Numerous studies have used functional analyses to prescribe interventions for severe behavior disorders. The majority of these studies have focused on behavior that is clearly maintained by socially mediated reinforcement, such as contingent access to attention, tangibles, or escape from instructional demands. However, a significant proportion of functional analyses do not yield conclusive results. We examined interventions for 3 children with severe disabilities following inconclusive functional analyses. First, preferred stimuli were identified for each child via a stimulus preference assessment. Second, a functional analysis was conducted for 2 of the 3 children. High rates of aberrant behavior were seen even (if not especially) in no-interaction sessions. The 3rd child was observed for several consecutive no-interaction sessions; behavior persisted in this condition. Third, interventions based on environmental enrichment were analyzed in an analogue setting. For all of the children, environmental enrichment decreased aberrant behavior if preferred stimuli were used in the procedure. To obtain further reductions in aberrant behavior, explicit reinforcement of toy play was required for 2 children, and a brief (5-s) time-out was necessary with 1 child. Finally, effects of treatment carried over to the school or home environment following teacher or family training. Results are discussed in the context of basic reinforcement principles and future directions for research.