Early Infant Development from a
Biological Point of View
Thomas F. Anders, M.D.
Charles H. Zeanah, M.D.
One might ask why clinicians or psychological theorists and researchers should be interested in biology. What is its relevance to practice? Although these questions may appear contrived, and the answers obvious, it is unfortunately true that most of us are too busy or too singularly focused to think in terms of the methods and objectives of other disciplines. Yet it is just in these intersections that new ideas, knowledge, and progress appear.
Three of the most comprehensive theories of human psychology were developed by men who began as biologists: Pavlov, Freud, and Piaget. They relied on biological principles in the construction of their theories, but used psychological explanations when limitations of investigative biotechnology precluded the empirical testing of their hypotheses. They never abandoned biology, however, as they attempted to link behavior and brain function. An understanding of biologic mechanisms
helps in determining the limits and adaptive significance of behavioral responses.
The division of human behavior into biological and psychological components is of course artificial. The two are inseparably related. Yet the past twenty years have witnessed a plethora of research on the biological determinants of behavior. Infant studies have led the way. The approaches have been diverse: from basic neurochemical and neurophysiologic processes that underlie cellular function to the biologic substrates of specific psychological phenomena, such as attachment, dreaming, learning, and play. And the gains have been great: from advances in biological psychiatry to a greatly expanded understanding of the developmental process. The fields of ethology, neurobiology, neurophysiology, neurochemistry, and chronobiology have participated in this exciting effort. Two recent books, The Roots of Human Behavior (Hofer, 1981) and Biological Psychology (Groves and Schlesinger, 1982), comprehensively review the contributions of biology to an understanding of human behavior.
In this paper we provide an overview, derived in part from these two books, and attempt to integrate some of the work as it pertains to infancy. We focus on four areas: (1) the structural development of the brain; (2) the emergence of prenatal and early infant behav____________________