Chapter 7 Learning and Adaptation: The Role of Experience

1. Chapter 7 Learning and Adaptation: The Role of Experience McGraw-Hill Ryerson Ltd. 2008

2. Adapting to the Environment • What is learning? • Process by which experience produces a relatively enduring change in behaviour or capabilities (knowing how) • Distinguish between • ‘Knowing how’ or learning and ‘doing’ or performance • Measure learning by actual changes in performance McGraw-Hill Ryerson Ltd. 2008

3. How do we learn? The search • Behaviorism • Focused on how organisms learn • Examined processes by which experience influences behavior • Treated organism as tabula rasa • Explained learning solely in terms of directly observable events • Avoided unobservable ‘mental states’ • Ethology • Focused on animal behaviour in natural environments • Focused on functions of behaviour McGraw-Hill Ryerson Ltd. 2008

4. Ethology • Fixed Action Patterns • Unlearned (innate) responses • E.g., gulls pecking at long objects with red markings • Releaser stimuli • Trigger fixed action pattern • Two things became clear • Fixed action patterns can be modified by experiences • What appeared to be instinctive - sometimes involved learning McGraw-Hill Ryerson Ltd. 2008

5. Biology, Cognition & Culture • Environmental Shaping of Behaviour • Personal Adaptation • Involves learning • Interactions with immediate & past environments • Species Adaptation • Involves natural selection • Adaptations passed on through genes • Become part of species ‘nature’ McGraw-Hill Ryerson Ltd. 2008

6. Biology, Cognition & Culture • Theorists propose that brain is ‘prewired’ to learn • What must organisms learn? • Events important to survival and well-being • Stimuli that signal important events • Whether responses produce positive or negative consequences McGraw-Hill Ryerson Ltd. 2008

7. Biology, Cognition & Culture • Influences of Culture • Skills • Patterns of social behavior • Beliefs and preferences • Sense of identity • How brain organizes perceptions McGraw-Hill Ryerson Ltd. 2008

8. Habituation - Simple Learning • Habituation • Decrease in response strength to a repeated stimulus • Not same as sensory habituation • Habituation = simple form of learning • Sensory habituation = information is still available if it becomes relevant McGraw-Hill Ryerson Ltd. 2008

9. Classical Conditioning • Associating one stimulus with another - Pavlov • Learn to associate two stimuli • One stimulus elicits a response that was originally elicited only by the other stimulus • Acquisition • Period during which association is being learned • Have stimulus & a response to it - which requires no learning • Pair this response with another stimulus McGraw-Hill Ryerson Ltd. 2008

10. 4 Important Elements • Unconditioned stimulus (UCS) • elicits a reflexive or innate, unconditoned response (UCR) without prior learning • Unconditioned response (UCR) • response elicited by the UCS without prior learning • Conditioned stimulus (CS) • through association with the UCS, comes to elicit a conditioned response similar to the original UCR • Conditioned response (CR) • Response elicited by a conditioned stimulus • UCR & CR are same thing - What elicits them is different! McGraw-Hill Ryerson Ltd. 2008

11. So How Does It Work? • Food produces salivation = UCS - UCR • Pair food (UCS) & tone = learning trial • Tone begins to elicit salivation (UCR) • Tone is now conditioned stimulus (CS) • Now have: tone (CS) - salivation (CR) • Note: UCR & CR are same McGraw-Hill Ryerson Ltd. 2008

12. Types of CS-UCS pairings • Forward short-delay • CS (tone) still present when food (UCS) presented • Optimal learning • Forward trace • CS appears & then goes off • Best if delay is no more than 2-3 seconds • Simultaneous • Presented at same time • Learning is slower • Backward • Presented afterward • Little learning McGraw-Hill Ryerson Ltd. 2008

13. Factors that Enhance Acquisition • Multiple CS-UCS pairings • Intense, aversive UCS can produce one-trial learning • Forward (short-delay) pairing • Time interval between onset of CS & onset of UCS is short McGraw-Hill Ryerson Ltd. 2008

14. Extinction & Spontaneous Recovery • Extinction • Process in which CS is presented in absence of UCS • Causes CR to weaken and eventually disappear • 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 McGraw-Hill Ryerson Ltd. 2008

