Innate Knowledge (what an organism is born with) Experience leads to changes in knowledge

Innate Knowledge

(what an organism is born with)

Experience leads to changes in knowledge

and behavior

Learning refers to the process of adaptation

Of behavior to experience.

Memory refers to the permanent records that

Underlie this adaptation.

How experience changes an organism

Learning Perspective

EVENT Change inBehavior

Memory (Cognitive) Perspective

EVENT Change in whatorganism knows

Learning vs Cognitive (Memory) Perspectives

Learning focuses on simple tasks

Pavlovian Conditioning

built-in food salivationreflex

US UR

CS tone food salivation

tone salivation

new learnedassociation

Operant Conditioning

Animal makes random responsethen accidentally presses bar

R Re(response) (reward or

reinforcement)

Animal is more likely to press bar

Memory perspective focuses on complex tasks

Recall

Present a list of words (STUDY)

(wait)

Write down all the words (TEST)

Word Completion

S M T O

What’s the word?

Question answering

What is the red pigment that carriesoxygen in the blood called?

The Learning Perspective uses Animals as Subjects

can control environment

belief that laws of learning apply to all

animals

The memory perspective uses humans

•we care more about humans

•language stimuli

The learning perspective takes an AssociationisticApproach

Mind is a collection of innate reflexes and learnedassociations stored in the brain

Complex behavior is gradually built up out ofsimple associations

Memory perspective adoptsthe information processing approach

The brain is a computer

•It has software or programming called the mind

•It has a “programming language”

Experience constantly adds to the program

It has a “central processor”(innate knowledge)

It has a large “hard disk”(long-term store)

NID Experiment

Learning “It’s a conditioning study!”

42unconditioned

stimulus(US)

“forty-two”unconditioned

response(UR)

NID 42 “forty-two”

conditionedstimulus

(CS)

after learning NID “forty-two”

Memory “It’s a memory experiment”

cue item-to-be-recalledstudy NID 42test NID ?cued recall

Pavlovian Conditioning

Definitions

foodUS

air in eyeshock

. . .. . . . . .. . .

salivationUR

blink“ouch!”

US is paired with CS

CS UStone food salivation

tone salivationCRconditionedresponse

Sometimes the CR is like the URSometimes the CR tries to compensate for US

Example: If US is shock, CR is fearand behavior that compensatesfor pain

Forgetting Conditioning

Strengthof CR

AcquisitionExtinction

US ispaired

with CS

CS neverpaired

with US

Extinction

Is it because conditioning is gone?

OR

because conditioning is inhibited?

Inhibition Hypothesis

+CS US CS USacquisition inhibition

extinction

Loss Hypothesis

+CS US CS US CS USacquisition extinction

Evidence Favors Inhibition Hypothesis

1. Spontaneous Recovery

prob.of

CR

Suggests that the original learning was not lost

time

wait a while

2. Disinhibition Effect

External Inhibition

light food salivation

light salivation

light sali … TONE!

(salivation stops)

light food salivation

light salivation

light sali

extinction light sa

light nothing

light TONE!

salivation startsagain

Tone inhibits the inhibition from extinction

Shows extinction is due to inhibition, not loss

3. Stimulus-compounding experiments(Rescorla, 1979)

Experimental ControlGroup Group

Phase 1 Tone Shock (same)Tone Fear

Phase 2 Tone + Light - 0 Tone - 0Extinction

no shock Light - 0

stimuluscompound

Phase 3 Light + Buzzer - Shock

Test to see Experimental group developsif light fear more slowlyis inhibited

The light became a conditioned inhibitor of fear

Extinction leads to inhibition

What is learned in Pavlovian Conditioning?

S-R view OR S-S view

tone CS tone CS

food salivation food salivation US R US R

Which one is right?

Sensory Pre-conditioning Experiment

Phase 1 Buzzer . . . Light

CS2 CS1

Phase 2 Light . . . Food Salivation US

Light Salivation

Phase 3 (test) Buzzer . . . ?

What happens?

S-R view predicts no salivation

S-S view predicts salivation

Results show salivation supporting S-S view

Sensory pre-conditioning shows S-S association is learned

Buzzer Light Food

predictsbuzzer S-S Salivationcausessalivation

Buzzer Light Food

predictsbuzzer S-R Salivationdoes notcause salivation

Conclude: at least some of the learning is S-S

Konorski’s (1948) second-order conditioning experiment

Phase 1 light . . . food salivation

Phase 2 buzzer . . . light salivation

buzzer salivation

This is second-order conditioning

Phase 3 light . . . shock leg withdrawal

Test phase buzzer . . .

