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1 Psychological Science ©2013 W. W. Norton & Company, Inc.
Gazzaniga • Heatherton • Halpern Psychological Science FOURTH EDITION Chapter 6 Learning ©2013 W. W. Norton & Company, Inc.

2 “Old Brain, New Tricks” Brain researchers have new hope for people who struggle with words. As this ScienCentral News video explains, they’ve shown that treatment to improve the reading skills of adult dyslexics actually changes how the dyslexic brain processes information—teaching old trains new tricks.

3 Learning B. F. Skinner, who was inspired by the work of Watson and Pavlov, has been one of the most influential people in contemporary psychology Skinner believed that, to be scientists, psychologists had to study observable actions and focus on the behaviors people and nonhuman animals display

4 “Bird Brain Gene” Human speech and bird song may have more in common than we know, according to scientists at Duke University. As this ScienCentral News video reports, the research could lead to a new progress for people with genetic speech disorders.

5 6.1 What Ideas Guide the Study of Learning?
Define classical conditioning. Differentiate between US, UR, CS, and CR. Describe the role of learning in the development and treatment of phobias and drug addiction. Discuss the evolutionary significance of classical conditioning. Describe the Rescorla-Wagner model of classical conditioning. 5

6 6.1 What Ideas Guide the Study of Learning?
Skinner and other behaviorists dismissed the importance of introspection and mental states in favor of basic learning principles and scientific approaches to psychology. Learning theories have been used to improve quality of life and to train humans and nonhuman animals to learn new tasks. 6

7 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 classical (Pavlovian) conditioning: learning that two types of events occur together operant (instrumental) conditioning: learning that a behavior leads to a particular outcome

8 “Expert Nose” You may be skeptical when someone sniffs a glass of wine and says it has an “oaky bouquet” or “overtones of cherry and cinnamon.” But new research suggests that becoming an expert smeller is in reach for all of us. This ScienCentral News video explains.

9 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 had a huge influence on every area of psychology

10 “Live Learning” Have you ever wondered how babies learn to talk? As this ScienCentral News video reports, some researchers now think it’s more than just hearing the people around them.

11 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 noticed the dogs salivated as soon as they saw the bowls that usually contained food, suggesting a learnedresponse 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

12 FIGURE 6.2a Pavlov’s Apparatus and Classical Conditioning
Ivan Pavlov, pictured here with his colleagues and one of his canine subjects, conducted groundbreaking work on classical conditioning. 12

13 FIGURE 6.2b Pavlov’s Apparatus and Classical Conditioning
Pavlov’s apparatus collected and measured a dog’s saliva. 13

14 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 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. ringing bell Unconditioned stimulus (US): a stimulus that elicits a response, such as a reflex, without any prior learning, e.g. food Critical trials: neutral stimulus alone is tested, and effect on the reflex is measured

15 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 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 Can you think of any learned associations that have classically conditioned you?

16 FIGURE 6.3 Scientific Method: Pavlov’s Classical Conditioning
16

17 Acquisition, Extinction, and Spontaneous Recovery
Pavlov was influenced by Darwinand believed that conditioning is the basis of adaptive behaviors Acquisition: the gradual formation of an association between the CS and US The critical element in the acquisition of a learned association is time, or contiguity The CR is stronger when there is a very brief delay between the CS and the US For example, scary music begins to play right before a frightening scene in a movie—not during or after

18 Acquisition, Extinction, and Spontaneous Recovery
How long do learned behaviors persist? Animals must learn when associations are no longer adaptive extinction: a form of learning that the prior association no longer holds. The CR is weakened when the CS is repeated without the US, and eventually extinguishes Spontaneous recovery: a previously extinguished response reemerges after the presentation of the CS The recovery will fade unless the CS is again paired with the US Extinction inhibits the associative bond, but does not eliminate it

19 FIGURE 6.4 Acquisition, Extinction, and Spontaneous Recovery
19

20 Generalization, Discrimination, and Second Order Conditioning
In a learning situation, how does the brain determine which stimulus is relevant? stimulus generalization: responding to stimuli that are similar but not identical to the CS produce the CR stimulus discrimination: a differentiation between two similar stimuli when only one of them is consistently associated with the US Second-order conditioning: a CS becomes associated with other stimuli associated with the US. This phenomenon helps account for the complexity of learned associations

21 FIGURE 6.5 Stimulas Generalization
21

22 FIGURE 6.6 Stimulas Discrimination
22

23 Phobias and Addictions Have Learned Components
Classical conditioning helps explain many behavioral phenomena. Among the examples are phobias and addictions.

