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Learning and Conditioning

By Bradley Grant,2014-10-21 21:53
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Learning and Conditioning

Learning and Conditioning

    A vast amount of time and effort is spent on the business of learning, and any teacher or student will agree that learning is not always a simple matter. If a teacher tells a child to stay away from kids on the swings, the child may not always remember and obeyuntil a few collisions teach him his lesson. A

    kindergartener may need to watch her father tie his shoes dozens of times before she understands how to do it herself. Psychologists define learning as a change in behavior or knowledge that results from experience.

    Three kinds of learning are of particular importance to psychologists. Classical conditioning is learning that depends on associations between events, such as learning to walk far from the swings to avoid collisions. Operant conditioning is learning that depends on the consequences of behavior, such as learning that getting a good night’s sleep before an exam will help to earn a good grade. Observational learning involves learning by watching others, such as learning to tie shoelaces by watching someone else do it first.

Classical Conditioning

Russian physiologist Ivan Pavlov was the first to describe classical conditioning. In classical

    conditioning, also called “respondent conditioning” or “Pavlovian conditioning,” a subject comes to respond to a neutral stimulus as he would to another, nonneutral stimulus by learning to associate the two stimuli.

    Pavlov’s contribution to learning began with his study of dogs. Not surprisingly, his dogs drooled every time he gave them food. Then he noticed that if he sounded a tone every time he fed them, the dogs soon started to drool at the sound of the tone, even if no food followed it. The dogs had come to associate the tone, a neutral stimulus, with food, a nonneutral stimulus.

Conditioned and Unconditioned Stimuli and Responses

Psychologists use several terms to talk about classical conditioning. In Pavlov’s experiment, salivation

    was the unconditioned response, which is a response that occurs naturally. Food was the

    unconditioned stimulus, the stimulus that naturally evoked salivation. The tone was the conditioned

    stimulus, the stimulus that the dogs learned to associate with food. The conditioned response to the

    tone was salivation. The conditioned response is usually the same as, or similar to, the unconditioned response.

Example:

    Suppose Adam has a psychology class with Professor Smith, who is determined to teach him about classical conditioning. In the first class, Professor Smith whips out a revolver and shoots it into the air. The revolver is loaded with blanks, but when Adam hears the loud bang, he cringes out of surprise. Professor Smith repeats this action several times during the class. By the end of the hour, Adam cringes as soon as she whips out the revolver, expecting a bang. He cringes even if she doesn’t shoot. In this scenario, the unconditioned stimulus is the bang, the unconditioned response is cringing, the conditioned stimulus is the revolver, and the conditioned response is cringing.

Acquisition of Conditioned Responses

    Subjects acquire a conditioned response when a conditioned stimulus is paired with an unconditioned stimulus. Conditioning works best if the conditioned stimulus appears just before the unconditioned stimulus and both stimuli end at about the same time. In the above example, Professor Smith’s conditioning will work best if she displays the revolver right before firing and puts it away after shooting.

Extinction

    After Adam has been conditioned to cringe at the sight of the revolver, Professor Smith comes into the next class and pulls out the revolver again. He cringes, but she doesn’t shoot. If she pulls it out again and

    again on several occasions without shooting, Adam will soon stop cringing when she pulls it out. This process called extinction is the gradual weakening and disappearance of a conditioned response. Extinction happens when the conditioned stimulus appears repeatedly without the unconditioned stimulus.

Spontaneous Recovery

    Suppose that by the end of the second class, Adam has completely stopped cringing when Professor Smith pulls out the revolver. His conditioned response has been extinguished. However, if Professor Smith comes into class later in the semester and pulls out the revolver again, Adam may still cringe, though maybe a little less than before. This is called spontaneous recovery. Spontaneous recovery is

    the reappearance of an extinguished conditioned response when the conditioned stimulus returns after a period of absence.

Stimulus Generalization

    Now suppose Professor Smith conditions Adam again to respond to the revolver as she did in the first

    class. Soon he cringes every time she pulls out the revolver. While Adam is in this conditioned state, the professor pulls out a cell phone. Adam is likely to cringe at that too because of stimulus

    generalizationthe tendency to respond to a new stimulus as if it were the original conditioned stimulus. Stimulus generalization happens most often when the new stimulus resembles the original conditioned stimulus.

