Learning Chapter 8 1 Learning How Do We Learn? Classical Conditioning Pavlov’s Experiments Extending Pavlov’s Understanding Pavlov’s Legacy 2 Learning Operant Conditioning Skinner’s Experiments Extending Skinner’s Understanding Skinner’s Legacy Contrasting Classical & Operant Conditioning 3 Learning Learning by Observation Bandura’s Experiments Applications of Observational Learning 4 Definition Learning is a relatively permanent change in an organism’s behavior due to experience. Learning is more flexible in comparison to the genetically-programmed behaviors of Chinooks, for example. 5 How Do We Learn? Associative Learning-We learn by association. Our minds naturally connect events that occur in sequence. 2000 years ago, Aristotle suggested this law of association. Then 200 years ago Locke and Hume reiterated this law. 6 Stimulus-Stimulus Learning Learning to associate one stimulus with another. 7 Stimulus-Stimulus Learning Learning to associate one stimulus with another. 8 Response-Consequence Learning Learning to associate a response with a consequence. 9 Response-Consequence Learning Learning to associate a response with a consequence. 10 Behaviorism • Behaviorism- the view that psychology should be an objective science that studies behavior without reference to mental processes. Most researchers disagree with mental processes. 11 Watson Quote • Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. (1930) 12 Classical Conditioning Sovfoto Ideas of classical conditioning originate from old philosophical theories. However, it was the Russian physiologist Ivan Pavlov who elucidated classical conditioning. His work provided a basis for later behaviorists like John Watson and B. F. Skinner. Ivan Pavlov (1849-1936) 13 Pavlov’s Experiments Before conditioning, food (Unconditioned Stimulus, US) produces salivation (Unconditioned Response, UR). However, the tone (neutral stimulus) does not. Thus, UCSFOOD; UCR- SALIVATION 14 Pavlov’s Experiments During conditioning, the neutral stimulus (tone) and the US (food) are paired, resulting in salivation (UR). After conditioning, the neutral stimulus (now Conditioned Stimulus, CS) elicits salivation (now Conditioned Response, CR); Thus CS; TONE; and CR; SALIVATION 15 Acquisition Acquisition is the initial stage in classical conditioning in which an association between a neutral stimulus and an unconditioned stimulus takes place. 1. In most cases, for conditioning to occur, the neutral stimulus needs to come before the unconditioned stimulus. 2. The time in between the two stimuli should be about half a second. 16 Acquisition The CS needs to come half a second before the US for acquisition to occur. 17 Extinction When the US (food) does not follow the CS (tone), CR (salivation) begins to decrease and eventually causes extinction. 18 Spontaneous Recovery After a rest period, an extinguished CR (salivation) spontaneously recovers, but if the CS (tone) persists alone, the CR becomes extinct again. 19 Stimulus Generalization Tendency to respond to stimuli similar to the CS is called generalization. Pavlov conditioned the dog’s salivation (CR) by using miniature vibrators (CS) on the thigh. When he subsequently stimulated other parts of the dog’s body, salivation dropped. 20 Stimulus Discrimination Discrimination is the learned ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus. 21 Extending Pavlov’s Understanding Pavlov and Watson considered consciousness, or mind, unfit for the scientific study of psychology. However, they underestimated the importance of cognitive processes and biological constraints. 22 Cognitive Processes Early behaviorists believed that learned behaviors of various animals could be reduced to mindless mechanisms. However, later behaviorists suggested that animals learn the predictability of a stimulus, meaning they learn expectancy or awareness of a stimulus (Rescorla, 1988). 23 Biological Predispositions Pavlov and Watson believed that laws of learning were similar for all animals. Therefore, a pigeon and a person do not differ in their learning. However, behaviorists later suggested that learning is constrained by an animal’s biology. 24 Biological Predispositions Courtesy of John Garcia Garcia showed that the duration between the CS and the US may be long (hours), but yet result in conditioning. A biologically adaptive CS (taste) led to conditioning and not to others (light or sound). John Garcia 25 Biological Predisposition related to Classical Conditioning Even humans can develop classically to conditioned nausea. 