A recent article by Nicholas Wade of the New York Times focuses on a new hypothesis regarding the evolutionary divergence of humans from the phylogenetic branch resulting in chimps and bonobos. Much of it is based on suspect assumptions, which I’ll tackle at the end. But the research contains a fascinating observation regarding hunter-gatherers that illustrates just how flexible human behavior is.
The research, headed by Kim S. Hill and Robert S. Walker, compared different present-day bands of hunters and gatherers to test, in part, whether they consisted mostly of close relatives. Then they compared their observations to chimpanzees. Among other findings, sometimes male humans leave their home band to marry and sometimes females do, whereas chimps have a clear pattern of females moving to new bands.
And here, for me, is the highlight, which I’ve italicized: “the human pattern of residency is so variable that it counts as a pattern in itself.” That is, the researchers found the lack of a hard-wired ‘human nature’ (unless flexibility can be said to be hard-wired’).
The researchers’ larger project, as described in the article, is a bit suspect. Why? It depends on present-day hunter-gatherer bands being analogous to human ancestors during some distant period of the past. They may be, but this would be hard to know and dangerous to assume. Hunter-gatherers today have just as long a history as any other human alive today, and they and their ancestors have lived with all sorts of influence from non-hunter-gatherers.
Also the Times article suggests that the researchers do not consider the likelihood that chimpanzees have also changed considerably from their ancestors’ ways. It is logically possible that the common ancestor of humans, chimps, and bonobos was more like humans are today – relatively variable – and that chimps’ and bonobos’ less variable patterns solidified relatively recently, after their ancestors split from each other.