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Operant Conditioning:Schedules and Theories of

Reinforcement

Chapter 7

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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.

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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

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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

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Reinforcement Schedules

• Response based schedules– Fixed ratio FR– Variable ratio VR– Progressive ratio PR

• Time Based Schedules– Fixed interval FI– Variable interval

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Postreinforcement Pause

• PRP as a function of IRI– FI - ½ interval value.– FR pause increases as FR is increased, rate of

response also increases.

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Analysis of Reinforcement Schedules

• FR postreinforcement pause– Fatigue– Satiation– Remaining response

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• VR and VI response rates

• VR yoked VI• Rates are higher on

VR schedules even when rate of reinforcement is the same

• ?

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The VR-VI difference

• IRT reinforcement– IRTs are conditionable– Synthetic schedules

• Response-reinforcer correlation

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Other Schedules

• Response Rate Schedules– Differential reinforcement of low rates

• IRT > t

– Differential reinforcement of high rates• IRT < t

– Differential reinforcement of paced responding

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Noncontingent Schedules

• Fixed time schedule

• Variable time schedule

• Superstitious behavior– Skinner 1948

• Adjunctive behavior

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Contingent + Noncontingent Schedules

• Decrease in response rate– Long term contracts– Tenure

• Noncontingent reinforcement?????

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Schedule Combinations

• Multiple Schedule

• Mixed Schedule

• Chained Schedule

• Tandem Schedule

• Concurrent Schedule

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Factors affecting performance on a schedule

• Quality of reinforcer

• Rate of reinforcement

• Delay of reinforcement

• Amount of reinforcement

• Level of motivation

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Rate of Response on Schedules

• Dynamic interactions between

• Molecular aspects - moment-to-moment relationships

• Molar aspects- length of session

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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.

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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.)

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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.

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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.

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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.

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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.

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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.