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.
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.
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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.
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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.
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A
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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.
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B
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Principles of
Classical
Conditioning
|
Following his initial
discovery, Pavlov spent more than
three decades studying the processes underlying classical conditioning.
He and
his associates identified four main processes: acquisition, extinction,
generalization, and discrimination.
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B1
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Acquisition
|
The acquisition phase
is the initial learning of
the conditioned response—for example, the dog learning to salivate at
the sound
of the bell. Several factors can affect the speed of conditioning during
the
acquisition phase. The most important factors are the order and timing
of the
stimuli. Conditioning occurs most quickly when the conditioned stimulus
(the
bell) precedes the unconditioned stimulus (the food) by about half a
second. Conditioning
takes longer and the response is weaker when there is a long delay
between the
presentation of the conditioned stimulus and the unconditioned stimulus.
If the
conditioned stimulus follows the unconditioned stimulus—for example, if
the dog
receives the food before the bell is rung—conditioning seldom occurs.
|
B2
|
Extinction
|
Once learned, a conditioned
response is not
necessarily permanent. The term extinction is used to describe
the elimination
of the conditioned response by repeatedly presenting the conditioned
stimulus
without the unconditioned stimulus. If a dog has learned to salivate at
the
sound of a bell, an experimenter can gradually extinguish the dog’s
response by
repeatedly ringing the bell without presenting food afterward.
Extinction does
not mean, however, that the dog has simply unlearned or forgotten the
association between the bell and the food. After extinction, if the
experimenter lets a few hours pass and then rings the bell again, the
dog will
usually salivate at the sound of the bell once again. The reappearance
of an
extinguished response after some time has passed is called spontaneous
recovery.
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B3
|
Generalization
|
After an animal has learned
a conditioned
response to one stimulus, it may also respond to similar stimuli without
further training. If a child is bitten by a large black dog, the child
may fear
not only that dog, but other large dogs. This phenomenon is called generalization.
Less similar stimuli will usually produce less generalization. For
example, the
child may show little fear of smaller dogs.
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B4
|
Discrimination
|
The opposite of generalization
is discrimination,
in which an individual learns to produce a conditioned response to one
stimulus
but not to another stimulus that is similar. For example, a child may
show a
fear response to freely roaming dogs, but may show no fear when a dog is
on a
leash or confined to a pen.
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C
|
Applications of
Classical
Conditioning
|
After studying classical
conditioning in dogs and other
animals, psychologists became interested in how this type of learning
might
apply to human behavior. In an infamous 1921 experiment, American
psychologist
John B. Watson and his research assistant Rosalie Rayner conditioned a
baby
named Albert to fear a small white rat by pairing the sight of the rat
with a
loud noise. Although their experiment was ethically questionable, it
showed for
the first time that humans can learn to fear seemingly unimportant
stimuli when
the stimuli are associated with unpleasant experiences. The experiment
also
suggested that classical conditioning accounts for some cases of
phobias, which
are irrational or excessive fears of specific objects or situations.
Psychologists now know that classical conditioning explains many
emotional
responses—such as happiness, excitement, anger, and anxiety—that people
have to
specific stimuli. For example, a child who experiences excitement on a
roller
coaster may learn to feel excited just at the sight of a roller coaster.
For an
adult who finds a letter from a close friend in the mailbox, the mere
sight of
the return address on the envelope may elicit feelings of joy and
warmth.
Psychologists use classical
conditioning procedures to
treat phobias and other unwanted behaviors, such as alcoholism and
addictions.
To treat phobias of specific objects, the therapist gradually and
repeatedly
presents the feared object to the patient while the patient relaxes.
Through
extinction, the patient loses his or her fear of the object. In one
treatment
for alcoholism, patients drink an alcoholic beverage and then ingest a
drug
that produces nausea. Eventually they feel nauseous at the sight or
smell of
alcohol and stop drinking it. The effectiveness of these therapies
varies
depending on the individual and on the problem behavior. See Psychotherapy:
Behavioral Therapies.
|
D
|
Contemporary
Theories
|
Modern theories of classical
conditioning depart
from Pavlov’s theory in several ways. Whereas Pavlov’s theory stated
that the
conditioned and unconditioned stimuli should elicit the same type of
response,
modern theories acknowledge that the conditioned and unconditioned
responses
frequently differ. In some cases, especially when the unconditioned
stimulus is
a drug, the conditioned stimulus elicits the opposite response. Modern
research
has also shown that conditioning does not always require a close pairing
of the
two stimuli. In taste-aversion learning, people can develop disgust for a
specific
food if they become sick after eating it, even if the illness begins
several
hours after eating.
