This dissertation examines the thesis that it is the human language system which largely makes possible the human capacity for modifiability of responses called "intelligent" and "adaptive" modes of interaction with the environment. Chapter titles are (1) A Process View of Human Behavior, (2) Aspects of the Multi-Dimensional Nature of Cognitive Processes in the Very Young Child, (3) Linguistic Theory as a Model of Language Perception and Learning, (4) The Structure of Linguistically Initiated Behavioral Acts, (5) The Relationship of the Comprehension of Sentences to Their Complexity, (6) An Experimental Study of Linguistic and Other Psychological Factors in the R-EGULATION OF Behavior in Very Young Children, and (7) Discussion of Results. The author concludes that perceptual or attentional processes which involve expressions of orienting activity should be studied in regard to ontogenetic development and its relationship to the verbal system of preschool children. (MS)