Example:

    In the 1920s, the behaviorist John Watson and his colleague Rosalie Rayner did a famous study that

    demonstrated stimulus generalization. They gave a white rat to an eleven-month-old boy named Little Albert, who liked the rat and enjoyed playing with it. In the next stage of the experiment, the researchers repeatedly made a loud noise behind Albert while offering him the rat. Each time, Albert fell to the floor, frightened. When the researchers then offered the rat to him without making the noise, Albert showed fear of the rat and crawled away from it. The researchers were subsequently able to generalize Albert’s fear to other furry, white stimuli, including a rabbit, a dog, a fur coat, a Santa Claus mask, and Watson’s hair. This experiment is considered highly unethical by today’s standards.

Stimulus Discrimination

    Suppose Professor Smith used a gray revolver to condition Adam. Once Adam is conditioned, if she pulls out a brown revolver, he’ll initially cringe at that, too. But suppose Professor Smith never shoots when

    she pulls out the brown revolver and always shoots when she pulls out the gray one. Soon, Adam will cringe only at the gray revolver. He is showing stimulus discriminationthe tendency to lack a

    conditioned response to a new stimulus that resembles the original conditioned stimulus.

Higher-Order Conditioning

    Now suppose that after Adam has been conditioned to cringe at the sight of the revolver, Professor Smith comes to class one day and pulls out the revolver while yelling, “Fire!” She does this many times. Each

    time, Adam cringes because he is conditioned to respond to the revolver. If she then yells, “Fire!” without pulling out the revolver, Adam will still cringe due to higher-order conditioningthe process by which a

    neutral stimulus comes to act as a conditioned stimulus by being paired with another stimulus that already evokes a conditioned response.

Phobias and Conditioning

    A phobia is an intense, irrational fear that impairs a person’s ability to function normally or participate in normal activities. Phobias, such as Little Albert’s fear of rats and white, furry objects, may result from classical conditioning. For example, if someone has a near-drowning experience, he may become afraid of water in general.

In the late nineteenth century, psychologist Edward Thorndike proposed the law of effect. The law of

    effect states that any behavior that has good consequences will tend to be repeated, and any behavior that has bad consequences will tend to be avoided. In the 1930s, another psychologist, B. F. Skinner,

    extended this idea and began to study operant conditioning. Operant conditioning is a type of learning

    in which responses come to be controlled by their consequences. Operant responses are often new responses.

    Just as Pavlov’s fame stems from his experiments with salivating dogs, Skinner’s fame stems from his experiments with animal boxes. Skinner used a device called the Skinner box to study operant conditioning. A Skinner box is a cage set up so that an animal can automatically get a food reward if it makes a particular kind of response. The box also contains an instrument that records the number of responses an animal makes.

Psychologists use several key terms to discuss operant conditioning principles, including reinforcement

    and punishment.

Reinforcement

    Reinforcement is delivery of a consequence that increases the likelihood that a response will occur. Positive reinforcement is the presentation of a stimulus after a response so that the response will occur more often. Negative reinforcement is the removal of a stimulus after a response so that the response will occur more often. In this terminology, positive and negative don’t mean good and bad. Instead,

    positive means adding a stimulus, and negative means removing a stimulus.

Punishment

    Punishment is the delivery of a consequence that decreases the likelihood that a response will occur. Positive and negative punishments are analogous to positive and negative reinforcement. Positive

    punishment is the presentation of a stimulus after a response so that the response will occur less often. Negative punishment is the removal of a stimulus after a response so that the response will occur less often.

    Reinforcement helps to increase a behavior, while punishment helps to decrease a behavior.

Primary and Secondary Reinforcers and Punishers

Reinforcers and punishers are different types of consequences:

    ; Primary reinforcers, such as food, water, and caresses, are naturally satisfying.

    ; Primary punishers, such as pain and freezing temperatures, are naturally unpleasant.

    ; Secondary reinforcers, such as money, fast cars, and good grades, are satisfying because

    they’ve become associated with primary reinforcers.

    ; Secondary punishers, such as failing grades and social disapproval, are unpleasant because

    they’ve become associated with primary punishers.

    ; Secondary reinforcers and punishers are also called conditioned reinforcers and punishers

    because they arise through classical conditioning.