Psychologists today also
recognize that classical
conditioning does not automatically occur whenever two stimuli are
repeatedly
paired. For instance, suppose that an experimenter conditions a dog to
salivate
to a light by repeatedly pairing the light with food. Next, the
experimenter
repeatedly pairs both the light and a tone with food. When the
experimenter
presents the tone by itself, the dog will show little or no conditioned
response (salivation), because the tone provides no new information. The
light
already allows the dog to predict that food will be coming. This
phenomenon,
discovered by American psychologist Leon Kamin in 1968, is called blocking
because prior conditioning blocks new conditioning.
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IV
|
OPERANT
CONDITIONING
|
One of the most widespread
and important types
of learning is operant conditioning, which involves increasing a
behavior by following it with a reward, or decreasing a behavior by
following
it with punishment. For example, if a mother starts giving a boy his
favorite
snack every day that he cleans up his room, before long the boy may
spend some
time each day cleaning his room in anticipation of the snack. In this
example,
the boy’s room-cleaning behavior increases because it is followed by a
reward
or reinforcer.
Unlike classical conditioning,
in which the conditioned
and unconditioned stimuli are presented regardless of what the learner
does,
operant conditioning requires action on the part of the learner. The boy
in the
above example will not get his snack unless he first cleans up his room.
The
term operant conditioning refers to the fact that the learner
must operate,
or perform a certain behavior, before receiving a reward or punishment.
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A
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Thorndike’s Law
of Effect
|
Some of the earliest scientific
research on
operant conditioning was conducted by American psychologist Edward L.
Thorndike
at the end of the 19th century. Thorndike’s research subjects included
cats,
dogs, and chickens. To see how animals learn new behaviors, Thorndike
used a
small chamber that he called a puzzle box. He would place an animal in
the
puzzle box, and if it performed the correct response (such as pulling a
rope,
pressing a lever, or stepping on a platform), the door would swing open
and the
animal would be rewarded with some food located just outside the cage.
The
first time an animal entered the puzzle box, it usually took a long time
to
make the response required to open the door. Eventually, however, it
would make
the appropriate response by accident and receive its reward: escape and
food.
As Thorndike placed the same animal in the puzzle box again and again,
it would
make the correct response more and more quickly. Soon it would take the
animal
just a few seconds to earn its reward.
Based on these experiments,
Thorndike developed a
principle he called the law of effect. This law states that
behaviors
that are followed by pleasant consequences will be strengthened, and
will be
more likely to occur in the future. Conversely, behaviors that are
followed by
unpleasant consequences will be weakened, and will be less likely to be
repeated in the future. Thorndike’s law of effect is another way of
describing
what modern psychologists now call operant conditioning.
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B
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B. F. Skinner’s
Research
|
American psychologist
B. F. Skinner became one of the most
famous psychologists in history for his pioneering research on operant
conditioning. In fact, he coined the term operant conditioning.
Beginning in the 1930s, Skinner spent several decades studying the
behavior of
animals—usually rats or pigeons—in chambers that became known as Skinner
boxes. Like Thorndike’s puzzle box, the Skinner box was a barren
chamber in
which an animal could earn food by making simple responses, such as
pressing a
lever or a circular response key. A device attached to the box recorded
the
animal’s responses. The Skinner box differed from the puzzle box in
three main
ways: (1) upon making the desired response, the animal received food but
did
not escape from the chamber; (2) the box delivered only a small amount
of food
for each response, so that many reinforcers could be delivered in a
single test
session; and (3) the operant response required very little effort, so an
animal
could make hundreds or thousands of responses per hour. Because of these
changes, Skinner could collect much more data, and he could observe how
changing the pattern of food delivery affected the speed and pattern of
an
animal’s behavior.
Skinner became famous
not just for his research with
animals, but also for his controversial claim that the principles of
learning
he discovered using the Skinner box also applied to the behavior of
people in
everyday life. Skinner acknowledged that many factors influence human
behavior,
including heredity, basic types of learning such as classical
conditioning, and
complex learned behaviors such as language. However, he maintained that
rewards
and punishments control the great majority of human behaviors, and that
the
principles of operant conditioning can explain these behaviors.
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C
|
Principles of
Operant
Conditioning
|
In a career spanning more
than 60 years,
Skinner identified a number of basic principles of operant conditioning
that
explain how people learn new behaviors or change existing behaviors. The
main
principles are reinforcement, punishment, shaping, extinction,
discrimination,
and generalization.
