CH6_Learning6pp

8/7/2019 CH6_Learning6pp

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The changes in behaviourthat accumulate acrossgenerations are stored inthe genes

Evolution

The changes in behaviourthat accumulate over alifetime are stored in thecentral nervous system.

Learning

Two Types of Learning

Classical conditioning

Operant conditioning

Ivan Pavlov1849-1936

Ivan PavlovsPsychic Secretions

UnconditionedStimulus (UCS)

Before Learning

UnconditionedResponse (UCR)

Meat Powder Salivation


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NeutralStimulus

Before Learning

Bell No response

During Learning

Repeatedly pairUCS and Neutral

Stimulus

ConditionedStimulus (CS)

After Learning

ConditionedResponse (CR)

SalivationBell

The term psychic secretions waseventually replaced with the term,conditioning, and eventually becameknown as Classical Conditioning orPavlovian Conditioning.

Test Yourself

A. neutral stimulus

B. unconditioned stimulusC. unconditioned response

D. conditioned stimulus

E. conditioned response

Every time Roberts wife flushes the toilet when hes in theshower, the water becomes painfully hot. One day, asRobert is stepping into the shower, he hears a flushing soundand flinches. This flinch is an example of a(n):

What about Pavlovs Cat?

Pavlovs dog, cat andCousin Earl


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John Watson and Behaviorism

Psychology should be a purely objectiveexperimental branch of natural science

believed that psychology had failed as a

science disliked introspection and hypothetical

concepts (such as decisions, knowledge,perception, consciousness)

John B. Watson1878-1958

Black Box Psychology

Stimulus Response

THEMIND

Do NOT Open

Little Albert

video

Little Alberts fear of the white ratgeneralizes to the furry rabbit

video

Give me a dozen healthy infants, well-formed,and my own specified world to bring them up inand Ill guarantee to take any one at randomand train him to become any type of specialist Imight select -- doctor, lawyer, artist, merchant,

chief, and yes, even beggar-man and thief,regardless of his talents, penchants,tendencies, abilities, vocations, and the race ofhis ancestors.

-- J. B. Watson, 1924

Whatever happened to Watson?

I began to learn that it can be just as thrilling towatch the growth of a sales curve of a newproduct as to watch the learning curve ofanimals and men.

-- J. B. Watson, 1936


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Classical Conditioning Concepts

Generalization and discrimination

Higher-order conditioning

Extinction Spontaneous recovery

Practical applications

aversive conditioning

compensatory reaction hypothesis

Does Learning Generalize?

He who is bitten by the snake fears the lizard.

-- Bugandan proverb

In fact, the phenomenon ofgeneralization was one of themechanisms that Pavlov hopedwould permit conditioning to explainall kinds of complex behaviour.

Frequency of tuning fork in Hz

8000 10,0006000 12,000 14,000

Generalizationgradient

Dro p s o fs a l iva

20

10

0

CS used intraining

Generalization

Frequency of tuning fork in Hz

8000 10,0006000 12,000 14,000

Dro p s o fs a liva

20

10

0

DiscriminationWhat will happen if youonly give food after a10,000 Hz tone but not an8,000 or 12,000 Hz tone?

Higher-Order Conditioning Once an organism is conditioned, is it destinedalways to show a conditioned responsewhenever the conditioned stimulus ispresented?

Will Pavlovs dog always salivate to bells?

The answer is no.

If the CS is presented enough times withoutthe UCS, then the CR will eventuallyweaken and not occur.


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Extinction and Recovery Counterconditioning

A Clockwork Orange Antabuse

Compensatory-Reaction Hypothesis

Why didnt Vietnam vets crave heroinwhen they returned to the U.S.?

Why do diabetics blood sugar levelsgo UP just before they use insulin?

How is it that some drug addicts can overdosewhen theyve only taken their typical dosage?


DrugEffect

(e.g.,

bloodsugarlevelsindiabetic)

Time

DrugAdministered

DrugNOT

Expected

DrugAdministered

DrugExpected

DrugAdministered

DrugExpected

NEW USERNew Location

Small Dose

HABITUAL USERFamiliar Location

Small Dose

HABITUAL USERFamiliar Location

Large Dose

Compensatory Reaction can lead to cravings

Tolerance need more drug to get same eff ec


DrugEffect

(e.g.,

bloodsugarlevelsindiabetic)

DrugAdministered

Drug

NOTExpected

HABITUAL USERNew Location

Large Dose

Overdose without compensatory

reaction, drug is too strong


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Thorndikes Puzzle Box

Edward Thorndike(1874-1949)

Trial and error learning

Thorndikes Cats Learning Curve

First trial

Tendencyto perform

Scratching

Exploring

Sniffing

Grooming

Reaching

Lever-Pressing

Reward

Reaching with paw

Later trial

Tendencyto perform

Scratching

Lever-pressing

Exploring

Grooming

Reaching

Sniffing

Reaching with paw

Responses that produce a satisfying effectin a particular situation become more likelyto occur again in that situation.

Responses that produce a discomfortingeffect become less likely to occur again inthat situation.