24 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

25 Phobias and their Treatment
In 1919, John 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 wasbased on Freudian ideas about unconscious repressed sexual desires Watson proposed that phobias could be explained by simple learning principles, such as classical conditioning

26 Phobias and their Treatment
The “Little Albert” Research Method: Little Albert was presented with neutral objects (a white rat 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) 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

27 Phobias and their Treatment
Watson planned to conduct extinction trials to remove the learned phobias but Albert’s mother removed him from the study Do you think this type of research is ethical? Watson’s colleague, Mary Cover Jones, used classic conditioning techniques to develop effective behavioral therapies to treat phobias Counterconditioning –exposing a patient to small doses of the feared stimulus while they engage in an enjoyable task

28 Phobias and their Treatment
Systematic desensitization:a formal treatment based on counterconditioning Developed by behavioral therapist Joseph Wolpe in 1997 CS → CR1 (fear) connection can be broken by developing a CS → CR2 (relaxation) connection Psychologists now believe that exposure to the feared stimulus is more important than relaxation

29 FIGURE 6.7 Scientific Method: Watson’s “Little Albert” Experiment
29

30 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

31 Drug Addiction Psychologist Shepard Siegel (2005) 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 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

32 FIGURE 6.8 PET Scans Showing Activation of Limbic System Structures
Cocaine addicts were shown videos of nature scenes and videos of cocaine cues. The cocaine-related videos sparked activation in brain regions associated with reward and emotion, such as the anterior cingulate and the amygdala. Watching nature videos did not lead to increased activity in these areas. (Areas with greatest activation are shown in orange and red.) 32

33 Classical Conditioning Involves 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 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

34 Evolutionary Significance
Psychologist John Garcia and colleagues showed that certain pairings of stimuli are more likely to become associated than others conditioned food 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 Animals that associate a certain flavor with illness, and therefore avoid that flavor, are more likely to survive and pass along their genes

35 Evolutionary Significance
Learned adaptive responses may reflect the survival value that different auditory and visual stimuli have based on potential dangers associated with the stimuli What evolutionary value do you see in this learned behavior? Biological preparedness: Psychologist Martin Seligman (1970) argued that animals are genetically programmed to fear specific objects People are predisposed to wariness of outgroup members (Olsson, Ebert, Banaji, & Phelps, 2005)

36 FIGURE 6.9a Conditioned Food Aversion in Animals
(a) After eating a monarch butterfly, (b) this blue jay vomited and thus learned to avoid eating anything that looks like the butterfly. What evolutionary value do you see in this learned behavior? 36

37 FIGURE 6.9a Conditioned Food Aversion in Animals
(a) After eating a monarch butterfly, (b) this blue jay vomited and thus learned to avoid eating anything that looks like the butterfly. What evolutionary value do you see in this learned behavior? 37

38 Learning Involves Cognition
Classical conditioning is a way that animals come to predict the occurrence of events—which prompted psychologists to take a cognitive perspective on learning Robert Rescorla argued that for learning to take place, the conditioned stimulus must accurately predict the unconditioned stimulus Rescorla-Wagner model: states that the strength of the CS-US association is determined by the extent to which the unconditioned stimulus is unexpected or surprising

39 Learning Involves Cognition
Other aspects of classical conditioning consistent with the Rescorla-Wagner model: Orienting response: occurs when an animal encounters a novel stimulus Blocking effect: once a conditioned stimulus is learned, it can prevent the acquisition of a new conditioned stimulus Occasion setter: a stimulus associated with a CS that acts as a trigger for the CS

40 FIGURE 6.11 Rescorla-Wagner Model
The Rescorla-Wagner model of learning emphasizes the substitution of one stimulus for another. (a) Here a dog associates the sound of an electric can opener with the arrival of food. (b) With the substitution of a manual can opener for the electric one, the dog is initially surprised. What happened to the reliable predictor of the dog’s food? (c) The orienting response causes the dog to check the environment for a new stimulus. When the dog comes to associate the manual can opener with the arrival of food, the new stimulus has become the better predictor of the expected event: time to eat! 40

41 Critical Thinking Skill: Avoiding the Association of Events with Other Events That Occur at the Same Time People, and apparently other animals, have a strong need to understand what causes or predicts events. Their resulting associations can lead people to cling to superstitions What misfortunes could actually occur in the situations shown on the following slide?

