5 Steps to a 5 AP Psychology, 2010-2011 Edition (34 page)

Figure 10.2 Partial reinforcement schedules
.

fixed ratio schedule—know
how much
behavior for reinforcement
fixed interval schedule—know
when
behavior is reinforced
variable ratio schedule—
how much
behavior for reinforcement changes
variable interval schedule—
when
behavior is reinforced changes

Have you ever wondered how people develop superstitions? B. F. Skinner accounted for the development of superstitious behaviors in partial reinforcement schedule experiments he performed with pigeons. He found that if food pellets were delivered when a pigeon was performing some idiosyncratic behavior, the pigeon would tend to repeat the behavior to get more food. If food pellets were again delivered when the pigeon repeated the behavior, the pigeon would tend to repeat the behavior over and over, thus indicating the development of “superstitious behavior.” Although there was a correlation between the idiosyncratic behavior and the appearance of food, there was no causal relationship between the superstitious behavior and delivery of the food to the pigeon. But the pigeons acted as if there were. People who play their “lucky numbers” when they gamble or wear their “lucky jeans” to a test may have developed superstitions from the unintended reinforcement of unimportant behavior, too.

John B. Watson and B. F. Skinner typified behaviorists. They studied only behaviors they could observe and measure—the ABCs of behavior: antecedents, observable behaviors, and their consequences. They disregarded thought processes because they could not observe or measure them. They considered learned behaviors the result of nurture (the environment).

Cognitivists interpret classical and operant conditioning differently. Beyond making associations between stimuli and learning from rewards and punishment, cognitive theorists believe that humans and other animals are capable of forming expectations and consciously being motivated by rewards. Pavlov’s view of classical conditioning is called the
contiguity model
. He believed that the close time between the CS and the US was most important for making the connection between the two stimuli and that the CS eventually substituted for the US. Cognitivist Robert Rescorla challenged this viewpoint, suggesting a
contingency model
of classical conditioning that the CS tells the organism that the US will follow. Although the close pairing in time between the two stimuli is important, the key is how well the CS predicts the appearance of the UCS. Another challenge to Pavlov’s model is what Leon Kamin calls the
blocking
effect. Kamin paired a light (NS) with a tone (CS) that had already been classically conditioned with shock (UCS) to produce fear (CR). He found that he was unable to produce conditioned fear to the light alone. He argued that the rat had already learned to associate the signal for shock with the tone so that the light offered no new information. The conditioning effect of the light was blocked.

Although reinforcement or punishment that occurs immediately after a behavior has a stronger effect than delayed consequences, timing sometimes is less critical for human behavior. The ability to delay gratification—forgo an immediate but smaller reward for a postponed greater reward—often affects decisions. Saving money for college, a car, or something else special rather than spending it immediately is an example. People vary in the ability to delay gratification, which partially accounts for the inability of some people to quit smoking or lose weight.

Cognitive theorists also see evidence of thinking in operant conditioning.
Latent learning
is defined as learning in the absence of rewards. Edward Tolman studied spatial learning by conducting maze experiments with rats under various conditions. An experimental group of rats did not receive a reward for going through a maze for 10 days, while another group did. The rewarded group made significantly fewer errors navigating the maze. On day 11, both groups got rewards. On day 12, the previously unrewarded group navigated the maze as well as the rewarded group, demonstrating latent learning. He hypothesized that previously unrewarded rats formed a cognitive map or mental picture of the maze during the early nonreinforced trials. Once they were rewarded, they expected future rewards and, thus, were more motivated to improve.

Have you ever walked out of a class after leaving a problem blank on your test and suddenly the answer popped into your head?
Insight
is the sudden appearance of an answer or solution to a problem. Wolfgang Kohler exposed chimpanzees to new learning tasks and concluded that they learned by insight. In one study, a piece of fruit was placed outside Sultan’s cage beyond his reach. A short stick was inside the cage. After several attempts using the stick to reach the fruit were unsuccessful, Sultan stopped trying and stared at the fruit. Suddenly Sultan bolted up and, using the short stick, raked in a longer stick outside his cage. By using the second stick, he was able to get the fruit. No conditioning had been used.

A type of social cognitive learning is called modeling or
observational learning,
which occurs by watching the behavior of a model. For example, if you want to learn a new dance step, first you watch someone else do it. Next you try to imitate what you saw the person do. The cognitive aspect comes in when you think through how the person is moving various body parts and, keeping that in mind, try to do it yourself. Learning by observation is adaptive, helping us save time and avoid danger. Albert Bandura, who pioneered the study of observational learning, outlined four steps in the process: attention, retention, reproduction, and motivation. In his famous experiment using inflated “bobo” dolls, he showed three groups of children a scene where a model kicked, punched, and hit the bobo doll. One group saw the model rewarded, another group saw no consequences, the third group saw the model punished. Each child then went to a room with a bobo doll and other toys. The children who saw the model punished kicked, punched, and hit the bobo doll less than the other children. Later, when they were offered rewards to imitate what they had seen the model do, that group of children was as able to imitate the behavior as the others. Further research indicated viewing violence reduces our sensitivity to the sight of violence, increases the likelihood of aggressive behavior, and decreases our concerns about the suffering of victims. Feeling pride or shame in ourselves for doing something can be important internal reinforcers that influence our behavior.

