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Chapter 7
LEARNING AND CONDITIONING
LEARNING OBJECTIVES
At the end of this lesson the student will be able to:
1. Explain what is meant by associative learning. Know the distinction between
classical conditioning and operant conditioning.
2. Describe Pavlov’s experiments, and define and differentiate between the CR,
UCR, the CS, and the UCS.
3. Describe how generalization and discrimination function in classical conditioning.
4. Discuss the law of effect in relation to operant conditioning. Define extinction and
discrimination for operant conditioning in a “Skinner box.”
5. Define conditioned reinforcement, partial reinforcement, and punishment and
give examples of how these concepts apply to everyday life.
6. Explain the ethologist’s objections to a behavioristic approach to learning, and
their notion of behavioral constraints.
7. Cite evidence used by cognitivists to argue against the behaviorist approach to
learning.
FOCUS QUESTIONS
1. What is associative learning? What is the difference between classical and
operant conditioning as forms of associative learning?
2. How did Pavlov study learning processes? What research format did he use?
3. How do the concepts of generalization and discrimination help us understand
learning processes?
4. What is the law of effect? How do we use the concepts of extinction,
discrimination and shaping in operant conditioning?
5. How can the concepts of conditioned reinforcement, partial reinforcement and
punishment help us understand everyday behavior?
6. What is an “ethologist” and what objections do they have to behaviorism?
7. What criticisms do cognitive psychologists use against behaviorism?
KEY POINTS AND COMMENTARY
Learning may be defined as a relatively permanent change in behavior that is
the result of experience. We would distinguish learning as behavior change from other
processes such as maturation, which are supposed to be changes due to the physical
development of the organism.
The behaviorist school of thought that you will recall from Lesson 1 has
dominated the study of learning in psychology. This school believes that all behavior,
from the simplest response of a single-celled organism to the complexities of human
personality, is learned. Their research has focused on how organisms learn to make
associations between environmental stimuli, or between stimuli and responses. They
assumed that an understanding of behavior requires an explanation in terms of external,
observable factors rather than mental processes. They also believe that the building
blocks of learning were simple associations, and that these were built up into the
complex behaviors that characterize human beings. However, if we want to study the
basic processes of learning, we would do well to start with simpler organisms where the
processes can be more easily seen. The behaviorists therefore did a great deal of their
research using pigeons and rats.
Given that humans display much more complex behavior than rats and pigeons,
psychologists have come to view mental processes as being important to understanding
learning. Therefore the cognitive perspective has come to dominate the study of
complex learning.
Psychologists have come to distinguish between four basic kinds of learning.
Each of these will be covered in this Lesson:
1.
2.
3.
4.
Habituation
Classical conditioning
Instrumental conditioning
Complex learning
There is a lot of terminology in this Lesson that you will have to know.
Habituation
Habituation is the simplest form of learning. It is called nonassociative learning
because it involves learning something about the character of a single stimulus. All
organisms have an orienting response to new stimuli in their environment. When you
are sitting in a classroom and suddenly the noise of the heater comes on, you will
generally attend to it. After a while, however, you come to habituate to the sound and
you are no longer aware of it. Therefore habituation can be characterized as a
decreased behavioral response to an innocuous (harmless) stimulus. We consider this
the simplest form of learning because all organisms, even single-celled organisms,
show this response to stimuli in their environment.
Classical Conditioning
The study of learning as a process of making simple associations between
stimuli began with a Russian physiologist around 1900 – Ivan Pavlov. Pavlov was
studying the salivary response in dogs. In order to get the dog to salivate, he would
place a dish of food in front of the dog. After several times doing this, he noticed that the
dog would salivate at the mere sight of the food dish. He recognized that the dog had
made an association between the sight of the dish (a stimulus - S) and salivation
(response - R).
Pavlov embarked on an investigation of this simple learning process now called
classical conditioning. He tried to teach the dog to salivate to a new stimulus, turning
on a light. The form of his experiment was as follows:
The Classical Conditioning Experimental Paradigm
Step 1: Present the light (CS)
No response or irrelevant response
Step 2: Present food (UCS)
Dog salivates (UCR)
Step 3: Light (CS) + Food (UCS)
Dog salivates (UCR)
Step 4: Light (CS)
Dog Salivates (CR)
Commentary
Step 1: If we want to teach the dog to salivate in response to a light, we have to be
sure that the dog doesn’t already salivate to a light.
