Chapter 9

Role of the Response in Operant Conditioning

• Thorndike
• Performance of response necessary
• Tolman
• Formation of expectation
• McNamara, Long, & Wike (1956)
• Maze, running rats, basket rats

Is Reinforcement Necessary for Operant Conditioning

• Latent learning
• Not necessary for learning
• Necessary for performance

Tolman & Honzig (1930)

(Figure 1)

Expectations about the Reinforcer

• Stimulus-response association

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• Three-term contingency

• Value of the reinforcer

Is Reinforcement at Work in Classical Conditioning?

• Operant and classical conditioning
• Same or different?
• Two factor
• Two different learning processes
• One factor
• Common learning mechanism
• Hull (1943)

Gomezano & Coleman (1973)

• Eyeblink with rabbits
• US = shock CS = tone
• Classical group: 5mA shock each trial, regardless of response
• Omission group: eliminate shock by making eyeblink in response to CS
• One factor theory prediction
• Acquisition of CR faster and asymptote of learning higher in omission group

 

 

• In classical group, CR appears because it somehow reduces aversiveness of shock
• Results
• Acquisition of CR slower in omission group
• Extinction (not all CSs followed by US)

 

• Supports two-factor theory

Reinforcers

• Simple definition:
• A stimulus that increases the future probability of the behaviour that preceded it
• Circular argument

(Figure 2)

• Can the Behaviourists escape this dreaded logical trap?

Escape Route

• Development of independent criteria to identify reinforcing stimuli
• Rules
• Advance predictions

Need Reduction

• Primary reinforcers reduce biological needs
• Biological needs: Food, water
• Not biological needs: Sex, saccharin
• Undetectable biological needs: vitamins

Drive Reduction

• Strong stimuli aversive; reduction of stimulation is reinforcing
• e.g., hunger, sex, absence of pain drives
• Problems:
• Objective stimulus intensity measurement

Trans-situationality

• Stimulus that is reinforcer in one situation should be a reinforcer in another
• Reinforcing behaviours
• Reinforcable behaviours
• Often works with primary reinforcers
• Problems with other stimuli

Premack Principle

• No clear boundary between reinforcing and reinforcable behaviours
• Situation dependent
• Is it the stimulus or the associated behaviour that is reinforcing?

• Contingency
• Between behaviours
• One behaviour will reinforce a second behaviour
• High probability behaviour reinforces low probability behaviour
• Baseline probability scale
• Time
• Rank order
• Reinforcement relativity

Steps with Premack Principle

• 1. Measure behavioural probabilities; make scale
• 2. Test different operant/reinforcer contingencies

Example

• Behaviours
• Eat ice cream (I), play video game (V), read book (B)
• Baseline (30 minutes)
• Student 1: I (2min), V (8min), B (20min)
• Scale: I -- V -- B
• Student 2: I (8min), V (20min), B (2min)
• Scale: B -- I -- V
• Student 1: V reinforces I, B reinforces V & I
• Student 2: I reinforces B, V reinforces I & B

Premack’s Problems

• Baseline phase
  • Fair rating?
    • Very different behaviours

   

• Time problems
  • What if time not important to behaviour?
  • Behaviour duration?
  • Length of baseline period?

Premack’s Principle of Punishment

• Low probability (L) behaviours reduce high probability (H) behaviours
• L punishes H

Optimization

• Limited resources
• How to use them
• Maximize subjective value
• Value changes

Economic Concepts and Response Allocation

• How do constraints of operant conditioning --> changes in behaviour?
• Similarities to economics

The Economic Analogy

• Responses/time = money
• Total responses/time possible = income
• Schedule = price

• In operant behaviour
• # of possible responses
• # of responses required per reinforcer

Consumer Demand

• Demand curve
• Price of something and how much is purchased
• Elasticity of demand
• Elastic: increased price --> decreased purchase
• Inelastic: increased price --> little effect

(Figure 4)

Three Factors in Elasticity of Demand

• 1. Availability of substitutes
• Can’t substitute complementary reinforcers

 

• Can substitute non-complementary reinforcers

• 2. Price range
• e.g., FR3 to FR5 vs. FR30 to FR50
• 3. Income level
• Higher total response/time…the less effect cost increases have
• Increased income --> purchase luxury items
• Shurtleff et al. (1987)
• Two VI schedules; food, saccharin water
• High schedules: rats spend most time on food lever
• Low schedules: rats increase time on saccharin lever

Behavioural Economics and Drug Abuse

• Addictive drugs
• Animal models
• Elasticity
• Work for drug reinforcer on FR schedule
• Inelastic...up to a point

(Figure 5)

• Elsmore, et al. (1980)
• Baboons
• Food and heroin
• Availability of substitutes
• Behavioural economic theory does apply here

(Figure 6)