    Is It Primary or Secondary?

    To distinguish between primary and secondary reinforcers, people can ask themselves this question: “Would a newborn baby find this stimulus satisfying?” If the answer is yes, the reinforcer is primary. If the answer is no, it’s secondary. The same idea can be applied to punishers by asking whether a baby would

    find the stimulus unpleasant.

Shaping

    Shaping is a procedure in which reinforcement is used to guide a response closer and closer to a desired response.

Example:

    Lisa wants to teach her dog, Rover, to bring her the TV remote control. She places the remote in Rover’s

    mouth and then sits down in her favorite TV–watching chair. Rover doesn’t know what to do with the

    remote, and he just drops it on the floor. So Lisa teaches him by first praising him every time he accidentally walks toward her before dropping the remote. He likes the praise, so he starts to walk toward her with the remote more often. Then she praises him only when he brings the remote close to the chair. When he starts doing this often, she praises him only when he manages to bring the remote right up to her. Pretty soon, he brings her the remote regularly, and she has succeeded in shaping a response.

Reinforcement Schedules

    A reinforcement schedule is the pattern in which reinforcement is given over time. Reinforcement schedules can be continuous or intermittent. In continuous reinforcement, someone provides

    reinforcement every time a particular response occurs. Suppose Rover, Lisa’s dog, pushes the remote under her chair. If she finds this amusing and pats him every time he does it, she is providing continuous reinforcement for his behavior. In intermittent or partial reinforcement, someone provides

reinforcement on only some of the occasions on which the response occurs.

Types of Intermittent Reinforcement Schedules

    There are four main types of intermittent schedules, which fall into two categories: ratio or interval. In a ratio schedule, reinforcement happens after a certain number of responses. In an interval schedule,

    reinforcement happens after a particular time interval.

    ; In a fixed-ratio schedule, reinforcement happens after a set number of responses, such as

    when a car salesman earns a bonus after every three cars he sells.

    ; In a variable-ratio schedule, reinforcement happens after a particular average number of

    responses. For example, a person trying to win a game by getting heads on a coin toss gets

    heads every two times, on average, that she tosses a penny. Sometimes she may toss a penny

    just once and get heads, but other times she may have to toss the penny two, three, four, or

    more times before getting heads.

    ; In a fixed-interval schedule, reinforcement happens after a set amount of time, such as when

    an attorney at a law firm gets a bonus once a year.

    ; In a variable-interval schedule, reinforcement happens after a particular average amount of

    time. For example, a boss who wants to keep her employees working productively might walk by

    their workstations and check on them periodically, usually about once a day, but sometimes

    twice a day, or some-times every other day. If an employee is slacking off, she reprimands him.

    Since the employees know there is a variable interval between their boss’s appearances, they

    must stay on task to avoid a reprimand.

    Response Patterns

    These different types of reinforcement schedules result in different patterns of responses:

    ; Partial or intermittent schedules of reinforcement result in responses that resist extinction better

    than responses resulting from continuous reinforcement. Psychologists call this resistance to

    extinction the partial reinforcement effect.

    ; Response rate is faster in ratio schedules than in interval schedules. Ratio schedules depend

    on number of responses, so the faster the subject responds, the more quickly reinforcement

    happens.

    ; A fixed-interval schedule tends to result in a scalloped response pattern, which means that

    responses are slow in the beginning of the interval and faster just before reinforcement happens.

    If people know when reinforcement will occur, they will respond more at that time and less at

    other times.

    ; Variable schedules result in steadier response rates than fixed schedules because

    reinforcement is less predictable. Responses to variable schedules also cannot be extinguished

    easily.

    Extinction

As in classical conditioning, extinction in operant conditioning is the gradual disappearance of a

    response when it stops being reinforced. In the earlier example, Lisa’s dog, Rover, started to put the remote under her chair regularly because she continuously reinforced the behavior with pats on his head. If she decides that the game has gone too far and stops patting him when he does it, he’ll eventually stop the behavior. The response will be extinguished.

