CHAPTER 8
Conditioning and Learning
Theme: The principles of learning can be used to understand and manage behavior.
Preview
What Did You Learn in School Today?
When your aging author was in college we discovered an intriguing flaw in the dorm plumbing: Flush a toilet while someone was taking a shower and the cold water pressure would suddenly drop. This caused the shower to become scalding hot. Naturally, the shower victim screamed in terror as his reflexes caused him to leap backward in pain. Soon we discovered that if we flushed all
the toilets at once, the effects were multiplied many times over!
A toilet has to be one of the world’s most uninspiring stimuli.
But for a time, a whole flock of college students twitched involuntarily whenever they heard a toilet flush. Their reactions were the result of classical conditioning, a basic type of learning.
Classical conditioning is one of the topics of this chapter.
Now, let’s say that you are at school and you feel like you are “starving to death.” You locate a vending machine and deposit your last two quarters to buy a candy bar. Then you press the button, and . . . nothing happens. Being civilized and in complete control, you press the other buttons, try the coin return, and look for an attendant. Still nothing. Your stomach growls. Impulsively, you give the machine a little kick (just to let it know how you feel). Then, as you turn away, out pops a candy bar plus 25 cents change. Once this happens, chances are good that you will repeat the “kicking response” in the future. If it pays off several times more, kicking vending machines may become a regular feature of your behavior. In this case, learning is based on operant conditioning (also called instrumental learning).
Classical and operant conditioning reach into every corner of our lives. Are you ready to learn more about learning? If so, read on!
¡ Conditioning is a fundamental type of learning that affects many aspects of daily life.
¡ In classical conditioning, a neutral stimulus is repeatedly paired with a stimulus that reliably provokes a response.
By association, the neutral stimulus also begins to elicit a response.
¡ In operant conditioning, responses that are followed by reinforcement occur more frequently.
¡ To understand why people behave as they do, it is important to identify how their responses are being reinforced.
¡ Cognitive learning involves acquiring higher level information, rather than just linking stimuli and responses.
¡ We also learn by observing and imitating the actions of others.
¡ Behavioral principles can be used to manage one’s own behavior.
¡ Biological behavior patterns facilitate the learning of some responses while making others more difficult to learn.
Gateways to Learning
What is learning?
How does classical conditioning occur?
Does conditioning affect emotions?
How does operant conditioning occur?
Are there different kinds of operant reinforcement?
How are we influenced by patterns of reward?
What does punishment do to behavior?
What is cognitive learning?
Does learning occur by imitation?
How does conditioning apply to practical problems?
How does biology influence learning?
Key Questions
What Is Learning—Does Practice Make Perfect?
Most behavior is learned. Imagine if you suddenly lost all you had ever learned.What could you do? You would be unable to read, write, or speak. You couldn’t feed yourself, find your way home, drive a car, play the bassoon, or “party.” Needless to say, you would be totally incapacitated. (Dull, too!)
Learning is obviously important. What’s a formal definition of learning? Learning is a relatively permanent change in behavior due to experience. Notice that this definition excludes temporary changes caused by motivation, fatigue, maturation, disease, injury, or drugs. Each of these can alter behavior, but none qualifies as learning.
Isn’t learning the result of practice? It depends on what you mean by practice. Merely repeating a response will not necessarily produce learning. You could close your eyes and swing a tennis racket hundreds of times without learning anything about tennis. Reinforcement is the key to learning. Reinforcement
refers to any event that increases the probability that a response will occur again. A response is any identifiable behavior.
Responses may be observable actions, such as blinking, eating a piece of candy, or turning a doorknob. They can also be internal, such as having a faster heartbeat.
To teach a dog a trick, I could reinforce correct responses by giving the dog some food each time it sits up. Similarly, you could teach a child to be neat by praising her for picking up her toys. Learning can also occur in other ways. For instance, if a girl gets stung by a bee, she may learn to associate pain with bees and to fear them. In this case, the girl’s fear is reinforced by the discomfort she feels immediately after seeing the bee. Later, you’ll discover how such varied experiences lead to learning.
