Saturday, June 4, 2011

A Critique of the Killers-Have-More-Kids Idea

In a series of online posts (appearing on the Evolutionary Psychology Group at Yahoo.com)between March 30, 2008 and April 5, 2008, anthropologists Napoleon Chagnon and Douglas P. Fry discuss the assertion that among the Yanomami (or Yanomamö) of South America, those men who have participated in a killing have over three times the number of children as same-aged men who have not participated in killing.  This topic has become known as the unokai reproductive success controversy.

The posts involving the unokai reproductive success controversy from the spring of 2008 are herein reproduced in complete, unabridged form, as an accompaniment to a book chapter authored by Marta Miklikowska and Douglas P. Fry. The book chapter is titled "Natural Born Nonkillers: A Critique of the Killers-Have-More-Kids Idea" and appears in "Nonkilling Psychology," edited by Joám Evans Pim, with an anticipated publication date of July 2011. Upon publication, the book containing this chapter will be available both in paperback format and as a free download at the following link:

http://www.nonkilling.org/node/18

An Appendix at the end of the Miklikowska and Fry chapter contains excerpts from the Chagnon and Fry posts, but here at this site the original posts from 2008 on the Yanomami unokai controversy are presented in complete and unabridged form.

The discussion


10a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Laurence D. Krute" lkrute@mville.edu
    Date: Sat Mar 29, 2008 6:35 pm ((PDT))

A note on the Yanomami and leaving aside the questions of the reliability of Chagnon's data and the ahistoricity of his analysis,other anthropolgists have looked at Yanomami warfare in historical and ecological perspectives, notably Brian Ferguson and Allen Johnson.  Johnson in particular in his book on cultural evolution notes that Yanomami in fact inhabit an environmentally circumscribed area, an interriverine upland area of limited resources basically surrounded by swamp and one which yields bitter manioc, a staple requiring extensive labor to process, which combined with a growing population before more extensive contact  with Western society in the late 20th century resulted in the very high level of endemic violence that Chagnon and others found. Thus, they should not be considered a counter-argument to DeWaal.

Dr. Laurence Krute Associate Dean--Graduate Advising
School of Education
Manhattanville College
2900 Purchase Street Purchase, NY 10577
voice:914 323-5366
fax:914 323-5493



-----Original Message-----
From: "Joao Sousa" <j.d.sousa@sapo.pt>
Sent 3/29/2008 1:58:12 AM
To: 
evolutionary-psychology@yahoogroups.com
Subject: Re: [evol-psych] News: Has Science Found a Way to End All Wars?

