Shared behaviors are woven throughout human social life. In the course of interaction, social partners mimic one another and align their actions to help or cooperate with one another. Over longer timescales, group members share social and communicative conventions and learn cultural skills from one another. What is the developmental pathway through which infants come to understand and engage in these types of shared behaviors? Are they independent of one another, or are there links in the cognitive or developmental processes through which they arise? I will present looking time studies demonstrating that infants' expectations and evaluations of multiple types of shared behavior (i.e. social imitation and group conventions) are integrated with their developing understanding of social groups and affiliation. I will also describe the development of a novel neuroimaging approach for disambiguating the roles of social value (e.g. social engagement and friendliness) and information value (e.g. novel and learnable patterns or behaviors) in guiding infants' social attention in different contexts, and then apply this approach to show that infants perceive social value in individuals who align themselves with others.