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