Schedules of Reinforcement

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Schedules of Reinforcement

• The Effects of Intermittently Reinforcing Behavior

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Schedules of Reinforcement

• Behavior is not necessarily going to be
  reinforced every time it occurs
• In real life, behavior is not often reinforced
  each time it occurred
• A reinforcement schedule is a rule stating which
  instances of behavior, if any, will be reinforced
• Intermittent reinforcement refers to
  reinforcement that is not administered to each
  instance of a response

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Advantages of Intermittent Reinforcement

• Economizing on time and reinforcers when
  reinforcement does not have to be administered
  for each instance of a behavior
• Building persistent behavior which is much more
  resistant to extinction
• Delays the effects of satiation since fewer
  reinforcements need to be delivered

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Types of Schedules

• Continuous reinforcement every instance of a
  behavior is reinforced
• Ratio schedules Reinforcement is based on the
  number of behaviors required
• Interval schedules Reinforcement is based on the
  passage of time
• Duration schedules Reinforcement is based on the
  continued performance of a response for a period
  of time
• Fixed schedules The requirements for
  reinforcement are always the same
• Variable schedules The requirements for
  reinforcement change randomly

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Schedules of Reinforcement

• Continuous reinforcement refers to reinforcement
  being administered to each instance of a response
• Intermittent reinforcement lies between
  continuous reinforcement and extinction

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An Example of Continuous Reinforcement

• Each instance of a smile is reinforced

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Fixed Ratio Reinforcement

• A fixed number of responses is required for each
  reinforcement
• These schedules are designated FRn where nthe
  number of responses required
• These schedules usually produce rapid rates of
  responding with short post-reinforcement pauses
• The length of the pause is directly proportional
  to the number of responses required

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An example of Fixed Ratio Reinforcement

• Every fourth instance of a smile is reinforced

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Graph of Fixed Ratio Responding
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Fixed Interval Reinforcement

• These schedules require the passage of a
  specified amount of time before reinforcement
  will be delivered contingent on a response
• No response during the interval is reinforced
• The first response following the end of the
  interval is reinforced
• This schedule usually produces a scalloped
  pattern of responding in which little behavior is
  produced early in the interval, but as the
  interval nears an end, the rate of responding
  increases
• This also produces an overall low rate of
  responding

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Graph of Fixed Interval Responding
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Variable Schedules of Reinforcement

• Variable schedules differ from fixed schedules in
  that the behavioral requirement for reinforcement
  varies randomly from one reinforcement to the
  next
• This usually produces a more consistent pattern
  of responding without post-reinforcement pauses
• Variable ratio schedules produce an overall high
  consistent rate of responding
• Variable interval schedules produce an overall
  low consistent rate of responding

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An Example of Variable Ratio Reinforcement

• Random instances of the behavior are reinforced

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Graph of Variable Ratio Responding
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Graph of Variable Interval Responding
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Fixed and Variable Duration Schedules

• The response is required to continue for a
  specified or variable period of time for
  reinforcement to be delivered
• These schedules produce a continuous rate of
  behavior since that is the requirement for
  reinforcement

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Extinction of Intermittently Reinforced Behavior

• The less often and the more inconsistently
  behavior is reinforced, the longer it will take
  to extinguish the behavior, other things being
  equal
• Behaviors that are reinforced on a thin
  schedule are more resistant to extinction than
  behaviors reinforced on a more dense schedule
• Behavior that is reinforced on a variable
  schedule will be more resistant to extinction
  than behavior reinforced on a fixed schedule

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Reducing Reinforcer Density

• Large amounts of behavior can be obtained with
  very little reinforcement using intermittent
  schedules
• Initially, behavior needs dense schedules of
  reinforcement to establish it, preferably
  continuous reinforcement
• As the behavior is strengthened, reinforcement
  can be gradually reduced in frequency
• Start with as low a density as the behavior can
  tolerate and decrease the density as responding
  is strengthened

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• If it is reduced too quickly, signs of extinction
  may be observed
• Response rate may slow down
• Inconsistent responding may be seen
• May see an increase in other responses
• This is known as schedule strain
• If this happens, retreat to a denser
  reinforce-ment schedule
• Adding a conditioned reinforcer in between
  reinforcements can help bridge the gap

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Variations of Reinforcement Schedules I Limited
Hold

• This is applied when a faster rate of responding
  is desired with a fixed interval schedule
• Response rate can be slowed down if response is
  not made soon after the end of the interval
• By limiting how long the reinforcer is available
  following the end of the interval, responding can
  be speeded up
• If the response is not made within that period,
  the reinforcement is lost and another is not
  available until the end of the next interval

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Variations of Reinforcement Schedules II
Concurrent Schedules

• Two or more basic schedules are operating
  independently at the same time for two or more
  different behaviors
• The organism has a choice of behaviors and
  schedules
• This provides a better analog for real-life
  situations because reinforcement is often
  available for more than one response class or
  from more than one source or both

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Concurrent Schedules (contd)

• When similar reinforcement is scheduled for each
  of the concurrent responses
• the response receiving the higher frequency
  of reinforcement will increase in rate
• the response requiring the least effort
  will increase in rate
• the response providing the most immediate
  reinforcement will increase in rate

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Matching Law and Maximizing

• The proportion of responses made to each schedule
  will be proportionate to the ratio of reinforcers
  available under each schedule
• Maximizing subjects switch back and forth
  between alternatives to receive maximum
  reinforcers
• Concurrent ratio schedules little
  switching back and forth
• Concurrent interval schedules the subjects
  can earn close to all of the reinforcements on
  both schedules

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Example of the Matching Law

• You are speaking to 2 people, providing them with
  information that is of interest to them.
• When you look at each person, person A is looking
  at you (the reinforcement) about 75 of the time
  and looking away about 25 of the time.
• Person B is looking at you about 25 of the time
  and looking away about 75 of the time.
• About what percent of the time will you be
  looking at each person?

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Variations of Reinforcement Schedules II Chained
Schedules

• Two or more basic schedule requirements are in
  place, one schedule occurring at a time but in a
  specified sequence
• There is usually a cue that is correlated with a
  specific schedule and is present as long as the
  schedule is in effect
• Reinforcement for responding in the 1st component
  is the presentation of the 2nd
• Reinforcement does not occur until the final
  component is performed

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Variations of Reinforcement Schedules III
Conjunctive Schedules

• The requirements for two or more schedules must
  be met simultaneously
• Task/interval interactions
• When the task requirements are high and the
  interval is short, steady work throughout the
  interval will be the result
• When task requirements are low and the
  interval long, many nontask behaviors will be
  observed