15. Generalization & Discrimination • Generalization • Stimuli similar to initial CS elicit a CR • Aids in survival • Discrimination • CR occurs to one stimulus but not to another • Weaker responses as stimuli become less similar McGraw-Hill Ryerson Ltd. 2008

16. Higher Order Conditioning • Chain of events which has 2 CS stimuli • Expands influence of classical conditioning on behaviour McGraw-Hill Ryerson Ltd. 2008

17. Classical Conditioning: Therapies • Exposure Therapy • Extinction of CR through exposure to CS without presence of UCS • Systematic desensitization • Muscular relaxation paired with gradual exposure to fear-inducing stimulus • Flooding • Exposure to fearful stimulus • VR Exposure therapy • Effective for phobias McGraw-Hill Ryerson Ltd. 2008

18. Other Influences of Classical Conditioning • Attraction to other people • Positive, negative attitudes • Conditioned aversions • Anticipatory nausea and vomiting (ANV) • Immune system McGraw-Hill Ryerson Ltd. 2008

19. Law of Effect • 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 • Based on concept of Instrumental Learning • Organism’s behavior is instrumental in bringing about certain outcomes McGraw-Hill Ryerson Ltd. 2008

20. Operant Conditioning • Skinner • Operant conditioning facilitates personal adaptation • Reinforcement • Response strengthened by outcome that follows • Punishment • Response weakened by outcome that follows McGraw-Hill Ryerson Ltd. 2008

21. Operant Conditioning • Skinner’s Analysis of Operant Behaviour • A: antecedents of behaviour • B: behaviors • C: consequences that follow behaviour • IF A is present • AND B is emitted • THEN C will occur • Relations between A & B = contingencies McGraw-Hill Ryerson Ltd. 2008

22. Operant and Classical Conditioning • Classical • Behaviour changes due to association of two stimuli (CS-UCS) presented prior to the response (CR) • Focuses on elicited behavior • Operant • Behaviour changes as a result of consequences that follow it • Focuses on emitted behaviors McGraw-Hill Ryerson Ltd. 2008

23. Consequences • Positive Reinforcement • Response is strengthened by presentation of a stimulus (the positive reinforcer) that follows it • Primary reinforcers • Stimuli that are reinforcing because they satisfy biological needs (e.g. food, drink) • Secondary reinforcers • Acquire reinforcing properties through association with primary reinforcers (e.g. money, praise) McGraw-Hill Ryerson Ltd. 2008

24. Consequences • Negative reinforcement • Response strengthened by removal (or avoidance) of an aversive stimulus (negative reinforcer) • Negative reinforcers avoid or remove something unpleasant • Use sunscreen to ‘avoid’ sunburn, therefore increase behaviour of using sunscreen McGraw-Hill Ryerson Ltd. 2008

25. Consequences • Operant Extinction • Weakening and eventual disappearance of an operant response • Why? • Response is no longer reinforced • Resistance to extinction influenced by pattern of reinforcement that has maintained behaviour • Good alternative to punishment McGraw-Hill Ryerson Ltd. 2008

26. Consequences • Positive Punishment • Aversive punishment • Response weakened by subsequent stimulus presentation • E.g. spanking or scolding • Negative Punishment • Response cost • Response weakened by removal of stimulus • Examples: • loss of privileges or money • misbehaving child gets “time out” that removes opportunity to watch TV or play McGraw-Hill Ryerson Ltd. 2008

27. Immediate vs Delayed Consequences • Immediate • Stronger effect on behaviour • Delay of gratification • Involves ability to forego immediate reward for more satisfying outcome later • Individual variability • May have role in drinking, smoking, criminal behaviour etc. McGraw-Hill Ryerson Ltd. 2008

28. Shaping & Chaining • Shaping • Reinforce successive approximations toward a final response • Chaining • Reinforce each response with opportunity to perform the next response • Develops a sequence of behaviors McGraw-Hill Ryerson Ltd. 2008

29. Generalization & Discrimination • Generalization • Operant response occurs to a new antecedent stimulus or situation similar to the original one • Operant Discrimination • Operant response occurs to one antecedent stimulus but not another • Stimulus Control • A discriminative stimulus influences a behaviour McGraw-Hill Ryerson Ltd. 2008