These traits are especially pronounced in the ape species Pan paniscus. More commonly known as bonobos, they are darker-skinned and more slender than common chimpanzees and have markedly different lifestyles. "No deadly warfare," de Waal says, "little hunting, no male dominance, and enormous amounts of sex." Their promiscuity, he speculates, reduces violence both within and between bonobo troops, just as intermarriage does between human tribes. What may start out as a confrontation between two bonobo communities can turn into socializing, with sex between members, grooming, and play.De Waal suspects that environmental factors contribute to the bonobos' benign character; food is more abundant in their dense forest habitat than in the semi-open woodlands where chimpanzees live. Indeed, his experiments on captive primates have established the power of environmental factors. In one experiment, rhesus monkeys, which are ordinarily incorrigibly aggressive, grew up to be kinder and gentler when raised with mild-mannered stump-tailed monkeys. I disagree here. Many species don't have problems finding food, yet high levels of aggression occur. Napoleon Chagnon testified the violence of the Yanomami, a people he says has a notoriously fullfilled diet. Yanomami had usually better nutrition than poor people in pre-industrial Europe. Their forests would sustain many more of them, if they were not so war-prone.De Waal has also reduced conflict among monkeys by increasing their interdependence and ensuring equal access to food. Applying these lessons to humans, de Waal sees promise in alliances, such as the European Union, that promote trade and travel and hence interdependence. "Foster economic ties," he says, "and the reason for warfare, which is usually resources, will probably dissipate." Too optimistic, although I'm all for EU as is de Waal.Lethal violence certainly occurred among those nomadic hunter-gatherers, Fry acknowledges, but for the most part it consisted not of genuine warfare but of fights between two men, often over a woman. These fights would sometimes precipitate feuds between friends and relatives of the initial antagonists, but members of the band had ways to avoid these feuds or cut them short. For example, Fry says, third parties might step between the rivals and say, "`Let's talk this out' or `You guys wrestle, and the winner gets the woman.'" Fry has sought to determine what distinguishes peaceful societies from more violent ones. One clue comes from his fieldwork among the Zapotec, peasant farmers descended from an ancient, warring civilization in Oaxaca, Mexico. There, Fry studied two Zapotec communities, which he labeled with the pseudonyms San Andreas and La Paz. San Andreas's rates of male-on-male violence, spousal abuse, and child abuse are five times higher than those in La Paz. The reason, Fry suspects, is that women in La Paz have long contributed to the income of their families by making and selling pottery, thus earning the respect of the males Fry believes that empowering females may reduce the rate of violence committed within and by a nation. He notes that in Finland-which has a low rate of crime and violence compared with other developed countries-a majority of the cabinet ministers and more than 40 percent of the members of Parliament are women. "I don't see this as a panacea," Fry adds, recalling "iron lady" Margaret Thatcher, "but there are good reasons for having a balance of the more caring sex in government." I'm all for this. Should be extended to the UN and all nations. Our last hope. The anthropologist Richard Wrangham is one of several scientists at Harvard who pre¬sent a much darker view of human nature than Fry does. In his 1996 book, Demonic Males: Apes and the Origins of Human Violence (co¬authored with Dale Peterson), Wrangham argues that "chimpanzee-like violence preceded and paved the way for human war, making modern humans the dazed survivors of a continuous, 5-million-year habit of lethal aggression." Natural selection has favored combative, power-hungry males, he contends, "because with extraordinary power males can achieve extraordinary reproduction." "I worked in the Congo," Wrangham remarks drily when I call him in England, where he is en route to Africa to study chimpanzees. "It's hard for me to feel that we're a peaceful species when you have hundreds of thousands of people being killed there." Wrangham says de Waal is exaggerating the significance of the bonobos, and he scoffs at Fry's attempt to minimize warfare among hunter-gatherers by excluding "feuds." I'm with Wrangham.But like his more sanguine colleagues, Wrangham believes we can overcome our propensity for aggression. Primate violence is not blind and compulsive, he asserts, but rather calculating and responsive to circumstance. Chimpanzees fight "when they think they can get away with it," he says, "but they don't when they can't. And that's the lesson that I draw for humans." Wrangham notes that male hunter-gatherers within the same band rarely kill each other; their high mortality rates result from conflict between groups. Wrangham even agrees with Fry on how to decrease conflicts both between and within nations. He points out that as female education and economic opportunities rise, birthrates tend to fall. A stabilized population lessens demands on governmental and medical services and on natural resources; hence, the likelihood of social unrest also decreases. Ideally, Wrangham says, these trends will propel more women into government. "My little dream," he confesses, is that all nations give equal decision-making power to two entities, "a House of Men and a House of Women."
Like Wrangham, the archaeologist Steven LeBlanc is critical of scientists who emphasize the peaceful aspects of human nature. At Harvard's Peabody Museum of Archaeology and Ethnology, where he serves as director of collections, LeBlanc points to a piece of carved wood hanging on his office wall. This, he notes, is a spear employed by Australian Aborigines (who, according to Fry, rarely or never waged war). A short, bearded, excitable man, LeBlanc accuses Fry of perpetuating "fairy tales" about levels of violence among hunter-gatherers and other pre-state people.
+++
LeBlanc contends that researchers have unearthed evidence of warfare as far back as they have looked in human prehistory, and ethnographers have observed significant levels of violence among hunter-gatherers such as the !Kung. In his book Constant Battles: Why We Fight (with Katherine E. Register), he espouses a bleak, Malthusian view of human prehistory, in which war keeps breaking out as surging populations outstrip food supplies. Warfare, he writes, "has been the inevitable consequence of our ecological-demographic propensities." Still, when asked point-blank if humans can stop fighting wars, LeBlanc replies, "Yes, I think it's completely possible." He notes that many warlike societies-notably Nazi Germany and imperial Japan and even the Yanomami, a notoriously fierce Amazonian tribe-have embraced peace. Ta ta ta... Complex wars by complex nation states have nothing to do with aggressiveness, with Demonic Male behaviour, etc.

