PS261 Chapter Notes - Chapter 5: Stereotypy, Operant Conditioning, Contiguity
Chapter Five − Instrumental Conditioning: Foundations
5.5 − Fundamental Elements of Instrumental Conditioning
- The essence of instrumental behaviour is that it is controlled by its consequences
- Involves three elements −
o Instrumental Response
o Instrumental Reinforcer
o Response-Reinforcer Relation
5.5.a − The Instrumental Response
Behavioural Variability vs. Stereotypy
- Thorndike: stamping in of an S-R association
- Skinner: behaviour being strengthened or reinforced
- Both emphasized that:
o Reinforcement increases the likelihood that a response will be repeated
o Instrumental Conditioning produces repetitions of the same response
▪ Produces uniformity/stereotypy in behaviour
- Criteria for reinforcement is an abstract dimension of behaviour
o Behaviour required for reinforcement is defined as doing something new, unlike
what participant has done before
▪ Response variability basis for instrumental reinforcement
- Page & Neuringer (1985):
o Pigeons had to peck two response keys 8 times to get food
▪ No patterns could be the same for 50 trials − required novel patterns
- Variability in responding increases with reinforcement
o Established as an operant
- Absence of explicit reinforcement of variability:
o Responding becomes more stereotyped with continued conditioning
▪ Thorndike and Skinner were correct in saying this
Relevance/Belongingness in Instrumental Conditioning
- Belongingness: certain responses naturally belong with the reinforcer because of the
animal’s evolutionary history
o Ex. Three-Spined Stickleback
▪ Mating season − males establish territories where they court females but
chase away other males
▪ Used male/female as a reinforce
• If male, biting of rod increased
• If female, effective reinforcement of other responses
▪ Biting does not belong with presentation of female − sign of aggression
- Instinctive Drift: extra responses that develop in reinforcement situations, which the
animals instinctively perform when obtaining the stimulus
o Ex. Pigs and Food − would root the food
find more resources at oneclass.com
find more resources at oneclass.com
▪ Raccoons and Food − would rub the food together in a miserly fashion
Behaviour Systems and Constraints on Instrumental Conditioning
- When an animal is food-deprived and in a situation where food may be encountered
o Feeding system becomes activated and begins to engage in food-related activities
- Instrumental conditioning procedure superimposed on this behaviour system
o Effectiveness of increasing response depends on the compatibility of that response
with the pre-existing organization of the feeding system
- The nature of other responses that emerge during training depends on the behavioural
components of the feeding system
5.5.b − The Instrumental Reinforcer
Quantity and Quality of the Reinforcer
- Quantity and quality of reinforcer determines the effectiveness of the reinforcement
o If small and poor quality − not effective in increasing instrumental responding
- Results are more complicated in free-operant situations
- Effects of the quality and quantity of reinforcement depend on many factors
o Such as how many responses to obtain reinforce
- Progressive Ratio Schedule:
o Used to evaluate magnitude of effects of reinforcer on instrumental responding
o Participant has to make increasing numbers of responses to obtain reinforce
- Voucher Program for Rehab Patients:
o Vouchers can be exchanged for money
o Increase in magnitude of reinforcer contributed to abstinence level
o Getting paid right after test was more effective than delayed payment
Shifts in Reinforcer Quality or Quantity
- Effectiveness of reinforcer depends not only on its own properties
o Also, how that reinforcer compares with others that the individual has recently experienced
- Effects of particular amount/type of reinforcer depend on quantity and quality of the
reinforcers the individual has experienced previously
o Large reward especially GOOD after reinforcement with small reward
o Small reward especially POOR after reinforcement with large reward
- Response to new reward is enhanced by previous experience with contrasting reward magnitude
o Rats ran faster if they were earlier presented to small reward, then exposed to
large reward
▪ Compared to rats exposed to large reward
- Positive Contrast: elevated responding for favourable reward
o Resulting from prior experience with less attractive outcome
- Negative Contrast: depressed responding for a small reward
o Due to prior experience with a better outcome
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The essence of instrumental behaviour is that it is controlled by its consequences. Thorndike: stamping in of an s-r association. Both emphasized that: reinforcement increases the likelihood that a response will be repeated. Instrumental conditioning produces repetitions of the same response: produces uniformity/stereotypy in behaviour. Criteria for reinforcement is an abstract dimension of behaviour: behaviour required for reinforcement is defined as doing something new, unlike what participant has done before, response variability basis for instrumental reinforcement. Page & neuringer (1985): pigeons had to peck two response keys 8 times to get food, no patterns could be the same for 50 trials required novel patterns. Variability in responding increases with reinforcement: established as an operant. Absence of explicit reinforcement of variability: responding becomes more stereotyped with continued conditioning, thorndike and skinner were correct in saying this. Belongingness: certain responses naturally belong with the reinforcer because of the. Relevance/belongingness in instrumental conditioning animal"s evolutionary history: ex.