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C1
|
Reinforcement
|
In operant conditioning,
reinforcement refers to
any process that strengthens a particular behavior—that is, increases
the
chances that the behavior will occur again. There are two general
categories of
reinforcement, positive and negative. The experiments of Thorndike and
Skinner
illustrate positive reinforcement, a method of strengthening
behavior by
following it with a pleasant stimulus. Positive reinforcement is a
powerful
method for controlling the behavior of both animals and people. For
people,
positive reinforcers include basic items such as food, drink, sex, and
physical
comfort. Other positive reinforcers include material possessions, money,
friendship, love, praise, attention, and success in one’s career.
Depending on the circumstances,
positive
reinforcement can strengthen either desirable or undesirable behaviors.
Children may work hard at home or at school because of the praise they
receive
from parents and teachers for good performance. However, they may also
disrupt
a class, try dangerous stunts, or start smoking because these behaviors
lead to
attention and approval from their peers. One of the most common
reinforcers of
human behavior is money. Most adults spend many hours each week working
at
their jobs because of the paychecks they receive in return. For certain
individuals, money can also reinforce undesirable behaviors, such as
burglary,
selling illegal drugs, and cheating on one’s taxes.
Negative reinforcement is a
method of strengthening a behavior by following it with the removal or
omission
of an unpleasant stimulus. There are two types of negative
reinforcement:
escape and avoidance. In escape, performing a particular behavior
leads
to the removal of an unpleasant stimulus. For example, if a person with a
headache tries a new pain reliever and the headache quickly disappears,
this
person will probably use the medication again the next time a headache
occurs.
In avoidance, people perform a behavior to avoid unpleasant
consequences. For example, drivers may take side streets to avoid
congested
intersections, citizens may pay their taxes to avoid fines and
penalties, and
students may do their homework to avoid detention.
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C2
|
Reinforcement
Schedules
|
A reinforcement schedule
is a rule that specifies
the timing and frequency of reinforcers. In his early experiments on
operant
conditioning, Skinner rewarded animals with food every time they made
the
desired response—a schedule known as continuous reinforcement.
Skinner
soon tried rewarding only some instances of the desired response and not
others—a schedule known as partial reinforcement. To his
surprise, he
found that animals showed entirely different behavior patterns.
Skinner and other psychologists
found that partial
reinforcement schedules are often more effective at strengthening
behavior than
continuous reinforcement schedules, for two reasons. First, they usually
produce more responding, at a faster rate. Second, a behavior learned
through a
partial reinforcement schedule has greater resistance to extinction—if
the
rewards for the behavior are discontinued, the behavior will persist for
a
longer period of time before stopping. One reason extinction is slower
after
partial reinforcement is that the learner has become accustomed to
making
responses without receiving a reinforcer each time. There are four main
types
of partial reinforcement schedules: fixed-ratio, variable-ratio,
fixed-interval, and variable-interval. Each produces a distinctly
different
pattern of behavior.
On a fixed-ratio schedule,
individuals
receive a reinforcer each time they make a fixed number of responses.
For
example, a factory worker may earn a certain amount of money for every
100
items assembled. This type of schedule usually produces a stop-and-go
pattern
of responding: The individual works steadily until receiving one
reinforcer,
then takes a break, then works steadily until receiving another
reinforcer, and
so on.
On a variable-ratio schedule,
individuals
must also make a number of responses before receiving a reinforcer, but
the
number is variable and unpredictable. Slot machines, roulette wheels,
and other
forms of gambling are examples of variable-ratio schedules. Behaviors
reinforced on these schedules tend to occur at a rapid, steady rate,
with few
pauses. Thus, many people will drop coins into a slot machine over and
over
again on the chance of winning the jackpot, which serves as the
reinforcer.
On a fixed-interval schedule,
individuals
receive reinforcement for their response only after a fixed amount of
time
elapses. For example, in a laboratory experiment with a fixed-interval
one-minute schedule, at least one minute must elapse between the
deliveries of
the reinforcer. Any responses that occur before one minute has passed
have no
effect. On these schedules, animals usually do not respond at the
beginning of
the interval, but they respond faster and faster as the time for
reinforcement
approaches. Fixed-interval schedules rarely occur outside the
laboratory, but
one close approximation is the clock-watching behavior of students
during a
class. Students watch the clock only occasionally at the start of a
class
period, but they watch more and more as the end of the period gets
nearer.
