ARNOLD GESELL On His Eightieth Birthday.

The article profiles child psychologist Arnold Gesell, one of the pioneers of child development studies. After an extended period of preparation and training at Wisconsin in education, with G. Stanley Hall at Clark in psychology, and finally in medicine at Yale, interspersed with practical experience in these fields, Gesell adopted the infant and preschool periods as his specific area of concentration. He then began the long and tedious task of categorization and quantification of behavior patterns, establishing the norms and the methods upon which countless investigators and clinicians have based their work in the last three or four decades. Over the years he gradually developed a very broad conceptual model of development, embracing and integrating levels from the anatomical through the physiological and psychological to the social and cultural. Amongst a number of methodological advances in child development, Gesell contributed cinemanalysis as a means of systematic time-space study of frozen sections of behavioral morphology. Another was the co-twin control method of investigation. Arnold Gesell's contributions to science are as many and as long as his bibliography which consists of hundreds of monographs, papers, and books.