"I don't think it's a coincidence that of all the kinds of ways human beings could organize themselves into networks, that's what we do. We evince degree assortativity, and I don't think it's a coincidence that we do that. We assemble ourselves into groups, the group now has this property, this germ- resistance property, which is a property of the group, but which, as it turns out, also benefits and affects us. Now, being a member of that group, we are less likely to acquire pathogens.
And this sets the stage for a set of ideas that we and others have been exploring that shed light on multi-level selection and other kinds of contentious ideas in the biological and the social sciences. And we have a number of fellow travelers on this road—László Barabási, Dirk Helbing, Tooby and Cosmides, Frans de Waal, Nowak, Rand, Santos—people working on these related areas of interactions among animals and people, and what this means. In fact, David Rand and Josh Green and Martin Nowak just had a nice paper this past year — I was asked to highlight some papers—looking at whether you can use time to response as a kind of heuristic for understanding are people intuitive cooperators and rationally selfish, or do they exercise rational self-control over a kind of instinctive greed? The data they presented in that paper, to my eyes, was quite compelling—that we are intuitively wired to cooperate."
Via Howard Rheingold