Variable-interval schedules also
require the passage of time before providing reinforcement, but the
amount of
time is variable and unpredictable. Behavior on these schedules tends to
be
steady, but slower than on ratio schedules. For example, a person trying
to
call someone whose phone line is busy may redial every few minutes until
the
call gets through.
|
C3
|
Punishment
|
Whereas reinforcement
strengthens behavior, punishment
weakens it, reducing the chances that the behavior will occur again. As
with
reinforcement, there are two kinds of punishment, positive and negative.
Positive
punishment involves reducing a behavior by delivering an unpleasant
stimulus if the behavior occurs. Parents use positive punishment when
they
spank, scold, or shout at children for bad behavior. Societies use
positive
punishment when they fine or imprison people who break the law. Negative
punishment, also called omission, involves reducing a behavior by
removing
a pleasant stimulus if the behavior occurs. Parents’ tactics of
grounding
teenagers or taking away various privileges because of bad behavior are
examples of negative punishment.
Considerable controversy
exists about whether punishment is
an effective way of reducing or eliminating unwanted behaviors. Careful
laboratory experiments have shown that, when used properly, punishment
can be a
powerful and effective method for reducing behavior. Nevertheless, it
has
several disadvantages. When people are severely punished, they may
become
angry, aggressive, or have other negative emotional reactions. They may
try to
hide the evidence of their misbehavior or escape from the situation, as
when a
punished child runs away from home. In addition, punishment may
eliminate
desirable behaviors along with undesirable ones. For example, a child
who is
scolded for making an error in the classroom may not raise his or her
hand
again. For these and other reasons, many psychologists recommend that
punishment be used to control behavior only when there is no realistic
alternative.
|
C4
|
Shaping
|
Shaping is a reinforcement
technique that is used to teach animals or people behaviors that they
have
never performed before. In this method, the teacher begins by
reinforcing a
response the learner can perform easily, and then gradually requires
more and
more difficult responses. For example, to teach a rat to press a lever
that is
over its head, the trainer can first reward any upward head movement,
then an
upward movement of at least one inch, then two inches, and so on, until
the rat
reaches the lever. Psychologists have used shaping to teach children
with
severe mental retardation to speak by first rewarding any sounds they
make, and
then gradually requiring sounds that more and more closely resemble the
words
of the teacher. Animal trainers at circuses and theme parks use shaping
to
teach elephants to stand on one leg, tigers to balance on a ball, dogs
to do
backward flips, and killer whales and dolphins to jump through hoops.
|
C5
|
Extinction
|
As in classical conditioning,
responses learned in
operant conditioning are not always permanent. In operant conditioning, extinction
is the elimination of a learned behavior by discontinuing the reinforcer
of
that behavior. If a rat has learned to press a lever because it receives
food
for doing so, its lever-pressing will decrease and eventually disappear
if food
is no longer delivered. With people, withholding the reinforcer may
eliminate
some unwanted behaviors. For instance, parents often reinforce temper
tantrums
in young children by giving them attention. If parents simply ignore the
child’s tantrums rather than reward them with attention, the number of
tantrums
should gradually decrease.
|
C6
|
Generalization
and
Discrimination
|
Generalization and discrimination
occur in operant
conditioning in much the same way that they do in classical
conditioning. In generalization,
people perform a behavior learned in one situation in other, similar
situations. For example, a man who is rewarded with laughter when he
tells
certain jokes at a bar may tell the same jokes at restaurants, parties,
or
wedding receptions. Discrimination is learning that a behavior
will be
reinforced in one situation but not in another. The man may learn that
telling
his jokes in church or at a serious business meeting will not make
people
laugh. Discriminative stimuli signal that a behavior is likely to be
reinforced.
The man may learn to tell jokes only when he is at a loud, festive
occasion
(the discriminative stimulus). Learning when a behavior will and will
not be
reinforced is an important part of operant conditioning.
|
D
|
Applications of
Operant Conditioning
|
Operant conditioning techniques
have practical
applications in many areas of human life. Parents who understand the
basic
principles of operant conditioning can reinforce their children’s
appropriate
behaviors and punish inappropriate ones, and they can use generalization
and
discrimination techniques to teach which behaviors are appropriate in
particular situations. In the classroom, many teachers reinforce good
academic
performance with small rewards or privileges. Companies have used
lotteries to
improve attendance, productivity, and job safety among their employees.
Psychologists known as
behavior therapists use the
learning principles of operant conditioning to treat children or adults
with
behavior problems or psychological disorders. Behavior therapists use
shaping
techniques to teach basic job skills to adults with mental retardation.
