Social penumbras predict political attitudes.

To explain the political clout of different social groups, traditional accounts typically focus on the group's size, resources, or commonality and intensity of its members' interests. We contend that a group's penumbra-the set of individuals who are personally familiar with people in that group-is another important explanatory factor that merits systematic analysis. To this end, we designed a panel study that allows us to learn about the characteristics of the penumbras of politically relevant groups such as gay people, the unemployed, or recent immigrants. Our study reveals major and systematic differences in the penumbras of various social groups, even ones of similar size. Moreover, we find evidence that entering a group's penumbra is associated with a change in attitude on group-related policy questions. Taken together, our findings suggest that penumbras are pertinent for understanding variation in the political standing of different groups in society.