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Learning
Learning
- Adaptive change in behavior that results
from past experiences
- Nonassociative Learning
- Habituation
- Sensitization
- Classical Conditioning
- Instrumental Learning/Operant
Conditioning
Habituation
- Ability to discontinue response to highly repetitive stimuli
- Sokolov (1963)
Sensitization
- Increase in responsiveness as result of - repeated application of stimulus - aversive stimulus
Habituation and Sensitization
Characteristics of Habituation and Sensitization
Time course
Sensitization is usually temporary -sensitization can last for up to a week but not generally a long-term effect. -with a stronger stimulus, the effects last longer.
Short-term habituation: -rapid presentations of a stimulus with a short interval between presentations -results in habituation quickly but see spontaneous recovery -the degree of spontaneous recovery depends on length of rest interval.
Habituation can be short-term or long-term, depending on presentation and interval between stimuli.
Long-term habituation: -one stimulus presentation a day -see more long-term effects -see less spontaneous recovery
- Short-term habituation
- Spontaneous recovery
- Long-term habituation
- Rate of habituation faster for short ISI
- Rate of habituation faster for weaker stimuli
- Below-zero habituation
- Habituation is specific – generalization gradient
- Dishabituation
- Habituation of dishabituation
Habituation/Dishabituation
- GSR measured at onset of either high or low tone - Tone gradually elicits less anxiety
- 15 th^ trial is the opposite tone - high for low group & low for high group
Stimulus specificity
Habituation is stimulus-specific -if you change the stimulus, see recovery of the response
Sensitization is not highly stimulus-specific -if an animal is aroused, it is usually aroused to a variety of cues
Pavlov Classical Conditioning
- Process by which a neutral stimulus (CS) comes to be associated with another stimulus (UCS) that elicits a response (UCR)
- Results in elicitation of response by CS
Pavlov paired the clicking of a metronome with food.
Clicker Food (never used a bell)
Dogs normally salivate with food but not with the clicker
After a few of these pairings, dogs began to salivate when the metronome came on.
Stimuli
Four major terms apply to Pavlovian Conditioning experiments
Responses
US Unconditioned stimulus Biologically potent stimulus that reliably evokes an unlearned or reflexive reaction (i.e., food)
CS Conditioned stimulus Biologically weak stimulus The CS may evoke an orienting response, but not the strong response evoked by the US (i.e., metronome)
UR Unconditioned response The unlearned response triggered by the US Powerful and reflexive (i.e., salivation to food)
CR Conditioned response It is elicited by the CS and represents the learned behavior (i.e., salivation to the Metronome)
Sequence in Conditioning
- Initially the neutral stimulus elicits no response
- UCS elicits reflexive response (UCR)
- Pair NS w/ UCS & elicit UCR
- CS elicits salivation
Timing
Appetitive & Aversive
Conditioning
Appetitive
- US is an event the organism seeks out & considers pleasant - food - physical touch - warmth
Aversive
- US is an event the organism avoids & considers unpleasant - shock - painful stimulus - air puff in eye
Phases of Learning
- Acquisition – phase w/strengthening of response through repeated reinforcements
Extinction
- Diminishment of response when reinforcement is discontinued
Acquisition & Extinction Acquisition and Extinction
Conditioned Drug Tolerance
- Siegel, et al., 1978
- Experimental Group: CS (light change & noise reduction) paired with UCS (injection of morphine) for 9 days
- Placebo Control Group (CS paired with injection of saline)
- Unpaired Control Group
- Test: present CS, inject every rat with morphine, place rat on hot surface - Measure latency to lick their paws (lick when they feel pain)
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Placebo Experimental Control
Mean Latency to Lick Paw
