Will Baby Crawl? (page 2)

Maybe yes, maybe no, says anthropologist David Tracer, whose study of children in Papua New Guinea supports the view that milestones of child development vary with culture.

In much of the developed world, popular wisdom holds that crawling is universal. All infants go through a crawling stage to gain the strength and coordination they need to take their first steps, right?

Not necessarily, say a number of researchers including David Tracer, an associate professor of anthropology and health and behavioral sciences at the University of Colorado at Denver. Since 1988, Tracer has been conducting field research among the Au people of Papua New Guinea--a nation of 1,400 islands and 4 million people north of Australia. That's where he observed that Au children do not crawl, but learn to walk anyway.

Infant crawling rarely happens in indigenous cultures, says Tracer, a biocultural anthropologist. He has documented that Au babies are carried by their mothers or siblings 86 percent of the time during the infants' first 12 months. When they are put down, the young children are usually placed in a sitting position, not on their stomachs. Instead of crawling, Au youngsters go through an upright "scooting" phase--pushing themselves along with their hands and scooting on their backsides.

The neuromuscular development of children is strongly conditioned by the cultural context in which they grow up and by the way the children are handled as infants, says Tracer. Au parents discourage crawling for good reason: In doing so they reduce the risk of their babies contracting parasites and diarrheal disease. Nutritional deficiencies also impact the development of Au children, who usually start walking a few months later than youngsters in the United States and Europe.

David Tracer didn't set out to study crawling. He was in New Guinea to explore the relationships between Au mothers and children, and to research child health issues such as nutrition, growth, and development -- with the help of a grant from NSF's Directorate of Social, Behavioral, and Economic Sciences (Division of Behavioral and Cognitive Sciences). But his early observation that Au children don't crawl led him into deeper explorations of culture, biology, and child development.