. Suppose a psychologist wants to condition a dog to salivate at the sound of a bell. Before conditioning, an unconditioned stimulus (food in the mouth) automatically produces an unconditioned response (salivation) in the dog. The term unconditioned indicates that there is an unlearned, or inborn, connection between the stimulus and the response. During conditioning, the experimenter rings a bell and then gives food to the dog. The bell is called the neutral stimulus because it does not initially produce any salivation response in the dog. As the experimenter repeats the bell-food association over and over again, however, the bell alone eventually causes the dog to salivate. The dog has learned to associate the bell with the food. The bell has become a conditioned stimulus, and the dog’s salivation to the sound of the bell is called a conditioned response.