Transcript PSY402 Theories of Learning

PSY402
Theories of Learning
Chapter 9, Theories and Applications
of Aversive Conditioning
More Drawbacks
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Suppressive effects may generalize
from an undesirable behavior to
other desirable behaviors.
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Punishment may not generalize to
similar undesirable behaviors.
The person may not recognize the
contingency between the behavior
and the punishment.
Explaining Avoidance
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The existence of avoidance behavior
implies a cognitive process:
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Behaving in order to prevent an
aversive event.
Behaviorists like Hull needed to
explain this without cognition.
Mowrer’s two-factor theory was
developed to explain this – but it
has problems needing explanation.
Mowrer’s Two-Factor Theory
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Mowrer proposed a drive-based
two-factor theory to avoid
explaining avoidance using
cognitive (mentalistic) concepts.
Avoidance involves two stages:
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Fear is classically conditioned to the
environmental conditions preceding an
aversive event.
Cues evoke fear -- an instrumental
response occurs to terminate the fear.
Mowrer’s View (Cont.)
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We are not actually avoiding an
event but escaping from a feared
object (environmental cue).
Miller’s white/black chamber – rats
escaped the feared white chamber,
not avoided an anticipated shock.
Fear reduction rewards the escape
behavior.
Criticisms of Two-Factory Theory
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Avoidance behavior is extremely
resistant to extinction.
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Should extinguish with exposure to CS
without UCS, but does not.
Levis & Boyd found that animals do
not get sufficient exposure duration
because their behavior prevents it.
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Avoidance persists if long latency cues
exist closer to the aversive event.
Is Fear Really Present?
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When avoidance behavior is welllearned the animals don’t seem to
be afraid.
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An avoidance CS does not suppress
operant responding (no fear).
However, this could mean that the
animal’s hunger is stronger than the
fear.
Strong fear (drive strength) is not
needed if habit strength is large.
Avoidance without a CS
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Sidman avoidance task – an
avoidance response delays an
aversive event for a period of time.
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There is no external cue to when the
aversive event will occur – just
duration. Temporal conditioning.
How do animals learn to avoid
shock without any external cues for
the classical conditioning of fear?
Kamin’s Findings
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Avoidance of the UCS, not just
termination of the CS (and the fear)
matters in avoidance learning.
Four conditions:
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Response ends CS and prevents UCS.
Reponse ends CS but doesn’t stop UCS.
Response prevents UCS but CS stays.
CS and UCS, response does nothing
(control condition).
D’Amato’s Acquired Motive View
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D’Amato proposed that both pain
and relief motivate avoidance.
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Anticipatory pain & relief responses.
Shock elicits unconditioned pain
response RP and stimulus SP
motivates escape.
Classically conditioned cues sP elicit
anticipatory pain response rP that
motivates escape from the CS.
Anticipatory Relief Response
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Termination of the UCS produces an
unconditioned relief response RR
with stimulus consequences SR.
Conditioned cues elicit an
anticipatory relief response rR with
stimulus consequences sR.
Example: dog bite elicits pain
response, sight of dog elicits
anticipatory pain, house elicits relief
A Discriminative Cue is Needed
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During trace conditioning no cue is
present when UCS occurs and no
avoidance learning occurs.
A second cue presented during
avoidance behavior slowly acquires
rR-sR conditioning.
Similarly, in a Sidman task, cues
predict relief -- associated with
avoidance behavior, not the UCS.
Flooding (Response Prevention)
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Flooding -- forcing a person to
experience a feared stimulus until
they realize no UCS will occur.
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Also called response prevention.
Effectiveness increases with longer
exposure to the feared stimulus.
Also used to treat obsessivecompulsive disorder – suppresses
obsessive behaviors and fear.
Thorndike’s Negative Law of Effect
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Thorndike suggested that
punishment weakens an S-R bond.
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Skinner’s finding that suppression of
behavior is temporary contradicts this.
The effect of punishment must be
something different than weakening
of the S-R bond.
Guthrie’s View of Punishment
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When a punishment occurs, the
response to it is conditioned to the
environment during the event.
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Freezing, jumping, flinching.
The effect on behavior depends on
the UCR elicited by the shock.
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Shock to forepaws inhibits running but
a shock to hindpaws facilitates it.
Monkeys struggle more when shocked.
Guthrie’s Competing Response
Theory
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Guthrie suggested that punishment
works only if the response elicited
by the punishment is incompatible
with the punished behavior.
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Gerbils punished for standing upright
do it more, not less.
Problems with Guthrie’s Theory
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Response competition alone is
insufficient to make punishment
effective.
When punishment is contingent
instead of just co-occurring, it is
more effective.
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Contingent means the punishment
happens only when the behavior
occurs, not independent of it, randomly
Este’s Motivational View
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When a behavior is rewarded, the
motivational system becomes
associated with the behavior.
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The response occurs the next time the
motivational system is activated.
Punishment works by changing the
motives.
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Stimuli associated with punishment
inhibit the motivational state.
Support for Estes
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Thirsty rats were trained to lever
press for water and “dry lick” for air
on alternate days.
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Punishment of both behaviors had a
greater effect on dry licking (a thirstrelated behavior) than lever pressing.
If the behavior rather than the motive
were being suppressed no such
difference should occur.
Results differed with hungry rats.
Applications of Punishment
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Widespread use of punishment
(e.g., spanking) probably does not
serious harm.
Two applications:
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Persistent vomiting decreased.
Tree-climbing behavior suppressed.
Use of such punishment may be
preferable to ineffective methods.
Ethical Use of Punishment
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Cruel and unusual punishments
prohibited by 8th Amendment of US
Constitution.
Rights of individual must be
safeguarded.
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APA Ethical Principles of Psychologists
Least restrictive alternative
Balance punisher pain against pain
if the behavior is left untreated.