Therapists use reinforcement techniques to teach self-care skills to
people
with severe mental illnesses, such as schizophrenia, and use punishment
and extinction
to reduce aggressive and antisocial behaviors by these individuals.
Psychologists also use operant conditioning techniques to treat
stuttering,
sexual disorders, marital problems, drug addictions, impulsive spending,
eating
disorders, and many other behavioral problems. See Behavior
Modification.
|
V
|
LEARNING BY
OBSERVATION
|
Although classical and
operant conditioning are
important types of learning, people learn a large portion of what they
know through
observation. Learning by observation differs from classical and operant
conditioning because it does not require direct personal experience with
stimuli, reinforcers, or punishers. Learning by observation involves
simply
watching the behavior of another person, called a model, and
later
imitating the model’s behavior.
Both children and adults
learn a great deal through
observation and imitation. Young children learn language, social skills,
habits, fears, and many other everyday behaviors by observing their
parents and
older children. Many people learn academic, athletic, and musical skills
by
observing and then imitating a teacher. According to Canadian-American
psychologist Albert Bandura, a pioneer in the study of observational
learning,
this type of learning plays an important role in a child’s personality
development. Bandura found evidence that children learn traits such as
industriousness, honesty, self-control, aggressiveness, and
impulsiveness in
part by imitating parents, other family members, and friends.
Psychologists once thought
that only human beings could
learn by observation. They now know that many kinds of animals—including
birds,
cats, dogs, rodents, and primates—can learn by observing other members
of their
species. Young animals can learn food preferences, fears, and survival
skills
by observing their parents. Adult animals can learn new behaviors or
solutions
to simple problems by observing other animals.
|
A
|
Bandura’s
Experiments
|
In the early 1960s Bandura
and other researchers
conducted a classic set of experiments that demonstrated the power of
observational learning. In one experiment, a preschool child worked on a
drawing while a television set showed an adult behaving aggressively
toward a
large inflated Bobo doll (a clown doll that bounces back up when knocked
down).
The adult pummeled the doll with a mallet, kicked it, flung it in the
air, sat
on it, and beat it in the face, while yelling such remarks as 'Sock him
in the
nose … Kick him … Pow!' The child was then left in another room filled
with
interesting toys, including a Bobo doll. The experimenters observed the
child
through one-way glass. Compared with children who witnessed a nonviolent
adult
model and those not exposed to any model, children who witnessed the
aggressive
display were much more likely to show aggressive behaviors toward the
Bobo
doll, and they often imitated the model's exact behaviors and hostile
words.
In a variant of the original
experiment,
Bandura and colleagues examined the effect of observed consequences on
learning. They showed four-year-old children one of three films of an
adult
acting violently toward a Bobo doll. In one version of the film, the
adult was
praised for his or her aggressive behavior and given soda and candies.
In another
version, the adult was scolded, spanked, and warned not to behave that
way
again. In a third version, the adult was neither rewarded nor punished.
After
viewing the film, each child was left alone in a room that contained a
Bobo
doll and other toys. Many children imitated the adult’s violent
behaviors, but
children who saw the adult punished imitated the behaviors less often
than
children who saw the other films. However, when the researchers promised
the
children a reward if they could copy the adult’s behavior, all three
groups of
children showed large and equal amounts of violent behavior toward the
Bobo
doll.
Bandura concluded that
even those children who did not
see the adult model receive a reward had learned through observation,
but these
children (especially those who saw the model being punished) would not
display
what they had learned until they expected a reward for doing so. The
term latent
learning describes cases in which an individual learns a new
behavior but
does not perform this behavior until there is the possibility of
obtaining a
reward.
|
B
|
Bandura’s Theory
of
Imitation
|
According to Bandura’s
influential theory of imitation,
also called social learning theory, four factors are necessary for a
person to
learn through observation and then imitate a behavior: attention,
retention,
reproduction, and motivation. First, the learner must pay attention
to
the crucial details of the model’s behavior. A young girl watching her
father
bake a cake will not be able to imitate this behavior successfully
unless she
pays attention to many important details—ingredients, quantities, oven
temperature, baking time, and so on. The second factor is retention—the
learner
must be able to retain all of this information in memory until it is
time to use it. If the person forgets important details, he or she will
not be
able to successfully imitate the behavior. Third, the learner must have
the
physical skills and coordination needed for reproduction of the
behavior. The young girl must have enough strength and dexterity to mix
the
ingredients, pour the batter, and so on, in order to bake a cake on her
own.
