1 INTRODUCTION Individuals with developmental disabilities engage in higher rates of challenging behavior compared to their typically developing peers (Antonacci et al., 2008; Crocker, et al., 2006; Poppes et al., 2010). About 40% of individuals with an autism spectrum disorder (ASD) engage in challenging behavior (Kanne & Mazurek, 2011). If challenging behaviors are left untreated, they may continue or even worsen over an individual's lifetime (Horner et al., 2002).