Chapter 5: Operant Conditioning Basics
2/28/2015
conditioned reinforcement
similar to second-order classical conditioning.
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US in S-OCC akin to primary reinforcer in OC.
CS2 in S-OCC is akin to initial neutral stimulus that has
become the conditioned reinforcer.
clicking sound paired with food, then can teach animal
to press bar when clicking sound is SR. (R will
eventually disappear because click no longer
accompanied by food)
generalized reinforcers (e.g. money) are a special class
of conditioned reinforcers; they are associated with a
large number of different primary reinforcers.
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a response chain is a sequence of behaviours that
must occur in a specific order, with the primary
reinforcer occurring after the last response.
Skinner -- each response in the chain is reinforced
by a conditioned reinforcer, which becomes the
discriminative stimulus for the next response.
the conditioned reinforcers are reinforcers because
they bring the animal closer to the primary reinforcer.
backward chaining (reinforce last response, then add
prior, etc.), forward chaining (reinforce 1st response,
then first and second...), total task methods
(reinforce only all responses).
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Biological Constraints on
Operant Conditioning
A. Instinctive Drift
pigs learn to carry coins to a bank for a reward.
over time however, other behaviours intrude
(dropping and rooting for coin) and slow their
success rate.
intruding behaviours related to how animal
forages, so with repeated experience the animals
behaviour drifted from reinforced behaviours to
more instinctive behaviours (instinctive drift).
mini-golf
(SD) A R1
(SR, SD) B R2
(SR, SD) C R3
(SR, SD) D R4
(SR, SD) E R5
(SR, SD) F R6
(SR ) finish game
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Instinctive Drift
B. Autoshaping
goes against operant conditioning
theory, instinctive behaviour not
consistent with environment, and
more importantly, animals exhibited
behaviours that were not reinforced
for behaviours that were reinforced.
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to shape pigeons to key-peck, Brown and
Jenkins deprived them and then trained them to
eat from a grain dispenser – then illuminated key
for 8 seconds and then darkened key and food
was delivered.
pigeons started to peck the illuminated key even
though it was not required to get food.
why do pigeons peck the key, even though it is
not required for reinforcement?
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Chapter 5: Operant Conditioning Basics
2/28/2015
Autoshaping
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Autoshaping
Superstitious behaviour
Brown and Jenkins, may be superstitious
behaviour.
light causes animal to look at key, which is
apparently reinforced. Next trial animal looks at
key but not immediately reinforced so
approaches key, which is apparently reinforced...
and so on.
Raichlin photographed pigeons when
reinforcement was given and there was no
evidence of this progressive behaviour.
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as classical conditioning
only peck the lighted key if it predicts food (like CSUS relationship in classical conditioning)
if food is SR, than peck key with beak wide open; if
water is SR than peck key with beak more closed
(as in drinking)
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Wasserman study: chicks - both
snuggling and wing extension are
warmth related behaviours
• fits with stimulus substitution theory (CS becomes
US) -- lighted key “becomes” water or food.
can’t explain every situation (if another rat predicts
food, they don’t gnaw on rat but sniffed or other forms
of social contact)
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Autoshaping as the intrusion of
instinctive behaviour patterns
Autoshaping
Williams and Williams showed that if you did not
give food when they pecked the lighted key
(punished by omitting food), they still acquired
key-peck response and performed it for about 1/3
of the trials.
so whatever factors produced key-pecking were
strong enough to override punishment
contingency
not superstitious behaviour
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key light (before heat lamp) snuggling;
warmth before wing expansion
physical properties determine form
Timberlake and Grant: different reinforcers
evoke different systems of behaviour (e.g.
warmth related) – Behaviour Systems
Analysis
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