Chapter 6

Learning

Cognitive Functions of the Mind

Mediate adaptive behaviours

• Interactions between person and world

Form internal representations of the world

• Perception, memory

Reflect on this knowledge (transform in imagination)

• Reasoning, problem-solving, decision, choice

Use knowledge to guide behaviour

• Action

Communicate knowledge to others

• Language

Major function of the mind is to engage in these cognitive functions

and mediate adaptive behaviour to mediate interactions between

individual and the world.

Traditional View of Learning

Associationists – Mind forms associations between:

Stimulus

– events in environment

– correlates and consequences

Responses

– organism’s action

– correlates and consequences

Some Associations are Innate

Reflexes

– Involve individual muscles (patella reflex, eye blink)

Taxes

– Involve entire body (innate S-R patterns)

– Positive (move towards), Negative (move away)

Instincts

– Shaped by evolution to help organism adapt to a particular

environment

– Very discriminating

– Can be VERY complex patterns of behaviour

Tinbergen (1947)

Limitations of Innate Responses

Work fine as long as environment doesn’t change,

but can become maladaptive...

Need to have mechanism for

individual species to modify

responses to stimulation...

And THAT is what happens by

virture of learning.

Learning Defined

Relatively permanent change in current or potential

behaviour occurring as a result of experience.

– Not drugs

– Not injury

– Not maturation

All organisms with nervous system have some capacity to

learn.

Permits individual organisms ability to acquire new

behaviours under new circumstances – adding to the

repertoire already present as a result of evolution

Classical Conditioning

Ivan Pavlov (early 1900’s) Physiologist who did

Nobel prize winning research on digestion,

discovered (partly by accident) that neutral stimuli

had the capacity to elicit reflexive responses.

Classical Conditioning Terms

Unconditioned Stimulus (UCS) – reliably evokes a

reflex response on part of organism.

Unconditioned Response (UCR) – is the reflex

response reliably evoked by UCS.

Conditioned Stimulus (CS) – a previously neutral

stimulus that, once paired with UCS, has acquired

the capacity to elicit the same response as UCS.

Conditioned Response (CR) – a learned response

to a CS. (This happens after many pairings [i.e.

TRIALS] of CS with UCS).

Processes of Classical Conditioning

Acquisition – process by which a CS acquires the power to evoke a CR. – Reinforcement of CS by UCS

– Response gains strength (measured in terms of magnitude and probability) as trials continue.

Extinction – process by which the CS loses power to evoke CR by withdrawal of reinforcement.

– No reinforcement CR loses strength

Spontaneous Recovery – (itself subject to extinction) – Rest after extinction

– Retest CS alone (will see some degree of CR)

Re-Acquisition - relearn faster – CS reinforced by UCS

– Shows CR is not “lost” rather inhibited or suppressed

Generalization – CS0 vs. CS1…..CSn (baby Albert)

Discrimination – response to two CS for a time but eventually organism is able to discriminate as one CS is reinforced while the other is not.

XXX 6.8

XX 6.7

XX 6.10 Higher-Order Conditioning is another of the Processes of

Classical Conditioning.

Classical Conditioning: More Terminology

Stimulus contiguity = occurring together in time and space

3 types of Classical Conditioning

– Simultaneous conditioning: CS and UCS begin and end together

– Short-delayed conditioning: CS begins just before the UCS, end together

– Trace conditioning: CS begins and ends before UCS is presented

Too Extreme but...

Pavlov felt ALL forms of learning are basically variants

on Classical Conditioning. Now we know that’s too

extreme be we do understand that to a very large

extent, the laws of Classical Conditioning are laws of

emotional life.

By virtue of processes like Classical Conditioning, we

acquire our fears, aversions, joys, preferences, etc.

Some of these are innate but most we have learned to

respond to as a result of a process very similar to

Classical Conditioning.

Classical Conditioning in Everyday Life...

Conditioned Fears

Conditioned Emotional Responses

Conditioning and Physiological Responses

Conditioning in Advertising

Conditioning and drug effects

Thorndike’s Puzzle Box

Conclusion learning motivated by reward

F 6.11

Instrumental Learning ~ Thorndike’s Laws of Learning (1913)

Law of Readiness – learning is motivated by an organism’s internal state (which activates a whole sequence of behaviours.

Law of Effect – Responses that lead to reward, are strengthened while those not leading to reward are weakened.

Law of Exercise – Connections between stimuli and responses are strengthened by practice (repetition) and weakened by disuse.

Operant Conditioning

B.F. Skinner (1953) – principle of reinforcement

Operant Conditioning

B.F. Skinner (1904-1990)

"All we need to know in order to

describe and explain behaviour is

this: actions followed by good

outcomes are likely to recur, and

actions followed by bad outcomes

are less likely to recur." (Skinner, 1953)

Instrumental Learning/ Operant Conditioning

General Principles:.

Organisms acquire adaptive behaviour through the experience of success or failure.

Organisms OPERATE on their environment and their behaviour changes their environment. (Skinner,1953)

Behaviour is INSTRUMENTAL to obtaining a desired outcome. (Thorndike,1913)

Whereas in Classical Conditioning we see animals forming associations between CS and UCS, in Operant Conditioning, the associations are between behaviour(s) and outcome(s).