Antecedents and Consequences
Unlocking the secrets of learning begins with noting what happens before and after a response. Events that precede a response are called antecedents. Effects that follow a response are consequences.
Paying careful attention to the “before and after” of learning is a key to understanding it.
Learning Any relatively permanent change in behavior that can be attributed to experience.
Reinforcement Any event that increases the probability that a particular response will occur.
Response Any identifiable behavior.
Antecedents Events that precede a response.
Consequences Effects that follow a response.
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Classical Conditioning
Classical conditioning is based on what happens before a response.
We begin with a stimulus that reliably triggers a response.
Imagine, for example, that a puff of air (the stimulus) is aimed at your eye. The air puff will make you blink (a response) every time. The eye blink is a reflex (automatic, nonlearned response).
Now, assume that we sound a horn (another stimulus) just before each puff of air hits your eye. If the horn and the air puff occur together many times, what happens? Soon, the horn alone will make you blink. What took place? Clearly, you’ve learned something. Before, the horn didn’t make you blink. Now it does.
Similarly, if your mouth waters each time you eat a cookie, you may learn to salivate when you merely see a cookie, a picture of cookies, a cookie jar, or other stimuli that preceded salivation.
In classical conditioning, antecedent events become associated with one another: A stimulus that does not produce a response is linked with one that does (a horn is associated with a puff of air to the eye, for example).We can say that learning has occurred when the new stimulus will also elicit (bring forth) responses (œFig. 8.1).
Operant Conditioning
In operant conditioning, learning is based on the consequences of responding. A response may be followed by a reinforcer (such as food). Or by punishment. Or by nothing. These results determine whether a response is likely to be made again (Fig.
8.1). For example, if you wear a particular hat and get lots of compliments (reinforcement), you are likely to wear it more often.
If people snicker, insult you, call the police, or scream (punishment), you will probably wear it less often.
Now that you have an idea of what happens in the two basic kinds of learning, let’s look at classical conditioning in more detail.
Classical Conditioning—Does the Name Pavlov Ring a Bell?
How was classical conditioning discovered? At the beginning of the twentieth century, something happened in the lab of Russian physiologist Ivan Pavlov that brought him lasting fame.
The event now seems so trivial that a lesser man might have ignored it: Pavlov’s subjects drooled at him.
Actually, Pavlov was studying digestion. To observe salivation, he placed meat powder or some tidbit on a dog’s tongue.
After doing this many times, Pavlov noticed that his dogs were salivating before the food reached their mouths. Later, the dogs even began to salivate when they saw Pavlov enter the room.Was this misplaced affection? Pavlov knew better. Salivation is normally a reflex. For the animals to salivate at the mere sight of food, some type of learning had to have occurred. Pavlov called it conditioning (œFig. 8.2). Because of its importance in psychology’s history, it is now called classical conditioning (also known as Pavlovian conditioning or respondent conditioning).
Pavlov’s Experiment
How did Pavlov study conditioning? After Pavlov observed that meat powder made his dogs salivate, he began his classic experiments (Fig. 8.2). To begin, he rang a bell. At first, the bell was a neutral stimulus (it did not evoke a response). Immediately after Pavlov rang the bell, he placed meat powder on the dog’s tongue, which caused reflex salivation. This sequence was repeated many times: bell, meat powder, salivation; bell, meat powder, salivation. Eventually (as conditioning took place), the
Result: Horn Eye blink Classical Conditioning
Response
Eye blink
Key relationship Key relationship Stimulus
Horn
Stimulus
Air puff Result: Whistle Sit-up
Reinforcer
Food
Whistle
Sit-up
Time Antecedents Response Consequences
œ Figure 8.1 In classical conditioning, a stimulus that does not produce a response is paired with a stimulus that does elicit a response.After many such pairings, the stimulus that previously had no effect begins to produce a response. In the example shown, a horn precedes a puff of air to the eye. Eventually the horn alone will produce an eye blink. In operant conditioning, a response that is followed by a reinforcing consequence becomes more likely to occur on future occasions. In the example shown, a dog learns to sit up when it hears a whistle.
