Transcript The Disequilibrium Principle

Operant Conditioning:
Schedules and Theories of
Reinforcement
Chapter 7
1
Importance of Schedules of
Reinforcement
• Rule for the presentation of stimuli that
precede operants and the consequences that
follow them.
• Schedules are the fundamental determinants
of behavior.
• Rate and temporal patterns of responding
• Probability of responding.
2
Terminology
• Partial reinforcement effect (greater resistance to
extinction following partial reinforcement)
– Discrimination hypothesis
– Generalization decrement hypothesis
• Contingency of reinforcement - features defined
by the schedule
• Steady-state performance
• Strained performance
3
Schedules of Reinforcement
• CRF - continuous reinforcement FR 1
• Fixed Ratio- FR an FR schedule
– Postreinforcement pause
– run of responses
• Variable Ratio – VR
• Fixed Interval – an FI scallop
– Long term - break and run
– Humans
• Variable Interval - VI
4
Reinforcement Schedules
• Response based schedules
– Fixed ratio FR
– Variable ratio VR
– Progressive ratio PR
• Time Based Schedules
– Fixed interval FI
– Variable interval
5
Postreinforcement Pause
• PRP as a function of IRI
– FI - ½ interval value.
– FR pause increases as FR is increased, rate of
response also increases.
6
Analysis of Reinforcement
Schedules
• FR postreinforcement pause
– Fatigue
– Satiation
– Remaining response
7
• VR and VI response
rates
• VR yoked VI
• Rates are higher on
VR schedules even
when rate of
reinforcement is the
same
• ?
8
The VR-VI difference
• IRT reinforcement
– IRTs are conditionable
– Synthetic schedules
• Response-reinforcer correlation
9
Other Schedules
• Response Rate Schedules
– Differential reinforcement of low rates
• IRT > t
– Differential reinforcement of high rates
• IRT < t
– Differential reinforcement of paced responding
10
Noncontingent Schedules
• Fixed time schedule
• Variable time schedule
• Superstitious behavior
– Skinner 1948
• Adjunctive behavior
11
Contingent + Noncontingent
Schedules
• Decrease in response rate
– Long term contracts
– Tenure
• Noncontingent reinforcement?????
12
Schedule Combinations
•
•
•
•
•
Multiple Schedule
Mixed Schedule
Chained Schedule
Tandem Schedule
Concurrent Schedule
13
Factors affecting performance on a
schedule
•
•
•
•
•
Quality of reinforcer
Rate of reinforcement
Delay of reinforcement
Amount of reinforcement
Level of motivation
14
Rate of Response on Schedules
• Dynamic interactions between
• Molecular aspects - moment-to-moment
relationships
• Molar aspects- length of session
15
What Constitutes Reinforcement?
• A reinforcer is something that increases the
likelihood of the preceding response.
– This can be confusing because it leads to a
circular explanation.
– It can also be confusing because although
generally a reinforcer is a pleasant event, it
doesn’t have to be.
– What constitutes a “pleasant event” can be hard
to define or vary from person to person.
16
What Constitutes Reinforcement?
• Many reinforcers satisfy biological needs, such as
hunger.
• Addictive behaviors don’t seem to give much
pleasure to the addict (although they may be
negatively reinforcing - done to avoid the unpleasant
condition of not having access to the drug.)
• Some reinforcers don’t satisfy any immediate need,
but may represent a future opportunity to have
greater access to resources (such as a good grade –
you can’t eat it, but getting many of them may raise
your chances of having more to eat later in your
life.)
17
Theories of Reinforcement
• Drive reduction theory – an event is
reinforcing to the extent it is associated with
a reduction in some type of physiological
drive.
– However, some types of reinforcers not
associated with drive reduction.
• Incentive motivation – reinforcement
derived from some aspect of the reinforcer.
18
What Constitutes Reinforcement?
• The Premack Principle
– The Premack Principle states that the
opportunity to engage in frequent behavior will
be a reinforcer for any less-frequent behavior.
• A person who prefers going to the movies to going
to museums can be reinforced for extra trips to the
museum with free movie passes.
19
What Constitutes Reinforcement?
• The Disequilibrium Principle
– The disequilibrium principle states that each
person has a preferred pattern of dividing time
between various activities and if the person is
removed from that pattern a return to it will be
reinforcing.
• A person who must work overtime for the next three
weekends makes an extra effort to finish up the
assigned work to return to his preferred activity of
playing golf.
20
Response Deprivation Hypothesis
• A behavior can serve as a reinforcer when
(1) access to the behavior is restricted and
(2) and its frequency thereby falls below its
preferred level of occurrence.
21
Behavioral Bliss Point Approach
• An organism that has free access to
alternative activities will distribute its
behavior in such a way as to maximize
overall reinforcement.
• Contingencies can move us away from the
bliss point.
• Organism will try to accommodate by
maximization of bliss point.
22