Messages in this topic (5)


12a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Napoleon Chagnon" 
chag99@charter.net
    Date: Sun Mar 30, 2008 8:22 pm ((PDT))

On 3/29/08 2:22 PM, "Laurence D. Krute" <lkrute@mville.edu> wrote:
[Hide Quoted Text]

A note on the Yanomami and leaving aside the questions of the reliability of Chagnon's data and the ahistoricity of his analysis, other anthropolgists have looked at Yanomami warfare in historical and ecological perspectives, notably Brian Ferguson and Allen Johnson.  Johnson in particular in his book on cultural evolution notes that Yanomami in fact inhabit an environmentally circumscribed area, an interriverine upland area of limited resources basically surrounded by swamp and one which yields bitter manioc, a staple requiring extensive labor to process, which combined with a growing population before more extensive contact with Western society in the late 20th century resulted in the very high level of endemic violence that Chagnon and others found.
            I would like to make a few general suggestions to some of the contributors to and readers of this list.  Some people seem to think that casting idle opinions carries as much academic authority as presenting an argument that rests on a consideration of the sometimes abundant data that lies behind the Œthread¹ under discussion.   Human behavioral evolution, for example, is the central theme in this discussion group.  Presumably participants in the discussion are familiar with the general history of this field.   But I was recently astonished that one of the frequent contributors was not aware of who Robert L. Trivers is---or what his enormous contribution to evolutionary biology and the development of evolutionary psychology has entailed.

            Krute¹s posting reveals a different kind of problem: accepting and perpetuating hearsay prejudicial Œevidence¹ about the works of others. He demonstrates considerable ignorance of my long-term research among the Yanomamö Indians of the Venezuelan/Brazilian border region and the rather large amount of quantitative data I have amassed and published over the past 35 years.   His posting leads me to conclude that he has no idea about what I¹ve published nor any idea about the details of the several controversies my data and publications provokedŠor why they might even be described as
controversial.  Yet he seems to dismiss my efforts as possibly unreliable, ahistorical, geographically and ecologically uninformed, etc., deficiencies that presumably R. Brian Ferguson and Allen Johnson have independently remedied.

        I want to attempt to correct the record on these topics and comment on why some of my critics persist in dismissing my findings as Œcontroversial¹.

           The initial Œcontroversy¹ about my work began in the late 1960s when Marvin Harris and several other prominent anthropologists were attempting to create a Œcultural materialist¹ theory of anthropology and human behavior that had no room for the evolved behavioral attributes of the human organism. Indeed, their theory began with the premise that the Œhuman organism¹ had to be Œfactored out¹ of any scientific anthropological theory of Œculture¹---and that human warfare was a kind of cultural behavior par excellence.  Cultural materialist theoreticians not only did not want ideas
or insights from Œbiology¹ or Œpsychology¹ to be incorporated into their theory, they were openly and adamantly hostile to them---as was the French sociologist Emile Durkheim a century earlier when he struggled to create a ³science of society² in his struggle to wrest sociology from the clutches of social psychology and psychology within which it was then embedded.

