Transcript Learning II Memory & the Hippocampus

Introduction to Approaches in Psychology
Learning & Conditioning
Keith Clements
Aims
To introduce students to the key
features of operant and classical
conditioning.
 To consider what is learnt during each
type of conditioning.
 To consider the relevance of
conditioning to human behaviour.
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Habituation
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The simplest form of learning is habituation.
The response to a repeated stimulus will decline across
repetitions.
We know this is learning, rather than fatigue for example,
because the response will reoccur if the stimulus is
changed.
Habituation is a form of non-associative learning, it
involves only one stimulus.
We will be concentrating on associative learning, involving
two stimuli (one is associated with the other).
Behaviourism
Founded by John Watson in 1913
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Psychology as the study of behaviour
Learning as the centerpiece of Psychology
Focused on the relationship between
behaviour and stimuli and events in the
environment.
The legacy of behaviourism
Common Misconceptions:
 Learning is of little relevance to human behaviour
 Learning results in Stimulus-Response links
What actually happens:
 Individuals learn about the association between two
events.
 If A happens then B will follow
To study this in non-human species the association
needs to lead to a change in behaviour.
Classical conditioning
Involves stimuli which produce reflexive responses
Bell
No
response
Neutral
Stimulus
Food
Unconditioned
Stimulus
Reflex
Salivation
Unconditioned
Response
Classical Conditioning 2
During conditioning (Acquisition)
Bell
Bell
Conditioned
Stimulus
Food
Test for conditioning
Salivation
Salivation
Conditioned
Response
Operant Conditioning
Involves stimuli which have motivational
significance.
The
consequences
which
follow
behaviours influence the likelihood of their
being repeated
Operant Conditioning
Presented
Removed
Appetitive
Positive reinforcement
Positive event follows
response e.g. reward
Aversive
Punishment
Discomfort follows
response e.g. punishment
Punishment
Positive state removed
after response e.g. timeout or omission training
Negative reinforcement
Discomfort removed after
response e.g. escape or
avoidance learning
Evidence against S-R explanations
Sensory preconditioning
Rescorla & Durlach (1981)
1 Rats drank water flavoured with saccharin & Quinine
2 They drank saccharin water and were made ill
This produced a learned taste aversion, rats avoid
drinking saccharin water.
They also avoided quinnine-flavoured water
Evidence against S-R explanations
Reinforcer devaluation
Colwill & Rescorla (1985)
Rats learned
 To press a lever to obtain food
 To pull a chain to obtain sugar water
One group was made ill after eating the food pellets.
When both responses were available this group made
fewer presses but continued to pull the chain
Illness after drinking sugar water had the opposite
effect.
Revision questions 1
1) Your flatmate refuses to do the washing-up. Armed
with the knowledge that they hate pop music but love
classical music, how would you change their behaviour
using the following?
Positive reinforcement
Negative reinforcement
Human learning
Several recent studies apply procedures from the study
of learning in animals to human learning about
contingencies.
These principles apply to situations where learning
occurs as a result of experience of the relevant
contingencies. Human behaviour often obeys the same
rules as that of other species.
Human behaviour can also be influenced by other
processes, including verbal rules. Such rule-governed
behaviour may be insensitive to its consequences.
Shanks et al (1989)
Animal learning is sensitive to the delay between stimuli. Pavlov
found little evidence of learning with more than a few seconds delay
between CS & US. Operant reinforcers should be administered soon
after the reinforced behaviour.
Subjects could press a key which was followed 75% of the time by a
stimulus. The delay between press and stimulus was 0, 2, 4 or 8
seconds.
Subjects judged how likely the stimulus was to follow the key press.
With delays of 4 seconds subject's judgements did not differ from
control groups, for whom the stimulus was independent of the key
press
Practical applications
Classical conditioning and emotional responses.
Phobias may be viewed as learned fear responses. Such learning
may be particularly common in relation to biologically significant
stimuli. Seligman (1972) suggests that such stimuli may be
evolutionarily prepared to take part in fear conditioning.
 Positive responses may also be conditioned. Stimuli associated
with food or drugs may acquire conditioned responses which
encourage consumption.
 Exposure-based therapies (such as systematic desensitization)
aim to extinguish such maladaptive conditioned responses.
Practical applications 2
Behaviour Modification
Uses operant principles to modify human
behaviour.
Includes
Shaping
Conditioned Reinforcers
References
Essential Reading
Chapter 7 in Carlson, Martin & Buskist (2004) covers learning,
applications are covered in more detail on pages 747-749.
Further reading.
Those who want to go into the topic in more depth could look at the
following
Schwartz, B & Robbins, S.J. (1995). Psychology of learning and
behaviour. London : Norton.
Revision questions 2
A child is startled and falls off his chair while watching
pigeons through a window. He subsequently becomes
distressed when birds fly near him. A psychologist sees
the child for a number of sessions. In each, a caged bird
is gradually moved nearer to the child, until the child
begins to feel uncomfortable. After several sessions the
child can watch the bird flying out of it’s cage without
fear.
Describe the acquisition of the child’s fear in terms of
classical conditioning, identifying the different stimuli
and responses.