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9/1/2009 Learning and Adaptation Thomas Karlsson Adapting to the Environment What is learning? • Process by which experience produces a relatively enduring change in behavior or capabilities (knowing how) 6-2 Adapting to the Environment Environmental Shaping of Behavior • Personal adaptation (via laws of learning) • Species adaptation (via evolution, natural selection) 6-3 1 9/1/2009 Adapting to the Environment Behaviorism • Focused on how organisms learn • Discovered laws of learning that apply to virtually all organisms 6-4 Adapting to the Environment Behaviorism cont. • Treated organism as tabula rasa • Explained learning solely in terms of directly observable events 6-5 Adapting to the Environment Ethology • Focused on animal behavior in natural environments • Focused on functions of behavior 6-6 2 9/1/2009 Adapting to the Environment Ethology • Special focus on adaptive significance of behavior: How behavior influences chances of survival, reproduction • Different species learn different behaviors to survive. 6-7 Adapting to the Environment Ethology • Fixed Action Patterns • Unlearned (innate) responses • Can be modified by experiences 6-8 Adapting to the Environment Cognitive Neuroscience • Gestalt Psychology • Cognitive Psychology • Expertise 6-9 3 9/1/2009 Adapting to the Environment Habituation • Decrease in response strength to a repeated stimulus 6-12 Forms of Learning Habituation Classical Conditioning Operant Conditioning Observational Learning Cognitive Learning/anticipation Insight Learning 6-13 Classical Conditioning Learn to associate two stimuli 6-14 • One stimulus elicits a response that was originally elicited only by the other stimulus 4 9/1/2009 Classical Conditioning Unconditioned stimulus (UCS) • Stimulus that elicits a reflexive or innate response (UCR) without prior learning 6-15 Classical Conditioning Unconditioned response (UCR) • Reflexive or innate response elicited by the UCS without prior learning 6-16 Classical Conditioning Conditioned stimulus (CS) • Stimulus that, through association with the UCS, comes to elicit a conditioned response similar to the original UCR 6-17 5 9/1/2009 Classical Conditioning Conditioned response (CR) • Response elicited by a conditioned stimulus 6-18 Classical Conditioning 6-19 Classical Conditioning Acquisition • Period during which CR is being learned 6-20 • Types of CS-UCS pairing Forward short-delay Forward trace Simultaneous Backward 6 9/1/2009 Classical Conditioning Factors that Typically Enhance Acquisition • Multiple CS-UCS pairings • An intense, aversive UCS can produce one-trial learning • Forward (short-delay) pairing • Time interval between onset of CS and onset of UCS is short 6-21 Classical Conditioning Extinction • Process in which CS is presented in absence of UCS • Causes CR to weaken and eventually disappear 6-22 Classical Conditioning Spontaneous Recovery • After a rest period, and without any new learning trials, the reappearance of a previously extinguished CR • Usually weaker than initial CR, extinguishes more rapidly 6-23 7 9/1/2009 6-24 Classical Conditioning Stimulus Generalization • Stimuli similar to initial CS elicit a CR • Aids in survival 6-25 6-26 8 9/1/2009 Classical Conditioning Discrimination • CR occurs to one stimulus but not to another 6-27 Classical Conditioning Higher-order conditioning • Neutral stimulus becomes a CS after pairing with already established CS 6-28 6-29 9 9/1/2009 6-30 6-31 Classical Conditioning Applications of Classical Conditioning • Conditioned fear responses • Therapies for fear, anxiety • Research 6-32 10 9/1/2009 Classical Conditioning Exposure Therapy • Extinction of CR through exposure to CS without presence of UCS 6-33 Classical Conditioning Types of Therapy Using Classical Conditioning • Systematic desensitization: Muscular relaxation paired with gradual exposure to fear-inducing stimulus • Flooding 6-34 Classical Conditioning Other Influences of Classical Conditioning • Attraction to other people • Positive, negative attitudes • Conditioned aversions (aversion therapy) • Anticipatory nausea and vomiting (ANV) • Allergic Reactions 6-35 11 9/1/2009 Classical Conditioning Aversion Therapy • Condition an aversion • Stimulus that triggers unwanted behavior is paired with a noxious UCS 6-36 Classical Conditioning Effects on Immune System • Neutral stimuli can be conditioned to increase or decrease immune functioning 6-37 • Procedure has been used to help fight disease 6-38 12 9/1/2009 6-39 Operant Conditioning Instrumental Learning (Thorndike, 1911) • Organism’s behavior is instrumental in bringing about certain outcomes 6-40 Operant Conditioning Thorndike’s Law of Effect • Response followed by a “satisfying” consequence becomes more likely to occur • Response followed by an “unsatisfying” consequence becomes less likely to occur 6-41 13 9/1/2009 6-42 6-43 Operant Conditioning What is Operant Conditioning? • Behavior is influenced by consequences that follow it (Skinner, 1938, 1953) 6-44 14 9/1/2009 Operant Conditioning Reinforcement • Response is strengthened by outcome