What happens?salivation or leg withdrawal

S-S view

light food salivation

buzzer

S-S

S-S

buzzer

S-S

S-S

shock leg withdrawal

Buzzer should lead to leg withdrawalS-S

S-R view

food salivation

light

S-R

buzzer

S-R

shock

leg withdrawal

Buzzer should lead to salivation

S-R

Conclude:

Both S-S and S-R learning occur

Conclude:

Both S-S and S-R learning occur

But why didn’t leg withdrawal occur inKonorski’s experiment?

Phase 1

light food

salivation

S-R

S-S

When do you get conditioning?

Pavlov “If CS and US occurat around the same time”

Temporal Contiguity View

Modern View (Rescorla)

“If the CS predicts whetherthe US will happen”

Contingency View

Contingency

Perfect positive contingency

thunder no thunder lightning 20 0

no lightning 0 345

prob (thunderlightning) = 1.0

prob (thunderno lightning) = 0

Strong negative contingency

sun no sun stars 1 200

no stars 200 60

Contiguity without Contingency

10 20

20 40

airplane

no plane

no

Stim 2 Stim 2 a b

c d

Stim 1

No Stim 1

bird andplane are paired

A quick test for contingency

a·d > c·bthen positive

a·d = c·bzero contingency

a·d < c·bthen negative

no bird bird

prob.(birdplane) = .33prob.(birdno plane) = .33

You can have a positive contingency even whenpairing is the least frequent possibility

Example: can you learn that

and “cat” are associated?

“cat” no “cat”

100 900 1,000

200 9,800 10,000

see

no

prob (“cat” ) = .10

prob (“cat”no ) = .02

hear

positive contingency

shock no shock

tone

no tone

0 4

4 0

perfect negativecontingency

tone becomes a conditioned inhibitorof fear

shock no shock

tone

no tone

4 0

0 3

perfect positivecontingency

tone leads to fear

Unpaired Experiment

Contingency and Conditioning

Standard Experiment

timetone tone tone tone

shockshock shockshock

shock no shock

tone

no tone

2 1

1 2

conditioningoccurs

shock no shock

tone

no tone

2 2

2 2

zerocontingency

Conclude: contingency, not contiguity matters

Partial positive contingency

No conditioning occurs even though tone and shockare occasionally paired

Random Pairing

S S

T

S

T T

S

T

Random Pairing Experiment

shock no shock

tone

no tone

20 20

20 20

zerocontingency

no conditioningoccurs

Shows that there must be some contingency

between CS and US to get conditioning.

Contiguity is not enough.

Fear vs Anxiety

•if tone predicts shock then animal becomes

afraid after tone

(like a phobia)

•if tone does not predict shock (random pairing)

animal ignores the tone and experiences

something like anxiety (unfocused fear)

Blocking Effect

phase 1 tone shock

16 times

phase 2 tone+light shock

8 times

phase 3 light alone

NO FEAR IS ELICITED!

Shows that contingency alone doesn’t produceconditioning

Get conditioning when

(a) CS predicts USAND

(b) CS tells something we didn’t already know

Explaining the Blocking Effect

trial 1 CS UStone shock

•CS is surprising US is surprising•Process CS and US•Create association between CS & US

trial 2 tone stock

trial 3

trial 8 CS memory of fear UStone shock shock

Shock is not surprising any more so no additional strengthening of association occurs

trial 3

trial 8

CS memory of shock CR fear tone US-shock

Tone fully activates memory of US shock, so when shock comes it is not at all surprising.No additional learning occurs.

Str

engt

h o

f C

S-U

S A

ssoc

iati

on

1 2 3 4 5 6 7 8

rapidlearning

no morelearning

Phase 2trial 9

CS1 CS2 memory

tone + light of shock fear

The light is surprising, so it is processed. But the tone completely predicts the shock

USshock

So the US shock is not processed, so no association is formed between light and shock.

Explains blocking effect

General Conclusion

Stimuli are associated when they provide information that the organism doesn’t already know.

Modern view of conditioning and the blocking effect

(1) Form association between stimuli only if they

are actively processed or “rehearsed” together.

(2) Stimuli are processed only if they are

unexpected

(3) As conditioning proceeds both the CS and US

become less surprising. So they are processed less

and, hence, less additional learning occurs.