            My data on Yanomamö violence and warfare threatened the cultural materialist view because I was able to make an empirically defensible case that Yanomamö violence and warfare was not invariably  Œcaused by¹ contests over scarce, strategic, material resources but frequently began with arguments over access to and control of nubile femalesŠa reproductive resource as distinct from a material resource. Once begun, Yanomamö conflicts often escalated and frequently became violent and lethal---usually first within a residential group (a village) and, after a homicide, between
the two now-separated (fissioned) groups.  Other groups (villages) depending on their immediate past history and relatedness to the original principals, took sides and formed alliances with one or the other.  Blood revenge, sexual jealousy, male status, village size  and  the size of the several allied villages, and many other factors were intimately  involved and were components to be considered in a reasonable explanation of the observable events.  Marvin Harris¹ position was that humans only fought over scarce strategic material resources, and speculated that high-quality animal protein was the alleged resource in short supply.

            Harris had absolutely no data that suggested this was true for the Yanomamö.  He simply asserted it.  This became the famous Œprotein controversy¹ in anthropology and it emerged immediately prior to the publication in 1975 of Sociobiology, E. O. Wilson now classic book, and a book that was widely denounced and condemned by cultural anthropologists.[i] Why?   They condemned it because, in part, it convincingly argued that organisms other than humans developed Œsocieties¹ and had highly evolved Œsocial behavior¹ that could only be understood by understanding the
behavioral attributes of organisms and the evolution of the genetic adaptations that emerged over time to facilitate these kinds of social behaviors.  Kin recognition mechanisms  among, for example, ants, bees, termites, and other species was an important topic in sociobiology---and kin selection was a fundamental evolutionary process that led to the spread and retention of many of these adaptations.  Thus, most of the truly important questions about Why some organisms are social and others are not were being asked by biologists---especially entomologists who studied eusocial insects. Anthropologists simply assumed that being ³social² was somehow or other ³natural² and didn¹t require explanation.   Why humans are social is one of the most fundamental questions that anthropologists should ask, but they don¹t.

            To address Harris¹ concerns I developed a research project, funded by NSF, among the Yanomamö in 1975 and brought 3 of my graduate students (from Penn State) into the Yanomamö area to collect data on precisely how much protein the Yanomamö actually consumed.

            Because knowledge of the dispute between me and Harris had become widely known in anthropology, a number of senior anthropologists urged me to meet with Harris and discuss our theoretical differencesŠand how to reconcile them with the data I was about to collect.  I agreed to meet with Harris and several of his graduate student disciples on the eve of our departure for the Yanomamö.  We met in New York in early 1975 in the apartment of Allen Johnson, one of Harris¹ students.  Brian Ferguson, another of  Harris¹ students, was also there.  These are the two anthropologists mentioned in Krute¹s posting.  We solicited advice and suggestions from Harris and his students on what kinds of data they thought we should collect that would help decide this issue.  I recall Harris testily proclaiming that if I/we could show that the Yanomamö consumed the protein equivalent of ³one Big Mac per day² he would eat his hat.  Our data eventually showed that the Yanomamö were consuming amounts well in excess of that.[ii]

            Even while the Œprotein controversy¹ was still smoldering in the anthropological literature, another controversy was brewing because of the increasing Œperceived threat¹ to cultural anthropology caused by the increasing acceptance of ³sociobiology² in the hard sciences. This time my studies on Yanomamö kinship became the Œcontroversial¹ problem.  I published a number of  rather recondite papers on the importance of Yanomamö genealogies and kinship for understanding a number of important Yanomamö cultural institutions:  village fissioning, the limits to the size to which
villages could grow if organized by kinship and  marriage alliances, military alliances, violence, and politics.  But I adopted a rather quantitative approach and expressed the closeness of their kinship
relationships by using a statistic, originally developed by the American statistician/geneticist Sewall Wright in 1922 for analyzing inbreeding in sexually reproducing populations.