42 FIGURE 6.10a Questioning Superstitions
According to superstition, bad luck will come your way if a black cat crosses your path or if you walk under a ladder. What misfortunes could actually occur in the situations shown here? 42

43 FIGURE 6.10b Questioning Superstitions
According to superstition, bad luck will come your way if a black cat crosses your path or if you walk under a ladder. What misfortunes could actually occur in the situations shown here? 43

44 6.2 How Does Operant Conditioning Differ from Classical Conditioning?
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.

45 6.2 How Does Operant Conditioning Differ from Classical Conditioning?
Operant (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. 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. 45

46 FIGURE 6.12a Thorndike’s Puzzle Box
(a) Thorndike used puzzle boxes, such as the one depicted here, (b) to assess learning in animals. 46

47 FIGURE 6.12b Thorndike’s Puzzle Box
(a) Thorndike used puzzle boxes, such as the one depicted here, (b) to assess learning in animals. 47

48 FIGURE 6.13 Law of Effect By studying cats’ attempts to escape from a puzzle box, Thorndike was able to formulate his general theory of learning. 48

49 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 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

50 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

51 FIGURE 6.14a Skinner Box (a) B. F. Skinner and one of his subjects demonstrate (b) the operant chamber, now known as the Skinner box. 51

52 FIGURE 6.14b Skinner Box (a) B. F. Skinner and one of his subjects demonstrate (b) the operant chamber, now known as the Skinner box. 52

53 Shaping Sometimes animals take a long time to perform the precise desired action. What can be done? Shaping: an operant-conditioning technique that consists of reinforcing behaviors that are increasingly similar to the desired behavior successive approximations: anybehavior that even slightly resembles the desired behavior Suppose you wanted to teach yourself to do something. Which behavior would you choose, and how would you go about shaping it?

54 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

55 Reinforcer Potency David 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 How do you think you could use this principle on yourself?

56 Both Reinforcement and Punishment Can Be Positive or Negative
Reinforcement and punishment have the opposite effects on behavior Reinforcement increases a behavior’s probability Punishment decreases its probability Both reinforcement and punishment can be positive or negative This designation depends on whether something is given or removed, not on whether any part of the process is good or bad

57 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, e.g. a reward negative reinforcement: the removal of a stimulus to increase the probability of a behavior’s being repeated, e.g. requiring a rat to press a lever to turn off a shock

58 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, e.g. receiving a ticket for speeding negative punishment: the removal of a stimulus to decrease the probability of a behavior’s recurring, e.g. taking away driving privileges for bad behavior

59 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 How might this go wrong? Punishment often fails to offset the reinforcing aspects of the undesired behavior 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

60 FIGURE 6.16 Negative and Positive Reinforcement, Negative and Positive Punishment
Use this chart to help solidify your understanding of the terms in this section. 60

61 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 inwhich behavior is reinforced intermittently Partial reinforcement’s effect on conditioning depends on the reinforcement schedule

62 Ratio and Interval Schedules
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

63 Fixed and Variable Schedules
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

64 FIGURE 6.17 Behavior and Reinforcement
The curves on this graph show cumulative responses under different schedules of reinforcement over time. The steeper the line, the higher the response rate. Ratio reinforcement leads to the highest rates of response. 64

65 Behavioral Persistence
Continuous reinforcement is highly effective for teaching a behavior. If the reinforcement is stopped, however, the behavior extinguishes quickly variable-ratio schedule: persistent behavior thatonly sometimesresults in reward partial-reinforcement extinction effect: Behavior is more persistent under partial reinforcement than under continuous reinforcement Can this explain why gambling is so addictive?

