The problem of psychological mechanisms of formation of an outlook which was raised by N.A. Menchinskaya in the broad context of general psychological laws of the development of knowledge, of cognition as the intellectual component of personality development is discussed. The author presents findings of a comparative study of mental representations of the category of time in relation to the main components of cognitive experience in students of VI-IX classes. The study has confirmed the hypothesis that development of the conception of time is governed by the general principle of systems differentiation.