Learning and Memory

1. Learning and Memory Stimulus learning; elicited behavior

2. Definitions • Stimulus • Response • Elicit • Novelty • Salient • Trials

3. Elicited Behavior: Reflexes • Innate • Automatic responses • Fixed? • Examples • Patella tendon reflex • Newborn reflexes • Pain-withdrawal reflex • Very simple in the nervous system

5. Complex forms of elicited behavior • Fixed (Modal) action patterns • Tinbergen and Lorenz • Definition • Example • Eibl-Eidesfeldt (1975) and squirrels

6. Species of squirrel and nut burying behavior • Observed that once squirrel: Picks up the nut  climbs down to the ground  searches for a place at the bottom of tree trunk or large rock • MAP: Once found, scratches a hole with forelimbs  places the nut in hole  rams the nut in place with snout  covers with dirt • Is this innate? Maybe they learn by watching other squirrels. • Example – Herring-gulls and egg rolling behavior

7. Example: Herring-gull chicks

8. Examples of MAPs: three-spined stickleback

9. Human examples? – contagious yawning

10. Infant caregiving – A MAP? • Head large in proportion to the body • Protruding forehead large in proportion to the size of the rest of the face • Large ears and eyes below the midline of the head • Small nose • Short thick extremities • Rounded body shape • Soft elastic body surfaces • Round protruding cheeks • Animals that are “cute” have similar traits.

11. Key aspects of MAPS • Stereotypical behaviors, but not fixed • Sign stimulus • Key features of the sign stimulus are needed • Ex. Herring-gull bill • Ex. Sexual behavior in Japanese quail • Adaptive • Innate-releasing mechanism • Depend on situational factors – E.g., motivation, timing, etc. • Supernormal stimulus – • Gull example

13. Any superstimuli in humans?

14. Imprinting – immediate learning • Ducks and boxes • Critical periods • Memory lasts the life-span • Examples: Mice and odors • Zebra finches and mate choice • Westermark effect • Israeli kibbutz • Adaptive?

15. Changing elicited behavior: Habituation and Sensitization • Orienting response • Depends on the nature of the stimulus • Infants and OR • Habituation – reduction of the orienting response after repeated presentations. • Simplest form of learning • In all species including protozoa and isolated tissue • adaptive • Examples? • Not just the OR

16. Habituation of the Startle Response in Rats • http://go.owu.edu/~deswartz/videos/habituation.mov

17. Measuring Habituation • GSR • Heart rate changes • Eye fixation • Lever pressing

18. Sensitization • Opposite of habituation • Increased response with repeated stimulation. • Intense and salient stimuli • Examples: • Pain response • Annoying sounds • Fear-potentiated startle • Everyday examples?

19. Habituation is learning • Not sensory adaptation or fatigue • Can last over long periods of time (long-term habituation) • dishabituation

20. Habituation of reflexive behavior • Reflex is a 3 step process • Stimulus activates sense organ • Relay of sensory messages through interneurons to motor neurons • Activation of motor neurons causing muscle to move • Habituation occurs at the second step

21. Sensory adaptation Habituation Fatigue

22. Characteristics of habituation • Stimulus specificity of habituation: • Stimulus generalization • Generalization gradient

23. Effects of time: • A) Habituation will not occur if trials are very spaced. • greater stimulus frequency, greater habituation

24. Effects of time: • B) Responding may reoccur after a lapse of time: spontaneous recovery

25. Spontaneous Recovery Video • http://go.owu.edu/~deswartz/videos/spontaneous_recovery.mov

26. Effects of stimulus intensity – stronger the intensity, slower the habituation.

27. Effects of exposure to a second stimulus • Dishabituation • Sensitive to time: Attenuation of dishabituation when there is a time gap.

28. Dishabituation video • http://go.owu.edu/~deswartz/videos/dishabituation.mov

29. Savings in habituation 1st habituation 2nd habituation

30. Sensitization effects mirror habituation • More stimulus generalization • Sensitization = arousal

31. Habituation and sensitization in Aplysia

42. Theories of Habituation and Sensitization • Two underlying processes exist • 1) A Habituation process • 2) A Sensitization process • The observable behavior is the sum of these two processes. • The habituation effect is observed when the habituation process is greater than the sensitization process.

43. Dual Process examples Sensitization effect Habituation effect

44. Habituation and Human Infant Research • Used to study infant perception and cognition • Difficult to study

45. Looking Time Trials

46. Habituation-dishabituation procedure • The infant is exposed repeatedly to a stimulus until its looking at the stimulus is at a low value • Habituation is only possible if the infant remembers the stimulus • Dishabituation is only possible if the infant can compare the stimulus to the original stimulus

47. What do infants like to look at? • Moderately bright objects • Moderately complex objects • Changes as child develops • 3-week-olds like 2x2 checkerboards • 14-week-olds like 8x8 checkerboards • 4-month-olds initially preferred 2x2, but after repeated ex. Liked 24x24 • Prefer attractive faces