œ Figure 8.2 An apparatus for Pavlovian conditioning.A tube carries saliva from the dog’s mouth to a lever that activates a recording device (far left). During conditioning, various stimuli can be paired with a dish of food placed in front of the dog.
The device pictured here is more elaborate than the one Pavlov used in his early experiments.
CONDITIONING AND LEARNING 295
dogs began to salivate when they heard the bell (œFig. 8.3). By association, the bell, which before had no effect, began to evoke the same response as food. This was shown by sometimes ringing the bell alone. Pavlov then observed that the dog salivated even when no food was present.
Psychologists use several terms to describe these events. The bell in Pavlov’s experiment starts out as a neutral stimulus (NS). In time, the bell becomes a conditioned stimulus (CS) (a stimulus that, because of learning, will evoke a response). The meat powder is an unconditioned stimulus (US) (a stimulus innately capable of eliciting a response).Notice that the dog did not have to learn to respond to the US. Such stimuli naturally elicit reflexes or emotional reactions.
Because a reflex is innate, or “built in,” it is called an unconditioned
(nonlearned) response (UR). Reflex salivation was the UR in Pavlov’s experiment. When Pavlov’s bell also produced salivation, the dog was making a new response. Thus, salivation had become a conditioned (learned) response (CR) (Fig. 8.3).
¡Table 8.1 summarizes the important elements of classical conditioning.
Are all these terms really necessary? Yes, because they help us recognize similarities in various instances of learning. Let’s summarize the terms using an earlier example:
Before Conditioning Example
US 0UR Puff of air 0eye blink NS 0no effect Horn 0no effect
After Conditioning Example
CS 0CR Horn 0eye blink
Now let’s see if we can explain the shower and flushing toilet example described earlier. The unconditioned, or nonlearned, response was a reflex jump from the hot water. The unconditioned stimulus was the hot water (or the pain it caused). The conditioned stimulus was the sound of a flushing toilet. That is, the flushing sound was at first neutral. But as a result of conditioning, it became capable of eliciting a reflex.
Principles of Classical Conditioning— Teach Your Little Brother to Salivate
To observe conditioning, you could ring a bell, squirt lemon juice into a child’s mouth, and condition salivation to the bell.
The child’s reactions might then be used to explore other as-
Reflex An innate, automatic response to a stimulus; for example, an eye blink.
Classical conditioning A form of learning in which reflex responses are associated with new stimuli.
Operant conditioning Learning based on the consequences of responding.
Neutral stimulus A stimulus that does not evoke a response.
Conditioned stimulus A stimulus that evokes a response because it has been repeatedly paired with an unconditioned stimulus.
Unconditioned stimulus A stimulus innately capable of eliciting a response.
Unconditioned response An innate reflex response elicited by an unconditioned stimulus.
Conditioned response A learned response elicited by a conditioned stimulus.
Time
No salivation Meat powder (US) Meat powder (US) Salivation (UR) Salivation (UR) Salivation (CR) Reflex Reflex Conditioned reflex Associated
Before Conditioning During Conditioning (Acquisition) Test for Conditioning
Bell (NS) Bell (CS) Bell (CS)
œ Figure 8.3 The classical conditioning procedure.
TABLE
8.1 Elements of Classical Conditioning
ELEMENT SYMBOL DESCRIPTION EXAMPLE
Neutral stimulus NS A stimulus that does not evoke a response Bell Unconditioned stimulus US A stimulus innately capable of eliciting a response Meat powder Conditioned stimulus CS A stimulus that evokes a response because it has been repeatedly paired with an Bell unconditioned stimulus Unconditioned response UR An innate reflex response elicited by an unconditioned stimulus Reflex salivation Conditioned response CR A learned response elicited by a conditioned stimulus Salivation
296 CHAPTER 8
pects of classical conditioning. Let’s see how conditioning occurs.
