Zoe Liberman: University of California, Santa Barbara

Similarity influences myriad social relationships. From group membership to friendship, to marriage, to mere proximity, people who are similar to one another tend to be closer than people who are dissimilar. Here, I present research indicating that infants understand the importance of homophily in determining social structure: they expect people who are similar to one another to affiliate. I also explore questions about they types of similarity infants use to reason about the social world. I hypothesize that (1) similarities that have marked human social groups across evolutionary history may be attended to earliest , and (2) that different types of similarities will be most relevant for reasoning about different types of relationships (e.g., group members vs. friends vs. family members).