Advancing and Integrating the Cusp Concept to Understand Behavioral Repertoire Dynamics.

The behavioral repertoire grows and develops through a lifetime in a manner intricately dependent on bidirectional connections between its current form and the shaping environment. Behavior analysis has discovered many of the key relationships that occur between repertoire elements that govern this constant metamorphosis, including the behavioral cusp: an event that triggers contact with new behavioral contingencies. The current literature already suggests possible integration of the behavioral cusp and related concepts into a wider understanding of behavioural development and cumulative learning. Here we share an attempted step in that progression: an approach to an in-depth characterization of the features and connections underlying cusp variety. We sketch this approach on the basis of differential involvement of contingency terms; the relevance to the cusp of environmental context, accompanying repertoire, or response properties; the connections of particular cusps to other behavioral principles, processes, or concepts; the involvement of co-evolving social repertoires undergoing mutual influence; and the ability of cusps to direct the repertoire either toward desired contingencies or away from a growth-stifling repertoire. We discuss the implications of the schema for expanded applied considerations, the programming of unique cusps, and the need for incorporating cultural context into the cusp. We hope that this schema could be a starting point, subject to empirical refinement, leading to an expanded understanding of repertoire interconnectivity and ontogenetic evolution.

Threats to Internal Validity in Multiple-Baseline Design Variations.

Multiple baseline designs-both concurrent and nonconcurrent-are the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. In the past, there was significant controversy regarding the relative rigor of concurrent and nonconcurrent multiple baseline designs. The consensus in recent textbooks and methodological papers is that nonconcurrent designs are less rigorous than concurrent designs because of their presumed limited ability to address the threat of coincidental events (i.e., history). This skepticism of nonconcurrent designs stems from an emphasis on the importance of across-tier comparisons and relatively low importance placed on replicated within-tier comparisons for addressing threats to internal validity and establishing experimental control. In this article, we argue that the primary reliance on across-tier comparisons and the resulting deprecation of nonconcurrent designs are not well-justified. In this article, we first define multiple baseline designs, describe common threats to internal validity, and delineate the two bases for controlling these threats. Second, we briefly summarize historical methodological writing and current textbook treatment of these designs. Third, we explore how concurrent and nonconcurrent multiple baselines address each of the main threats to internal validity. Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs.

Revisiting an Analysis of Threats to Internal Validity in Multiple Baseline Designs.

In our previous article on threats to internal validity of multiple baseline design variations (Slocum et al., 2022), we argued that nonconcurrent multiple baseline designs (NCMB) are capable of rigorously demonstrating experimental control and should be considered equivalent to concurrent multiple baselines (CMB) in terms of internal validity. We were fortunate to receive five excellent commentaries on our article from experts in single-subject research design-four of whom endorsed the conclusion that NCMBs should be considered strong experimental designs capable of demonstrating experimental control. In the current article, we address the most salient points made in the five commentaries by further elaborating and clarifying the logic described in our original article. We address arguments related to classic threats including maturation, testing and session experience, and coincidental events (history). We rebut the notion that although NCMBs are strong, CMBs provide an increment of additional control and discuss the application of probability-based analysis of the likelihood of threats to internal validity. We conclude by emphasizing our agreement with many of the commentaries that selection of single-case experimental designs should be based on the myriad subtleties of research priorities and contextual factors rather than on a decontextualized hierarchy of designs.

Improving On-Task Behavior in Middle School Students With Disabilities Using Activity Schedules.

Middle school students receiving special education services for specific learning disabilities and other health impairments often struggle to remain on task and meet independent work demands. Although a variety of strategies have been documented as effective in improving on-task behavior in students with disabilities, most are not contextually appropriate for public schools. Activity schedules may provide an efficient, minimally intrusive, and low-effort intervention for middle school classrooms. In this study, a concurrent multiple-baseline design across participants with an embedded reversal was used to examine the effects of activity schedules on the on-task and on-schedule behavior of four middle school students with disabilities in a resource classroom. Results demonstrate increased on-task and on-schedule behavior for all participants in math and language arts settings, and students and teachers indicated both that they enjoyed the activity schedule and that it improved on-task behavior and work completion. Implications for practice and future research are discussed.

Minimizing Restraint and Seclusion in Schools: A Response to Beaudoin and Moore.

Increasing efforts have been made in the field of special education to identify positive, evidence-based practices (EBPs) to meet the needs of students who engage in problem behavior, with a major goal being to eliminate or limit the use of reactive measures such as restraint and seclusion ( Snell & Walker, 2014 ). Various stakeholders, including families and self-advocates, have voiced concerns about the dangers of restraint and seclusion and the lack of protection afforded to students who engage in severe problem behavior. In the previous article in this issue of Intellectual and Developmental Disabilities, Beaudoin and Moore (2018) echo these concerns in their account of a family's experience with restraint as told from the perspective of a father whose son was subjected to restraint, resulting in a number of adverse short- and long-term consequences that affected the entire family. In response to Beaudoin and Moore, we provide readers with a brief review of the current status of restraint and seclusion in school settings and evidence-based strategies that can be used to address severe problem behavior and reduce the need for restraint and seclusion. For readers interested in exploring restraint and seclusion in greater depth, we suggest recent work by Trader and colleagues (2017) . We also have outlined guidelines for behavior support planning that should be considered by various stakeholders as educators work toward establishing safe and supportive school environments that address a wide range of student behavioral needs.