Did two U.S. scientists start a genocidal epidemic in the Amazon, or was The New Yorker duped?
Still, there's no doubt that Chagnon has a more Hobbesian view of human nature than is popular in most anthropological circles. Tierney claims that Chagnon, to support this view, exaggerates Yanomamö violence. He doesn't mention the fact that the rates of violence Chagnon documents are not high compared with the rates found by anthropologists in other pre-state societies. Nor does he mention Chagnon's view that, if anything, the Yanomamö's rate of lethal violence is "much lower than that reported for other tribal groups."
Not only does Tierney generally ignore inconvenient data, citing only anthropologists who disagree with Chagnon. He also, time and again, has a way of magically turning anthropologists whose data support Chagnon into anthropologists who contradict him. For example, Tierney cites a study of the Jivaro by Elsa Redmond that he claims undermines one of Chagnon's Yanomamö findings: that the effective use of violence contributes to social status, the acquisition of multiple wives, and the having of many offspring.
Here is Tierney's summary of Redmond:
Among the Jivaro, head-hunting was a ritual obligation of all males and a required male initiation for teenagers. … Among the Jivaro leaders, however, those who captured the most heads had the fewest wives, and those who had the most wives captured the fewest heads.
Here is what Redmond actually says:
Yanomamo men who have killed tend to have more wives, which they have acquired either by abducting them from raiding villages, or by the usual marriage alliances in which they are considered more attractive as mates. The same is true of Jivaro war leaders, who might have four to six wives; as a matter of fact, a great war leader on the Upano River in the 1930s by the name of Tuki of José Grande had eleven wives. Distinguished warriors also have more offspring, due mainly to their greater marital success.
Similarly, Tierney cites anthropologist John Peters at various points in his argument that Chagnon exaggerates Yanomamö violence. But what Peters actually writes in his book Life Among the Yanomamo is far stronger than anything Chagnon has written: "Anyone who is even minimally acquainted with the Yanomami is familiar with the central role of war in this culture. Violence seems always just a breath away in all Yanomami relations."
Throughout the book, Tierney is comically self-aggrandizing, often presenting as his own discoveries things plainly described in Chagnon's publications. After complaining that Chagnon concealed the identity of villages from which some of his more controversial data were drawn, Tierney writes, "It took me quite a while to penetrate Chagnon's data, but, by combining visits to the villages in the field with GPS locations and mortality statistics, I can identify nine of the twelve villages where all the murderers come from in his Science article." Or, if he didn't want to do all that walking and calculating, he could have gotten this information by consulting sources listed in his own bibliography, such as a 1990 Chagnon article and Chagnon's Yanomamo Interactive CD.
Although Tierney's many misrepresentations are riveting, his omissions are equally important—and harder for fact-checkers to spot, since omissions don't have footnotes. They figure centrally in two of Tierney's core accusations: that Chagnon inadvertently introduced various diseases besides measles into the region just by going there; and that Chagnon, by giving pots, machetes, and other steel tools to the Yanomamö, somehow exacerbated the rate of warfare, thus influencing the very data he gathered.
Both of these claims are logically possible. But Tierney fails to mention some relevant facts (well known to him) that call them into question.
Tierney presents the Yanomamö as if they were isolated in a petri dish, except when Chagnon visited and sneezed. In reality, the Yanomamö are tens of thousands of people, surrounded by other people with real diseases who have regular transactions with them. Moreover, this 70,000-square-mile area is penetrated by thousands of non-Yanomamö: missionaries, gold miners (over 40,000), highway workers, government officials, tin miners, loggers, ranchers, rubber tappers, drug smugglers, soldiers, moralists like Tierney, and on and on. This whole area is beset by epidemics of various kinds, as the Yanomamö tragically encounter diseases from the industrialized world. So, the probability that Chagnon or Neel or Tierney in particular is the source of any specific epidemic is, crudely speaking, one divided by these tens of thousands. Yet Tierney strangely insists that disease, like war, somehow specifically dogs Chagnon's movements.
John Tooby is a professor of anthropology at the University of California, Santa Barbara. His books include The Adapted Mind: Evolutionary Psychology and the Generation of Culture and the forthcoming What Is Evolutionary Psychology?: Explaining the New Science of the Mind.