Philip R. Zelazo
To propose that the stimulation of infant reflexes may illuminate development from reflexive to instrumental behavior is not to urge large-scale engineering of humans, sheep, or crops, as Freedman suggests. It is unnecessary to invoke the wisdom of the Navajo to prevent an all-out restructuring of man by curious and carefree academics. In fact, to suggest that maturation occurs without stimulation in nature is not only inaccurate but potentially hazardous advice, as the work of Dennis ( 1960) implies. The same wise Navajo who would advise us to leave nature alone would also assert that we existed in unity with nature, implying, among other things, that nature would provide the stimulation that allowed maturation to occur. We do not develop in a vacuum; we have air to breathe, water to drink, food to eat, land to walk on. There is no dispute that man is designed for this environment and that stimulation is inherent in existence (Scarr-Salapatek, this volume). The stimulation that we have used in our research is within the normal range of conditions encountered by man.
The Kipsigis and Desert San believe that some infant responses must be exercised, as Super ( 1976) and Konner ( 1973) have carefully documented with words, numbers, and photographs. Super has shown that the Kipsigis infants display relative precocity of precisely those responses that are stimulated--most notably sitting, standing, and walking. Relative precocity of individual responses does not occur simply by carrying these children around in a sling. Although genetic differences exist among infants, as Freedman demonstrates, it is not clear that African infant precocity is the result of differences in gene pools. Warren ( 1972) reviewed the existing research and found that most of the purported demonstrations of precocity had serious methodological shortcomings. He concluded that "African infant precocity cannot be taken as an acceptably established