26 Pavlov’s Legacy Pavlov’s greatest contribution to psychology is isolating elementary behaviors from more complex ones through objective scientific procedures. Ivan Pavlov (1849-1936) 27 Applications of Classical Conditioning Brown Brothers Watson used classical conditioning procedures to develop advertising campaigns for a number of organizations, including Maxwell House, making the “coffee break” an American custom. John B. Watson 28 Applications of Classical Conditioning 1. Alcoholics may be conditioned (aversively) by reversing their positive-associations with alcohol. 2. Through classical conditioning, a drug (plus its taste) that affects the immune response may cause the taste of the drug to invoke the immune response. 29 Respondent Behavior- Operant & Classical Conditioning 1. Classical conditioning forms associations between stimuli (CS and US). Operant conditioning, on the other hand, forms an association between behaviors and the resulting events. 30 Operant Behavior- Operant & Classical Conditioning 2. Classical conditioning involves respondent behavior that occurs as an automatic response to a certain stimulus. Operant conditioning involves operant behavior, a behavior that operates on the environment, producing rewarding or punishing stimuli. 31 Skinner’s Experiments Skinner’s experiments extend Thorndike’s thinking, especially his law of effect. This law states that rewarded behavior is likely to occur again. Yale University Library 32 Using Thorndike's law of effect as a starting point, Skinner developed the Operant chamber, or the Skinner box, to study operant conditioning. Walter Dawn/ Photo Researchers, Inc. 33 From The Essentials of Conditioning and Learning, 3rd Edition by Michael P. Domjan, 2005. Used with permission by Thomson Learning, Wadsworth Division Operant Chamber Operant Chamber The operant chamber, or Skinner box, comes with a bar or key that an animal manipulates to obtain a reinforcer like food or water. The bar or key is connected to devices that record the animal’s response. 34 Shaping Shaping is the operant conditioning procedure in which reinforcers guide behavior towards the desired target behavior through successive approximations. Fred Bavendam/ Peter Arnold, Inc. Khamis Ramadhan/ Panapress/ Getty Images A rat shaped to sniff mines. A manatee shaped to discriminate objects of different shapes, colors and sizes. 35 Types of Reinforcers Any event that strengthens the behavior it follows. A heat lamp positively reinforces a meerkat’s behavior in the cold. Reuters/ Corbis 36 Primary & Secondary Reinforcers 1. Primary Reinforcer: An innately reinforcing stimulus like food or drink. 2. Conditioned Reinforcer: A learned reinforcer that gets its reinforcing power through association with the primary reinforcer. 37 POSITIVE REINFORCERS NEGATIVE REINFORCERS PRIMARY SECONDARY PRIMARY SECONDARY Food Money Electric shock Rejection Water Grades Intense heat Failure Sex Status Pain of any sort Criticism Warmth Praise Suffocation Avoidance Types of Reinforcers • Positive Reinforcers – A reinforcer that when presented increases the frequency of an operant. • Ex. A hungry rat presses a bar in its cage and receives food. The food is a positive condition for the hungry rat. The rat presses the bar again, and again receives food. The rat's behavior of pressing the bar is strengthened by the consequence of receiving food. Types of Reinforcement • Negative Reinforcers – A reinforcer that when removed increases the frequency of an operant. • Ex. A rat is placed in a cage and immediately receives a mild electrical shock on its feet. The shock is a negative condition for the rat. The rat presses a bar and the shock stops. The rat receives another shock, presses the bar again, and again the shock stops. The rat's behavior of pressing the bar is strengthened by the consequence of stopping the shock. Positive or Negative Reinforcement? 1. 2. 3. 4. 5. 6. 7. 8. Police pulling drivers over and giving prizes for buckling up. A child snaps her fingers until her teacher calls on her. A hospital patient is allowed extra visiting time after eating a complete meal. Receiving a city utility discount for participating in a recycling program. Grounding a teenager until his/her homework is finished. A parent nagging a child to clean up her room. A rat presses a lever to terminate a shock or a loud tone. A professor gives extra credit to students with perfect attendance. 1. PR 2. NR 3. PR 4. PR 5. 6. 7. NR NR NR 8. PR Potential Negative Effects of Punishment Recurrence of undesirable employee behavior Undesirable emotional reaction Antecedent Undesirable employee behavior Punishment by manager But Short-term leads to decrease in frequency long-term of undesirable employee behavior Aggressive, disruptive behavior Apathetic, noncreative performance Fear of manager Which tends to reinforce High turnover and absenteeism Schedules of Reinforcement • Ratio Version – having to do with instances of the behavior. • Ex. – Reinforce or reward the behavior after a set number or x many times that an action or behavior is demonstrated. • Interval Version – having to do with the passage of time. • Ex. – Reinforce the student after a set number or x period of time that the behavior is displayed. 