It is a delicate problem of psychology: what kind of benefit naïve sociology - an early emergent and widely used knowledge base for social categorization- could represent for humans? The debate is whether naïve sociology arises as a result of cumulative perceptual differentiation of group information, or it reflects a systematic semantic information selection. The aim of the proposal is to explore how young children reason about social categories (naïve sociology). Recent research suggest that infants are sensitive to the borders of culturally shared knowledge, indicated by language (Kinzler et al, 2007), or the conventionality of tool-use (Oláh et al, 2013, Zmyj et al, 2010). Based on these, we propose that the seemingly more complex function of naïve sociology, namely the systematic information selection for categorization of social partners has important epistemic advantages for humans: the identification of reliable sources of information for the sake of fast cultural knowledge acquisition.