Percentile reinforcement schedules have been used to systematically alter inter-response times, behavioral variability, breath carbon monoxide levels, duration of social behaviors, and various other properties of behavior. However, none of the previous studies have examined the effectiveness of percentile schedules in relation to the magnitude of muscular contractions. This control over magnitude of muscular responding has important implications relating to the strengthening of muscles and correct movements for patients receiving physical rehabilitation. There would be great utility in percentile schedules that can be implemented in rehabilitation situations by physical therapists and patients themselves to improve treatment outcomes – all of which could be possible without any behavioral training if the procedure is implemented via body sensors and smartphone applications. Using healthy adults and the aforementioned technology, this thesis focused on the design and testing of three percentile reinforcement schedule procedures to increase the strength of the vastus medialis muscle. Results indicate that the magnitude of muscular responses can be shaped using body sensors and contingent feedback, and the percentile schedule procedures have promising applications in the domain of physical therapy.

This study examined the use of shaping with a percentile schedule to increase the duration of the interaction following a bid for joint attention in children with autism. Specifically, the therapist initiated a bid for joint attention and reinforced longer successive approximations in seconds of sustained interaction with the therapist and activity. A percentile schedule ranked the most recent 10 observations and reinforcement was provided if the current observation equaled the sixth ranking. Most-to-least prompting was used if the child failed to meet the calculated criterion. Shaping with a percentile schedule of reinforcement was effective at increasing the duration of sustained interaction following a bid for joint attention, for all participants from an average baseline duration of 13 s to an average intervention duration of 215 s.

One of the defining characteristics of Autism Spectrum Disorder (ASD) is repetitive, rigid, or stereotyped patterns of behavior. A proposed approach to treating such patterns is to provide reinforcement for response variability. Though research demonstrates that the variability of responses can be influenced by contingencies of reinforcement, no studies have examined the effects of placing contingencies on different units of behavior. The purpose of this study was to examine effects of two modified percentile schedules on variety of completed drawings and individual lines drawn by students with ASD who had been referred for engaging in rigid patterns of behavior. For all three participants that completed drawing sessions, results indicated that drawing variability increased the most when reinforcement was contingent on the variability of the completed drawing, as opposed to a random ratio schedule of reinforcement or reinforcement being contingent on individual lines being varied.

In an effort to adapt a prize-based attendance and abstinence reinforcement program to the group therapy modality typically found in community substance abuse treatment, this study applied a contingency management (CM) procedure to behavior outcomes of the group as a whole. An algorithmic shaping percentile schedule was used to establish the outcome criteria determining group access to prize bowl drawings. Both the shaping schedule and hypothesized positive social support secondary to interdependent group contingencies aimed to initiate cocaine abstinence among cocaine abusing methadone-maintained participants having initial low rates of cocaine abstinence. In a multiple baseline across behaviors with reversals design, the procedure was applied to four target behaviors in sequence: incentive group attendance, urinalysis appointment attendance, opiate and cocaine abstinence. Results demonstrated clear improvement in group attendance during the shaping schedules. Effects on opiate abstinence were promising but not definitive; an increase in magnitude of reinforcement yielded a better response. There were no effects on cocaine abstinence using the percentile schedules tried. When shaping was conducted by an experienced psychologist in conjunction with an average 4-fold increase in reinforcer magnitude, 55% achieved some abstinence (compared to 18% in baseline). Participants were monitored for safety due to concern about coercion; no instances of physical violence occurred and infrequent instances of verbal negativity were managed using typical outpatient procedures. Results indicate that interdependent group CM is efficacious for attendance, and a feasible and acceptable procedure with appropriate monitoring. Future studies are needed to determine effective and appropriate shaping and reinforcement schedules in group CM to increase drug abstinence. / Educational Psychology