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Transcript of Learning relatively permanent change in behavior due to experience Associative Learning learning...
Learning Learning
relatively permanent change in behavior due to experience
Associative Learninglearning that two events occur together
two stimuli (classical conditioning) a response and its consequences (operant
conditioning)
Classical /Pavlovian Conditioning
We learn to associate two stimuli
Two related events:
Lightning
Stimulus 1
Thunder
Stimulus 2
Result after repetition
We see lightning
Stimulus
We wince anticipatingthunder
Response
Operant Conditioning
We learn to associate a response and its consequence
Response: Pushingvending machine button
Consequence:Receivinga candy bar
Learning
Behaviorism John B. WatsonPsychology…
should be an objective scienceshould study behavior without
reference to mental processes
Classical/Pavlovian Conditioning
Ivan Pavlov 1849-1936Russian physician/
neurophysiologistNobel Prize (1904)studied digestive secretions
Classical/Pavlovian Conditioning
Classical Conditioningorganism comes to associate two stimuli
lightning and thunder tone and food
begins with a reflexa neutral stimulus is paired with a stimulus
that evokes the reflexneutral stimulus eventually comes to evoke
the reflex
Classical/Pavlovian Conditioning
Pavlov’s device for recording salivation
Classical/Pavlovian Conditioning
Unconditioned Stimulus (UCS)stimulus that unconditionally triggers a
response natural & automatic food
Unconditioned Response (UCR)unlearned, naturally occurring response to the
unconditioned stimulus salivation when food is in the mouth
Unconditioned = Unlearned
Classical/Pavlovian Conditioning
Conditioned Stimulus (CS)originally neutral stimulus that, after
association with an unconditioned stimulus, comes to trigger a conditioned response
Conditioned Response (CR) learned response to a previously neutral
conditioned stimulus Conditioned = learned
Pavlov’s Classic ExperimentBefore Conditioning
During Conditioning After Conditioning
UCS (foodin mouth)
Neutralstimulus(tone)
Nosalivation
UCR (salivation)
Neutralstimulus(tone)
UCS (foodin mouth)
UCR(salivation)
CS(tone)
CR (salivation)
Classical/Pavlovian Conditioning
Acquisition the initial stage of classical conditioninga response is established and gradually
strengthenedassociating a neutral stimulus with an
unconditioned stimulus so that the neutral stimulus starts to evoke a conditioned response
Classical/Pavlovian Conditioning
Extinctiondiminishing of a conditioned
responsewhen an unconditioned stimulus
does not follow a conditioned stimulus
example: if tone is repeatedly sounded without food, dogs will salivate less and less
Classical/Pavlovian Conditioning
Strengthof CR
Pause
Acquisition(CS+UCS)
Extinction(CS alone)
Extinction(CS alone)
Spontaneousrecovery ofCR
Weak
Strong
Time
Classical/Pavlovian Conditioning
Spontaneous recoveryreappearance, after a rest period, of an
extinguished conditioned response
Generalization tendency to respond to stimuli that are
similar to the conditioned stimulus
GeneralizationDrops of salivain 30 seconds
60
50
40
30
20
10
0Hindpaw
Pelvis Shoulder Frontpaw
Thigh Trunk Foreleg
Part of body stimulated
Classical/Pavlovian Conditioning
Discrimination learned ability to distinguish between
a conditioned stimulus and other irrelevant stimuli
dogs learned to respond to a specific tone and not to other tones
Nausea Conditioning among Cancer Patients
UCS(drug)
UCR(nausea)
CS(waiting room)
CS(waitingroom) CR
(nausea)
UCS(drug)
UCR(nausea)
Little Albert’s Fear Conditioning
UCS(loud noise)
UCR(fear)
CS(rat)
CS(rat)
CR(fear)
UCS(loud noise)
UCR(fear)
Stimulus similarto rat (such as rabbit)
Conditioned fear(generalization)
Operant Conditioning Operant Conditioning
type of learning in which organisms associate their own actions with consequences
behavior is strengthened if followed by reinforcement
diminished if followed by punishment Law of Effect
Thorndike’s principle that rewarded behavior is likely to recur
Classical vs. Operant Conditioning
Operant Behavior complex or voluntary behaviors
push button, perform complex task
operates (acts) on environmentproduces consequences
Respondent Behavior (Classical Conditioning)occurs as an automatic response to
some stimulus (salivating in response to meat and a tone)
Operant Conditioning
B.F. Skinner (1904-1990)elaborated
Thorndike’s Law of Effect
developed behavioral technology
Operant Conditioning Operant Chamber
(“Skinner Box”) bar pressed by
animal to obtain food/water reinforcement
device attached to record rate of pressing
Operant Conditioning
ShapingReinforcers (e.g., food) gradually guide
actions toward a desired behavior
http://www.youtube.com/watch?v=mm5FGrQEyBY
Operant Conditioning Reinforcer
any event that strengthens the behavior it follows
Positive reinforcement strengthens a response by presenting a
pleasurable stimulus Negative reinforcement
strengthens a response by removing something unpleasant
Principles of Reinforcement
Primary Reinforcer innatesatisfies a biological need (e.g., food)
Secondary Reinforcerconditioned (learned)money; good grades
Immediate and Delayed Reinforcers Delayed gratification (think back to the kids &
marshmallows video!)