that follows it Punishment • Response is weakened by outcome that follows it 6-45 Operant Conditioning Skinner’s Analysis of Operant Behavior • A: antecedents of behavior • B: behaviors • C: consequences that follow behavior 6-46 Operant Conditioning Skinner’s Analysis of Operant Behavior • IF A is present • AND B is emitted • THEN C will occur 6-47 15 9/1/2009 Operant Conditioning Differences Between Classical and Operant Conditioning • Classical: Behavior changes due to association of two stimuli (CSUCS) presented prior to the response (CR) • Operant: Behavior changes as a result of consequences that follow it 6-48 Operant Conditioning Differences Between Classical and Operant Conditioning cont. • Classical: Focuses on elicited behavior • Operant: Focuses on emitted behaviors 6-49 Operant Conditioning Discriminative Stimulus • Signals that a particular response will produce certain consequences 6-50 16 9/1/2009 Operant Conditioning Positive Reinforcement • Occurs when a response is strengthened by the presentation of a stimulus (the positive reinforcer) that follows it 6-51 Operant Conditioning Positive Reinforcement • Primary reinforcers • Stimuli that organism finds reinforcing because they satisfy biological needs (e.g. food, drink) 6-52 Operant Conditioning • Secondary reinforcers • Acquire reinforcing properties through association with primary reinforcers (e.g. money, praise) 6-53 17 9/1/2009 Operant Conditioning Negative Reinforcement • Response strengthened by removal (or avoidance) of an aversive stimulus (the negative reinforcer) 6-54 Operant Conditioning Operant Extinction • Weakening and eventual disappearance of an operant response • Why? • Response is no longer reinforced 6-55 Operant Conditioning Operant Extinction cont. • Resistance to extinction influenced by pattern of reinforcement that has maintained behavior • Good alternative to punishment 6-56 18 9/1/2009 Operant Conditioning Aversive Punishment • Response weakened by subsequent stimulus presentation • E.g. spanking or scolding 6-57 Operant Conditioning Meta-analysis of Corporal Punishment Studies (Gershoff, 2002) • 88 studies; 36,000 participants • Punishment is somewhat effective in temporarily suppressing misbehavior 6-58 Operant Conditioning Gershoff (2002) cont. Punishment is associated with: • Decreased parent-child quality relationship • Poorer internalization of moral standards • Increased aggressive behavior during childhood and adulthood 6-59 19 9/1/2009 Operant Conditioning Gershoff (2002) cont. Punishment is associated with: 6-60 • Increased childhood and adulthood delinquent and antisocial behavior • Poorer childhood and adulthood mental health • Increased childhood risk of physical abuse and becoming an abuser as an adult Operant Conditioning 1) Corporal punishment Aggression Or? 2) Corporal punishment Aggression 6-61 Operant Conditioning Or? 3) Corporal punishment Aggression Third Variable 6-62 20 9/1/2009 Operant Conditioning Durrant (2000): After corporal punishment ban in Sweden • Decline in teenage theft, rape, narcotics trafficking, use of alcohol and other drugs, suicide 6-63 Operant Conditioning Response Cost • Response weakened by subsequent removal of a stimulus • Examples: loss of privileges or money misbehaving child gets “time out” that removes opportunity to watch TV or play 6-64 Operant Conditioning Effectiveness of Punishment (Holden, 2002) • Must occur after every transgression • Must be immediate • Must be intense • Must not be signaled by discriminative stimulus 6-65 21 9/1/2009 Operant Conditioning Shaping • Reinforce successive approximations toward a final response 6-66 Operant Conditioning Chaining • Reinforce each response with opportunity to perform next response • Develops a sequence of behaviors • Usually begin with final response in sequence and work back toward first response 6-67 Operant Conditioning Operant Generalization • Operant response occurs to a new antecedent stimulus or situation similar to the original one 6-68 22 9/1/2009 Operant Conditioning Operant Discrimination • Operant response occurs to one antecedent stimulus but not another 6-69 Stimulus Control • A discriminative stimulus influences a behavior Operant Conditioning Continuous Reinforcement • Every response of a particular type is reinforced Partial Reinforcement • Only some responses are reinforced 6-70 Operant Conditioning Types of Partial Reinforcement Schedules • Ratio: Certain percentage of responses are reinforced 6-71 23 9/1/2009 Operant Conditioning Types of Partial Reinforcement Schedules • Interval Certain amount of time must elapse between reinforcements 6-72 Operant Conditioning Types of Partial Reinforcement Schedules • Fixed Reinforcement occurs after a fixed number of responses or fixed time interval 6-73 Operant Conditioning • Types of Partial Reinforcement Schedules • Variable Reinforcement occurs after an average number of responses or passage of time 6-74 24 9/1/2009 Operant Conditioning Fixed Ratio Schedule (FR) • Reinforcement given after a fixed number of responses Variable Ratio Schedule (VR) • Reinforcement given after a variable number