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 LearningB. F. Skinner, who was inspired by the work of Watson and Pavlov, has been one of the most influential people in contemporary psychologySkinner 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 experienceAssociations develop through conditioning, a process in which environmental stimuli and behavioral responses become connectedclassical (Pavlovian) conditioning: learning that two types of events occur togetheroperant (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 approachesJohn 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 slateHe stated that the environment and its effects were the sole determinants of learningBehaviorism 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 animalPavlov noticed the dogs salivated as soon as they saw the bowls that usually contained food, suggesting a learnedresponseTwitmyer 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 ExperimentsClassical (Pavlovian) conditioning: A neutral object comes to elicit a response when it is associated with a stimulus that already produces that responseA typical Pavlovian experiment involves:Conditioning trials: neutral stimulus AND unconditioned stimulus are paired to produce reflex, e.g. salivationNeutral stimulus: anything the animal can see or hear as long as it is NOT associated with the reflex being tested, e.g. ringing bellUnconditioned stimulus (US): a stimulus that elicits a response, such as a reflex, without any prior learning, e.g. foodCritical 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 reflexUnconditioned stimulus (US): a stimulus that elicits a response, such as a reflex, without any prior learningConditioned stimulus (CS): a stimulus that elicits a response only after learning has taken placeConditioned response (CR): a response to a conditioned stimulus; a response that has been learnedCan you think of any learned associations that have classically conditioned you?
17 Acquisition, Extinction, and Spontaneous Recovery Pavlov was influenced by Darwinand believed that conditioning is the basis of adaptive behaviorsAcquisition: the gradual formation of an association between the CS and USThe critical element in the acquisition of a learned association is time, or contiguityThe CR is stronger when there is a very brief delay between the CS and the USFor 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 adaptiveextinction: 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 extinguishesSpontaneous recovery: a previously extinguished response reemerges after the presentation of the CSThe recovery will fade unless the CS is again paired with the USExtinction 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 CRstimulus discrimination: a differentiation between two similar stimuli when only one of them is consistently associated with the USSecond-order conditioning: a CS becomes associated with other stimuli associated with the US. This phenomenon helps account for the complexity of learned associations
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 situationFear conditioning: the process of classically conditioning animals to fear neutral objectsThe responses include specific physiological and behavioral reactionsfreezing: 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” experimentAt the time, the prominent theory of phobias wasbased on Freudian ideas about unconscious repressed sexual desiresWatson 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 responseDuring 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 masksConclusion: 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 studyDo 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 phobiasCounterconditioning –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 counterconditioningDeveloped by behavioral therapist Joseph Wolpe in 1997CS → CR1 (fear) connection can be broken by developing a CS → CR2 (relaxation) connectionPsychologists now believe that exposure to the feared stimulus is more important than relaxation
30 Drug AddictionClassical conditioning also plays an important role in drug addiction.Environmental cues associated with drug use can induce conditioned cravingsUnsatisfied cravings may result in withdrawal, an unpleasant state of tension and anxiety, coupled with changes in heart rate and blood pressureThe 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 AddictionPsychologist Shepard Siegel (2005) believed exposing addicts to drug cues was an important part of treating addictionExposure helps extinguish responses to the cues and prevents them from triggering cravingsSiegel and his colleagues conducted research into the relationship between drug tolerance and situationThe body has learned to expect the drug in that location and compensates by altering neurochemistry or physiology to metabolize itConversely, 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 associationPavlov and his followers believed that the association’s strength was determined by factors such as the intensity of the conditioned and unconditioned stimuliHowever, in the mid-1960s, a number of challenges to Pavlov’s theory suggested that some conditioned stimuli were more likely than others to produce learningContiguity 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 othersconditioned food aversion:the association between eating a food and getting sickResponse occurs even if the illness was caused by a virus or some other conditionEspecially likely to occur if the food was not part of the person’s usual diet. A food aversion can be formed in one trialAnimals 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 stimuliWhat evolutionary value do you see in this learned behavior?Biological preparedness: Psychologist Martin Seligman (1970) argued that animals are genetically programmed to fear specific objectsPeople 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 learningRobert Rescorla argued that for learning to take place, the conditioned stimulus must accurately predict the unconditioned stimulusRescorla-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 stimulusBlocking effect: once a conditioned stimulus is learned, it can prevent the acquisition of a new conditioned stimulusOccasion 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 TimePeople, and apparently other animals, have a strong need to understand what causes or predicts events. Their resulting associations can lead people to cling to superstitionsWhat 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 futureB. 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 EffectBy 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 effectHe objected to the subjective aspects of Thorndike’s law of effect: States of “satisfaction” are not observable empiricallySkinner believed that behavior occurs because it has been reinforcedreinforcer: a stimulus that follows a response and increases the likelihood that the response will be repeated
