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PSYC 100 Learning 3/11/2005 Lecture Outline Q Q Q Q Learning Classical Conditioning Operant Conditioning Cognitive-social theory . Learning Q Learning refers to an enduring change in the way an organism responds based on its experience ß Distinct from • Drug effects (caffeine-induced jitters are not learning) • Fatigue or illness Q Three assumptions of learning theories ß Responses are learned rather than innate ß Learning is adaptive ß Our experiments can uncover the laws of learning • These laws will apply to animals and to humans 1 Classical Conditioning Q The Russian physiologist Pavlov noted that reflexive salivation in dogs could be elicited by stimuli associated with feeding ß Reflex: Response that is reliably elicited by a stimulus • Food elicits salivation • Air puff elicits eye blink ß Reflexive stimulus and response are unconditioned ß Neutral stimulus is referred to as the conditioned stimulus (CS) ß CS is paired with the UCS over many trials ß Eventually comes to elicit a conditioned response (CR: resembles the UCR) Pavlov’s Experiment Conditioned Taste Aversion Q If a flavor is followed by an illness experience, animals will avoid the flavor in the future CS Taste + CS -----> Flavor UCS ----------> UCR Toxic event Nausea CR Nausea 2 Are These Examples of Classical Conditioning? Q A man listening to the radio feels a rush when Q Q Q Q he hears a song that was popular when he was using cocaine... A cat runs into the kitchen when the can opener is turning... A war veteran dives to the street upon hearing a car backfire... The smell of a steak produces salivation... A student feels nauseated when entering a classroom in which they earlier took a difficult exam Stimulus Generalization/Discrimination Q Generalization: If a response is conditioned to one stimulus, the organism may also respond to a similar stimulus, but not to a dissimilar stimulus (discrimination) ß Hovland study: CS Tone + UCS ----------> UCR Shock Pain CS alone produced changes in GSR (associated with anxiety) Acquisition and Extinction Q Acquisition of classical conditioning: ß Repeated pairings of CS and UCS Q Extinction: Refers to the weakening of conditioning evident when the CS is presented repeatedly without the UCS ß Spontaneous recovery: Refers to the reemergence of a previously extinguished CR 3 Classical Conditioning Issues Q Temporal order of presentation of CS and UCS is important ß Best conditioning: CS precedes UCS (forward) ß Worst conditioning: UCS precedes CS (backward) Classical Conditioning Issues Q Interstimulus interval (ISI) between CS and UCS is important for conditioning • ISI’s longer than 2 sec produce poor conditioning Q Prior conditioning history is important ß Latent Inhibition: Repeated exposure to a neutral stimulus alone (no UCS) makes it more difficult to use the stimulus as a CS in the future • Familiar ice cream taste is less likely to produce a CTA than a novel flavor Q Infant Albert Q Second-order conditioning Q Preparedness 3/11/2005 4 Operant Conditioning Q Law of Effect: Behavior is controlled by its consequences ß Thorndike experiment: Hungry cat learned to pull a string in order to leave a box and eat food from a bowl placed just outside the box Q Operant conditioning and instrumental conditioning: ß Responses operate on the environment and are instrumental in receiving reward 3/11/2005 Are These Examples of Operant Conditioning? Q Woman inserts coins into a coke machine, Q Q Q Q Q presses the third button and receives five cans of soda. For the next week, she presses the third button on every coke machine she encounters... Drug addict injects heroin into a vein… Rat presses a lever to obtain food… Woman pays $42.00 for groceries… Man turns off television that was blaring an MTV video… Student comes to class every day in order to take notes… Positive Reinforcement Q Reinforcer: An environmental stimulus that occurs after the response and increases the likelihood that the response will occur in the future ß Positive reinforcement: Process by which presentation of a stimulus after a response makes the response more likely to occur in the future ß Negative reinforcement: Termination of an aversive event makes a behavior more likely to occur in the future 5 Issues in Negative Reinforcement Q Negative reinforcement involves a situation in which a response that terminates an aversive stimulus will strengthen that response ß Taking an aspirin will reduce the headache and strengthen the behavior of aspirin-taking (sometimes referred to as escape-learning) ß Avoidance learning: A response prevents a potentially aversive event from occurring • Child cleans his room to avoid parental nagging Punishment Q Punishment decreases the likelihood that a response will occur Q Examples of punishing situations ß Presentation of an aversive stimulus (Positive) • Parent spanks a child for taking candy... • Owner swats a dog who has chewed her slippers... ß Removal of a reward (Negative) • Teenager who stays out past curfew is not allowed to drive the family car for 2 weeks... • Husband who forgets anniversary sleeps on couch for a week... Difficulties in Punishment Q Learner may not understand which operant behavior is being punished Q Learner may come to fear the teacher, rather than learn an association between the action and punishment (then avoids the teacher) Q Punishment may not undo existing rewards for a behavior Q Using punishment when the teacher is angry Q Punitive aggression may lead to future aggression 6 Schedules of Reinforcement Q Continuous reinforcement: Reinforcer is obtained for every response ß Intermittent schedules: Reinforcer is not obtained for every response • Ratio Schedules – Fixed Ratio: Every Nth response – Variable Ratio: The average is every Nth response • Interval Schedules: – Fixed Interval: After the elapse of N minutes • Variable Interval: On average, after N minutes Operant Conditioning (cont.) Q Q Q Q Q Shaping Superstitious behavior Discriminative stimulus Primary vs. secondary reinforcement Skinner: Walden II, Beyond Freedom and Dignity 3/11/2005 Expectancies and Conditioning Q Cognitive-social theory argues that we form expectancies about the consequences of our behaviors ß These expectancies determine what is rewarding Q Locus of control: Refers to general expectancy as to whether fate does or not determine outcomes in life ß Internal locus: Believe that their actions determine their fate ß External locus: Believe that their lives are governed by forces outside their control 7 Locus of Control Scale Q Higher-order cond. Q Explanatory style explain neg events pessimistic (depressive) internal, stable, global Positive illusions—illusory glow 3/11/2005 Observational Learning Q Modeling, vicarious conditioning Q Banduara Q Characteristics of models that promote learning: power, similarity, nurturance 3/11/2005 8