The severe destructive behavior (e.g., self-injury, aggression) of children with intellectual developmental disorder is prevalent, often dangerous, and negatively impacts social integration and quality of life (Borthwick-Duffy, 1994; Crocker et al., 2006). Function-based interventions that rely on differential reinforcement of alternative behavior reduce such problematic behavior effectively (Greer et al., 2016; Hagopian et al., 1998; Rooker et al., 2013), but the clinical utility of this approach is hampered in two critically important ways. First, schedules of reinforcement maintaining alternative behavior must be thinned to levels that are practical for caregivers to implement consistently in the home and in the community (Greer et al., 2016; Hagopian et al., 2011). This necessary process of schedule thinning often requires substantial time and resources to complete and typically comprises the most expensive portion of routine, clinical service delivery for this referral concern. Second, and exacerbating the first, is the consistent finding that schedule thinning often produces a form of treatment relapse called resurgence (Briggs et al., 2018; Mitteer et al., 2022; Muething et al., 2020; Shahan et al., 2020). The experimenters propose two clinically indicated, and theoretically grounded, methods of accelerating the process of schedule thinning while mitigating the resurgence of severe destructive behavior.
Recent research from the investigators has shown that the quantitative theory of resurgence called Resurgence as Choice (RaC) (Greer \& Shahan, 2019; Shahan et al., 2019; Shahan \& Craig, 2017) accurately describes how decrements in the availability of reinforcement predict the amount of resurgence of destructive behavior during the process of schedule thinning (Shahan \& Craig, 2017), a finding recently verified in a nonhuman animal study (Shahan et al., 2020). Importantly, clinical and laboratory research alike has shown, as RaC predicts, that simply thinning reinforcement in small, gradual steps, the approach most commonly used by clinicians, does not prevent resurgence-relapse inevitably occurs once the schedule reaches a break point (Briggs et al., 2018; Shahan et al., 2020; Shahan \& Craig, 2017; Shahan \& Greer, 2021). RaC theory states that motivation for the functional reinforcer maintaining destructive behavior (parameter a in RaC equations) plays an important role in determining whether and to what extent destructive behavior will resurge during schedule thinning (Greer et al., 2019; Shahan et al., 2019; Shahan \& Craig, 2017), a prediction well-supported by recent pilot work from the investigators on (a) individualizing the starting point for schedule thinning using a progressive interval assessment (PIA) (Miller et al., 2021) and (b) providing competing stimuli to hasten schedule thinning (Fuhrman et al, 2018; Miller et al., 2021). According to RaC theory, these two clinically indicated manipulations facilitate schedule thinning by respectively (a) tailoring the initial schedule of reinforcement to each patient's unique level of motivation for the functional reinforcer and (b) dampening motivation for the functional reinforcer by delivering an alternative and competing source of reinforcement. Additionally, theoretical and empirical work in the area of behavioral economics provides independent support for these two manipulations. This project will further the clinical and theoretical understanding of how motivational variables affect resurgence as it occurs in practice, and the project has the potential to substantially improve standards of care guiding the treatment of severe destructive behavior.
The experimenters will conduct a study to identify whether quantitatively informed refinements can improve efficiency and efficacy of reinforcement schedule thinning when treating severe destructive behavior. The project has three specific aims:
Specific Aim 1: The experimenters will extend pilot work on the utility of individualizing the starting point for reinforcement schedule thinning based on the results of a PIA. The experimenters will accomplish this by conducting reinforcement schedule thinning in two distinct stimulus contexts, one informed by the results of a PIA and another not so informed.
Specific Aim 2: Basing the starting point on a PIA, the experimenters will assess the extent to which providing competing stimuli from a competing stimulus assessment quickens the process of schedule thinning when competing stimuli are available in one, but not another, unique stimulus context.
Specific Aim 3: The experimenters will examine the potential interaction effects between these two approaches by conducting PIAs with no, low, moderate, and high competing stimuli to determine the schedule duration at which schedule thinning should commence with each competing stimulus.