Step 2: Now we want to make sure the dog will salivate to the food dish.
Step 3: Now we turn on the light just before we give him the food
Step 4: After doing Step 3 several times, we now turn on the light without giving the
dog any food:
Classical conditioning – a learning process in which a previously neutral stimulus
becomes associated with another stimulus through repeated pairing with that stimulus.
The word “conditioning” means “learned.” Note that this is a form of associational
learning, in which what is learned is an association between a stimulus and response.
The key elements of the classical conditioning paradigm are the following:
1. UCS: the Unconditioned Stimulus – a stimulus that automatically elicits a
response without prior conditioning (learning).
2. UCR: the Unconditioned Response - a reflexive or unlearned response
elicited by the UCS.
3. CS: the Conditioned Stimulus - the learned stimulus.
4. CR: the Conditioned Response - the learned response.
Elaborations of Classical Conditioning
Can this simple notion of learning associations really help us understand
complex behavior? The behaviorists argued that yes it can, and their investigations led
them to study a number of phenomena within the classical conditioning research
paradigm.
Learning curves: By repeating the association various times, we can determine how
long it takes an animal to learn to associate a new stimulus with a reflexive or previously
learned response. If we plot this on a graph, we will get an acquisition curve. We can
also see how long it would take for the animal to “unlearn” a response. If we repeatedly
turn on the light without presenting any food, the animal will eventually stop salivating to
the light. We then say that the behavior has been extinguished.
Second-order conditioning: Once the dog has learned to salivate in response to a
light, we can then teach the dog to salivate in response to a tone by pairing the light with
the tone. This represents a second step away from the original UCS.
Generalization: Once we teach the dog to salivate to a light, we find that the dog will
also salivate to lights of different colors. The more similar a new stimulus is to the
original CS, the more likely they are to evoke the conditioned response.
Discrimination: This is the opposite of generalization. In the previous example, we
could teach the dog to discriminate between lights of different colors by only presenting
the food with one color of light.
Classical Conditioning in Humans
As an example of classical conditioning in humans, we can consider an
experiment that was done by J.B. Watson, the founder of American behaviorism.
Watson was interested in explaining how we learn phobias, or exaggerated fears of
objects or situations such as rats, snakes, spiders, or heights.
Watson worked with a boy named “Little Albert” who was 11 months old. He
observed that the child was attracted to, and liked to touch, white furry animals such as
rats or rabbits. Watson first demonstrated that the child had no natural fear of rats by
presenting a rat to the boy. The boy reached out to touch the rat. On the second time
the rat was placed in front of the boy, Watson made a loud noise behind the boy by
striking two steel bars together, just as the boy reached for the rat. The boy stopped and
whimpered in fright. The third time the boy showed more fright, and by the fourth trial
when the rat was presented the boy crawled away hurriedly, showing fear of the rat.
Watson also found that the boy showed fear when given a woman’s white furry coat,
demonstrating stimulus generalization. We would say that the child has learned an
irrational fear.
Criticisms of Classical Conditioning
Predictability, or the cognitive criticism: Behaviorists assumed that associations
were made by organisms when stimuli and/or responses occurred together in time.
However, a rather well done experiment by Rescorla demonstrated that the crucial thing
was whether the conditioned stimulus was a reliable predictor of the unconditioned
stimulus. A stimulus can only be a predictor if some mental process is going on by
which the organism is trying to determine the likelihood of an event occurring.
Biological constraints: Ethologists, who study animal behavior from an evolutionary
point of view, have pointed out that not all animals learn the same things equally, as
assumed by the behaviorists. Rats, for example, will learn faster than humans that a
particular taste indicates that something might be poisonous. Biology does in fact play
an important role in what is learned and how easily.
Instrumental Conditioning
We saw how in classical conditioning we can teach a dog to elicit an innate or
previously learned behavior to a new stimulus, but how do we teach the dog new
behaviors? To do this we have developed another research paradigm called
instrumental conditioning, which says that certain responses are learned because of
how they affect the environment. More specifically, we are likely to repeat behaviors that
are successful in some way and lead to a reward. In behaviorist terms, we say that the
behaviors are reinforced.
E.L. Thorndike
The concept of instrumental conditioning was contained in Thorndike’s
experiments with “cats in a puzzle box.” In order to escape from a cage, cats had to
learn to move a latch. The first time they would do it accidentally, by bumping into it.
