Proceedings of the Annual Meeting of the Cognitive Science Society

Facebook sends users friend suggestions when they have friends in common with others. However, how do people actually consider mutual friendships when inferring whether two individuals are friends? We examined how people (N=352) rely on numerical factors when judging whether individuals are friends based on their mutual connections. Participants saw two target individuals and their friends within a group, and judged if the targets were friends with each other. Experiment 1 manipulated the number of mutual friends and the number of friends each target had. Experiment 2 manipulated the proportion of these two factors. People were more likely to infer friendships when I) targets had more mutual friends; II) targets had fewer friends each; and III) there was a high proportion of mutual friends, which are all factors that impact the likelihood of targets’ friendship. In sum, people consider relevant numerical information about mutual friends when making friendship judgments.