Learning and memory
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Learning and Memory. Stimulus learning; elicited behavior. Definitions. Stimulus Response Elicit Novelty Salient Trials. Elicited Behavior: Reflexes. Innate Automatic responses Fixed? Examples Patella tendon reflex Newborn reflexes Pain-withdrawal reflex

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Learning and Memory

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Learning and Memory

Stimulus learning; elicited behavior


Definitions

  • Stimulus

  • Response

  • Elicit

  • Novelty

  • Salient

  • Trials


Elicited Behavior: Reflexes

  • Innate

  • Automatic responses

  • Fixed?

  • Examples

    • Patella tendon reflex

    • Newborn reflexes

    • Pain-withdrawal reflex

  • Very simple in the nervous system


Complex forms of elicited behavior

  • Fixed (Modal) action patterns

    • Tinbergen and Lorenz

    • Definition

    • Example

      • Eibl-Eidesfeldt (1975) and squirrels


  • 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


Example: Herring-gull chicks


Examples of MAPs: three-spined stickleback


Human examples? – contagious yawning


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.


  • 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


  • Any superstimuli in humans?


  • 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?


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


Habituation of the Startle Response in Rats

  • http://go.owu.edu/~deswartz/videos/habituation.mov


Measuring Habituation

  • GSR

  • Heart rate changes

  • Eye fixation

  • Lever pressing


Sensitization

  • Opposite of habituation

  • Increased response with repeated stimulation.

  • Intense and salient stimuli

  • Examples:

    • Pain response

    • Annoying sounds

    • Fear-potentiated startle

    • Everyday examples?


  • Habituation is learning

    • Not sensory adaptation or fatigue

    • Can last over long periods of time (long-term habituation)

    • dishabituation


  • 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


Sensory

adaptation

Habituation

Fatigue


Characteristics of habituation

  • Stimulus specificity of habituation:

    • Stimulus generalization

    • Generalization gradient


  • Effects of time:

    • A) Habituation will not occur if trials are very spaced.

    • greater stimulus frequency, greater habituation


  • Effects of time:

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


Spontaneous Recovery Video

  • http://go.owu.edu/~deswartz/videos/spontaneous_recovery.mov


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


  • Effects of exposure to a second stimulus

  • Dishabituation

  • Sensitive to time: Attenuation of dishabituation when there is a time gap.


Dishabituation video

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


  • Savings in habituation

1st habituation

2nd habituation


  • Sensitization effects mirror habituation

  • More stimulus generalization

  • Sensitization = arousal


Habituation and sensitization in Aplysia


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.


Dual Process examples

Sensitization effect

Habituation effect


Habituation and Human Infant Research

  • Used to study infant perception and cognition

    • Difficult to study


Looking

Time

Trials


  • 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


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


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