Chapter 6Learning

©2015 W. W. Norton & Company, Inc.

Gazzaniga • Heatherton • Halpern

FIFTH EDITION

Psychological SciencePsychological Science

6.1 How Do We Learn?

Learning Objectives• Define learning,• Identify three types of learning processes.• Describe the nonassociative learning

processes: habituation and sensitization. Explain the significance of each.

Learning Results from Experience

• Learning: a relatively enduring change in behavior, resulting from experience– Associations develop through conditioning, a

process in which environmental stimuli and behavioral responses become connected

Learning Results from Experience

• Learning theory arose in the early twentieth century in response to Freudian and introspective approaches.– John B. Watson argued that only observable behavior was

a valid indicator of psychological activity, and that the infant mind was a tabula rasa, or blank slate.

– He stated that the environment and its effects were the sole determinants of learning.

• Behaviorism was the dominant paradigm into the 1960s, and it had a huge influence on every area of psychology.

There Are Three Types of Learning

• Nonassociative learning: responding after repeated exposure to a single stimulus, or event

• Associative Learning: linking two stimuli, or events, that occur together

• Observational: acquiring or changing a behavior after exposure to another individual performing that behavior

Habituation and Sensitization Are Simple Models of Learning

• Habituation: a decrease in behavioral response after repeated exposure to a stimulus– Especially if the stimulus is neither harmful nor

rewarding

• Dishabituation: an increase in a response because of a change in something familiar

Habituation and Sensitization Are Simple Models of Learning

• Sensitization: an increase in behavioral response after exposure to a stimulus– Stimuli that most often lead to sensitization are

those that are threatening or painful.

6.2 How Do We Learn PredictiveAssociations?

Learning Objectives• Define classical conditioning.• Differentiate between US, UR, CS, and CR.• Describe acquisition, extinction, spontaneous

recovery, generalization, discrimination, second-order conditioning, and blocking.

• Describe the Rescorla-Wagner model of classical conditioning, including the role of prediction error and dopamine in the strength of associations.

• Describe the role of conditioning in the development and treatment of phobias and addictions.

6.2 How Do We Learn PredictiveAssociations?

• We learn predictive associations through conditioning, the process that connects environmental stimuli to behavior.– Psychologists study two types of associative

learning. • Classical conditioning

• Operant conditioning

Behavioral Responses Are Conditioned

• Watson was influenced by Ivan Pavlov’s research on the salivary reflex, an automatic response when food stimulus is presented to a hungry animal.– Pavlov won a Nobel Prize in 1904 for his research

on the digestive system.

• Pavlov noticed the dogs salivated as soon as they saw the bowls that usually contained food, suggesting a learned response.

Behavioral Responses Are Conditioned

• Twitmyer made a similar observation of the knee-jerk reflex in humans: when paired with a bell, subjects can be conditioned to demonstrate the knee-jerk response without other triggers.

Pavlov’s Experiments

• Classical (Pavlovian) conditioning: a neutral object comes to elicit a response when it is associated with a stimulus that already produces that response.

• A typical Pavlovian experiment involves– Conditioning trials: neutral stimulus and unconditioned

stimulus are paired to produce a reflex (e.g., salivation).• Neutral stimulus: anything the animal can see or hear as long as it

is not associated with the reflex being tested (e.g., a ringing bell).

• Unconditioned stimulus (US): a stimulus that elicits a response, such as a reflex, without any prior learning (e.g., food)

Pavlov’s Experiments

– Critical trials: neutral stimulus alone is tested, and effect on the reflex is measured

Terminology of Pavlov’s Experiments

• Unconditioned response (UR): a response that does not have to be learned, such as a reflex

• Unconditioned stimulus (US): a stimulus that elicits a response, such as a reflex, without any prior learning

Terminology of Pavlov’s Experiments

• Conditioned stimulus (CS): a stimulus that elicits a response only after learning has taken place

• Conditioned response (CR): a response to a conditioned stimulus; a response that has been learned

Acquisition, Second-Order Conditioning, Extinction, and

Spontaneous Recovery• Pavlov was influenced by Darwin and believed

that conditioning is the basis of adaptive behaviors.

• Acquisition: the gradual formation of an association between the conditioned and unconditioned stimuli– The critical element in the acquisition of a learned

association is time, or contiguity.

Acquisition, Second-Order Conditioning, Extinction, and

Spontaneous Recovery• The CR is stronger when there is a very brief

delay between the CS and the US.– Scary music begins to play right before a

frightening scene in a movie—not during or after.

