PSY402 Theories of Learning

1. PSY402Theories of Learning Chapter 9 Biological Influences on Learning

2. Limits to Learning • How general are the laws of learning? • Skinner’s rules work in both lab and real-world settings, across species. • Learning doesn’t explain all aspects of behavior. • Organization of behavior already exists within an organism. • Learning modifies that organization.

3. Behavior Systems Approach • Timberlake – learning changes the integration, tuning, instigation or linkages within a behavior system. • Different cues are salient to different behavior modes. • Variations in learning occur across species because their behavior systems are different. • Variations in behavior are the result of predispositions and constraints.

4. Components of Rat Feeding System

5. Animal Misbehavior • Breland & Breland – trained 38 species of animals for Busch Gardens. • Elicitation of foraging and food-handling instincts interferes with performance of operant routines. • Instinctive drift • Pig and piggy bank • Raccoons and food-washing

6. Pig Misbehavior

7. Explaining Misbehavior • Does misbehavior result from operant food reinforcement or classical conditioning? • Timberlake’s appetitive structure view – both kinds of learning contribute to animal misbehavior. • Pairings with food are necessary but not sufficient to evoke misbehavior. • Children play with their food if allowed.

8. Schedule-Induced Behavior • Superstitious behavior – induced by FI schedules. (see videos on next slide) • The animal associates whatever it is doing at the time with the reinforcement. • Ritualistic, stereotyped behavior during the interval. • Two kinds of behavior: • Terminal – reinforcer-oriented • Interim – precedes or follows reinforcement

9. Superstitious Behavior Examples • https://www.youtube.com/watch?v=7XbH78wscGw – superstitious pigeons • https://www.youtube.com/watch?v=f8jm1KKPDIs – Frasier example of superstition • https://www.youtube.com/watch?v=Kik1qrUrBCk – dog training example

10. Schedule-Induced Polydipsia • Polydipsia – drinking too much water. • Occurs with a fixed interval (FI) schedule. • Rats are deprived of food then trained to bar press for food. • Rats consumed excessive amounts of water even though not water deprived. • May be an example of interim behavior – but does not occur before reinforcement.

11. Other Schedule-Induced Behaviors • Excessive wheel running – highest post reinforcement and during interim. • Attack targets of aggressive behavior. • Pigeons attack a stuffed model of another pigeon. • Similar behavior in squirrel monkeys and rats. • Animals continue to drink a flavor paired with illness. • Polydipsia is immune to flavor aversion learning.

13. Intervals Produce More Polydipsia SIP groups got periodic reinforcement PD groups got one big meal

14. Effects with Humans • Schedule-induced behavior may be a good animal model for alcoholism: • Use of an interval schedule is one of the few ways of inducing rats to drink ethanol. • More beer drinking with FI-90 schedule in game playing with humans. • Weaker in humans • Develops rapidly, stops quickly

15. Flavor-Aversion Learning • Long-delay learning – does not depend on contiguity. Can precede illness by hours. • Preparedness – certain stimuli are innately more likely to be associated with a UCS than others. • Visual cues more salient to birds • Taste cues more salient to rats • Salience depends on when the animals seeks its food (nocturnal or not).

16. Salience of Cues for Rats

17. Explanations • Learned-Safety theory – an evolved mechanism unique to flavor-aversion to protect animal. • Ingestional neophobia – small quantities consumed at first. Eat again if no illness occurs. • Concurrent-Interference view – long delay occurs because the animal doesn’t eat anything else for a while. Supported too.

18. Support for Learned Safety View Time & repetition led to learned safety for longer delay groups

19. Applications • Cancer chemotherapy (UCS) causing nausea may be associated with hospital food (CS). • Preexposure to food without the toxic drug or drug without food may help prevent food aversions. • Coyotes and wolves can be taught to avoid attacking and eating sheep using flavor-aversion learning.

20. Flavor Preference Learning • Two reasons for acquired flavor preference: • Sweetness preference – a non-sweet flavor is associated with sweetness. • Flavor-nutrient preference – flavor is associated with positive nutritional consequences • Young rats prefer glucose to sucrose because they cannot digest sucrose as well. • Humans prefer high fat cream cheese despite bitter • Dopamine receptors activated

21. Imprinting • Lorenz – social attachment process where young ducks follow their mother. • Ducks imprint to: • Moving objects with lifelike motion • Vocalizing objects, short rhythmic sounds, not high-pitched • Objects that are the right size • Occurs within 1 to 6 hours after hatching

22. Goslings Imprinted on Lorenz

23. Infant Love • Harlow – baby primates attach to soft terry cloth rather than wire. • Rocking rather than stationary • Warm rather than cold • Ainsworth – attachment to a responsive mother. • Occurs more easily during sensitive period of animal’s life. • 6 to 12 months for humans

24. Sexual Preference Imprinting • In birds, occurs early in development, long before sexual maturity, not modifiable later. • Not dependent on reinforcement • Birds can sexually imprint on another species, such as a human.

25. Nature of Imprinting • Both instinctive and associative processes are involved. • Associative-learning view – objects become familiar before fear system matures • Familiar objects reduce fear later, so become preferred due to relief. • Harlow’s studies contradict this. • Some objects are more imprintable (cloth versus wire mother).

26. Monkeys Prefer Cloth Mother

27. Instinctive View of Imprinting • Organisms contain an innate schema of the imprinting object • Evoluntary pressure to learn the right thing. • Response is hard to change. • Extinction does not lead to loss of preference for the imprinted object. • Abused primates and children cling to abusive mothers despite punishment.

28. Avoidance of Aversive Events • Species-specific defense reactions (SSDR) – instinctive responses to specific dangers. • Rats – running, freezing, fighting. • Cues predicting danger also select the specific response. • Escape and avoidance behaviors are learned more readily when they incorporate SSDRs.

29. Better Learning for SSDR SSDR

30. Reinforcement Area of Brain • Some people are intensely motivated to obtain reinforcement; others lack interest in it. • Brain systems may be involved in response to reinforcement. • Electrical brain stimulation (ESB) was used to study this. • Olds & Milner discovered rats would press a bar for stimulation of the hypothalamus.

31. Sample Cumulative Record

32. Two Reinforcement Pathways Motivation Memory

33. Rat Reinforcement System

34. Motivation-Reward Center • Medial forebrain bundle (MFB) in the limbic system is the brain’s reinforcement center. • Has both reward and motivating properties. • Motivation is stimulus-bound (behavior depends on what reward is available). • Presence of reinforcement enhances MFB functioning, increasing response to reinforcers. • Deprivation arouses MFB.

35. Memory-Learning Center • In addition to the MFB, a separate pathway facilitates storage of experiences. • Nigrostriatal pathway consolidates memory. • The other pathway (tegmentostriatal) is governed by dopamine. • Drugs like amphetamine and cocaine activate dopamine receptors. • Natural reinforcers (water, food) also increase dopamine.

36. Opiates Have Their Own Receptors • Opiates do not activate dopamine but their own opiate-sensitive receptors in the VTA. • Two kinds of receptors exist, one for dopamine another for opiates. • High responding in the NA leads to compulsive behavior, including gambling, hypersexuality, buying, restless leg syndrome. • Parkinsons treatment may cause high responding

37. Both Activate the NA