Our investigations aim to study some mediators of the child-environment interaction, based on a socio-interactionist approach which conceives the construction of knowledge, of language and of subjectivity as occurring by and through the interactions the individual establishes with other people, in a setting organized and structured by the adults according to their conceptions about child development and education. Some basic points have been raised for the construction of educational proposals for day care centers, which require a revision of the role of the caretaker and of day care professionals.