Abstract learning goes beyond classical and operant conditioning and shows that animals such as pigeons and dolphins can understand simple concepts and apply simple decision rules. In one experiment, pigeons pecked at different-colored squares. The pigeon was first shown a red square and then two squares—one red and the other green. In matching-to-sample problems, pecking the red square, or “same,” was rewarded. In oddity tasks, pecking the green square, or “different,” would bring the reward. To prove this wasn’t merely operant conditioning, the stimuli were changed, and in 80% of the trials, the pigeons proved successful in making the transfer of “same” or “different.”

Mirror neurons in the premotor cortex and other portions of the temporal and parietal lobes provide a biological basis for observational learning. The neurons are activated not only when you perform an action, but also when you observe someone else perform a similar action. These neurons transform the sight of someone else’s action into the motor program you would use to do the same thing and to experience similar sensations or emotions, the basis for empathy.

Taste aversions are an interesting biological application of classical conditioning. A few hours after your friend ate brussels sprouts for the first time, she vomited. Although a stomach virus (UCS) caused the vomiting (UCR), your friend refuses to eat brussels sprouts again. She developed a
conditioned taste aversion,
an intense dislike and avoidance of a food because of its association with an unpleasant or painful stimulus through backward conditioning. According to some psychologists, conditioned taste aversions are probably adaptive responses of organisms to foods that could sicken or kill them. Evolutionarily successful organisms are biologically predisposed or biologically prepared to associate illness with bitter and sour foods.
Preparedness
means that through evolution, animals are biologically predisposed to easily learn behaviors related to their survival as a species, and that behaviors contrary to an animal’s natural tendencies are learned slowly or not at all. People are more likely to learn to fear snakes or spiders than flowers or happy faces. John Garcia and colleagues experimented with rats exposed to radiation, and others exposed to poisons.
They found that rats developed conditioned taste aversions even when they did not become nauseated until hours after being exposed to a taste, which is sometimes referred to as the Garcia effect. Similarly, cancer patients undergoing chemotherapy develop loss of appetite. They also found that there are biological constraints on the ease with which particular stimuli can be associated with particular responses. Rats have a tendency to associate nausea and dizziness with tastes, but not with sights and sounds. Rats also tend to associate pain with sights and sounds, but not with tastes.

Sometimes, operantly conditioned animals failed to behave as expected. Wild rats already conditioned in Skinner boxes sometimes reverted to scratching and biting the lever. In different experiments, Keller and Marian Breland found that stimuli that represented food were treated as actual food by chickens and raccoons. The Brelands attributed this to the strong evolutionary history of the animals that overrode conditioning. They called this
instinctive drift
—a conditioned response that drifts back toward the natural (instinctive) behavior of the organism. Wild animal trainers must stay vigilant even after training their animals because they may revert to dangerous behaviors.

Directions:
For each item, choose the letter of the choice that best completes the statement or answers the question.

1.
Once Pavlov’s dogs learned to salivate to the sound of a tuning fork, the tuning fork was a(n)

(A) unconditioned stimulus

(B) neutral stimulus

(C) conditioned stimulus

(D) unconditioned response

(E) conditioned response

2.
Shaping is

(A) a pattern of responses that must be made before classical conditioning is completed

(B) rewarding behaviors that get closer and closer to the desired goal behavior

(C) completing a set of behaviors in succession before a reward is given

(D) giving you chocolate pudding to increase the likelihood you will eat more carrots

(E) inhibition of new learning by previous learning

3.
John loves to fish. He puts his line in the water and leaves it there until he feels a tug. On what reinforcement schedule is he rewarded?

(A) continuous reinforcement

(B) fixed ratio

(C) fixed interval

(D) variable ratio

(E) variable interval

4.
Chimpanzees given tokens for performing tricks were able to put the tokens in vending machines to get grapes. The tokens acted as

(A) primary reinforcers

(B) classical conditioning

(C) secondary reinforcers

(D) negative reinforcers

(E) unconditioned reinforcers

5.
Which of the following best reflects negative reinforcement?

(A) Teresa is scolded when she runs through the house yelling.

(B) Lina is not allowed to watch television until after she has finished her homework.

(C) Greg changes his math class so he doesn’t have to see his old girlfriend.

(D) Aditya is praised for having the best essay in the class.

(E) Alex takes the wrong medicine and gets violently ill afterwards.

6.
Watson and Rayner’s classical conditioning of “Little Albert” was helpful in explaining that

(A) some conditioned stimuli do not generalize

(B) human emotions such as fear are subject to classical conditioning

(C) drug dependency is subject to classical as well as operant conditioning

(D) small children are not as easily conditioned as older children

(E) fear of rats and rabbits are innate responses previously undiscovered

7.
Jamel got very sick after eating some mushrooms on a pizza at his friend’s house. He didn’t know that he had a stomach virus at the time, blamed his illness on the mushrooms, and refused to eat them again. Which of the following is the unconditioned stimulus for his taste aversion to mushrooms?