Acquisition, Second-Order Conditioning, Extinction, and

Spontaneous Recovery• Animals must learn when associations are no

longer adaptive.– Extinction: a process in which the conditioned

response is weakened when the conditioned stimulus is repeated without the unconditioned stimulus

Acquisition, Second-Order Conditioning, Extinction, and

Spontaneous Recovery• Spontaneous recovery: a process in which a

previously extinguished conditioned response reemerges after the presentation of the conditioned stimulus– The recovery will fade unless the CS is again

paired with the US.

Acquisition, Second-Order Conditioning, Extinction, and

Spontaneous Recovery• Extinction inhibits the associative bond, but

does not eliminate it.• Second-order conditioning: a CS becomes

associated with other stimuli associated with the US. This phenomenon helps account for the complexity of learned associations.

Generalization and Discrimination

• Stimulus generalization: learning that occurs when stimuli that are similar, but not identical, to the conditioned stimulus produce the conditioned response

• Stimulus discrimination: a differentiation between two similar stimuli when only one of them is consistently associated with the unconditioned stimulus

Classical ConditioningInvolves More Than Events Occurring at the Same Time

• Pavlov’s original explanation for classical conditioning was that any two events presented in contiguity would produce a learned association.– Pavlov and his followers believed that the

association’s strength was determined by factors such as the intensity of the conditioned and unconditioned stimuli.

Classical ConditioningInvolves More Than Events Occurring at the Same Time

• However, in the mid-1960s, a number of challenges to Pavlov’s theory suggested that some conditioned stimuli were more likely than others to produce learning.– Contiguity was not sufficient to create CS-US

associations.

Evolutionary Significance

• Psychologist Garcia and colleagues showed that certain pairings of stimuli are more likely to become associated than others.

• Conditioned taste aversion: the association between eating a food and getting sick– Response occurs even if the illness was caused by

a virus or some other condition– Especially likely to occur if the food was not part

of the person’s usual diet. A food aversion can be formed in one trial.

Evolutionary Significance

– Animals that associate a certain flavor with illness, and therefore avoid that flavor, are more likely to survive and pass along their genes.

– Learned adaptive responses may reflect the survival value that different auditory and visual stimuli have based on potential dangers associated with the stimuli.

Evolutionary Significance

• Biological preparedness: Psychologist Seligman argued that animals are genetically programmed to fear specific objects.– People are predisposed to wariness of outgroup

members.

Learning Involves Expectanciesand Prediction

• Classical conditioning is a way that animals come to predict the occurrence of events that prompted psychologists to try to understand the mental processes that underlie conditioning.– Robert Rescorla argued that for learning to take

place, the conditioned stimulus must accurately predict the unconditioned stimulus.

Learning Involves Expectanciesand Prediction

• Rescorla-Wagner model: a cognitive model of classical conditioning; it holds that the strength of the CS-US association is determined by the extent to which the unconditioned stimulus is unexpected.

Learning Involves Expectanciesand Prediction

• Other aspects of classical conditioning consistent with the Rescorla-Wagner model– Prediction error: the difference between the

expected and actual outcomes• A positive prediction error strengthens the association

between the CS and the US.

• A negative prediction error weakens the CS-US relationship.

Learning Involves Expectanciesand Prediction

– Blocking effect: once a conditioned stimulus is learned, it can prevent the acquisition of a new conditioned stimulus.• Blocking is similar to second-order conditioning, but it

involves a different process.

Dopamine and Predication Error

• Dopamine and Predication Error– What biological mechanisms are in effect during such

learning?

– Researcher examined how dopamine neurons respond during conditioning

– Prediction error signals alert us to important events in the environment.

– Recent support for the error prediction model using optogenetics• By using optogenetics to activate dopamine neurons, researchers

actually overcame the blocking effect.

Phobias and Addictions Have Learned Components

• Classical conditioning helps explain many behavioral phenomena.– Among the examples are phobias and addictions.

Phobias and Their Treatment

• Phobia: an acquired fear out of proportion to the real threat of an object or of a situation– Fear conditioning: the process of classically

conditioning animals to fear neutral objects

– The responses include specific physiological and behavioral reactions.

– Freezing: may be a hardwired response to fear that helps animals deal with predators

Phobias and Their Treatment

• In 1919, J. B. Watson became one of the first researchers to demonstrate the role of classical conditioning in the development of phobias by devising the “Little Albert” experiment.– At the time, the prominent theory of phobias was based

on Freudian ideas about unconscious repressed sexual desires.