Thorndikes Law of Effect

B.F. Skinner1904 -1990

B. F. Skinner and the Skinner Box

lightsto

peck

bar topress

magazinedelivers food

video


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Skinner believed that almost any behaviourcould be shaped by operant methods.

Shaping Behaviour

Pigeons, for example, could be trained towalk in circles, play ping-pong, or even playa tune on a small piano, if successiveapproximations to the desired behaviorwere reinforced.

Skinner believed the same idea could beused to explain how children learned to talk.

ShapingReward animal for successive approximations of

desired behavior

1) reward rat for approaching lever

2) reward rat for facing lever

3) reward rat for touching lever

4) reward rat for pressing lever

Reward must promptly follow behavior

Can get superstitious behavior if not careful

Animals candevelop astounding

skills throughshaping

Operant Conditioning The animal is reinforced for certain operations on

the environment

also called Instrumental or Skinnerian Conditioning

Reinforcement

an outcome that affects the likelihood of anoperant response re-occuring

Extinction Decline in operant responses with cessation

of reinforcement

Partial Reinforcement

Response is not rewarded on every trial Makes behavior more resistant to extinction

Can get extensive efforts for small rewards

Response Curve


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1. Fixed ratio: reinforced after a fixednumber of responses.

Partial Reinforcement Schedules

2. Variable ratio: reinforced after avariable number of responses.

3. Fixed Interval: reinforced after a givenamount of time has elapsed.

4. Variable Interval: reinforced after avariable interval of time has elapsed.

Try these

Classify the following situations based on thereinforcement schedule: You get 1 air mile for every $20 you spend at Shell

You may win a large amount playing video poker You study for the tests that your professor gives you once per month

You study regularly because your professor periodically gives popquizzes

You get one Coca-cola for every $1 of change you put in the vendingmachine

You check your snail mail which comes once per day

Your boss pays you $10/hour

Your boss pays you 5 cents for every letter you engrave

Your boss pays you a commission for each sale you make

Reinforcement Schedules Why do people gamble?

Types of Reinforcement

Reinforcement increases behavior positive uses addition of stimulus negative uses removal of stimulus

Punishment decreases behavior positive uses addition of stimulus negative uses removal of stimulus

Negative reinforcement punishment!!!

Try theseClassify the following

If you bring your umbrella, you wont get rained on

A parent tells a child they can watch TV if they finish theirhomework

If you get out of bed, your roommate will stop yelling at youto get up

A police officer gives a speeding motorist a ticket

A parent tells a child that if keeps acting up, he will get atime out

A dog gets a Milkbone if he rolls over and plays dead

If you take an aspirin, your headache pain will go away

If you get caught drunk driving, you will lose your license


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Differences Between Classical andOperant Conditioning.

In classical conditioning the delivery of thereinforcement (UCS) is controlled by theexperimenter.

In operant conditioning the delivery of thereinforcement is controlled by the animal orhuman subject.

1. Timing of events

2. Nature of responses that can betrained

In classical conditioning the responses areones that are generally referred to asinvoluntary (eye blinks, heart rate, etc.)

In operant conditioning, the responses areones that are generally described asvoluntary (pecking, hand movements,speech, etc).

Evolutionary Perspectives The strong behaviorist view: Anything can be

conditioned to anything else (classically) andany behavior can be trained (operantly)

Is this really true?

Why is it easier to train pigeons to peck andrats to bar press?

The Sauce Bearnaise Syndrome

In which our hero

develops a powerful

aversion to Sauce

Bearnaise*

*a tarragon-

flavoured white sauce

Martin goes out to dinner with his wife, and theyhave a lovely meal -- filet mignon with SauceBearnaise and asparagus.

They then go to see Tristan und Isolde (an operaby Richard Wagner).

In the middle of Act II, Martin becomes violently illand they have to go home.

Ever since then, Martin cannot abide the taste orsmell of Sauce Bearnaise.

He later finds out that he has the 24 hr stomach flu(as do three of his co-workers).

Is this a case of Classical Conditioning?

UCS

Illness Nausea

UCR

SauceBearnaise

CS CR


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What about the long gap between the CSand the UCS?

Problems with this explanation

Why is food the CS?

Why not Tristan und Isolde orWagnerian opera?

Why not the plate on which the foodwas served?

Why not his wife?

Bright, Noisy, Tasty Water Expts.

Are organisms evolutionarilyprepared to make particularassociations?

The Bright, Noisy, Tasty WaterExperiments

John Garcia

Animals come prepared tolearn some things but notothers.

Rats will learn to associateillness (caused by x-rays)with taste, but not visual orauditory information

Rats will learn to associatepain with visual or auditorycues, but not with taste.

Other food aversion effects unlike most other types of classical conditioning, the time window for

food aversion learning can be long (hours, days)

foods with a distinctive flavor are more likely to be associated with anillness

novel foods are more likely to be associated with an illness

different animals have different preparedness for food aversion learning

Many examples of preparedness to learn

Song-learning in birds

Language acquisition in humans

Maze learning in rats

Route finding in honeybees

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