Project Summary/Abstract Over 2 million people in the United States who have intellectual and developmental disabilities (IDD) engage in some form of problem behavior such as self-injury and aggression. Problem behavior is a major cause of suffering for these individuals and their caregivers, and adversely impacts society as a whole. Problem behavior increases caregivers' burden and strains healthcare and other service systems, as individuals who engage in problem behavior can require prolonged separation from caregivers and community through residential or hospital treatment. Behavioral treatments can be an effective means to treat problem behavior. One of the most common behavioral treatments is differential reinforcement of alternative behavior, frequently implemented as functional communication training. Most demonstrations of behavioral treatments, including functional communication training, are conducted in highly controlled settings by trained therapists. When these treatments are implemented in community settings (e.g., an individual's home) by caregivers, they will be challenged, which can lead to the recurrence and sustained relapse of problem behavior. Recurrence and relapse can be the first steps in a chain that leads to treatment failure. Fortunately, some tactics have been designed to sustain treatment effectiveness and mitigate two forms of relapse (resurgence and renewal) that result from two of three primary treatment challenges. These tactics function as inoculation (i.e., make problem behavior less likely to return). However, there are no tactics designed to specifically mitigate a third form of relapse: reinstatement This project involves a novel inoculation tactic to mitigate reinstatement and protect against the third common treatment challenge: extinction errors. The tactic in question is based on substantial conceptual and empirical evidence from behavioral economics, as well as our pilot work. The project uses an innovative translational- treatment model to better understand which of the proposed tactics (our novel tactic or the default standard-of- care approach) better inoculates against extinction errors through real-world analogues. The use of a translational-treatment model is consistent with other research examining the role of basic processes in behavioral treatment when collateral effects are unknown, and will also engender a thorough examination of the proposed tactics. In Aim 1, we will establish a proxy response, apply treatment to that proxy response, and examine the effectiveness of progressive ratio training in inoculating against extinction errors and mitigating response- dependent reinstatement. In Aim 2, we will establish a proxy response, apply treatment to that proxy response, and examine the effectiveness of progressive ratio training in inoculating against extinction errors and mitigating response-independent reinstatement. Outcomes of this research could improve the current standard of care for beha...