Dan O’Brien’s research and teaching is focused on the psychology and sociology of urban neighbourhoods. Dr. O’Brien has used this multidisciplinary approach to further research on “broken windows,” or the presence of disorder and deterioration in a neighbourhood, in a number of directions. He has published papers on: how people perceive and interpret neighbourhood disorder; the patterns of behavior that create or eliminate disorder within a neighborhood; and disorder’s relationship with other neighbourhood outcomes, like adolescent behavior. He has also done work on how individuals differ in their levels of prosociality (e.g., cooperation, sharing) across neighbourhoods. Many of these projects have been done in collaboration with interested city agencies and community groups.