Operant Conditioning

Skinner (1938) revised: the Law of Effect

Used operant conditioning chamber

Two changes: – Specifically defined “reinforcement” as strengthening the

connection between response and a consequence: R Sr

– Also defined “increase” as a change in probability of occurrence of a response (more definable)

When a response is followed by a REINFORCER, that response increases in probability.

When a response is followed by a PUNISHER that response decreases in probability

Operant Conditioning

Operant Conditioning

type of learning in which behaviour is strengthened if

followed by reinforcement or diminished if followed by

punishment.

Type of learning in which the future probability of a

behaviour is affected by its consequences.

Law of Effect

Thorndike’s principle that behaviours followed by favorable

consequences become more likely, and behaviours

followed by unfavorable consequences become less likely.

Skinner box:

Pigeon pecks or rat presses

bar to receive reinforcers

Operant Chamber

Skinner Box

chamber with a bar or

key that an animal

manipulates to obtain a

food or water reinforcer

contains devices to

record responses

Basic Processes in Operant Conditioning

Acquisition – the initial stage of learning operant

responses

Shaping – a gradual process consisting of

reinforcement of closer and closer approximations of

a desired response (KEY in pet tricks)

Extinction – gradual weakening and disappearance

of a response (no longer reinforced).

Stimulus Control

– Generalization

– Discrimination

Operant Conditioning

B.F. Skinner (1953) – principle of reinforcement

– Operant chamber – “Skinner Box” – F 6.13a

– Emission of response (because Operant Responses tend

to be voluntary, they are said to be “emitted” rather than

“elicited”).

– Reinforcement contingencies – antecedents, behaviours,

and consequences (ABC)

– Cumulative recorder – F 6.13b

Figure 6.13 Skinner box and cumulative recorder

Operant Conditioning

Reinforcer

any event that strengthens the behaviour it

follows.

Reinforcement Contingencies

Circumstances or rules that determines whether

response leads to reinforcer.

Shaping

operant conditioning procedure in which

reinforcers guide behaviour toward closer and

closer approximations of a desired goal.

XX 6.12

Operant Conditioning

XX 6.18

Reinforcement: Consequences that Strengthen Responses

Delayed Reinforcement (immediate produces fastest

conditioning)

– Longer delay, slower conditioning

Primary Reinforcers - events that are inherently

reinforcing because they satisfy biological needs (food, water,

warmth, sex, and maybe affection expressed through hugging and close bodily

contact).

– Satisfy biological needs

Secondary Reinforcers - events that acquire reinforcing

qualities by being associated with primary reinforcers. (money, good

grades, attention, flattery, praise, and applause).

– Conditioned reinforcement

Schedules of Reinforcement

Continuous Reinforcement

reinforcing the desired response each time it occurs

Partial (Intermittent) Reinforcement reinforcing a response only part of the time

results in slower acquisition

greater resistance to extinction

Schedules of Reinforcement

Fixed Ratio (FR)

reinforces a response only after a specified number of

responses

faster you respond the more rewards you get

different ratios

very high rate of responding

like piecework pay

Variable Ratio (VR)

reinforces a response after an unpredictable number of

responses

average ratios

like gambling, fishing

very hard to extinguish because of unpredictability

Schedules of Reinforcement

Fixed Interval (FI)

reinforces a response only after a specified time has

elapsed

response occurs more frequently as the anticipated time

for reward draws near

Variable Interval (VI)

reinforces a response at unpredictable time intervals

produces slow steady responding

like pop quiz

XX 6.17

Schedules of Reinforcement

Variable Interval

Number of

responses

1000

750

500

250

0 10 20 30 40 50 60 70

Time (minutes)

Fixed Ratio

Variable Ratio

Fixed Interval

Steady responding

Rapid responding

near time for

reinforcement

80

Partial Reinforcement Schedules

Fixed Ratio: every nth response is reinforced

Fixed interval: the first response after x

amount of time is reinforced

Variable ratio: an average of every nth

response is reinforced (hardest to extinguish)

Variable interval: the first response after an

average of x amount of time is reinforced

Big Bang…

Reinforcers vs. Punishers Positive vs. Negative

Reinforcer = rate of response INCREASES

Punisher = rate of response DECREASES

Positive: something is ADDED to environment

Negative: something is TAKEN AWAY from

environment

NOTE that both reinforcement AND punishment can

be in positive and negative forms.

XX 6.20

Punishment

A consequence that decreases an organism’s tendency to make a particular response.

• aversive event that decreases the behaviour that it follows.

• powerful controller of unwanted behaviour

Punishment

Punishment

How to make it more effective while reducing its side effects:

• Apply swiftly (if delay too great, ineffective).

• Use punishment just severe enough to be effective.

• Make it consistent (if you want to eliminate a response, punish

the response every time).

• Explain the punishment (reason for punishment should be made very clear. Punishment combined with reasoning if more effective than either alone).

• Use noncorporal punishment, such as withdrawal of privileges.