66 Psychology: Knowledge You Can Use—Can Behavior Modification Help Me Stick with an Exercise Program?
Consider these steps: Identify a behavior you wish to change Set goals Monitor your behavior Select a reinforcer and decide on a reinforcement schedule Reinforce the desired behavior Modify your goals, reinforcements, or reinforcement schedules, as needed

67 Behavior Modification
Behavior modification: the use of operant- conditioning techniques to eliminate unwanted behaviors and replace them withdesirable 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

68 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

69 Biological Constraints
Animals have a hard time learning behaviors that run counter to their evolutionary adaptation Marian and Keller Breland used operant-conditioning techniques to train animals but ran into difficulty when the tasks were incompatible with innate adaptive behaviors Conditioning is most effective when the association between the response and the reinforcement is similar to the animal’s built-in predispositions For example, Bolles argued that animals have built-in defense reactions to threatening stimuli

70 “Talent vs. Practice” Is talent something you’re born with, or can practice really make perfect? Experts on expertise—who’ve studied the minds of experts in fields from sports to medicine—have the answer. As this ScienCentral News video explains, they’re applying it to life or death situations.

71 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 either a period of inaction or of contemplation 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 is subsequently repeated

72 Figure 6.20 Scientific Method: Tolman’s Study of Latent Learning
72

73 6.3 Does Watching Others Affect Learning?
Describe the concept of the meme. Define observational learning. Generate examples of observational learning, modeling, and vicarious learning. Discuss contemporary evidence regarding the role of mirror neurons in learning.

74 6.3 Does Watching Others Affect Learning?
Teaching someone to perform a complex task requires more than reinforcing arbitrary correct behaviors. We learn many behaviors, including attitudes, through observation. 74

75 Learning Can Be Passed On through Cultural Transmission
Meme: a unit of knowledge transmitted within a culture Memes can be conditioned through association or reinforcement, but are often learned by watching the behavior of other people Through social learning, some behaviors are passed along from one generation to the next

76 Learning Can Occur through Observation and Imitation
Observational learning: the acquisition or modification of a behavior after exposure to at least one performance of that behavior Observational learning is a powerful adaptive tool for humans and other animals Can you think of some examples of observational learning in animals?

77 Bandura’s Observational Studies
Bandura’s studies suggest that exposing children to violence may encourage them to act aggressively

78 FIGURE 6.22 Scientific Method: Bandura’s Bobo Doll Studies
78

79 Media and Violence The extent to which media violence impacts aggressive behavior in children is debated 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 There may be extraneous variables that affect both TV habits AND violent tendencies Based on what you have just learned, how might media impact behavior?

80 FIGURE 6.23 Media and Violent Behavior
Studies have shown that playing violent video games desensitizes children to violence. 80

81 “Violent Games” As the content of video games becomes more and more violent, researchers are debating whether virtual violence can lead kids to the real thing. This ScienCentral News video has more.

82 Social Learning of Fear
Susan 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 play a role in fear-learning in humans too

83 FIGURE 6.24 Scientific Method: Fear Response in Rhesus Monkeys
83

84 Demonstration and Imitation
modeling: the imitation of behavior through observational learning 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

85 FIGURE 6.26 Imitation and Smoking
This shot appears in the movie The Killer Inside Me (2010). The movie’s title might be appropriate, because eye-catching images such as this one contribute to viewers’ sense that smoking is a mature, cool, sexy behavior worth imitating. Notice how the character’s pose is wrapped by the tight framing, the colors, and the swirls. These effects give the impression that the life of Lou Ford (played by Casey Affleck) depends on some mysterious power in his cigarette. 85

86 Vicarious Reinforcement
vicarious learning: learning the consequences of an action by watching others being rewarded or punished for performing the action A key distinction in learning is between the acquisition of a behavior and its performance In other words, learning a behavior does not necessarily lead to performing that behavior

87 Mirror Neurons What happens in the brain during imitation learning?
mirror neurons: neurons that are activated when one observes another individual engaging in an action and when one performs the action that was observed May serve as the basis of imitation learning, but the firing of mirror neurons does not always lead to imitative behavior May be the neural basis for empathy and play a role in humans’ ability to communicate through language Debatable if brain activity reflects prior learning rather than imitation

88 6.4 What Is the Biological Basis of Learning?
Discuss the role of dopamine and the nucleus accumbens in the experience of reinforcement. Define habituation, sensitization, and long- term potentiation. Describe the neural basis of habituation, sensitization, long-term potentiation, and fear conditioning.