– Watson proposed that phobias could be explained by simple learning principles, such as classical conditioning.

Phobias and Their Treatment

• The “Little Albert” Research Method– Little Albert (11 months old) was presented with

neutral objects (a white rat, rabbit, dog, and costume masks) that provoked a neutral response.

– During conditioning trials, when Albert reached for the white rat (CS), a loud clanging sound (US) scared him (UR).

Phobias and Their Treatment

– Results: eventually, the pairing of the rat (CS) and the clanging sound (US) led to the rat’s producing fear (CR) on its own. The fear response generalized to other stimuli presented with the rat initially, such as the costume masks.

– Conclusion: classical conditioning can cause people to fear neutral objects.

Phobias and Their Treatment

• Watson planned to conduct extinction trials to remove the learned phobias but Albert’s mother removed the child from the study.– Is this type of research ethical?

• Watson’s colleague, Mary Cover Jones, used classic conditioning techniques to develop effective behavioral therapies to treat phobias in 3-year-old Peter.– Counterconditioning: exposing a patient to small doses of

the feared stimulus while he or she engages in an enjoyable task

Drug Addiction

• Classical conditioning also plays an important role in drug addiction.– Environmental cues associated with drug use can induce

conditioned cravings.

– Unsatisfied cravings may result in withdrawal, an unpleasant state of tension and anxiety, coupled with changes in heart rate and blood pressure.

– The sight of drug cues leads to activation of the prefrontal cortex and various regions of the limbic system and produces an expectation that the drug high will follow.

Drug Addiction

• Psychologist Siegel believed exposing addicts to drug cues was an important part of treating addiction. – Exposure helps extinguish responses to the cues

and prevents them from triggering cravings.

Drug Addiction

• Siegel and his colleagues conducted research into the relationship between drug tolerance and situation.– The body has learned to expect the drug in that

location and compensates by altering neurochemistry or physiology to metabolize it.

– Conversely, if addicts take their usual large doses in novel settings, they are more likely to overdose because their bodies will not respond sufficiently to compensate.

6.3 How Does Operant Conditioning Change Behavior?

Learning Objectives• Define operant conditioning.• Distinguish between positive reinforcement,

negative reinforcement, positive punishment, and negative punishment.

• Distinguish between schedules of reinforcement.

• Identify biological and cognitive factors that influence operant conditioning.

6.3 How Does Operant Conditioning Change Behavior?

• Operant Conditioning (Instrumental Conditioning): a learning process in which the consequences of an action determine the likelihood that it will be performed in the future– B. F. Skinner chose the term operant to express

the idea that animals operate on their environments to produce effects.

6.3 How Does Operant Conditioning Change Behavior?

• Edward Thorndike performed the first reported carefully controlled experiments in comparative animal psychology using a puzzle box.– Law of Effect: any behavior that leads to a

“satisfying state of affairs” is likely to occur again, and any behavior that leads to an “annoying state of affairs” is less likely to occur again.

Reinforcement Increases Behavior

• Thirty years after Thorndike, Skinner developed a more formal learning theory based on the law of effect.– He objected to the subjective aspects of

Thorndike’s law of effect: states of “satisfaction” are not observable empirically.

Reinforcement Increases Behavior

• Skinner believed that behavior occurs because it has been reinforced.– Reinforcer: a stimulus that follows a response and

increases the likelihood that the response will be repeated.

The Skinner Box

• An operant chamber that allowed repeated conditioning trials without requiring interaction from the experimenter– Contained one lever connected to a food supply

and another connected to a water supply

Shaping

• Sometimes animals take a long time to perform the precise desired action. What can be done to make them act more quickly?– Shaping: an operant-conditioning technique that

consists of reinforcing behaviors that are increasingly similar to the desired behavior

– Successive approximations: any behavior that even slightly resembles the desired behavior

Reinforcers Can Be Conditioned

• Primary reinforcers: satisfy biological needs such as food or water

• Secondary reinforcers: events or objects established through classical conditioning that serve as reinforcers but do not satisfy biological needs (e.g., money or compliments)

What to Believe? Using Psychological Reasoning

• Seeing Relationships That Do Not Exist: How Do Superstitions Start?– The list of people’s superstitions is virtually endless.

