Louis Proyect: The Unrepentant Marxist

July 30, 2009

Yanomami Science Wars, part four

Filed under: Yanomami — louisproyect @ 6:11 pm

What Napoleon Chagnon believed

Although it is brief article (7 ½ pages, including 42 footnotes), Napoleon Chagnon’s “Life Histories, Blood Revenge, and Warfare in a Tribal Population” has the merit of encapsulating all the themes that would make him famous in anthropological circles. Since it appeared in the February 26, 1988 issue of Science Magazine, a publication that is behind a subscriber’s firewall, I have made it available at http://www.columbia.edu/~lnp3/chagnon.pdf as well.

Because I plan to summarize some of the best-known opposition to Chagnon’s theories in subsequent posts, it only makes sense to establish first what he stood for. He begins by making a distinction between his own approach and more traditional views that centered on the struggle to control scarce food resources:

Violence is a potent force in human society and may be the principal driving force behind the evolution of culture (1). For two reasons, anthropologists find it difficult to explain many aspects of human violence. First, although ethnographic reports are numerous, data on how much violence occurs and the variables that relate to it are available from only a few primitive societies. Second, many anthropologists tend to treat warfare as a phenomenon that occurs independently of other forms of violence in the same group. However, duels may lead to deaths which, in turn, may lead to community fissioning and then to retaliatory killings by members of the two now-independent communities. As a result many restrict the search for the causes of the war to issues over which whole groups might contest-such as access to rich land, productive hunting regions, and scarce resources-and, hence, view primitive warfare as being reducible solely to contests over scarce or dwindling material resources (2). Such views fail to take into account the developmental sequences of conflicts and the multiplicity of causes, especially sexual jealousy, accusations of sorcery, and revenge killings, in each step of conflict escalation.

For Chagnon, the real source of violence is the male struggle for control over females rather than food. Since his theory (as we shall see) rests on the assumptions that the Yanomami enjoyed an ample supply of food in the rainforest, the only explanation for “warfare” is a fundamentalist Darwinian struggle for the survival of one’s genetic material. As Chagnon puts it:

Specifically… the mechanisms that constitute organisms were designed by selection to promote survival and reproduction in the environments of evolutionary adaptedness. This implies that organisms living in such environments can be generally expected to act in ways that promote survival and reproduction or, as many biologists now state it, their inclusive fitnesses…

If you want to understand this by analogy, think in terms of a chimpanzee band in the middle of Africa that is in close proximity to an ample supply of food. But no matter how much food there is, the male chimpanzees will fight for dominance in the pack since that assures that his genes will have the best chance to propagate the species. After all, the genes of the best fighters will be of the most use in breeding a chimp troupe that can survive its enemies in the wild. So for Chagnon this is the best way to understand the Yanomami. If this seems far-fetched, it must be understood that this is the core belief of sociobiology that finds expression in Jared Diamond’s “The Third Chimpanzee” (i.e., homo sapiens). Like Chagon who he acknowledges, Diamond views warfare as rooted in our genes—or perhaps man’s need to spread his genes.

The bulk of the article consists of Chagnon’s data in support of his theory. Most of it is pretty much along the lines of:

The number of (living) unokais [killers] in the current population is 137, 132 of whom are estimated to be 25 or older, and represent 44% of the men age 25 or older (15). A retrospective perusal of the data indicates that this has generally been the case in those villages whose unokais have not killed someone during the past 5 years. I have recorded 282 violent deaths during 23 years of studies of villages in the region under consideration , deaths that occurred sometime during the past 50 to 60 years. These include victims who were residents of villages in this area or victims from immediately adjacent areas killed by residents or now-deceased former residents of the groups considered here. Of these 282 violent deaths, the number of victims of living unokais is 153. These victims were killed during approximately the past 35 years. All the unokais come from the villages under discussion, but not all of the victims do; some are from villages in adjacent areas beyond the focus of my field studies.

If you skip ahead to the Discussion section of Chagnon’s article, you will find him once again restating the sociobiological premises of the article without ever using the word sociobiology. Despite his reluctance to use the term, there is little doubt that this trend sees him as a member in good standing, if not a founding figure.

A number of problems are presented by these data. First, high reproductive success among unokais is probably caused by a number of factors, and it is not clear what portion might be due to their motivation to seek violent retribution when a kinsman is killed. I can only speculate about the mechanisms that link a high reproductive success with unokai status, but I can cast doubt on some logical possibilities. For example, it is known that high male reproductive success among the Yanomamo correlates with membership in large descent groups. If unokais come disproportionately from these groups, that might explain the data: both could be caused by a third variable. But unokais do not come disproportionately from larger descent groups. The three largest patrilineal descent groups among the Yanomamo considered here include 49.4% of the population, but only 48.9% of the unokais. The four largest descent groups include 55.9% of the population but only 55.5% of the unokais.

Second, it is possible that many men strive to be unokais but die trying and that the apparent higher fertility of those who survive may be achieved at an extraordinarily high mortality rate. In other words, men who do not engage in violence might have a lower risk of mortality due to violence and produce more offspring on average than men who tried to be unokais. This explanation would be supported by data indicating that a disproportionate fraction of the victims of violence were unokais. The data do not appear to lend support to this possibility. Of 15 recent killings, four of the victims were females: there are no female unokais. Nine of the males were under 30 years of age, of whom four were under an estimated 25 years of age. Although I do not have the unokai histories of these individuals, their ages at death and the political histories of their respective villages at the time they were killed suggest that few, if any of them, were unokais. Also, recent wars in two other regions of the study area resulted in the deaths of approximately 15 additional individuals, many of whom were very young men who were unlikely to have been unokais.

Leaving aside the sociobiology that these paragraphs fairly reek of, there is of course the question of Chagnon’s data. As so often happens in academia, there is a tendency to cherry-pick if not fabricate data to support your theory. In subsequent posts—devoted to Chagnon’s critics—this question will certainly come up.

1 Comment »

  1. This is a proud but often overlooked moment of human evolution, an indispensable manual for sociobiology to shed a light on the jouissance of individual terrorism:

    Comment by Mehmet Çagatay — July 30, 2009 @ 9:35 pm

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