Escape/Avoidance Learning Soloman & Wynne, 1953

Two kinds of association

• Lights shock (C.C)

• Vaulting barrier shock goes away (O.C.)

Response during shock ESCAPE

Response prior to shock AVOIDANCE

Two-Factor Theory (Mower, 1947)

• 1st condition fear to light

• 2nd reinforce escape/avoidance by

association of light to shock

Significance of Operant Conditioning

Voluntary behaviours come under control of environmental events.

behaviour outcome

Ubiquitous – all vertebrates and many non-vertebrates can show this type of learning.

Thorndike/Skinner felt ALL learning was a variant on Operant Conditioning. This view is also too extreme but it’s very clear that the laws of Operant Conditioning appear to account for much of the acquisition and display of a great deal of adaptive (and not so adaptive) behaviours.

• Habits

• Incentives (all behaviours that organisms learn to do under the

condition of incentives).

Operant vs Classical Conditioning

Table 6.1 Comparison of Basic Processes in Classical and Operant Conditioning

Assumptions of S-R Theory

Association by contiguity

– Co-occurrence in space and time

Arbitrariness

– Any stimuli any response

Empty Organism

– Understand animal’s behaviour solely in terms of S-R…

input and responding output.

– “Black Box” connects S’s and R’s (why? how? Don’t care).

Passive Organism (hidden assumption and metaphor of conditioning)

– Animals aren’t trying to figure anything out.

Assumptions of S-R Theory

No sense of expectations or free will on the part of

the organism.

Things happening “to” the organism.

Now know that these assumptions are all wrong…

But we need to talk about them because they

DOMINATED the psychology of learning for half a

century!

Still see residues in some psychology theories today.

Changes in Our Understanding of Conditioning

Biological Constraints on Conditioning

– Breland and Breland (1961) – misbehavior of organisms

– Instinctive Drift

– Conditioned Taste Aversion – Garcia & Koelling (1966) –

Figure 6.22

– Preparedness and Phobias

Cognitive Influences on Conditioning

– Signal relations

– Response-outcome relations

– Latent learning – F 6.23

Evolutionary Perspectives on learning

Experiments that Challenged…

Garcia and Koelling (1966)

research on conditioned taste

aversion. see p.239; Figure 6-23

Rats – Compound CS

Bright light

Loud noise

Sweet water

US 1) Foot shock (immediate)

2) X-Ray (delayed nausia)

Later given choice of water source

1) Bright & Noisy 2) Sweet

Shocked rats preferred sweet source

X-Rayed rats preferred bright and noisy

Association between sight and sound shock

Association between taste nausia

Seligman and Haager (1972)

taste aversion “Sauce bérnaise”

see p.238; Figure 6-22

Experiments that Challenged…

These landmark experiments showed that associations are NOT

arbitrary.

Avoidance learning capitalizes on species-specific repertoire of

defensive reactions built in by evolution.

Learning seems to be governed by what’s now known as

PREPAREDNESS PRINCIPLE (Seligman,1970)

By virtue of its evolutionary history, every species is

predisposed to form certain kinds of associations.

– Prepared (predisposed to acquire)

– Unprepared (not predisposed to acquire)

– Contraprepared (not possible to acquire)

Organism CANNOT be treated as if it is “empty”.

Have to know about the internal biological structures to know what

it can and can’t learn – how brain has been shaped by evolution.

RATS vs. BIRDS

Cognition and Learning

Latent learning (Tolman, 1932)

– Learning that occurs but is not apparent until there is some reason to demonstrate it

Cognitive map (Tolman,1932)

– A mental representation of the layout of one’s environment. For example, after exploring a maze, rats act as if they have learned a cognitive map of it.

Overjustification effect

– The effect of promising a reward for doing what one already likes to do. The person may now see the reward, rather than the intrinsic interest, as the motivation for performing the task.

Cognition and Learning

Intrinsic Motivation

desire to perform a behavior for its own

sake and to be effective

Extrinsic Motivation

desire to perform a behavior due to

promised rewards or threats of

punishments

Other Cognitive Processes in Learning

Learned Helplessness (Seligman, 1967)

– Occurs when an organism believes that behaviors are not related to consequences

– When people’s past experience leads them to believe that nothing they can do will change their lives, they tend to stop trying.

Insight (Kohler, 1947)

– The sudden grasp of new relationships that are necessary to solve a problem and that were not learned in the past.

– Kohler’s studies of chimpanzee problem-solving

Observational Learning: Basic Processes

Albert Bandura (1977, 1986) – Observational learning

– Vicarious conditioning

– Bandura, Ross, & Ross (1963) – featured study p. 245-246

4 key processes – attention

– retention

– reproduction

– motivation

acquisition vs. performance

Bandura, Ross, & Ross (1963) featured study - p. 245 – 246 – Figure 6.25

Observational Learning and the Media Violence Controversy

Studies demonstrate that exposure to TV and

movie violence increases the likelihood of

physical aggression, verbal aggression,

aggressive thoughts, and aggressive emotions

The association between media violence and

aggression is nearly as great as the correlation

between smoking and cancer – F 6.26 – third

variable problem

Figure 6.27. Comparison of the relationship between media violence and aggression to other

correlations.