The Collaboration Imperative: How Social Fluidity Powered Human Predominance

The myth of the lone outsider fighting and winning because he believes in himself is a powerful image that still resonates in some sectors of human society. The 'my way or the high way' approach, made popular by actors such as John Wayne, businessmen like Donald Trump and politicians like Jean-Marie Le Pen. Recent research has begun to reveal a different reality. It appears that one of the reasons man's antecedents prevailed over their evolutionary competitors had to do with an ability to work with others not necessarily related to them.

Michael Marshall explores the research in New Scientist via Thierry de Baillon:

"Human hunter-gatherer societies swap members more flexibly than groups of other animals do. That could help explain why humans developed such powerful brains and advanced technology, while chimpanzees didn't.

People have been hunter-gatherers for almost all our 200,000-year history, so modern hunter-gatherer societies are a window on our past, argues Kim Hill of Arizona State University in Tempe.

Hill and colleagues gathered census information on 32 hunter-gatherer societies around the world. In all of them, both males and females could leave the group into which they were born for another, or could remain. In typical animal societies, only one sex disperses like this; in chimps it is normally the females.

Because of the mixed dispersal, many members of a hunter-gatherer society are unrelated. Hill says this could explain our willingness to cooperate with unrelated individuals.

Do I know you?
Humans also rely on social learning to pass on knowledge and build on past achievements to a far greater degree than chimps do. Hill says our unusual hunter-gatherer societies could have promoted that too, by massively increasing the number of people an individual would encounter over their lifetime. Chimpanzees meet two orders of magnitude fewer individuals on average than do human hunter-gatherers, says Hill, so it would not be worth chimps' while to evolve the extra brainpower needed for such extensive social learning.

The idea that friendly intergroup relations aided the evolution of social learning and our capacity for cumulative culture is "both intriguing and plausible", says Wesley Allen-Arave of the University of New Mexico in Albuquerque.

However, Sarah Blaffer Hrdy of the University of California, Davis, is not convinced that human societies are as unique as Hill claims. Some other species may extend cooperation to non-kin, she says. And humans are not the only species, nor the only primate, in which either sex may sometimes disperse. Howler monkeys are one example of a primate that behaves this way, she says – but their societies are less well-studied.