The social meaning of common knowledge across development

Common knowledge can be a potent sign of shared social attributes among people, but not all knowledge is socially meaningful to the same extent. For instance, compared to shared knowledge of cultural practices, knowledge of self-evident facts might be a poorer indicator of shared group membership among individuals. Two studies explored adults' and 6-to-9 years old children's social inferences based on what others know as well as their sensitivity to the distinctions in the diagnostic potential of different kinds of knowledge. Participants were presented with targets who were knowledgeable about familiar things that are either culture-specific (e.g., a traditional dance) or general (e.g., a self-evident fact), and asked to make inferences about their language and where they live. Adults and 8-year-olds privileged culture-specific knowledge over general knowledge when making both kinds of inferences about the targets, whereas 6-year-olds did not distinguish between the two knowledge types. Thus, what others know is socially meaningful from early in life, and across development, children become increasingly aware of the diagnostic potential of culture-specific knowledge when making social inferences about others. These findings suggest novel social implications of knowledge assessment.