The Structure of Adult Friendship Choices

This paper examines bias toward status-similarity in adult friendships in Detroit and a West German city. Principles of meeting and mating, by which strangers are converted to acquaintances and acquaintances to friends, are stated. One of these, the proximity principle, claims that the more similar people are, the more likely they will meet and become friends. This principle is tested in matrices of friendship choice for twelve social characteristics. Two statistical measures of bias are used (odds ratio and marginal ratio) and their properties discussed. Compared to a random-choice model, adult friendships show strong bias toward status similarity for all social characteristics. Bias is strongest for edge categories of ranked statuses and for best friends. The less similar two people are in social characteristics, the less likely they are to be close friends. Demographic characteristics tend to show more bias toward homogeneous choices than other characteristics. These findings are explained and further analyses of adult friendship structure and dynamics are discussed.