4 Basic Schedules of Reinforcement • Fixed-interval schedule • Variable-interval schedule • Fixed-ratio schedule • Variable-ratio schedule Fixed-Interval Schedule • Fixed-interval schedule – A schedule in which a fixed amount of time must elapse between the previous and subsequent times that reinforcement will occur. • No response during the interval is reinforced. • The first response following the interval is reinforced. • Produces an overall low rate of responding • Ex. I get one pellet of food every 5 minutes when I press the lever Fixed Interval Reinforcement Variable-Interval Schedule • Variable-interval Schedule – A schedule in which a variable amount of time must elapse between the previous and subsequent times that reinforcement is available. • Produces an overall low consistent rate of responding. • Ex. – I get a pellet of food on average every 5 minutes when I press the bar. Variable Interval Reinforcement Fixed-Ratio Schedule • Fixed-ratio Schedule – A schedule in which reinforcement is provided after a fixed number of correct responses. • These schedules usually produce rapid rates of responding with short post-reinforcement pauses • The length of the pause is directly proportional to the number of responses required • Ex. – For every 5 bar presses, I get one pellet of food An Example of Fixed Ratio Reinforcement • Every fourth instance of a smile is reinforced Fixed Ratio Reinforcement Variable-Ratio Schedule • Variable-ratio Schedule – A schedule in which reinforcement is provided after a variable number of correct responses. • Produce an overall high consistent rate of responding. • Ex. – On average, I press the bar 5 times for one pellet of food. An Example of Variable Ratio Reinforcement • Random instances of the behavior are reinforced Variable Ratio Reinforcement TYPE MEANING OUTCOME Fixed Ratio Reinforcement depends on a definite number of responses Activity slows after reinforcement and then picks up Variable Ratio Number of responses needed for reinforcement varies Greatest activity of all schedules Fixed Interval Reinforcement depends on a fixed time Activity increases as deadline nears Variable Interval Time between reinforcement varies Steady activity results Comparisons of Schedules of Reinforcement SCHEDULE FORM OF REWARD INFLUENCE ON PERFORMANCE EFFECTS ON BEHAVIOR Fixed interval Reward on fixed time basis Leads to average and irregular performance Fast extinction of behavior Fixed ratio Reward tied to specific number of responses Leads quickly to very high and stable performance Moderately fast extinction of behavior Variable interval Reward given after varying periods of time Leads to moderately high and stable performance Slow extinction of behavior Variable ratio Reward given for some behaviors Leads to very high performance Very slow extinction of behavior 1. 2. 3. 4. 5. FI, VI, FR, or VR? When I bake cookies, I can only put one set in at a time, so after 10 minutes my first set of cookies is done. After another ten minutes, my second set of cookies is done. I get to eat a cookie after each set is done baking. After every 10 math problems that I complete, I allow myself a 5 minute break. I look over my notes every night because I never know how much time will go by before my next pop quiz. When hunting season comes around, sometimes I’ll spend all day sitting in the woods waiting to get a shot at a big buck. It’s worth it though when I get a nice 10 point. Today in Psychology class we were talking about Schedules of Reinforcement and everyone was eagerly raising their hands and participating. Miranda raised her hand a couple of times and was eventually called on. 1. FI 2. FR 3. VI 4. VI 5. VR FI, VI, FR, or VR? 6. Madison spanks her son if she has to ask him three times to clean up his room. 7. Emily has a spelling test every Friday. She usually does well and gets a star sticker. 8. Steve’s a big gambling man. He plays the slot machines all day hoping for a big win. 9. Snakes get hungry at certain times of the day. They might watch any number of prey go by before they decide to strike. 10. Mr. Vora receives a salary paycheck every 2 weeks. t 11. Christina works at a tanning salon. For every 2 bottles of lotion she sells, she gets 1 dollar in commission. 12. Mike is trying to study for his upcoming Psychology quiz. He reads five pages, then takes a break. He resumes reading and takes another break after he has completed 5 more pages. 