of responses, centered around an average 6-75 Operant Conditioning Fixed Interval Schedule (FI) • First correct response after a fixed time interval is reinforced 6-76 Variable Interval Schedule (VI) • Reinforcement given for first correct response after a variable time interval, centered around an average 6-77 25 9/1/2009 Operant Conditioning Continuous-Partial Reinforcement Differences With continuous reinforcement: • More rapid learning • Consequences easier to perceive • Extinction more rapid 6-78 Operant Conditioning Escape Conditioning • Learn responses to terminate aversive stimuli Avoidance Conditioning • Learn responses to avoid aversive stimuli 6-79 6-80 26 9/1/2009 Operant Conditioning Two-Factor Theory of Avoidance Learning (Mowrer, 1947; Rescorla & Solomon, 1967) • Both classical and operant conditioning are involved 6-81 6-82 Operant Conditioning Applications: Education and Workplace • Teaching machines (Skinner) and computer-assisted instruction Immediate feedback Self-paced learning • Token economies: Desired behavior reinforced with tokens, exchangeable for rewards 6-83 27 9/1/2009 Operant Conditioning Applications: Specialized Animal Training • Animals assist people who have disabilities • Animals assist police, military • Animals perform in entertainment industry 6-84 Operant Conditioning Applications: Modifying Problem Behaviors • Applied Behavior Analysis • Behavior modification 6-85 6-86 28 9/1/2009 Operant Conditioning Modifying Behavior • Specify the problem • Collect baseline data • Identify antecedents (A) and consequences (C) • Develop plan to modify A, C • Implement program and measure progress 6-87 6-88 Crossroads of Conditioning Biological Constraints • Preparedness (Seligman, 1970) Animals are biologically predisposed to learn some associations more easily than others • Occurs through evolution 6-89 29 9/1/2009 Crossroads of Conditioning Conditioned taste aversions • Organism becomes ill (nausea, vomiting) after eating a food • The food (taste, sight, smell) then becomes a CS that triggers a CR of disgust, repulsion 6-90 Crossroads of Conditioning Conditioned taste aversions • Influenced by biological preparedness Sweet water readily becomes a CS when paired with nausea Lights, sounds are less likely to become a CS when paired with nausea 6-91 Crossroads of Conditioning Conditioned fear • Influenced by biological preparedness Lights, sounds readily become a CS when paired with electric shock Sweet water is less likely to become a CS when paired with electric shock 6-92 30 9/1/2009 Crossroads of Conditioning Evolution and Preparedness • Biological preparedness for fears among humans • Using electric shock as UCS, easier to condition fear to sight of snakes and spiders than to sight of flowers 6-93 Crossroads of Conditioning Biological Constraints on Operant Conditioning • Instinctive Drift A conditioned operant response “drifts back” toward instinctive behavior 6-94 Crossroads of Conditioning Cognition and Conditioning • Early behaviorist approach was known as S-R (stimulus-response) psychology • Assumed relatively automatic formation of bonds between S and R 6-95 31 9/1/2009 Crossroads of Conditioning S-O-R (Cognitive) Model of Learning • O = organism’s cognitive representation of the world 6-96 Crossroads of Conditioning Insight (Kohler, 1925) • Sudden perception of useful relationships that can solve problems • Challenged ideas about trialand-error learning 6-97 Crossroads of Conditioning Cognitive Maps (Tolman, 1948) • Mental representations of spatial layouts • Suggests that learning provides knowledge and expectation of “what leads to what” 6-98 32 9/1/2009 Crossroads of Conditioning Cognition in Classical Conditioning • Expectancy Model (Rescorla & Wagner, 1972) CS produces an expectancy that the UCS will follow 6-99 Crossroads of Conditioning Cognition in Operant Conditioning • Organisms develops an awareness or expectancy of response-consequence contingencies 6-100 Crossroads of Conditioning Cognition in Operant Conditioning • Latent Learning Learning that occurs at Time A but is not demonstrated until Time B when there is an incentive 6-101 33 9/1/2009 Crossroads of Conditioning Cognition in Operant Conditioning • Cognitive self-evaluations Self-evaluations can serve as reinforcers and punishers 6-102 Observational Learning What is observational learning? • Learning that occurs by observing the behavior of a model 6-103 Observational Learning Social-Cognitive Theory; also known as Social Learning Theory (Bandura, 1969, 2004) • People learn by observing the behavior of models AND • by acquiring self-efficacy 6-104 34 9/1/2009 Observational Learning The Modeling Process (Bandura) • Attention • Retention • Reproduction • Motivation 6-105 Observational Learning Self-Efficacy • a person’s belief that she or he has the capability to perform behaviors that will produce a desired outcome 6-106 Observational Learning Impact of Social Cognitive Theory • Imitation of aggression and prosocial behavior • International development of mass media projects to reduce social problems (e.g., AIDs, national illiteracy) 6-107 35