Transcript Differential Reinforcement: Antecedent Control and Shaping

Differential Reinforcement:
Antecedent Control and Shaping
Lecture Notes for SPEC 3020
November 17, 2009
Stimulus Control
• Bringing responses the learner already
knows under the control of the appropriate
cue or signal
Shaping
• Molding an existing response into the
desired behavior
Setting Events
• Conditions and events that exist or occur
at times or settings outside the
environment being observed
Discriminative Stimuli
• Discrimination develops as a result of differential
reinforcement. A certain response results in
positive reinforcement (SR+) in the presence of
a given stimulus or group of stimuli that are said
to be discriminative stimuli (SDs) for the
response. The same response is not reinforced
in the presence of a second stimulus or group of
stimuli, referred to as S-deltas. After a period of
time, the response will occur reliably in the
presence of the SD and infrequently, if at all, in
the presence of the S-delta. The SD is then said
to occasion the response.
Simple Discrimination
• A response is reinforced only in the
presence of the occasioning stimulus.
Concept
• A class of stimuli that have characteristics
in common; all members of the class
occasion the same response.
• In order to learn a concept, a student must
discriminate based on specific
characteristics common to a large number
of stimuli, thus forming an abstraction.
Prompts
• An additional stimulus that increases the
probability that the SD will occasion the desired
response.
• Offered after an SD has been presented and
failed to occasion the reponse.
• Verbal, visual, modeling, physical guidance,
• Effective Prompting
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Focus attention on the SD
Be as weak as possible
Fade as rapidly as possible
Avoid unplanned prompts
Verbal Prompts
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Rules
Instructions
Hints
Self-operated
Visual Prompts
Modeling
• Characteristics that increase models’
effectiveness
– Similar to themselves
– Competent
– Have prestige
Physical Guidance
Fading
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Gradual removal of prompts
Errorless learning
Graduated Guidance
Time Delay (Good and Brophy)
Increasing Assistance
Teaching Complex Behaviors
• Task Analysis—Breaking complex
behavior into its component parts
• Chaining—Forming components of a task
analysis
– Backward chaining
– Forward chaining
– Total Task Presentation
Shaping
• Differential reinforcement of successive
approximation to a specific target behavior
– Terminal behavior
– Initial behavior
– Intermediate behaviors