Finally, the learner must have the motivation to imitate the
model. That
is, learners are more likely to imitate a behavior if they expect it to
lead to
some type of reward or reinforcement. If learners expect that imitating
the
behavior will not lead to reward or might lead to punishment, they are
less
likely to imitate the behavior.
|
C
|
Theory of
Generalized Imitation
|
An alternative to Bandura’s
theory is the theory of
generalized imitation. This theory states that people will imitate the
behaviors of others if the situation is similar to cases in which their
imitation was reinforced in the past. For example, when a young child
imitates
the behavior of a parent or an older sibling, this imitation is often
reinforced with smiles, praise, or other forms of approval. Similarly,
when
children imitate the behaviors of friends, sports stars, or celebrities,
this imitation
may be reinforced—by the approval of their peers, if not their parents.
Through
the process of generalization, the child will start to imitate these
models in
other situations. Whereas Bandura’s theory emphasizes the imitator’s
thought
processes and motivation, the theory of generalized imitation relies on
two
basic principles of operant conditioning—reinforcement and
generalization.
|
D
|
Factors
Affecting
Imitation
|
Many factors determine
whether or not a person will
imitate a model. As already shown, children are more likely to imitate a
model
when the model’s behavior has been reinforced than when it has been
punished.
More important, however, are the expected consequences to the learner. A
person
will imitate a punished behavior if he or she thinks that imitation will
produce some type of reinforcement.
The characteristics of
the model also influence the
likelihood of imitation. Studies have shown that children are more
likely to
imitate adults who are pleasant and attentive to them than those who are
not.
In addition, children more often imitate adults who have substantial
influence
over their lives, such as parents and teachers, and those who seem
admired and
successful, such as celebrities and athletes. Both children and adults
are more
likely to imitate models who are similar to them in sex, age, and
background.
For this reason, when behavior therapists use modeling to teach new
behaviors
or skills, they try to use models who are similar to the learners.
|
E
|
Influence of
Television
|
In modern society, television
provides many
powerful models for children and abundant opportunities for
observational
learning. Many parents are concerned about the behaviors their children
can observe
on TV. Many television programs include depictions of sex, violence,
drug and
alcohol use, and vulgar language—behaviors that most parents do not want
their
children to imitate. Studies have found that by early adolescence, the
average
American child has watched thousands of dramatized murders and countless
other
acts of violence on television.
For many years, psychologists
have debated the
question of whether watching violence on television has detrimental
effects on
children. A number of experiments, both inside and outside the
laboratory, have
found evidence that viewing television violence is related to increased
aggression in children. Some psychologists have criticized this
research,
maintaining that the evidence is inconclusive. Most psychologists now
believe,
however, that watching violence on television can sometimes lead to
increased
aggressiveness in children.
The effects of television
on children’s behaviors
are not all negative. Educational programs such as “Sesame Street” give
children the opportunity to learn letters of the alphabet, words,
numbers, and
social skills. Such programs also show people who solve problems and
resolve
differences through cooperation and discussion rather than through
aggression
and hostility.
|
VI
|
OTHER FORMS OF
LEARNING
|
Although psychologists
who study learning have focused the
most attention on classical conditioning, operant conditioning, and
observational learning, they have also studied other types of learning,
including language learning, learning by listening and reading, concept
formation, and the learning of motor skills. These types of learning
still
involve the principles of conditioning and observational learning, but
they are
worth considering separately because of their importance in everyday
life.
|
A
|
Language
Learning
|
Learning to speak and
understand a language is one
of the most complex types of learning, yet all normal children master
this
skill in the first few years of their lives. The familiar principles of
shaping, reinforcement, generalization, discrimination, and
observational
learning all play a role in a child’s language learning. However, in the
1950s
American linguist Noam Chomsky proposed that these basic principles of
learning
cannot explain how children learn to speak so well and so rapidly.
Chomsky
theorized that humans have a unique and inborn capacity to extract word
meanings, sentence structure, and grammatical rules from the complex
stream of
sounds they hear. Although Chomsky’s theory is controversial, it has
received
some support from scientific evidence that specific parts of the human
brain
are essential for language. When these areas of the brain are damaged, a
person
loses the ability to speak or comprehend language.
|
B
|
Learning by
Listening and
Reading
|
Because people communicate
through language, they can
learn vast amounts of information by listening to others and by reading.
Learning through the spoken or written word is similar to observational
learning, because it allows people to learn not simply from their own
experiences, but also from the experiences of others. For example, by
listening
to a parent or instructor, children can learn to avoid busy streets and
to
cross the street at crosswalks without first experiencing any positive
or
negative consequences. By listening to and observing others, children
can learn
skills such as tying a shoelace, swinging a baseball bat, or paddling a
canoe.
