This book by noted child psychologist Jean Piaget discusses the development of sensorimotor and practical intelligence in the first two years of development. It examines how children, at first directly assimilating the external environment to their own activity, later, in order to extend this assimilation, form an increasing number of schemata which are both more mobile and better able to intercoordinate. The increasing coherence of the schemata thus parallels the formation of a world of objects and spatial relationships. This book examines four sequential phases in the development of schemata: 1) Development of object concept; 2) Spatial field and the elaboration of groups of displacements; 3) The development of causality; and 4) The temporal field. According to Piaget, it is justifiable to study these phases separately, for the description of behavior is not sufficient to account for all products of intellectual activity. It is also the subject's own interpretation of things which are analyzed in this work. The symmetry between the representation of things and the functional development of intelligence is presented as the directional line of the evolution of the concepts of object, space, causality, and time. This organization of reality occurs to the extent that the self is freed from egocentrism by assigning itself a place as a thing among things, an event among events. The transition from "chaos to cosmos", are examined through the lens of perception and representation of the world in the first two years of life. The book explores how the development of schemata can only be explained in connection with the mechanism of intellectual assimilation in the individual.

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