Transcript PPT

Chapter 4
Using Reinforcement to
Increase Operant Behavior
What Is Reinforcement?
• reinforcement is a process of applying a
consequence that strengthens behavior
• the consequence is a stimulus called a reinforcer
• focus on the outcome of reinforcement
(strengthening) rather than interpret what each
individual views as good and bad
• reward is usually not used as a synonym for
reinforcer
Positive and Negative
Reinforcement
• some distinguish between positive reinforcers and
negative reinforcers
– positive refers to a consequence that is given
– negative refers to a consequence that is taken
away
• negative reinforcement is not a technical term for
punishment
• some have argued that we should drop the terms
positive and negative
Reward Value
• reward value is the degree to which a
consequence will change behavior
• strength of a consequence can vary from time to
time
• value of a reinforcer can be influenced by its
quality and quantity
Unconditioned and
Conditioned Reinforcers
• unconditioned or primary reinforcers do not
have to be learned
• conditioned or secondary reinforcers acquire
their value through association with other
reinforcers
• the process that develops the value of a
conditioned reinforcer can modify the value of
primary reinforcers
Unconditioned and Conditioned
Reinforcers (continued)
• value of reinforcers differs across individuals
because of differential experiences
Why Are Reinforcers
Reinforcing?
• consequences may serve to strengthen behavior by
reducing biological drives
• drive reduction is not necessary for reinforcers to
change behavior
• sensory stimulation may serve to reinforce
• the rate of a behavior can reflect on reward value
Types of Positive Reinforcers
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tangible reinforcers
activities
social reinforcers
feedback
tokens
covert reinforcers
Tangible and Consumable
Reinforcers
• tangible reinforcers are material objects
• consumable reinforcers are items we ingest
• food can serve as a reinforcer, but it has several
drawbacks
Activities as Reinforcers
• the opportunity to engage in a behavior can have
reinforcing value
• the Premack principle holds that a behavior that
occurs at a higher rate than another can serve to
reinforce the other
• comparison of rates can be complicated by how an
instance of behavior is defined
Activities as Reinforcers (continued)
• the response deprivation hypothesis suggest that
the Premack principle works because we work to
overcome restrictions placed on higher-rate
behavior
Social Reinforcers
• social reinforcers are consequences that involve
personal communication from others
• social reinforcers are easy to deliver, can be
applied immediately, are not very disruptive
• because social reinforcers occur naturally outside
of therapy, they tend to insure generalization of
treatment
Feedback
• feedback is information about characteristics of
performance
• feedback can be direct or implied by reinforcers
applied
• feedback with other reinforcers such as praise can
work better than feedback alone
• biofeedback is a procedure in which an individual
is given feedback about physiological response
Tokens
• tokens are symbolic reinforcers that can “buy”
other (backup) reinforcers
• without backup reinforcers, tokens are simply
serving as feedback or social reinforcers
• token systems can offer a more complex set of
contingencies
• token systems can help overcome problems
associated with consumables
Covert Reinforcers
• covert reinforcers are imaginal consequences
• covert reinforcers might not have as much value as
their overt counterparts; they are available and
easy to apply
Identifying Potential Reinforcers
• speculation about what might serve as high-value
reinforcers can be based on demographic factors
and on simple observation
• indirect assessment methods verify reinforcing
value using interviews or questionnaires to ask the
individual what they find pleasurable
Identifying Potential Reinforcers
(continued)
• while indirect methods may be easier and faster to
apply, they may be less valid and they can be used
only with subjects with necessary verbal abilities
Enhancing Reinforcer
Effectiveness
strengthen reinforcers by:
• associating them with other more powerful
reinforcers
• presenting a brief sample of the reinforcer before
the behavior occurs
• modeling the use of the reinforcers with others
Shaping
• shaping is used to develop complex behavior by
gradually increasing expectations for delivery of
reinforcers
• qualitative shaping requires that the quality of
the performance of the task become better
• quantitative shaping requires increases in