Listening to the teacher and reading are essential parts of most
classroom learning.
Much of what we read and
hear is quickly
forgotten. Learning new information requires that we retain the
information in
memory and later be able to retrieve it. The process of forming
long-term
memories is complex, depending on the nature of the original information
and on
how much a person rehearses or reviews the information. See Memory.
|
C
|
Concept
Formation
|
Concept formation occurs
when people learn to classify different objects as members of a single
category. For example, a child may know that a mouse, a dog, and a whale
are
all animals, despite their great differences in size and appearance.
Concept
formation is important because it helps us identify stimuli we have
never
encountered before. Thus, a child who sees an antelope for the first
time will
probably know that it is an animal. Even young children learn a large
number of
such concepts, including food, games, flowers, cars, and houses.
Although
language plays an important role in how people learn concepts, the
ability to
speak is not essential for concept formation. Experiments with birds and
chimpanzees have shown that these animals can form concepts.
|
D
|
Learning Motor
Skills
|
A motor skill is the ability
to perform
a coordinated set of physical movements. Examples of motor skills
include
handwriting, typing, playing a musical instrument, driving a car, and
most
sports skills. Learning a motor skill is usually a gradual process that
requires practice and feedback. Learners need feedback from a teacher or
coach
to tell them which movements they are performing well and which need
improvement. While learning a new motor skill, the learner should direct
full
attention to the task. Some motor skills, if learned well, can be
performed
automatically. For example, a skilled typist can type quickly and
accurately
without thinking about every keystroke.
|
VII
|
THEORIES OF
LEARNING
|
Early in the 20th century,
some psychologists
believed that it might be possible to develop a single, general theory
that
could explain all instances of learning. For instance, the so-called
one-factor
theory proposed that reinforcement was the single factor that controlled
whether learning would or would not occur. However, latent learning and
similar
phenomena contradicted this theory by showing that learning could occur
without
reinforcement.
In recent years, psychologists
have abandoned
attempts to develop a single, all-purpose theory of learning. Instead,
they
have developed smaller and more specialized theories. Some theories
focus on
classical conditioning, some on operant conditioning, some on
observational
learning, and some on other specific forms of learning. The major
debates in
learning theory concern which theories best describe these more specific
areas
of learning.
In studying learning,
psychologists follow two main
theoretical approaches: the behavioral approach and the cognitive
approach.
Recall that learning is acquiring knowledge or developing the ability to
perform new behaviors. Behavioral psychologists focus on the change that
takes
place in an individual’s behavior. Cognitive psychologists prefer to
study the
change in an individual’s knowledge, emphasizing mental processes such
as
thinking, memory, and problem solving. Many psychologists combine
elements of
both approaches to explain learning.
|
A
|
The Behavioral
Approach
|
The term behaviorism was
first used by John
B. Watson in the early 1910s. Later, B. F. Skinner expanded and
popularized the
behavioral approach. The essential characteristic of the behavioral
approach to
learning is that events in the environment are understood to predict a
person’s
behavior, not thoughts, feelings, or other events that take place inside
the
person. Strict behaviorists believe that it is dangerous and
unscientific to
treat thoughts and feelings as the causes of a person’s behavior,
because no
one can see another person’s thoughts or feelings. Behaviorists maintain
that
human learning can be explained by examining the stimuli, reinforcers,
and
punishments that a person experiences. According to behaviorists,
reinforcement
and punishment, along with other basic principles such as generalization
and
discrimination, can explain even the most advanced types of human
learning,
such as learning to read or to solve complex problems.
|
B
|
The Cognitive
Approach
|
Unlike behaviorists, cognitive
psychologists believe
that it is essential to study an individual’s thoughts and expectations
in
order to understand the learning process. In 1930 American psychologist
Edward
C. Tolman investigated cognitive processes in learning by studying how
rats learn
their way through a maze. He found evidence that rats formed a
“cognitive map”
(a mental map) of the maze early in the experiment, but did not display
their
learning until they received reinforcement for completing the maze—a
phenomenon
he termed latent learning. Tolman’s experiment suggested that
learning
is more than just the strengthening of responses through reinforcement.
Modern cognitive psychologists
believe that learning
involves complex mental processes, including memory, attention,
language, concept
formation, and problem solving. They study how people process
information and
form mental representations of people, objects, and events.
|
C
|
Evaluation of
the Two
Approaches
|
During the first half
of the 20th century,
behaviorism was the dominant theoretical approach in the field of
learning.