            Anthropologists don¹t, in general, quantify things like kinship---but they like to make swooping generalizations about what it isŠand especially what it isn¹t.  The genealogies I had collected were 4 to 6 generations deep and, complicating them, systematic reciprocal Yanomamö marriage alliances led to a great deal of Œinbreeding¹.  Almost all related individuals among the  Yanomamö were related in multiple and complex ways, and the simplest way to demonstrate this complexity (and express it quantitatively) was by using Wright¹s coefficient of relatedness.  The first of my publications [iii]  demonstrated a correlation between closeness of kinship relatedness and village fissioning:  close relatives tended to remain together and separate from less-closely related individuals. Wilson¹s Sociobiology book argued that something like this is to be expected in small populations of socially organized organisms---favoring close kin over distant kin, and all kin over non-kin.  He summarized the arguments of other prominent evolutionary biologists, especially the work of William D.
Hamilton whose now-famous papers (1964) on ³inclusive fitness² (now more widely known as ³kin selection²) not only became a key issue in explaining eusociality in some species of insects, but became the most important ultimate reason why kinship knowledge and behavior among humans in particular was central to understanding human evolution and the role that cooperation and competition played in human evolution.[iv]     One could perpetuate one¹s genes by, as J. P. S. Haldane is alleged to have argued, by ³laying down his life for eight cousins² because a cousin carries, on average, 1/8th of one¹s genes that are identical by immediate common descent.  In a stroke, it made clear, in an evolutionary sense, why the natives studied by anthropologists placed such profound importance on kinshipŠand this insight did not come from an anthropologist, but from a biologist.

            One must understand that repugnance for these ideas when applied to humans was nearly universal among cultural  anthropologists.  For nearly a century cultural anthropologists had gone out of the way to show that kinship had absolutely nothing to do with biology.    Textbook examples included such grandiose proclamations like:  ³Kinship is purely cultural and has nothing to do with biologyŠsome tribes in Africa even call their fathers by a kinship term that means mother!²  In the aftermath of Wilson¹s Sociobiology, a then prominent anthropologist---Marshall Sahlins---took it upon himself to give the Anthropological profession¹s Œofficial response¹ to Wilson¹s Sociobiology book by publishing a scathing, sarcastic, and extremely hostile book entitled  The Use and Abuse of Biology.[v] It was widely touted in cultural anthropological circles that Sahlins¹ book dealt the Œdeath blow¹ to the theory of sociobiology.   Among other things, Sahlins laid down a challenge to Œsociobiologists¹ by claiming something to the effect that no human society known to anthropologists organizes the Œcalculus¹ of its social life in ways predicted by kin selection. Almost immediately a prominent biologist---Richard D. Alexander, an expert on sociality among crickets---responded by pointing out that at least one society was known to at least one anthropologist that organized the Œcalculus¹ of much of its social life precisely along lines predicted by kin selection:  Chagnon¹s Yanomamö, as  demonstrated in several of Chagnon¹s recently published papers.

            Without wanting to become, or having any say in the matter, I was now one of the hated Sociobiologists.  Marshall Sahlins, incidentally, was one of my professors at the University of Michigan.  He apparently never forgave me for creating ³Yanomamö: The Sociobiology People²---as is clear from his cynical comparison of me and my Yanomamö research to the activities of the Nazis in his favorable review of Tierney¹s Darkness in El Dorado.[vi]

            In short, Krute seems to assume that much, if not all, of the criticisms of my publications based on many years of field research among the Yanomamö---and the alleged Œsuspect nature¹ of my data---derives from an epistemologically neutral set of dispassionate academics who have real knowledge about the data I collected as distinct from a politically motivated skepticism and rejection of that data without even examining it. The more significant fact is that my data conflicts with the fundamental
assumptions behind the theoretical positions championed by most of my critics.  Neither Brian Ferguson nor Allen Johnson have ever been to the Yanomamö and have never collected a single piece of Yanomamö data. Ferguson seems to be continuing the now settled issue of an alleged shortage of dietary protein to explain my voluminous data on Yanomamö warfare.  To be sure, he has invoked other allegedly  ³scarce strategic material resources² such as a shortage of machetes, control over the ŒYanomamö trade routes through the jungle¹, and other imaginary if not preposterous scenarios.  His
theory is, in a humorous way, like the theory of why the harmless, gentle Bushman now fight---as implied in the popular film The Gods Must Be Crazy. The theory goes as follows.  A careless bush pilot, flying over the Kalahari Desert, discards his coca-cola bottle out of his plane¹s window.  It lands near a Bushman camp, causing the previously non-warlike Bushman to begin fighting over it, a novel social phenomenon caused because some capitalist outsider introduced an extraneous item that was scarce, valuable, material----and therefore worth fighting for.   (See my review of Ferguson¹s
Yanomami Warfare).[vii]    This theory is similar to what I and a few cynical colleagues call the Hot Breath theory of warfare in the Americas after 1492, when Columbus and his men landed on the shores of  the western hemisphere, took a deep breath, then exhaled.  The hotness of their breaths drifted across the continent and  caused 6 million Native North Americans who were previously peace-loving, cooperative, and harmless to become nasty, warlike, and brutish.