Acquisition
During acquisition, or training, a conditioned response must be reinforced (strengthened) (œFig. 8.4). Classical conditioning is reinforced when the CS is followed by, or paired with, an unconditioned stimulus. For our child, the bell is the CS, salivating is the UR, and the sour lemon juice is a US. To reinforce salivating to the bell, we must link the bell with the lemon juice.
Conditioning will be most rapid if the US (lemon juice) follows
immediately after the CS (the bell).With most reflexes, the optimal delay between CS and US is from one-half second to about 5 seconds (Schwartz & Robbins, 1995).
Higher Order Conditioning
Once a response is learned, it can bring about higher order conditioning. In this case, a well-learned CS is used to reinforce further learning. That is, the CS has become strong enough to be used like an unconditioned stimulus. Let’s illustrate again with our salivating child.
As a result of earlier learning, the bell now makes the boy salivate. (No lemon juice is needed.) To go a step further, you could clap your hands and then ring the bell. (Again, no lemon juice would be used.) Through higher order conditioning, the child would soon learn to salivate when you clapped your hands (œFig. 8.5). (This little trick could be a real hit with friends and neighbors.)
Higher order conditioning extends learning one or more steps beyond the original conditioned stimulus. Many advertisers use this effect by pairing images that evoke good feelings (such as people smiling and having fun) with pictures of their products.
Obviously, they hope that you will learn, by association, to feel good when you see their products (Johnsrude et al., 1999).
Expectancies
Many psychologists believe that classical conditioning is related to information that might aid our survival.According to this informational view, we look for associations among events. Doing so creates new mental expectancies, or expectations about how events are interconnected.
How does classical conditioning alter expectancies? Notice that the conditioned stimulus reliably precedes the unconditioned stimulus. Because it does, the CS predicts the US (Rescorla, 1987). During conditioning, the brain learns to expect that the US will follow the CS. As a result, the brain prepares the body to respond to the US. Here’s an example: When you are about to get a shot with a hypodermic needle, your muscles tighten and there is a catch in your breathing.Why? Because your body is preparing for pain. You have learned to expect that getting poked with a needle will hurt. This expectancy, which was acquired during classical conditioning, changes your behavior.
Extinction and Spontaneous Recovery
After conditioning has occurred, what would happen if the US no longer followed the CS? If the US never again follows the CS, conditioning will extinguish, or fade away. Let’s return to the boy and the bell. If you ring the bell many times and do not follow it with lemon juice, the boy’s expectancy that “bell precedes lemon juice”will weaken. As it does, he will lose his tendency to salivate when he hears the bell. Thus, we see that classical conditioning can be weakened by removing reinforcement (see Fig.
8.4). This process is called extinction.
If conditioning takes a while to build up, shouldn’t it take time to reverse? Yes. In fact, it may take several extinction sessions to completely reverse conditioning. Let’s say that we ring the bell until the child quits responding. It might seem that extinction is complete.
However, the boy will probably respond to the bell again on the following day, at least at first. The reappearance of a response fol-
16 14 12 10 8 6 4 2 4 8 12 0 14 12 10 8 6 4 2 2 4 6 0 810 Test trials during acquisition Test trials during extinction Drops of saliva to CS Drops of saliva to CS
œ Figure 8.4 Acquisition and extinction of a conditioned response. (After Pavlov, 1927.)
Before Conditioning
US
Lemon juice
UR
Salivation During Conditioning
Salivation Test for Conditioning
CS
Bell
CR
Salivation Higher Order Conditioning
CS1 CS2
CS2
Salivation Test for Conditioning Clap
Salivation
— CS
—
Clap
œ Figure 8.5 ...
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