When put back in the cage, they wouldn’t go over to the latch and lift it with their paw,
they would move around so they would bump into it again. In other words, the cat would
repeat the same behavior that got them out of the cage the first time. Thorndike called
this the law of effect, This states that when an animal is responding randomly in a
situation, those behaviors that lead to positive responses will be repeated.
B.F. Skinner
B.F. Skinner was the most influential of the behaviorists in the last century. He
systematically studied learning processes in rats and pigeons, and wrote a novel about
a futuristic society based on learning principles called Waldon Two.
Shaping Behavior in the Skinner Box
Skinner invented the “Skinner box” – a cage for a rat or pigeon that was used to
train the animal to press a bar or peck a circle to receive rewards. When a rat, for
example, was placed in the box for the first time it would do rat kinds of things, like
explore around the cage sticking his nose into corners, self-grooming, etc. To train the
rat to press the lever to receive food, Skinner would stand by and watch the rat. When
the rat got close to the lever Skinner would reward him with a food pellet that would
drop into the tray in the cage. After just a few times of this that rat would be hanging out
around the lever. Then Skinner would wait to reward the rat until he was actually
touching the lever with some part of his body, and continuing in this way until the rat
was pushing the lever to get his own reward. This process is called shaping, and is the
basic principle behind the training of animals in the circus and zoos.
Just like for classical conditioning, there are a number of concepts that are
important to know for understanding instrumental conditioning, and especially for
applying the learning principles to human learning. Your text will give illustrations of all
of the following:
Important Concepts of Instrumental Learning
Reinforcement: instead of “reward,” behaviorists use the word reinforcement,
which is defined as anything that increases the probability of a response.
Positive reinforcement: when a behavior is followed by a stimulus that is
desirable.
Negative reinforcement: when a behavior prevents an aversive stimulus from
occurring.
Punishment: when an aversive stimulus or the removal of a desired stimulus
decreases the probability of a behavior.
Conditioned reinforcers: a stimulus that has been consistently paired with a
primary reinforcer.
Generalization and discrimination: these terms mean the same as they do for
classical conditioning.
Schedules of reinforcement: refers to the frequency or pattern by which
reinforcement is obtained after behaviors. There are four types of schedules 1)
fixed ratio schedule, 2) variable ratio schedule, 3) fixed interval schedule, and 4)
variable interval schedule.
Escape and avoidance conditioning: when training involves teaching the animal
to escape from or avoid an aversive stimulus.
The influence of the instrumental conditioning paradigm has been considerable.
It has been used to develop successful applications in education and has led to the
development of a number of therapies for treating certain kinds of abnormal behavior.
The concepts are pervasive in modern psychology.
There have however been criticisms of the behaviorist assumptions and some of
their results. Just as for classical conditioning, the criticisms have come mainly from
cognitive psychologists and from animal ethologists.
Complex Learning
Even though the behaviorist perspective with its focus on overt behavior
dominated American psychology for much of the last century, there was always a group
of psychologists who believed that an understanding of learning processes had to take
into account mental processes.
One of the first was Edward Tolman, who believed that rats running through a
complex maze to find food were not simply learning responses to immediate stimuli, but
were learning cognitive maps of the mazes they ran.
By complex learning we mean that an organism (not just humans) learns
mental representations of the world as they go about it, and then operate on those
representations instead of the world itself. Sometimes this will mean a mental
representation of stimuli or events, but often something more complex like a map of the
environment or an abstract concept like the notion of cause. As the cognitive
psychologists have pointed out, some notion of mental events seems necessary for
explaining some of the research findings in the area of learning.
Insight Learning
The behaviorists had characterized learning as a rather slow process of trial and
error, as associations between stimuli and between stimuli and responses were built up.
However, we know that animals, and especially us, don’t always learn that way. Have
you ever been stuck on a problem, turn your back on it for a while, and then suddenly
realize the solution? This is called insight learning. Something comes together and we
have an “ah ha!” experience.
Wolfgang Köhler nicely demonstrated this process in the 1920’s in his work with
chimpanzees and problem solving.
It seems that there are two phases to complex learning. First, we arrive at a
solution by the application of a problem-solving method. Second, we store that solution
in our memory and retrieve it whenever a similar problem situation presents itself.
It also seems in actual learning situations that prior beliefs are important for
directing our attention and determining what is learned.