SEVERAL STUDIES ON SENSORIMOTOR FUNCTIONS IN INFANTS WERE REPORTED. DAY-TO-DAY OBSERVATIONS WERE MADE OF INSTITUTIONALIZED INFANTS IN AN ATTEMPT TO COLLECT BASELINE DATA ON ADAPTIVE ABILITIES IN CHILDREN. THE EVOLUTION OF FUNDAMENTAL SENSORIMOTOR SKILLS WAS TRACED TO PROVIDE CLUES FOR THE STUDY OF ENVIRONMENTAL EFFECTS ON THE DEVELOPMENTAL PROCESS. AFTER HAVING ACQUIRED SUFFICIENT BASELINE DATA, EXPERIMENTAL MODIFICATIONS OF REARING CONDITIONS WERE CONDUCTED TO TEST IDEAS GENERATED IN PART BY THE OBSERVATIONS THEMSELVES AND IN PART FROM GENERAL THEORETICAL VIEWS. SUCH VISUAL-MOTOR BEHAVIORS AS VISUALLY DIRECTED REACHING, VISUAL ACCOMMODATION, AND THE BLINK RESPONSE TO AN APPROACHING VISIBLE TARGET WERE DETERMINED TO CONSTITUTE BASIC TOOLS PREREQUISITE TO EARLY EXPLORATION AND INFORMATION PROCESSING. IN ADDITION, SUCH MODIFICATIONS OF THE REARING CONDITIONS AS INCREASED HANDLING, MOTILITY, AND ENRICHMENT OF VISUAL SURROUNDINGS SHOWED THAT ACQUISITIONS OF VISUAL-MOTOR SKILLS WAS "PLASTIC," OR SUBJECT TO CHANGE AS A RESULT OF THE EVENTS EXPERIENCED. (GD)