Presentation on theme: "Shaping Chapter 19 Systematically and differentially reinforcing successive approximations to a terminal behavior It’s a treatment and a natural process."— Presentation transcript:
Systematically and differentially reinforcing successive approximations to a terminal behavior It’s a treatment and a natural process Typically used to teach behavior that is not yet occurring at all Example from Wolf, Risley, and Mees (1964): Wearing glasses 24 Shaping
The process: Reinforcement is provided for responses that have a certain predetermined quality AND Reinforcement is withheld for responses that don’t have that quality (extinction) The effects: Responses similar to those that have been reinforced occur more frequently Responses similar to those that have NOT been reinforced occur less frequently (extinction) Extinction typically leads to new behavior 24 Differential Reinforcement
Begin shaping by reinforcing responses that… Are similar or a prerequisite to the terminal behavior And are already in the learner’s current repertoire When the initially reinforced responses become more frequent… Shift the criterion for reinforcement to responses that are a closer approximation of the terminal behavior 24 Successive Approximations
24 Wolf et al. (1964) Touching glasses Picking up glasses Putting glasses up to face Placing glasses in position Beginning End
Wolf et al. (1964) “Put on your glasses” RESPONSE Step 1: Touch glasses Step 2: Pick up glasses Step 3: Put up to face Step 4: Place in position S R+ No S R+ RESPONSE Step 1: N/A Step 2: Touch glasses Step 3: Pick up glasses Step 4: Put up to face (EXTINCTION)
Advantages of Behavioral Shaping Positive procedure Can be used to teach new behaviors especially those that cannot easily be leaned by physical cues or verbal prompts Can be combined with other behavior change procedures such as chaining
Disadvantages of Behavioral Shaping Time consuming Progress is not always linear The individual does not always proceed from from one behavior to the next in a continuous, uninterrupted flow Clinical judgment is involved how rapidly to increase requirements and how much each requirement should be increased. Often there are subtle changes in the behavior that are difficult to detect by an unskilled clinician Very hard to get IOA on intermediate behaviors
Use a prompt such as Instruction Physical guidance Model Give the person a rule If you do x, you will get y 24 Increasing the Efficiency of Shaping
Estimate how long it will take to reach the terminal behavior Can the person who will do the shaping be trained to do it well in the time available? Would it be more efficient to simply target the terminal step? 24 Before Deciding to Use Shaping
Select the terminal behavior Consider behavior that will continue to be reinforced in the natural environment Define the behavior precisely Determine the criterion for success at each step Analyze the response class Response class: Group of behaviors with the same function Helps you identify the approximations that might be emitted in the shaping sequence Identify the first behavior to reinforce It should already occur sometimes Should be a member of the targeted response class Eliminate distractions Proceed in gradual stages Limit the number of approximations at each level Continue to reinforce when the terminal behavior is achieved 24 Shaping Guidelines
Questions How are shaping and chaining alike? How are they different? How are shaping and prompting alike? When do you use each? What research design would you use when shaping a particular behavior over time?
A sequence of responses in which the result of each response (except for the last) is: a conditioned reinforcer for that response an S D for the next response the reinforcer for the last response maintains the reinforcing effectiveness of the conditioned reinforcers in the chain Behavior Chain
Putting on Pants Pick up pants at waistband facing forward Sit down Put feet through pant leg openings Pull pants over ankles Stand up Pull pants up to waist
Step 1: Pick up pants at waistband facing forward SR+ / SD: Pants are in your hand and facing forward Step 2: Sit down SR+ / SD: You’re sitting down holding pants Step 3: Put feet through leg openings SR+ / SD: Your feet are through the leg openings Step 4: Pull pants over ankles SR+ / SD: Pants are over your ankles Step 5: Stand and pull pants up to waist SR+: Pants are up
Definitions Behavior chain The result of the performance of a sequential series of behaviors Chaining The way in which these behaviors are linked together E.g., ?
Before a chain is taught, each of its behaviors must be identified Task Analysis: the process of breaking a complex skill or series of behaviors into smaller, teachable units Also, the list of the steps Observe, consult an expert, do it yourself! Should be individualized and include mastery criteria for % correct over time and relevant behavioral dimensions (e.g., latency at each step) Task Analysis
Practice Work with someone else and write a task analysis for a skill Actually go through the motions of the skill if you can! After you write the steps, practice to make sure you didn’t skip any! Modify as necessary
Determine which components of the task analysis a person can already perform independently – 2 ways: Single-Opportunity Method No prompting or contrived reinforcement Present the S D and record + or – on your task analysis data sheet Stop the individual as soon as you score a - Do this over several days or sessions Multiple-Opportunity Method Same as single, but you allow the individual to continue if a - occurs Assessing Mastery Level
3 Types of Chaining Forward Chaining Teach the first step of the task analysis Reinforce this response Next, teach the second step Reinforce after the first AND second steps have occurred in succession Each succeeding step requires the cumulative performance of all previous steps in the correct order
Making the Bed: Forward Chain Pull top sheet up as far as it will go. Tug at both sides to smooth out the wrinkles. Pull blanket up and smooth out the wrinkles. Fold blanket and sheet back together. Pull bed spread up and smooth out. Fold bed spread back. Put pillow on. Bring bed spread up over pillow.
3 Types of Chaining Total Task Chaining Variation of forward chaining Learner receives training on every step in the task analysis during every session Teacher prompts when necessary Continue teaching until learner is independent will all steps
Making the Bed: Total Task Pull top sheet up as far as it will go. Tug at both sides to smooth out the wrinkles. Pull blanket up and smooth out the wrinkles. Fold blanket and sheet back together. Pull bed spread up and smooth out. Fold bed spread back. Put pillow on. Bring bed spread up over pillow.
3 Types of Chaining Backward Chaining Teach the last step of the task analysis Reinforce this response Next, teach the second to last step Reinforce after the second to last AND last steps have occurred in succession This sequence proceeds backward through the chain until all the steps in the task analysis have taught in reverse order and practice cumulatively Advantage: learner comes in contact with the terminal reinforcer during every teaching session Examples: pasting with Robby, teaching Bailey to blow a bubble
Making the Bed: Backward Chain Pull top sheet up as far as it will go. Tug at both sides to smooth out the wrinkles. Pull blanket up and smooth out the wrinkles. Fold blanket and sheet back together. Pull bed spread up and smooth out. Fold bed spread back. Put pillow on. Bring bed spread up over pillow.