amount of behavior
Shaping (continued)
• the first step in a shaping program is to do a task
analysis
• task analysis breaks down complex behavior into
a sequence of smaller steps
• progress can be accelerated by using shortcuts to
stimulus control
Timing and Schedules
of Reinforcement
• initially, immediately reinforce every instance of
behavior
• once behavior is established, reduce the frequency
of reinforcement (thinning)
• intermittent or partial reinforcement procedures
reinforce fewer than every instance of behavior
Timing and Schedules of
Reinforcement (continued)
• schedules of reinforcement are systems used to
describe the pattern and frequency of delivery of
intermittent reinforcement
• extinction involves the elimination of a previously
established reinforcer
• reliance on reinforcement can be phased out by
gradually increasing the delay between behavior
and consequence
Chaining Methods
• three methods can be employed to teach a chain of
behaviors:
– forward chaining begins with the first link in a
task; when a link is mastered, an additional link
is added as a new requirement for
reinforcement
Chaining Methods (continued)
– backward chaining follows a similar
procedure to forward chaining except that the
first step is to complete the last link; additional
steps are added, and the completion of the task
is the only task that is reinforced
– total-task presentation requires the
completion of the whole series to be reinforced
Using Reinforcers to
Develop Behavior Chains
• prior to training, conduct task analysis on complex
behaviors
• all approaches should use prompts
• steps should be simple enough to insure success
Using Group and
Individual Contingencies
• social reinforcers controlled by group members
can strengthen misbehavior of an individual
• lottery procedures allow individuals in a group to
earn chances to win large rewards by engaging in
appropriate behavior
• group contingencies consequate the cumulative
behavior of a group
Can Rewards Undermine
Behavior Control?
when children are extrinsically reinforced for a
preferred behavior they may become less likely to
engage in that behavior when those reinforcers are
not available
• the effect is not that widespread
• the effect seems to be limited to certain types of
behaviors and reinforcers
• the suppression is only temporary
Who Will Administer
Reinforcement?
• peer-administered reinforcement has effectively
increased performance in academic settings
• self-administered reinforcement often is used in
self-control
• reinforcement can deviate from specified
contingencies
Who Will Administer
Reinforcement? (continued)
• reinforcement errors can be reduced by:
– teaching more accurate self-assessment
– making target behaviors more public
– reinforcing accurate assessment
Escape
• in escape conditioning, a behavior eliminates an
aversive stimulus
• escape can maintain both adaptive and
maladaptive behaviors
• extinction can eliminate maladaptive escape
responses
• negatively reinforcing behaviors that are
incompatible with the maladaptive response can
eliminate an escape response
Avoidance
• in avoidance conditioning we engage in a
behavior that will keep an aversive stimulus from
being presented
• contact with the aversive stimulus does not occur
when successfully avoided
• avoidance learning may involve both respondent
and operant conditioning
Avoidance (continued)
• avoidance can become very strong and persistent
• persistence may be the result of cognitive factors
Factors Affecting Negative
Reinforcement Effectiveness
• negative reinforcement is stronger when the
reward value is high
• much of our behavior is controlled through
negative reinforcement
• few behavioral treatments apply negative
reinforcement
Factors Affecting Negative
Reinforcement Effectiveness
(continued)
• use of physically aversive consequences serve as
bad models and can lead to aggressive behavior
Tips on Using Reinforcement
• select consequences with strong reward value and
apply consistently
• avoid reinforcers that work against the desired
outcome
• make clear the contingency between behavior and
reinforcer
• vary reinforcers
• maintain high reward value
• use naturally occurring reinforcers whenever
possible
Tips on Using Reinforcement
(continued)
• Consequences should effect immediately, but use
reinforcers that are minimally disruptive of the
learned behavior
• thin the schedule of reinforcement once behavior
is established
• eliminate counterproductive, extraneous
reinforcers
Tips on Using Reinforcement
(continued)
• avoid reinforcers that may be difficult to withhold
• periodically view data to verify behavior is
increasing