Knowledge of behavior change with age can inform our understanding of maturation and contextual influences on functions and precursors of behavior and optimal timing of supports. The author reviewed current information on age-related change in problem behaviors related to etiology of intellectual disability and synthesized behavioral research using select domains of the Aberrant Behavior Checklist (hyperactivity/noncompliance, lethargy/social withdrawal, irritability/agitation, and stereotypic behavior). Syntheses of available data demonstrated an absence of problem behavior for many individuals with Down syndrome and normative behaviors in all domains (except irritability/agitation) for individuals with Prader–Willi syndrome and (except for hyperactivity/noncompliance) for those with fragile X and Angelman syndromes. Significant behavior problems across all domains were evident for individuals with Smith–Magenis syndrome and autism spectrum disorder. The author identified problems with available data and concluded that web-based technologies offer an avenue for collaborative and sustainable longitudinal research. Such technologies may engage individuals and their communities in participatory research and enrich the information available for these groups.