A recent paper by Yi Li and his colleague uses data from an experimental study of randomly-assigned roommates to investigate peer influence on aggressive behavior, smoking and sexual behavior. Findings suggest that the traditional wisdom of “one takes on the color of one’s company” is an oversimplification of peer dynamics. They find that the magnitude and direction of peer influence depend on predisposition, gender, and the nature of the behavior. Peer effects on individuals predisposed towards a given behavior tend to be larger than peer effects on individuals without such a predisposition. Peer influence on aggressive behavior is more pronounced among men than among women. Peer effects on smoking are negative among women. For concurrent sexual partnering, a highly private behavior, there is no evidence of peer effects. This paper is published in Journal of Health and Social Behavior.

The full paper is available here.