Environmental effects on motor development: the case of "African infant precocity".

In order to clarify the extent and cause of African infants' precocity in motor development, as reported by Geber and others, 64 babies and their families were intensively studied in a rural Kenyan community. It was found that the motor skills of sitting and walking, which the Kenyan babies acquired early (by American standards), are (a) specifically taught by the caretakers and (b) can be practised in the course of their usual daily routines. They are not advanced in skills which are not taught or practised. Middle-class urban Kenyan children from the same ethnic background were found generally to be intermediate in both environmental encouragement and rate of advancement. Preliminary results from other groups in Kenya suggest that encouragement of motor development is widespread and that for behaviors which are differentially encouraged among groups, the average age of attainment is predictable from environmental measures.