– Culture influences specific superstitions.• In North America and Europe, the number 13

• In China, Japan, Korea, and Hawaii, the number 4

– Many sports stars, including Michael Jordan and Wade Boggs, engage in superstitious behaviors.

What to Believe? Using Psychological Reasoning

• The Scientific Study of Superstition– B.F. Skinner started the scientific study of

superstitious behavior in 1948, using pigeons as subjects.

– The pigeons developed a number of superstitious behaviors that they normally would not perform.

– Because these pigeons were performing particular actions when the reinforcers were given, their actions were accidentally reinforced. This type of learning is called autoshaping.

What to Believe? Using Psychological Reasoning

• Associating Events that Occur Together in Time– Both animals and humans have a tendency to

associate events that occur together in time. This tendency is incredibly strong because the brain is compelled to figure things out.

– Pigeons develop behaviors that look like superstitions and people look for reasons to explain outcomes; the observed association serves that purpose.

What to Believe? Using Psychological Reasoning

• Associating Events That Occur Together in Time– Critical thinking requires us to understand

psychological reasoning and be aware of the tendency to associate events with other events that occur at the same time.

Reinforcer Potency

• Premack theorized about how a reinforcer’s value could be determined.– The key is the amount of time an organism, when

free to do anything, engages in a specific behavior associated with the reinforcer.

• Premack principle: using a more valued activity can reinforce the performance of a less valued activity.

Positive and Negative Reinforcement

• Reinforcement—positive or negative—increases the likelihood of a behavior.– Positive reinforcement: the administration of a

stimulus to increase the probability of a behavior’s being repeated

– Negative reinforcement: the removal of a stimulus to increase the probability of a behavior’s being repeated

Operant Conditioning Is Influenced by Schedules of Reinforcement

• How often should reinforcers be given?– Continuous reinforcement: a type of learning in

which behavior is reinforced each time it occurs

– Partial reinforcement: a type of learning in which behavior is reinforced intermittently

– Partial reinforcement’s effect on conditioning depends on the reinforcement schedule.

Operant Conditioning Is Influenced by Schedules of Reinforcement

• Partial reinforcement can be administered according to either the number of behavioral responses or the passage of time.– Ratio schedule: Reinforcement is based on the number of

times the behavior occurs.

– Interval schedule: Reinforcement is provided after a specific unit of time.

• Ratio reinforcement generally leads to greater responding than does interval reinforcement.

Operant Conditioning Is Influenced by Schedules of Reinforcement

• Partial reinforcement can also be given on a fixed schedule or a variable schedule.– Fixed schedule: Reinforcement is provided after a

specific number of occurrences or after a specific amount of time.

– Variable schedule: Reinforcement is provided at different rates or at different times.

Schedules of Reinforcement

• Fixed Interval schedule (FI): occurs when reinforcement is provided after a certain amount of time has passed

• Variable Interval schedule (VI): occurs when reinforcement is provided after the passage of time, but the time is not regular

Schedules of Reinforcement

• Fixed Ratio schedule (FR): occurs when reinforcement is provided after a certain number of responses have been made

• Variable Ratio schedule (VR): occurs when reinforcement is provided after an unpredictable number of responses

Schedules of Reinforcement

• Continuous reinforcement is highly effective for teaching a behavior. If the reinforcement is stopped, however, the behavior extinguishes quickly.– Partial-reinforcement extinction effect: the

greater persistence of behavior under partial reinforcement than under continuous reinforcement• This explains why gambling is so addictive.

Positive and Negative Punishment

• Punishment reduces the probability that a behavior will recur– Positive punishment: the administration of a

stimulus to decrease the probability of a behavior’s recurring

– Negative punishment: the removal of a stimulus to decrease the probability of a behavior’s recurring

Effectiveness of Parental Punishment

• For punishment to be effective, it must be reasonable, unpleasant, and applied immediately so that the relationship between the unwanted behavior and the punishment is clear.– Punishment often fails to offset the reinforcing

aspects of the undesired behavior.

Effectiveness of Parental Punishment

• Research indicates that physical punishment is often ineffective, compared with grounding and time-outs.– Many psychologists believe that positive

reinforcement is the most effective way of increasing desired behaviors while encouraging positive parent/child bonding.

Behavior Modification

• Behavior modification: the use of operant-conditioning techniques to eliminate unwanted behaviors and replace them with desirable ones– Token economies operate on the principle of

secondary reinforcement. Tokens are earned for completing tasks and lost for bad behavior. Tokens can later be traded for objects or privileges.

