The effects of differential and lag reinforcement schedules on varied verbal responding by individuals with autism

Increasing response diversity in children with autism

Repetitive and invariant behavior is a diagnostic feature of autism. We implemented a lag reinforcement schedule to increase response diversity for 6 participants with autism aged 6 to 10 years, 4 of whom also received prompting plus additional training. These procedures appeared to increase the variety of building-block structures, demonstrating that an intervention that includes differential reinforcement can increase response diversity for children with an autism spectrum disorder.

Measuring and reducing college students' procrastination

We examined college students' procrastination when studying for weekly in-class quizzes. Two schedules of online practice quiz delivery were compared using a multiple baseline design. When online study material was made available noncontingently, students usually procrastinated. When access to additional study material was contingent on completing previous study material, studying was more evenly distributed. Overall, the mean gain in percentage correct scores on weekly in-class quizzes relative to pretests was greater during contingent access than during noncontingent access conditions.

Social skills interventions for individuals with autism: evaluation for evidence-based practices within a best evidence synthesis framework

This paper presents a best evidence synthesis of interventions to increase social behavior for individuals with autism. Sixty-six studies published in peer-reviewed journals between 2001 and July 2008 with 513 participants were included. The results are presented by the age of the individual receiving intervention and by delivery agent of intervention. The findings suggest there is much empirical evidence supporting many different treatments for the social deficits of individuals with autism. Using the criteria of evidence-based practice proposed by Reichow et al. (Journal of Autism and Developmental Disorders, 38:1311-1318, 2008), social skills groups and video modeling have accumulated the evidence necessary for the classifications of established EBP and promising EBP, respectively. Recommendations for practice and areas of future research are provided.

A review of empirical support for differential reinforcement of alternative behavior

Differential reinforcement of alternative behavior (DRA) is one of the most common behavior analytic interventions used to decrease unwanted behavior. We reviewed the DRA literature from the past 30 years to identify the aspects that are thoroughly researched and those that would benefit from further emphasis. We found and coded 116 empirical studies that used DRA, later grouping them into categories that met APA Division 12 Task Force criteria. We found that DRA has been successful at reducing behaviors on a continuum from relatively minor problems like prelinguistic communication to life-threatening failure to thrive. DRA with and without extinction is well established for treating destructive behavior of those with developmental disabilities, and to combat food refusal.

Increasing vocal variability in children with autism using a lag schedule of reinforcement

Variability has been demonstrated to be an operant dimension of behavior (Neuringer, 2002; Page & Neuringer, 1985). Recently, lag schedules have been used to demonstrate operant variability of verbal behavior in persons with a diagnosis of autism (e.g., Lee, McComas, & Jawor, 2002). The current study evaluated the effects of a Lag 1 schedule on the vocal variability of 2 nonverbal children with a diagnosis of autism. Results showed systematic increases in variability during the Lag 1 schedule. Implications of lag schedules for speech and language training are discussed.

Median-based overlap analysis for single case data: a second study

This article takes a further look at the percentage of data points exceeding the median (PEM) analysis method for single-case research data, first presented in this journal by Hsen-Hsing Ma. Ma examined the relationship between PEM and the established percentage of nonoverlapping data (PND) and then applied PEM in a meta-analysis of 61 data sets, correlating their authors' judgments of intervention effectiveness with PEM. The present article covers PEM's historical and statistical context and then applies the new measure in a field test with 165 contrasts between a baseline phase A and a treatment phase B. For comparison, Pearson r , Kruskal-Wallis W, PND, and IRD (improvement rate difference) indices also are calculated and correlated with PEM, and all distributions are examined. Expert visual analysis ratings of the 165 graphs are correlated with all indices. PEM surpassed PND in its validation by other established measures. However, PEM was weaker in distribution shape and visual judgment validation. More strongly validated than either PEM or PND was the new nonparametric measure, IRD.

The effects of lag schedules and preferred materials on variable responding in students with autism

Effects of a Lag 1 reinforcement schedule on appropriate and varied responding to the social question, "What do you like to do?" and effects of the proportion of preferred stimuli present during training on the amount of varied responding in each session were investigated with students with autism. An ABAB reversal design and a multielement design were used to evaluate the effects of the Lag schedule and proportion of preferred stimuli, respectively. Results showed that a Lag 1 schedule was effective at increasing varied vocal responding for 2 of 3 participants. The proportion of stimuli that were preferred did not affect the amount of varied responding emitted.

Reinforced variability in animals and people: implications for adaptive action

Although reinforcement often leads to repetitive, even stereotyped responding, that is not a necessary outcome. When it depends on variations, reinforcement results in responding that is diverse, novel, indeed unpredictable, with distributions sometimes approaching those of a random process. This article reviews evidence for the powerful and precise control by reinforcement over behavioral variability, evidence obtained from human and animal-model studies, and implications of such control. For example, reinforcement of variability facilitates learning of complex new responses, aids problem solving, and may contribute to creativity. Depression and autism are characterized by abnormally repetitive behaviors, but individuals afflicted with such psychopathologies can learn to vary their behaviors when reinforced for so doing. And reinforced variability may help to solve a basic puzzle concerning the nature of voluntary action.

Promoting response variability and stimulus generalization in martial arts training

The effects of reinforcement and extinction on response variability and stimulus generalization in the punching and kicking techniques of 2 martial arts students were evaluated across drill and sparring conditions. During both conditions, the students were asked to demonstrate different techniques in response to an instructor's punching attack. During baseline, the students received no feedback on their responses in either condition. During the intervention phase, the students received differential reinforcement in the form of instructor feedback for each different punching or kicking technique they performed during a session of the drill condition, but no reinforcement was provided for techniques in the sparring condition. Results showed that both students increased the number of different techniques they performed when reinforcement and extinction procedures were conducted during the drill condition, and that this increase in response variability generalized to the sparring condition.

Levels of Bcl-2 and P53 are altered in superior frontal and cerebellar cortices of autistic subjects

1. Autistic disease (AD) is a severe neuropsychiatric disorder affecting 2-4 children per 10,000. We have recently shown reduction of Bcl-2 and increase in P53, two important markers of apoptosis, in parietal cortex of autistic subjects. 2. We hypothesized that brain levels of Bcl-2 and P53 would also be altered in superior frontal cortex and cerebellum of age-, sex, and postmortem-interval (PMI)-matched autistic subjects (N = 5 autistic, N = 4 controls). 3. Brain extracts were prepared from superior frontal cortex and cerebellum and subjected to Western blotting. 4. Results showed that levels of Bcl-2 decreased by 38% and 36% in autistic superior frontal and cerebellar cortices, respectively when compared to control tissues. By the same token, levels of P53 increased by 67.5% and 38% in the same brain areas in autistic subjects vs. controls respectively. Calculations of ratios of Bcl-2/P53 values also decreased by 75% and 43% in autistic frontal and cerebellar cortices vs. controls respectively. The autistic cerebellar values were significantly reduced (p < 0.08) vs. control only. There were no significant differences in levels of beta-actin between the two groups. Additionally, there were no correlations between Bcl-2, P53, and beta-actin concentrations vs. age or PMI in either group. 5. These results confirm and extend previous data that levels of Bcl-2 and P53 are altered in three important brain tissues, i.e. frontal, parietal, and cerebellar cortices of autistic subjects, alluding to deranged apoptotic mechanisms in autism.