NICHOLAS A. CHRISTAKIS: Who are the kindred spirits in all this work at the intersection of the natural and social sciences? One man whose work I admire a lot is Brian Uzzi at the Kellogg School at Northwestern. Brian has done some of the seminal work on networks and on scientific collaboration.
Now, recently a paper that James and I did with Coren Apicella and Frank Marlowe appeared in Nature; it mapped the social networks of the Hadza hunter-gatherers. We had a sample of 200 people. There are only about a thousand Hadza left on the planet. They live in a very traditional way. They sleep under the stars. They don’t build any dwellings. They have very few possessions. They hunt and they gather for their food. They’re a pre-agricultural and natural fertility population.
Because we were interested in the kind of deep evolutionary origin of human social networks, we were animated by this question: if there’s a biological origin for human social networks, and we’ve been making networks of a similar kind since we were very ancient—that is to say, for tens of thousands of years—it should be the case that Hadza social networks look the same as ours.
Conversely, if the structure of human social networks depended upon modern telecommunications, or the invention of cities, the network should look very different. We hit upon this idea of mapping the social networks of a hunter-gatherer population, which I don’t think had ever been done before. Coren drove around 4,000 square kilometers around Lake Eyasi in Tanzania, and we created a kind of Facebook for the Hadza, a series of posters that had a photographic census of every adult Hadza. And every Hadza we could find, we asked them who their social connections were, and we mapped the networks of the Hadza. This paper was just in Nature a few months ago.
What we found was that Hadza social networks look just like ours. In every kind of way we could study these networks, mathematically, they didn’t differ from ours. Our sample size in that project was 205 respondents. Which is the majority of adults who still live in the traditional way of the Hadza on the planet. Incidentally, the Hadza have a click language, and we think they are one of the oldest populations with one of the oldest lifestyles on the planet.
We published this paper, and then Brian sends us an e-mail—which is still one of my favorite e-mails I’ve gotten as a scientist—and he goes, “Kudos.” He goes, “While everyone else is chasing big data, you go in the other direction and chase small data.” Just 205 people, and yet, I think, from those 205 people, we were able to extract some insights that were not trivial.