Schedules of Reinforcement
Continuous Reinforcementreinforcing the desired response each time it
occursextinction occurs rapidly
Partial (Intermittent) Reinforcement reinforcing a response only part of the timeresults in slower acquisitiongreater resistance to extinctiongambling; occasionally giving in to tantrums
Schedules of Reinforcement
Fixed Ratio (FR)schedule that reinforces a response only
after a specified number of responses the faster you respond, the more rewards
you getdifferent ratiosvery high rate of responding like piecework payexample: free sub after buying 10
Schedules of Reinforcement
Variable Ratio (VR)reinforces a response after an
unpredictable number of responsesslot machines; fly fishingvery hard to extinguish because of
unpredictability
Schedules of Reinforcement
Fixed Interval (FI)reinforces a response only after a
specified time has elapsedresponse occurs more frequently as
the anticipated time for reward draws near
checking cookies in oven
Schedules of Reinforcement
Variable Interval (VI)schedule that reinforces a response at
unpredictable time intervalsproduces slow, steady respondinglike pop quiz
Schedules of Reinforcement
Variable Interval
Number of responses
1000
750
500
250
010 20 30 40 50 60 70
Time (minutes)
Fixed Ratio
Variable Ratio
Fixed Interval
Steady responding
Rapid respondingnear time forreinforcement
80
Punishment aversive event that decreases
the behavior that it follows
Problems with Punishment
Punished behavior is not forgotten, it's suppressed May just learn discrimination (behavior not okay in
one setting, but still does it elsewhere)
Causes increased aggression shows that aggression is a way to cope with
problems
Problems with Punishment
Creates fear Does not necessarily guide toward desired
behavior Punishment often just teaches how to avoid the
punishment Most psychologists favor emphasis on
reinforcement Notice what the individual is doing right and affirm
them for it
Operant vs Classical Conditioning
Comparison of Classical and Operant ConditioningClassical Conditioning Operant Conditioning
The response Involuntary, automatic “Voluntary,” operates on environment
Acquisition Associating events; CS announces Associating response with a conse- UCS. quence (reinforcer or punisher).
Extinction CR decreases when CS is repeatedly Responding decreases when reinforce- presented alone. ment stops.
Cognitive Subjects develop expectation that Subjects develop expectation that a processes CS signals the arrival of UCS response will be reinforced or punished;
they also exhibit latent learning, without reinforcement.
Biological Natural predispositions constrain Organisms best learn behavior similar to predispositions stimuli and responses can easily be their natural behaviors; unnatural be- associated. haviors instinctively drift back toward
natural ones.
Observational Learning
Observational Learning learning by observing and imitating the
behavior of others Modeling
process of observing and imitating behavior Prosocial Behavior
positive, constructive, helpful behavioropposite of antisocial behavior
Observational Learning Albert Bandura
pioneer researcher of observational learning
Bobo Doll Study http://www.youtube.co
m/watch?v=vdh7MngntnI
Negative Observational Learning
antisocial effects TV – powerful source of observational
learning Link between viewing violence and
aggressive behavior Desensitization – become increasingly
indifferent to violence after prolonged exposure