Chapter 6 - Schedules of Reinforcement and Choice Behaviour Flashcards
What is a schedule of reinforcement?
It is the rule that determines how and when a response will be reinforced
What are the two types of reinforcement rates?
- continuous reinforcement
2. partial reinforcement
What is continuous reinforcement?
Reinforcing every correct response
- most efficient way to condition a new response
- rare in real life
What is partial reinforcement?
Reinforcing some, but not all responses
- more effective at maintaining or increasing the rate of response (and produces long lasting responses)
What is the consequence of having different schedules?
There are distinct rates and patterns of responses with varying degrees of resistance to extinction
What are the two basic types of partial reinforcement schedules?
- ratio
2. interval
What do ratio types require?
A certain number of responses to be made before one is reinforced
What do interval types require?
A certain amount of time to elapse before a reinforcer is given
What are the two basic categories within ratio and interval partial reinforcement schedules?
- fixed
2. variable
Describe fixed ratio (FR) schedules
FR schedules
- reinforcement is given if the subject completes a pre-set number of responses (ex. FR5 = after 5 responses, the subject is rewarded)
- continuous reinforcement (CRF) is the same as FR1
What do we observe with fixed ratio schedules?
- ratio run: when the subject exhibits the same response again and again - shows that learning has occurres
- post-reinforcement pause: taking a break in performing after reward has been given
- ratio strain: a pause during the ratio run, following a sudden, significant increase in ratio requirement (they stop performing because of an increase in requirement)
Describe variable ratio (VR) schedules
- the number of responses required to get each reinforcer is not fixed (it is random around a particular number - usually the average)
- numerical value of the ratio indicates the average number of responses required per reinforcer (ex. VR7 means that on average, 7 responses are required before a reinforcer is introduced)
- the reinforcer is less predictable, therefore there is less likelihood of pausing between responses (due to the fact that the very next response could be reinforced)
When are interval schedules reinforced?
Only if they occur after a certain amount of time has passed
- time is the factor, but a response is still required to obtain a reinforcer
Describe a fixed interval (FI) schedule?
- a response is only reinforced if a constant or fixed amount of time has elapsed from the previous delivery of a reinforcer (ex. FI5 = five minutes have to elapse)
What is a fixed interval scallop?
Time towards the end of the interval will increase the rate of responding
- more responses closer to the time and fewer immediately after
Describe a variable interval (VI) schedule?
- a response is reinforced only if it occurs more than a variable amount of time after the delivery of an earlier reinforcer
- because VI are less predictable, just like VR, there is a steady rate of response with little break in between
Which two reinforcement schedules have the strongest response rate?
- Fixed ratio
- variable ratio
- the organism learns that it is causing the reward with its behaviour
What is the distinguishing characteristic of a fixed interval schedule?
The scallops
Which schedule produces the highest rate of responding, and is the most resistant to extinction?
variable ratio schedules, because the organism doesn’t know when the response will be reinforced
What are the similarities between ratio and interval schedules?
- in both FR and FI schedules there is a typical pause after each reinforcer, and an increased rate of response just before the delivery of the next reinforcer
- in both VR and VI schedules the response rate is steady without predictable pauses
What is the difference between ratio and interval schedules?
Different rate of response even when reinforcement frequency is similar
Why would different schedules with similar rates of reinforcement produce different rates of behaviour?
- reinforcement of inter-response times (IRT):
- the faster you respond, the more likely you are to receive reinforcement (probabilistic)
- variable ratio schedules reinforce shorter IRTs
- interval schedules favour long IRTs - feedback function:
- higher responding is reinforced more (only in ratio schedules)
Define choice behaviour
The voluntary act of selecting or separating from two or more things that which is preferred
What factors are our everyday choices influenced by?
- reinforcer: quality and quantity
- behaviour: type of response, schedule of reinforcement
- available alternatives
- delay in reinforcement
What is a concurrent schedule of reinforcement?
2 schedules of reinforcement are in effect at the same time
- the subject is free to switch between responses
- allows for continuous measurement of choice because the organism is free to switch between options at any time
Describe Hernstein’s Matching Law
- can only be used for prediction of VI schedules only
- the relative rate of responding is matched to the relative rate of reinforcement
- accurate in predicting generalized rates of reinforcement
- takes into consideration all possible outcomes
What is the formula for Hernstein’s Matching Law?
BL/BL+BR = rL/rL+rR
or
BL/Br = rL/rR
- the rate of reinforcement from option A (ex. 480/20 = 24)
- the rate of reinforcement from option B (ex. 480/60 = 8)
- add these two (ex. 32)
- divide rate of reinforcement of option A (24) by the total number of reinforcers possible (32) = 0.75
- do same for option B = 8/32 = 0.25
- answers should be proportions
What is the implication of Hernstein’s Matching Law?
Rate of a particular response does not depend on the rate of reinforcement of that response alone
- an operant response must compete with all other behaviours for an individual’s time
- therefore, it is impossible to predict how a reinforcer will affect a behaviour without taking context into account
What are the theories of choice behaviour?
maximization: organisms distribute their actions among response alternatives in order to maximize the amount of reinforcers possible in that situation
1. molecular maximizing: the choice is made according to the option that is most likely to be reinforced immediately
2. molar maximizing: the choice is made so that the highest number of reinforcers are collected in the long run (maximizing over time)
What is a concurrent-chain schedule of reinforcement?
choosing one option makes the other one unavailable
- two stages:
1. choice link (the choice)
2. terminal link (decided by the choice link)
Define self-control
Choosing a large delayed reward over an immediate small reward
- more difficult to choose a long term reward over a short term reward because of the delay
With a direct choice, what is an animal likely to choose?
An immediate and small reward
With a concurrent-chain procedure, what is an animal more likely to choose?
A delayed large reward
What is the value discounting function?
- tries to anticipate what the decision will be
- value of the reinforcer (V) is directly related to reward magnitude (M) and inversely related to reward delay (D)
- k is the discounting rate parameter that indicates how rapidly reward value declines as a function of delay
- when the value of the small reward decreases beyond the wait time, you would be more likely to wait for the large reward
What is the formula of the value discounting function?
V = M/(1+kD)
How does self-control look for people who are addicted to heroin?
- they show steeper value discounting functions
- they are more impulsive and would take the immediate small reward over a delayed large reward
How can delay discounting and impulsivity affect daily life?
- slower reward discounting: associated with higher grades
- faster reward discounting: associated with unsafe sex
- slower delay discounting with age (because we are less impulsive as we grow up)
- all depend on k factor **
How can we train someone to have more self-control?
- training with delayed reinforcement increases likelihood of choosing a larger delayed reward in the future
- pre-commitment: make the decision to choose a larger delayed alternative in advance in a manner that is difficult or impossible to change later on
What 5 steps can we take to modify our behaviour?
- identify the target behaviour
- gather and record baseline data
- plan your behaviour modification program
- choose your reinforcers
- set the reinforcement conditions and begin recording your progress