Biology and Cognition Influence Operant Conditioning

• Behaviorists such as Skinner believed that all behavior could be explained by straightforward conditioning principles.– However, a great deal about behavior remains

unexplained.

– Biology constrains learning, and reinforcement does not always have to be present for learning to take place.

Biological Constraints

• Animals have a hard time learning behaviors that run counter to their evolutionary adaptation.– Breland and Breland used operant-conditioning

techniques to train animals but ran into difficulty when the tasks were incompatible with innate adaptive behaviors.

Biological Constraints

• Conditioning is most effective when the association between the response and the reinforcement is similar to the animal’s built-in predispositions.– Bolles argued that animals have built-in defense

reactions to threatening stimuli.

Acquisition/Performance Distinction

• Tolman’s studies involved rats running through mazes.– Cognitive map: a visual/spatial mental

representation of an environment

• The presence of reinforcement does not adequately explain insight learning, but it helps determine whether the behavior will be subsequently repeated.

Acquisition/Performance Distinction

• Tolman argued that learning can take place without reinforcement.– Latent learning: takes place in the absence of

reinforcement

– Insight learning: A solution suddenly emerges after a period either of inaction or of contemplation.

Dopamine Activity Underlies Reinforcement

• People often use the term reward as a synonym for positive reinforcement.– Skinner and other traditional behaviorists defined

reinforcement strictly in terms of whether it increased behavior.

• The neurotransmitter dopamine is involved in addictive behavior and plays an important role in reinforcement.

Dopamine Activity Underlies Reinforcement

• When hungry rats are given food, they experience an increased dopamine release in the nucleus accumbens, a structure that is part of the limbic system: The greater the hunger, the greater the dopamine release.– More dopamine is released under deprived

conditions than under nondeprived conditions.

Dopamine Activity Underlies Reinforcement

• In operant conditioning, dopamine release sets the value of a reinforcer, and blocking dopamine decreases reinforcement.– Dopamine blockers are can also help people with

Tourette’s syndrome regulate their involuntary body movements.

Dopamine Activity Underlies Reinforcement

•Robinson and Berridge introduced an important distinction between the wanting and liking aspects of reward.– A smoker may want a cigarette but not especially

enjoy it.•Dopamine appears to be especially important in wanting a reward.

6.4 How Does Watching Others Affect Learning?

Learning Objectives• Define observational learning.• Generate examples of observational learning,

modeling, and vicarious learning.• Discuss contemporary evidence regarding the

role of mirror neurons in learning.

Learning Can Occur Through Observation and Imitation

• Observational learning: the acquisition or modification of a behavior after exposure to another individual performing that behavior (aka Social Learning)– Observational learning is a powerful adaptive tool

for humans and other animals.

Bandura’s Observational Studies

• Bandura’s studies suggest that exposing children to violence may encourage them to act aggressively.

Modeling (Demonstration and Imitation)

• Modeling: the imitation of observed behavior– Modeling is effective only if the observer is

physically capable of imitating the behavior.

– Imitation is much less common in nonhuman animals than in humans.

– Adolescents who associate smoking with admirable figures are more likely to begin smoking.

Vicarious Learning (Reinforcement and Conditioning)

• Vicarious learning: learning the consequences of an action by watching others being rewarded or punished for performing the same action– A key distinction in learning is between the

acquisition of a behavior and its performance.

– Learning a behavior does not necessarily lead to performing that behavior.

Watching Violence in Media May Encourage Aggression

• The extent to which media violence impacts aggressive behavior in children is debatable.– Some studies demonstrate desensitization to

violence after exposure to violent video games.

– However, it is difficult to draw the line between “playful” and “aggressive” behaviors in children.

• Most research in the area of TV and aggression shows a relationship between exposure to violence on TV and aggressive behavior.

Fear Can Be Learned Through Observation

• Mineka noticed that lab-reared monkeys were not afraid of snakes the way monkeys in the wild are.– Her research demonstrated that animals’ fears

can be learned through observation.

• Social forces also play a role in fear-learning in humans.

Mirror Neurons Are Activated by Watching Others

• Mirror neurons: neurons in the brain that are activated when one observes another individual engage in an action and performs a similar action– May serve as the basis of imitation learning, but

the firing of mirror neurons does not always lead to imitative behavior

– Possibly the neural basis for empathy and a possible role in humans’ ability to communicate through language