Stimulus Discrimination

If Lisa enjoys Rover’s antics with the TV remote only in the daytime and not at night when she feels tired,

    Rover will put the remote under her chair only during the day, because daylight has become a signal that tells Rover his behavior will be reinforced. Daylight has become a discriminative stimulus. A discriminative stimulus is a cue that indicates the kind of consequence that’s likely to occur after a response. In operant conditioning, stimulus discrimination is the tendency for a response to happen

    only when a particular stimulus is present.

Stimulus Generalization

    Suppose Lisa’s dog, Rover, began to put the remote under her chair not only during the day but also whenever a bright light was on at night, thinking she would probably pat him. This is called stimulus generalization. In operant conditioning, stimulus generalization is the tendency to respond to a new

    stimulus as if it is the original discriminative stimulus.

    Biological Influences

    Conditioning accounts for a lot of learning, both in humans and nonhuman species. However, biological factors can limit the capacity for conditioning. Two good examples of biological influences on conditioning are taste aversion and instinctive drift.

Taste Aversion

    Psychologist John Garcia and his colleagues found that aversion to a particular taste is conditioned only by pairing the taste (a conditioned stimulus) with nausea (an unconditioned stimulus). If taste is paired

with other unconditioned stimuli, conditioning doesn’t occur.

    Similarly, nausea paired with most other conditioned stimuli doesn’t produce aversion to those stimuli. Pairing taste and nausea, on the other hand, produces conditioning very quickly, even with a delay of several hours between the conditioned stimulus of the taste and the unconditioned stimulus of nausea. This phenomenon is unusual, since normally classical conditioning occurs only when the unconditioned stimulus immediately follows the conditioned stimulus.

Example:

    Joe eats pepperoni pizza while watching a movie with his roommate, and three hours later, he becomes nauseated. He may develop an aversion to pepperoni pizza, but he won’t develop an aversion to the movie he was watching or to his roommate, even though they were also present at the same time as the pizza. Joe’s roommate and the movie won’t become conditioned stimuli, but the pizza will. If, right after eating the pizza, Joe gets a sharp pain in his elbow instead of nausea, it’s unlikely that he will develop an

    aversion to pizza as a result. Unlike nausea, the pain won’t act as an unconditioned stimulus.

An Evolutionary Adaptation

    The combination of taste and nausea seems to be a special case. Researchers think that learning to quickly associate taste and nausea is an evolutionary adaptation, since this association helps people to know what foods to avoid in order to survive.

Instinctive Drift

    Instinctive drift is the tendency for conditioning to be hindered by natural instincts. Two psychologists, Keller and Marian Breland, were the first to describe instinctive drift. The Brelands found that through operant conditioning, they could teach raccoons to put a coin in a box by using food as a reinforcer. However, they couldn’t teach raccoons to put two coins in a box. If given two coins, raccoons just held on

    to the coins and rubbed them together. Giving the raccoons two coins brought out their instinctive food-washing behavior: raccoons instinctively rub edible things together to clean them before eating them. Once the coins became associated with food, it became impossible to train them to drop the coins into the box.

Cognitive Influences

    Researchers once thought of conditioning as automatic and not involving much in the way of higher mental processes. However, now researchers believe that conditioning does involve some information

processing.

    The psychologist Robert Rescorla showed that in classical conditioning, pairing two stimuli doesn’t

    always produce the same level of conditioning. Conditioning works better if the conditioned stimulus acts as a reliable signal that predicts the appearance of the unconditioned stimulus.

Example:

    Consider the earlier example in which Adam’s professor, Professor Smith, pulled out a revolver in class

    and shot it into the air, causing Adam to cringe. If Adam heard a gunshot only when Professor Smith pulled out her revolver, he would be conditioned to cringe at the sight of the revolver. Now suppose Professor Smith sometimes took out the revolver as before and fired it. Other times, she played an audio recording of a gunshot without taking out the revolver. The revolver wouldn’t predict the gunshot sound as well now, since gunshots happen both with and without the revolver. In this case, Adam wouldn’t

    respond as strongly to the sight of the revolver.

    The fact that classical conditioning depends on the predictive power of the conditioned stimulus, rather than just association of two stimuli, means that some information processing happens during classical conditioning. Cognitive processes are also involved in operant conditioning. A response doesn’t increase just because satisfying consequences follow the response. People usually think about whether the response caused the consequence. If the response did cause the consequence, then it makes sense to keep responding the same way. Otherwise, it doesn’t

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