30. Schedules of Reinforcement • Continuous Reinforcement • Every response of a particular type is reinforced • Partial Reinforcement • Only some responses are reinforced • Types of Partial Reinforcement Schedules • Ratio: • Certain percentage of responses are reinforced • Interval • Certain amount of time must elapse between reinforcements McGraw-Hill Ryerson Ltd. 2008

31. Schedules of Reinforcement • Types of Partial Reinforcement Schedules • Fixed • Reinforcement occurs after a fixed number of responses or fixed time interval • Variable • Reinforcement occurs after an average number of responses or passage of time McGraw-Hill Ryerson Ltd. 2008

32. Now Combine These • 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 • Fixed Interval Schedule (FI) • First correct response after a fixed time interval is reinforced • Variable Interval Schedule (VI) • Reinforcement given for first correct response after a variable time interval, centered around an average McGraw-Hill Ryerson Ltd. 2008

33. Learning & Extinction • Continuous reinforcement • More rapid learning • Consequences easier to perceive • Extinction more rapid • Partial reinforcement • Slower learning • More resistant to extinction - especially on VR schedule • Gambling is reinforced on a VR schedule • Do not know which response will be reinforced! Could always be the next one! • Difficult to extinguish McGraw-Hill Ryerson Ltd. 2008

34. Escape and Avoidance • Escape Conditioning • Learn responses to terminate aversive stimuli • Avoidance Conditioning • Learn responses to avoid aversive stimuli • Two-factor theory of avoidance • Both classical conditioning and operant conditioning • Association between 2 stimuli develops • Classical conditioning • Negative reinforcement maintains avoidance response • Operant conditioning McGraw-Hill Ryerson Ltd. 2008

35. Neuroscience of Fear Conditioning • Amygdala • Visual presentation of fearful event increased activity in right amygdala • Also have lower frontal cortex activity • PTSD • Increased activity in right amygdala with decreased frontal cortex activity McGraw-Hill Ryerson Ltd. 2008

36. Biology & Learning • Biological Preparedness • Biologically prewired to learn behaviours related to survival • Behaviours contrary to natural tendencies slowly learned - if at all! • Constraints: Classical Conditioning • Learned taste aversions (Garcia et al., 1985) • Rats easily learn taste aversion • Lights & sounds don’t matter McGraw-Hill Ryerson Ltd. 2008

37. Fear Certain Things? • Are we biologically prepared to fear certain things? • Most phobias develop for things that have evolutionary significance • Snakes, spiders, dangerous places • Few phobias for harmful elements • Guns, knives etc. McGraw-Hill Ryerson Ltd. 2008

38. Constraints on Operant Conditioning • Instinctive drift • Conditioned response ‘drifts back’ toward instinctive behaviour • Caution for those who adopt wild animals McGraw-Hill Ryerson Ltd. 2008

39. Learning & the Brain • Nucleus acumbens & dopamine involved in ability to experience reward • Enriched environments produce more dendrites & synapses McGraw-Hill Ryerson Ltd. 2008

40. Cognition & Learning • S-O-R (Cognitive) Model of Learning • O = organism’s cognitive representation of world • Expanded on limited view of S (stimulus) and R (response) model McGraw-Hill Ryerson Ltd. 2008

41. Insight & Cognitive Maps • Insight (Kohler, 1925) • The ‘Eureka Moment’! • Sudden perception of useful relationships • Cognitive maps (Tolman) • Mental representations of spatial layouts • Learning provides knowledge and expectation of “what leads to what” McGraw-Hill Ryerson Ltd. 2008

42. Cognition in Conditioning • Classical conditioning • Expectancy Model (Rescorla & Wagner, 1972) • CS produces expectancy that UCS will follow • Operant conditioning • Develop awareness of response-consequence contingencies • Latent Learning • Occurs at Time A; not demonstrated until Time B • Self-evaluations • Can serve as reinforcers and punishers McGraw-Hill Ryerson Ltd. 2008

43. When Others Pave the Way • Observational learning • Learning that occurs by observing the behaviour of a model • Highly adaptive • If learning were trial & error on our own we would learn very slowly • Learn important events • When things are about to occur • How to respond McGraw-Hill Ryerson Ltd. 2008

44. Modeling • The Modeling Process (Bandura, 1977) • Four Basic Steps • Attention • Retention • Reproduction • Motivation McGraw-Hill Ryerson Ltd. 2008