This study explored the effects of type of behavioral treatment and living environment on college students' (N=216) person-perceptions and causal attributions of deviant behaviors of a 17-year-old with mental retardation or normal intelligence. The results suggested that positive behavioral approaches and normalized community settings, at least as described in this study, were deemed more acceptable to the students, who also believed the positive treatments would be more likely to work. Positive behavioral treatments and normalized community settings were associated with greater perceptions of person-competency and future progress. Similar positive evaluations of competencies and expectations for progress were made for clients labeled as having normal intelligence. An analysis of causal attributions suggested that the causes of deviant behaviors of persons in institutional settings were seen as more controllable by the client, while the label of mental retardation was associated with causes perceived as less controllable, more stable, and less the result of others. (The clinical implications for the social validity of behavioral treatments, environmental settings, and handicapping labels, as well as the organization of person-beliefs and the causal-structure of these beliefs, are discussed.) (Author)