6. FR 7. FI 8. VR 9. VI 10. FI 11. FR 12. FR FI, VI, FR, or VR? 13. Megan is fundraising to try to raise money so she can go on the annual band trip. She goes door to door in her neighborhood trying to sell popcorn tins. She eventually sells some. 14. Kylie is a business girl who works in the big city. Her boss is busy, so he only checks her work periodically. 15. Mark is a lawyer who owns his own practice. His customers makes payments at irregular times. 16. Jessica is a dental assistant and gets a raise every year at the same time and never in between. 17. Andrew works at a GM factory and is in charge of attaching 3 parts. After he gets his parts attached, he gets some free time before the next car moves down the line. 18. Brittany is a telemarketer trying to sell life insurance. After so many calls, someone will eventually buy. 13. VR 14. VI 15. VI 16. FI 17. FR 18. VR Applications of Operant Conditioning • Programmed Learning – A method of learning in which complex tasks are broken down into simple steps, each of which is reinforced. Errors are not reinforced. • Ex. – Hooked on Phonics Applications of Operant Conditioning • Socialization – Guidance of people into socially desirable behavior by means of verbal messages, the systematic use of rewards and punishments, and other methods of teaching. • Ex. – Children play with other children who are generous and non-aggressive and avoid those who are not. Applications of Operant Conditioning • Behavior Modification Praise this Ignore this Applications of Operant Conditioning • Token Economy – An environmental setting that fosters desired behavior by reinforcing it with tokens (secondary reinforcers) that can be exchanged for other reinforcers. • Ex. – Book It! Other Types of Learning • Insight Learning – In Gestalt psychology, a sudden perception of relationships among elements of the “perceptual field”, permitting the solution of a problem. • Latent Learning – Learning that is hidden or concealed. • Observational Learning – Acquiring operants by observing other engage in them. Insight Learning • Wolfgang Kohler – German Gestalt psychologist • Experiments with Chimpanzees • Sultan learned to use a stick to rake in bananas placed outside his cage. • When the bananas were placed outside of Sultan’s reach, he fitted two poles together to make a single pole long enough to reach the food Insight Learning “Aha” Learning • • Cognitive Map – A mental representation or “picture” of the elements in a learning situation, such as a maze. – Ex. – if someone pukes in the hall that you usually take to your next class you will still be able to find your way because of your mental representation of this school. Insight Learning Latent Learning • E.C. Tolman – experiment with rats. • Rats learn about their environments in the absence of reinforcement. • Some rats went through maze for food goals, while others were given no reinforcement for several days. • After 10 days, rewards were put in with the rats that had previously been given no rewards for 2 or 3 trials. • Those rats reached the food box as quickly as the rats that had been getting reinforcement for over a week. • Rats learn about mazes in which they roam even if they are unrewarded for doing so. • • • • • Observational Learning Albert Bandura Bobo doll experiment Assistant placed in room with doll Beat doll with hammer and hit doll Kindergarten children watched this display of aggression in a separate room. • When placed in the room, they too were extremely aggressive with the doll • Happened without ever being rewarded for the behavior. • http://www.npr.org/templat es/story/story.php?storyId= 1187559 •Modeling Monkey see, monkey do! •Disinhibition Get away with or are rewarded for violence They always “get the girl/guy/money/car - etc. •Increased arousal Works the audience up Watch the fans at a sporting event Watch your friends watch the WWF •Habituation We become used to - desensitization Immediate & Delayed Reinforcers 1. Immediate Reinforcer: A reinforcer that occurs instantly after a behavior. A rat gets a food pellet for a bar press. 2. Delayed Reinforcer: A reinforcer that is delayed in time for a certain behavior. A paycheck that comes at the end of a week. We may be inclined to engage in small immediate reinforcers (watching TV) rather than large delayed reinforcers (getting an A in a course) which require consistent study. 76 Reinforcement Schedules 1. Continuous Reinforcement: Reinforces the desired response each time it occurs. 2. Partial Reinforcement: Reinforces a response only part of the time. Though this results in slower acquisition in the beginning, it shows greater resistance to extinction later on. 77 Ratio Schedules 1. Fixed-ratio schedule: Reinforces a response only after a specified number of responses. e.g., piecework pay. 2. Variable-ratio schedule: Reinforces a response after an unpredictable number of responses. This is hard to extinguish because of the unpredictability. (e.g., behaviors like gambling, fishing.) 