Since the 1950s, however, cognitive psychology has steadily gained in
popularity, and now more psychologists favor a cognitive approach than a
strict
behavioral approach. Cognitive psychologists and behaviorists will
continue to
debate the merits of their different positions, but in many ways these
two
approaches have different strengths that complement each other. With its
emphasis on memory and complex thought processes, the cognitive approach
appears well suited for investigating the most sophisticated types of
human
learning, such as reasoning, problem solving, and creativity. The
behavioral
approach, which emphasizes basic principles of conditioning,
reinforcement, and
punishment, can provide explanations of why people behave the way they
do and
how they choose between different possible courses of action.
|
VIII
|
FACTORS THAT
INFLUENCE
LEARNING ABILITY
|
A variety of factors determine
an individual’s
ability to learn and the speed of learning. Four important factors are
the
individual’s age, motivation, prior experience, and intelligence. In
addition,
certain developmental and learning disorders can impair a person’s
ability to
learn.
|
A
|
Age
|
Animals and people of
all ages are capable of the
most common types of learning—habituation, classical conditioning, and
operant
conditioning. As children grow, they become capable of learning more and
more
sophisticated types of information. Swiss developmental psychologist
Jean
Piaget theorized that children go through four different stages of
cognitive
development. In the sensorimotor stage (from birth to about 2 years of
age),
infants use their senses to learn about their bodies and about objects
in their
immediate environments. In the preoperational stage (about 2 to 7 years
of
age), children can think about objects and events that are not present,
but
their thinking is primitive and self-centered, and they have difficulty
seeing
the world from another person’s point of view. In the concrete
operational
stage (about 7 to 11 years of age), children learn general rules about
the
physical world, such as the fact that the amount of water remains the
same if
it is poured between containers of different shapes. Finally, in the
formal
operational stage (ages 11 and up), children become capable of logical
and
abstract thinking. See also Child Development.
Adults continue to learn
new knowledge and skills
throughout their lives. For example, most adults can successfully learn a
foreign language, although children usually can achieve fluency more
easily. If
older adults remain healthy, their learning ability generally does not
decline
with age. Age-related illnesses that involve a deterioration of mental
functioning, such as Alzheimer’s disease, can severely reduce a person’s
ability to learn.
|
B
|
Motivation
|
Learning is usually most
efficient and rapid when
the learner is motivated and attentive. Behavioral studies with both
animals
and people have shown that one effective way to maintain the learner’s
motivation is to deliver strong and immediate reinforcers for correct
responses. However, other research has indicated that very high levels
of
motivation are not ideal. Psychologists believe an intermediate level of
motivation is best for many learning tasks. If a person’s level of
motivation
is too low, he or she may give up quickly. At the other extreme, a very
high
level of motivation may cause such stress and distraction that the
learner
cannot focus on the task. See Motivation.
|
C
|
Prior Experience
|
How well a person learns
a new task may depend
heavily on the person’s previous experience with similar tasks. Just as a
response can transfer from one stimulus to another through the process
of
generalization, people can learn new behaviors more quickly if the
behaviors
are similar to those they can already perform. This phenomenon is called
positive
transfer. Someone who has learned to drive one car, for example,
will be
able to drive other cars, even though the feel and handling of the cars
will
differ. In cases of negative transfer, however, a person’s prior
experience can interfere with learning something new. For instance,
after
memorizing one shopping list, it may be more difficult to memorize a
different
shopping list.
|
D
|
Intelligence
|
Psychologists have long
known that people differ
individually in their level of intelligence, and thus in their ability
to learn
and understand. Scientists have engaged in heated debates about the
definition
and nature of intelligence. In the 1980s American psychologist Howard
Gardner
proposed that there are many different forms of intelligence, including
linguistic, logical-mathematical, musical, and interpersonal
intelligence. A
person may easily learn skills in some categories but have difficulty
learning
in others. See Intelligence.
|
E
|
Learning and
Developmental Disorders
|
A variety of disorders
can interfere with a
person’s ability to learn new skills and behaviors. Learning and
developmental
disorders usually first appear in childhood and often persist into
adulthood.
Children with attention-deficit hyperactivity disorder (ADHD) may not be
able
to sit still long enough to focus on specific tasks. Children with
autism
typically have difficulty speaking, understanding language, and
interacting
with people. People with mental retardation, characterized primarily by
very
low intelligence, may have trouble mastering basic living tasks and
academic
skills. Children with learning or developmental disorders often receive
special
education tailored to their individual needs and abilities.