50 The Skinner BoxAn operant chamber that allowed repeated conditioning trials without requiring interaction from the experimenterContained 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 ShapingSometimes 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 behaviorsuccessive approximations: anybehavior that even slightly resembles the desired behaviorSuppose 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 watersecondary 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 PotencyDavid Premack theorized about how a reinforcer’s value could be determinedThe key is the amount of time an organism, when free to do anything, engages in a specific behavior associated with the reinforcerPremack principle: Using a more valued activity can reinforce the performance of a less valued activityHow 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 behaviorReinforcement increases a behavior’s probabilityPunishment decreases its probabilityBoth reinforcement and punishment can be positive or negativeThis 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 behaviorpositive reinforcement: the administration of a stimulus to increase the probability of a behavior’s being repeated, e.g. a rewardnegative 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 recurpositive punishment: the administration of a stimulus to decrease the probability of a behavior’s recurring, e.g. receiving a ticket for speedingnegative 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 clearHow might this go wrong?Punishment often fails to offset the reinforcing aspects of the undesired behaviorResearch indicates that physical punishment is often ineffective, compared with grounding and time-outsMany 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 occurspartial reinforcement: a type of learning inwhich behavior is reinforced intermittentlyPartial 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 timeratio schedule: Reinforcement is based on the number of times the behavior occursinterval schedule: Reinforcement is provided after a specific unit of timeRatio 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 schedulefixed schedule: Reinforcement is provided after a specific number of occurrences or after a specific amount of timevariable 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 quicklyvariable-ratio schedule: persistent behavior thatonly sometimesresults in rewardpartial-reinforcement extinction effect: Behavior is more persistent under partial reinforcement than under continuous reinforcementCan 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 changeSet goalsMonitor your behaviorSelect a reinforcer and decide on a reinforcement scheduleReinforce the desired behaviorModify 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 onesToken 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 principlesHowever, a great deal about behavior remains unexplainedBiology 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 adaptationMarian and Keller Breland used operant-conditioning techniques to train animals but ran into difficulty when the tasks were incompatible with innate adaptive behaviorsConditioning is most effective when the association between the response and the reinforcement is similar to the animal’s built-in predispositionsFor 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 reinforcementlatent learning: takes place in the absence of reinforcementinsight learning: A solution suddenly emerges after either a period of inaction or of contemplationTolman’s studies involved rats running through mazescognitive map: a visual/spatial mental representation of an environmentThe 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 cultureMemes can be conditioned through association or reinforcement, but are often learned by watching the behavior of other peopleThrough 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 behaviorObservational learning is a powerful adaptive tool for humans and other animalsCan 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
79 Media and ViolenceThe extent to which media violence impacts aggressive behavior in children is debatedSome studies demonstrate desensitization to violence after exposure to violent video gamesHowever, it is difficult to draw the line between “playful” and “aggressive” behaviors in childrenThere may be extraneous variables that affect both TV habits AND violent tendenciesBased 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 areHer research demonstrated that animals’ fears can be learned through observationSocial 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 learningModeling is effective only if the observer is physically capable of imitating the behaviorImitation is much less common in nonhuman animals than in humansAdolescents 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 actionA key distinction in learning is between the acquisition of a behavior and its performanceIn 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 observedMay serve as the basis of imitation learning, but the firing of mirror neurons does not always lead to imitative behaviorMay be the neural basis for empathy and play a role in humans’ ability to communicate through languageDebatable 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 pleasureincreases wanting for the object or event that produced the rewardThe neurotransmitter dopamine is involved in addictive behavior and plays an important role in reinforcement
91 Pleasure Centersintracranial self-stimulation: self-administered shock to pleasure centers of the brainStarving rats prefer ICSS to food over 80 percent of the timeThe neural mechanisms underlying both ICSS and natural reward appear to use the same neurotransmitter: dopamineThis suggests dopamine serves as the neurochemical basis of positive reinforcement in operant conditioningInterfering 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 RewardThe nucleus accumbens is a subcortical brain region that is part of the limbic systemMore dopamine is released under deprived conditions than under nondeprivedconditionsDo 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 reinforcementDopamine blockers are can also help people with Tourette’s syndrome regulate their involuntary body movementsRobinson and Berridge (1993) introduced an important distinction between the wanting and liking aspects of rewardFor example, a smoker may want a cigarette but not especially enjoy itDopamine appears to be especially important in wanting a reward
95 Secondary Reinforcers Also Rely on Dopamine Natural reinforcers appear to signal dopamine reward directlySecondary reinforcers at first fail to trigger dopamine release but may do so readily after they are paired with unconditioned stimuliMoney 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 releasehabituation: a decrease in behavioral response after repeated exposure to a nonthreatening stimulussensitization: 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 activatedThrough LTP, intense stimulation of neurons strengthens synapses, increasing the likelihood that one neuron’s activation will increase the firing of other neuronsLTP effects are most easily observed in brain sites known to be involved in learning and memory, such as the hippocampusResearch 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 neuronsJoseph Tsien modified genes in mice to make the genes’ NMDA receptors more efficientTsein’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 MiceDoogie 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 ConditioningLTP in the amygdala appears to play a role in fear conditioningJoseph LeDoux’s research suggests that fear conditioning might produce long-lasting learning through the induction of LTPHeightened 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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