78 Interval Schedules 1. Fixed-interval schedule: Reinforces a response only after a specified time has elapsed. (e.g., preparing for an exam only when the exam draws close.) 2. Variable-interval schedule: Reinforces a response at unpredictable time intervals, which produces slow, steady responses. (e.g., pop quiz.) 79 Schedules of Reinforcement 80 Punishment An aversive event that decreases the behavior it follows. 81 Punishment Although there may be some justification for occasional punishment (Larzelaere & Baumrind, 2002), it usually leads to negative effects. 1. 2. 3. 4. Results in unwanted fears. Conveys no information to the organism. Justifies pain to others. Causes unwanted behaviors to reappear in its absence. 5. Causes aggression towards the agent. 6. Causes one unwanted behavior to appear in place of another. 82 Extending Skinner’s Understanding Skinner believed in inner thought processes and biological underpinnings, but many psychologists criticize him for discounting them. 83 Cognition & Operant Conditioning Evidence of cognitive processes during operant learning comes from rats during a maze exploration in which they navigate the maze without an obvious reward. Rats seem to develop cognitive maps, or mental representations, of the layout of the maze (environment). 84 Latent Learning Such cognitive maps are based on latent learning, which becomes apparent when an incentive is given (Tolman & Honzik, 1930). 85 Motivation Intrinsic Motivation: The desire to perform a behavior for its own sake. Extrinsic Motivation: The desire to perform a behavior due to promised rewards or threats of punishments. 86 Biological Predisposition Photo: Bob Bailey Biological constraints predispose organisms to learn associations that are naturally adaptive. Breland and Breland (1961) showed that animals drift towards their biologically predisposed instinctive behaviors. Marian Breland Bailey 87 Skinner’s Legacy Skinner argued that behaviors were shaped by external influences instead of inner thoughts and feelings. Critics argued that Skinner dehumanized people by neglecting their free will. Falk/ Photo Researchers, Inc . 88 Applications of Operant Conditioning Skinner introduced the concept of teaching machines that shape learning in small steps and provide reinforcements for correct rewards. LWA-JDL/ Corbis In School 89 Applications of Operant Conditioning Reinforcement principles can enhance athletic performance. In Sports 90 Applications of Operant Conditioning Reinforcers affect productivity. Many companies now allow employees to share profits and participate in company ownership. At work 91 Applications of Operant Conditioning In children, reinforcing good behavior increases the occurrence of these behaviors. Ignoring unwanted behavior decreases their occurrence. 92 Operant vs. Classical Conditioning 93 Learning by Observation © Herb Terrace Higher animals, especially humans, learn through observing and imitating others. ©Herb Terrace The monkey on the right imitates the monkey on the left in touching the pictures in a certain order to obtain a reward. 94 Reprinted with permission from the American Association for the Advancement of Science, Subiaul et al., Science 305: 407-410 (2004) © 2004 AAAS. Mirror Neurons Neuroscientists discovered mirror neurons in the brains of animals and humans that are active during observational learning. 95 Learning by observation begins early in life. This 14-month-old child imitates the adult on TV in pulling a toy apart. Meltzoff, A.N. (1998). Imitation of televised models by infants. Child Development, 59 1221-1229. Photos Courtesy of A.N. Meltzoff and M. Hanuk. Imitation Onset 96 Bandura's Bobo doll study (1961) indicated that individuals (children) learn through imitating others who receive rewards and punishments. Courtesy of Albert Bandura, Stanford University Bandura's Experiments 97 Applications of Observational Learning- Modeling Unfortunately, Bandura’s studies show that antisocial models (family, neighborhood or TV) may have antisocial effects. Must model acceptable social behavior 98 Positive Observational Learning Bob Daemmrich/ The Image Works Fortunately, prosocial (positive, helpful) models may have prosocial effects. 99 Gentile et al., (2004) shows that children in elementary school who are exposed to violent television, videos, and video games express increased aggression. Ron Chapple/ Taxi/ Getty Images Television and Observational Learning 100 Modeling Violence Children modeling after pro wrestlers Glassman/ The Image Works Bob Daemmrich/ The Image Works Research shows that viewing media violence leads to an increased expression of aggression. 101