Developmental Psychobiology: The Significance of Infancy

Easton ( 1972). A study of reflexive behavior in infants may provide evidence to document or clarify the assumption of cephalocaudal development--a belief that has thoroughly influenced our view of early motor development including our tests of infant development. An equally important issue concerns the explication of the process by which cortical inhibition of reflexes occurs. We may ask empirically what the relation is between motor and mental development in infancy--a question of direct consequence for the assessment of infant development.

Answers to these central questions can be produced from renewed research interest in reflexive behavior. Moreover, their resolution will also provide data for the larger question concerning genetic differences. Thus, although few psychologists would deny that the human infant comes into the world with a complex set of reflexive units in virtually every area of his psysiological constitution, few have studied the relevance of these units for the infant's behavioral development. Early behavioristic psychologists may have inadvertently deflected us from this course by emphasizing the classical association of neutral stimuli to reflexive responses. When it became clear that classical conditioning had to be stretched too far to account for much of our complex behavior, we lost interest in the reflexive unit. The suggestion that some behaviors may evolve from reflexive to instrumental actions may serve as a limited corrective. Those behaviors that are crucial to man's basic survival may be highly canalized and one mechanism for expression (and relatively easy study) may be the reflexive pattern--both motor and cognitive.

The approaches to the study of genetic and environmental determinants of infant development can and perhaps should take many directions. Questions about genetic determination are fundamental to questions of genetic differences and should perhaps share a greater portion of the current research effort.

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Bayley, N. "Psychological development of the child, Part III: Mental measurement". In F. Falkner (Ed.), Human development. Philadelphia: Saunders, 1966. Pp. 397-407.

Cameron, J., Livson, N., & Bayley, N. "Infant vocalizations and their relationship to mature intelligence". Science, 1967, 157, 331-333.

Easton, T. A. "On the normal use of reflexes". American Scientist, 1972, 60, 591-599.

Erlenmeyer-Kimling, L., & Stern, S. E. "Technical comment: Heritability of IQ by social class: Evidence inconclusive". Science, 1973, 182, 1044-1045.

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