Download Theoretical Approaches and questions in Operant Conditioning

Theoretical Approaches and
Questions in Operant Conditioning
Psychology 3306
Responses and reinforcers
• How important are responses and reinforcers?
• Thorndike and Skinner would say that it is
essential
• Tolman said ‘umm, not completely
• Cognitive maps
• Latent learning
So you don’t need a reinforcer?
• Perhaps it strengthens the S-R bond, but is not
necessary
• Maybe it becomes part of a representation?
• Colwill and Rescorla, 1985
• Chain - > water
• Lever - > food
• Food - > poison
That sound you hear is Skinner spinning in
his grave
• Rats won’t press the lever!
• Therefore, the response and reinforcer have
been connected, but not directly
• It seems that associations are made between
all three parts of the three term contingency
Are there 2 types of learning?
• Yes, operant and classical
• No, it is all associative learning
• What a stupid question….
Pushing the limits
• Heart rate conditioning
• Biofeedback
• Not always successful
So what is a reinforcer?
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Some event that increases the likelihood of….
ENOUGH!
Maybe it is need or drive reduction?
Premack’s ideas
Is food the reinforcer, or is it the act of eating?
Premack’s principle
• Given 2 responses arranged in an operantconditioning procedure, more probable
behaviors will reinforce less probable
behaviors; less probable response will not
reinforce more probable ones
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Premack (1963) - study in Cebus monkeys
Lever Pressing (L) : highest probability
Door Opening (D) : medium probability
Plunger Pulling (P) : lowest probability
reinforces D; L reinforces P; P does NOT reinforce
either D or L, etc.
• “Premackian reinforcers”: activities that act as
reinforcers (reading, playing)
• Useful (and less costly) in token economies than
object-based reinforcers
Applications
• Mitchell & Stoffelmayr (1973) use Premack’s principle in
schizophrenics
• Reinforcement items like candy, cigarettes, etc. usually not
effective in schizophrenic patients
• Sitting is a highly probable behavior in negative-symptom
schizophrenics (catatonia, social withdrawal)
• therapists made sitting contingent on doing small amount of
work or activity; improved their negative symptoms
• In unruly nursery-school children, high probability behaviors
(running around, screaming) made contingent on low
probability behaviors (sitting quietly, paying attention)
Behavioural economics
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Open economies
Closed economies
Elasticity of demand
And behavioural ecology
Stimulus Control
• Relationship between S and R
• Reynolds (1961) - Attention in the pigeon
• 2 pigeons reinforced for pecking to compound
stimulus of white triangle on red background
projected on response key
• rate of pecking was then observed in each
subject to a white triangle and a red
background singularly
Why do you get a gradient?
• Sort of the study of generalization and
discrimination
• How do you get data?
– Probe trials
– Test phases
– Both done in extinction
• Is it a property of the nervous system?
– Pavlov
– Hubel and Wiesel
Perhaps it is learning?
• Lashley and Wade figured it was how the
animal was trained
• Borne out by Jenkins and Harrison’s work
• Non differential
• Presence absence
• Explicit training
Duck you
• Peterson (1960) and his ducklings, only saw
yellow
• They did not show gradients with colour!
• Oops
• Probably depends on the modality and the
species being tested really
• Or, could be relational Kohler and his chickens
• Gonzalez, Gentry, & Bitterman (1954) - chimpanzee had to
pick among 9 squares of varying sizes
• Squares 1,5, & 9 presented, subject reinforced for choosing #
5 (intermediate size)
• on test trial chimp reinforced no matter which square chosen
• if given 4, 7, & 9 relational theory says subject will choose # 7,
absolute theory says subject
will choose square closest # 5 ( # 4)
• subjects usually chose the intermediate size square of
whichever three squares were presented
Peak Shift
OK, so that is odd
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Why does that happen?
Excitatory gradient
Inhibitory grandient
As the Violent Femmes
would say, you gotta
add it up
Bird brain is not an insult
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Concept learning
Natural needed?
How long lasting
Delius (1982)
Honig and Stewart (1988)
The field of comparative cognition really grew
out of much of this stuff