89 6.4 What Is the Biological Basis of Learning?
When animals and people learn, what changes in the brain? Researchers are rapidly identifying the neurophysiological basis of learning. Similar brain activity occurs for most rewarding experiences. 89

90 Dopamine Activity Underlies Reinforcement
Positive reinforcement works in two ways: provides the subjective experience of pleasure increases wanting for the object or event that produced the reward The neurotransmitter dopamine is involved in addictive behavior and plays an important role in reinforcement

91 Pleasure Centers intracranial self-stimulation: self-administered shock to pleasure centers of the brain Starving rats prefer ICSS to food over 80 percent of the time The neural mechanisms underlying both ICSS and natural reward appear to use the same neurotransmitter: dopamine This suggests dopamine serves as the neurochemical basis of positive reinforcement in operant conditioning Interfering with dopamine eliminates self-stimulation as well as naturally motivated behaviors

92 FIGURE 6.27 Intracranial Self-Stimulation (ICSS)
Here a rat presses a lever to administer ICSS. 92

93 Dopamine and Reward The nucleus accumbens is a subcortical brain region that is part of the limbic system More dopamine is released under deprived conditions than under nondeprivedconditions Do you have the intuition that food tastes better when you are hungry? 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 Robinson and Berridge (1993) introduced an important distinction between the wanting and liking aspects of reward For example, a smoker may want a cigarette but not especially enjoy it Dopamine appears to be especially important in wanting a reward

94 FIGURE 6.28 Pleasure Centers of the Brain
94

95 Secondary Reinforcers Also Rely on Dopamine
Natural reinforcers appear to signal dopamine reward directly Secondary reinforcers at first fail to trigger dopamine release but may do so readily after they are paired with unconditioned stimuli Money is a secondary reinforcer that activates dopamine systems

96 Habituation and Sensitization Are Simple Models of Learning
Kandel’s work on the aplysia has shown that habituation and sensitization, two simple forms of learning, occur through alteration in neurotransmitter release habituation: a decrease in behavioral response after repeated exposure to a nonthreatening stimulus sensitization: an increase in behavioral response after exposure to a threatening stimulus

97 Long Term Potential Is a Candidate for the Neural Basis of Learning
long-term potentiation (LTP): the strengthening of a synaptic connection, making the postsynaptic neurons more easily activated Through LTP, intense stimulation of neurons strengthens synapses, increasing the likelihood that one neuron’s activation will increase the firing of other neurons LTP effects are most easily observed in brain sites known to be involved in learning and memory, such as the hippocampus Research has also supported Hebb’s rule that neurons that fire together wire together

98 “Smart Mice” They didn’t mean to create smart mice, but that’s what happened when neurologists genetically altered mice to lack a certain brain protein. As this ScienCentral News story explains, the chance discovery could lead to new drugs to treat learning and memory disorders.

99 LTP and the NMDA Receptor
LTP occurs when NMDA receptors are stimulated by nearby neurons Joseph Tsien modified genes in mice to make the genes’ NMDA receptors more efficient Tsein’s “Doogie Mice” learned novel tasks quicker and showed increased fear conditioning

100 FIGURE 6.30 Long-Term Potentiation (LTP)
(a) This diagram depicts the basic process used in testing for LTP between two neurons. (b) This graph shows the steps involved in LTP. 100

101 FIGURE 6.31 Doogie Mice Doogie mice (such as the one pictured here) and regular mice were given a test of learning and memory. In the first part, both kinds of mice had the chance to familiarize themselves with two objects. In the second part, the researchers replaced one of the objects with a novel object. The Doogie mice quickly recognized the change, but the normal mice did not recognize it. 101

102 Fear Conditioning LTP in the amygdala appears to play a role in fear conditioning Joseph LeDoux’s research suggests that fear conditioning might produce long-lasting learning through the induction of LTP Heightened activity in the amygdala, when subjects watched another person’s distress, suggests that similar mechanisms are involved in conditioned and observational fear learning

103 “Wiring the Brain” Interested in lifelong learning? Here’s some good news. As this ScienCentral News video reports, brain researchers have uncovered one mechanism that controls how out brains make new connections.


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