When density matters: Environmental control as a determinant of crowding effects in laboratory and residential settings.

The relationship between density and environmental controllability is clarified with effects previously attributed to density reinterpreted as due to the loss of environmental control. A selected review of the experimental literature is used to demonstrate the central role of environmental control in a wide range of crowding situations. Moreover, an analysis of correlational data relating to residential density to health and social organization suggests that density has deleterious effects <i>only</i> on those (susceptible populations) who lack control over their environments.