Identifying & Enhancing the Effectiveness of Positive Reinforcement

Transcription

1 Identifying & Enhancing the Effectiveness of Positive Reinforcement PIAZZA ET AL (2011) FISHER ET AL CH 9 What is a positive reinforcer? u It is based on the of the stimulus u E.G., I use M&Ms as a reinforcer for potty training u It is based on an 1

2 Stimulus Preference Tests u Pace et al.(1985) introduced a procedure to test stimulus preference in persons with ID, and then demonstrated the reinforcing properties of preferred vs non preferred items. u Since then several methods of assessing preference have been demonstrated Single Stimulus Assessment u Pace et al.(1985) u 16,each one presented alone u approach ( reaching, touching) results in 5 sec with the stimulus ( ie, they could eat or play with the item) u No approach within 5 sec, -> prompt again u Still no approach à remove and continue u Item chosen 80% of opportunities =preferred u Items h< 50% of opportunities = non-preferred u Preferred item functioned as reinforcers for an arm raise u Non-preferred item did NOT function as reinforcers 2

3 Single Stimulus Assessment Limitations 1. There is no ranking if many or all items are approached. 2. Some preferred item do not function as reinforcers Paired Choice Preference Assessment u Fisher et al (1992)- replication of Pace(1985) u Present and see which is chosen. u Block attempts to choose both u Same procedure as Pace et al. (1985) u Identified a rank ordering of all the stimuli u Compared to single item procedure and only stimuli high on both functioned a SR+ 3

4 Paired Choice Preference Assessment u 2 Limitations of the choice method u It can take a longer time to do and may not reflect the constantly changing preference for items u Choice assessments my prompt aberrant behavior, especially in persons with aberrant behavior maintained by tangible items Multiple Stimulus Assessment u Windsor et al. (1994): 1. which one do you want < 20sec get item 2. > 20 sec. no response next trial 3. Resulted in a ranking of items but no SR+ test was done 4

5 Multiple stimulus Without Replacement test (MSWO) u Deleon & Iwata (1996) extended Windsor et al by presenting sets of 7 stimuli and presentations u Resulted in a finer ranking of less preferred items u Preferred items all were demonstrated to be reinforcers Multiple stimulus Without Replacement test (MSWO) u Comparison of (MSWO) to MSW and Paired u Rank order- all identified highly preferred items\ u For lesser preferred all 3 tests highly correlated u MSW fastest(16.5 m); MSWO (21.8) Paired(53.3) u Fewer items selected in the MSW u MSWO produced a refined ranking 5

6 Free- Operant assessment & others u Roane et al (1998) u u Compared to paired stimulus u Free operant quicker and had less aberrant behavior u Activity restriction- free operant more differentiated patterns than simple free operant u Duration: I item at a time, measure contact durationless stable rankings than paired Other popular methods u Vocal Report: only effective with language able persons and u Care-giver Nomination: Basically a history of inaccuracies u RAISD some improvement as it controls caregiver descriptions u Pictorial: Can work with some non-language persons (ABLA-Williams) 6

7 Other popular methods/issues u. Preference for different treatments Children can choose between 2 nd links by selecting and initial link u Group Arrangements, It is possible to gain fairly good measures of preference for different activities of many kids using MTS observations of actual participation u The effectiveness of reinforcers does with preference assessments Methods for Evaluating Reinforcement Effects u Simple vs Complex responses u : the objective is not to teach a significant skill u Single vs Concurrent operants u are useful for measuring reinforcing value u show reinforcing value u Progressive Ratio Schedules (PR) u The response requirements for a given SR+ are (e.g., fr5, then FR10, then FR15) to test how much a given SR+ will maintain behavior 7

8 Issues Related to Specific Stimuli u Choice as SR+ u Must per se as opposed to preferred items as SR+ u Using the same SR+ stimuli, choice has been shown to be more reinforcing u However when choice is for low preference stimuli and high Pref are given by the experimenter, kids have chosen the experimentor delivered stimuli u Edible Stimuli u in lower functioning Persons so they should be assessed separately Factors Influencing Effectiveness of SR+ u : Reinforcement is more effective at higher rates, with less Delay and with higher quality u : Varying Sr+ types will enhance Sr+ value ( from low to medium preference) u Changes over time: Studies have shown both. It appears that change is the result of changing u Vs : Idiosyncratic 8