            Ultimately, what is really at issue behind much of the criticism of my work are two nearly Œsacred¹ Anthropological Truths, given down from above to the anthropological laity by self-appointed Ayatollahs like Sahlins.  The first one is that warfare is rare to non-existent in the pristine primitive world of hunters and gatherers because Original Man is basically a nice critter, a Noble  Savage.  Many of my anthropological critics seem to be upset to the point of suggesting that my data on Yanomamö warfare and violence is Œsuspect¹, Œexaggerated¹, Œcooked¹, Œcontroversial¹, etc. and might my data might possibly cause people to question this Noble Savage view because my empirical findings are plausible, meticulously documentedŠand have become widely known.  I also have the impression that my  anthropological critics have preemptively disqualified me and my data on their fear that I might possibly someday make the claim that warfare is a good thing, an inevitable and natural thing because it is ³genetically wired into² the human design.  Some of my anthropological opponents have already made the claim that ³Chagnon claims there is a gene for warfare!²  Marvin Harris for example.

            The second issue is the question of whether or not anthropology is a ³science² and whether or not it can be ³scientific² if the humans in human behavior can be ³factored out.²  If it is a ³science² then what is it a science of?   Most cultural anthropologists would say ³it is a science of culture² but that necessarily implies that only humans have culture (learned, shared traditions), and if they admit that other organisms have Œlearned traditions¹ then they can¹t expect, for example, primatologists or
other animal behavioralists, to join them denying that the evolved behavioral characteristics of primates and other non-human animals are totally irrelevant to understanding these Œlearned traditions¹.  The only Œnature¹ that humans have, according to most cultural anthropologists, is a Œcultural¹ nature: there is no such thing as a human nature.

            This second issue is, in turn, a Œspecial case¹ of the larger epistemological struggle between Science and Postmodernism. Many cultural anthropologists strongly believe that anthropology is not and should not be a science---there is no such thing as a Œreal¹ world independent of human observers, and no such thing as a repeatable observation on that external world.  They  prefer the Œinterpretive¹  approach used by Postmodernists, many of whom argue that all Œfacts¹ are simply culturally biased Œrepresentations¹Šfigments of an observer¹s imagination, inevitably
contaminated by the biases of the observer.

            Brian Ferguson is adamantly opposed to evolutionary biology as it applies to humans.  He was invited to comment on a paper I gave in the 1990s at The School for American Research, launching his critique of my paper with the following argument:  ³I don¹t understand why you sociobiologists keep bringing in reproduction.  After all, when you have enough to eat reproduction is more or less automatic.² By this line of reasoning, Darwin really didn¹t have to write his two-volume 1871 book, The Descent of Man and Selection in Relation to Sex, and spend so much time discussing sexual selection.  After all, when animals have enough to eat, they don¹t really have to waste energy growing antlersŠbecause reproduction is more or less automatic. As recently as the mid 1990s I heard Marvin Harris warn an audience of anthropologists in a plenary lecture at an annual meeting of the American Anthropological Association with words to the effect Œ..that if we do not succeed in debunking and repudiating sociobiology we will have only ourselves as anthropologists to blame when it is accepted by the academic community.¹  Participants in this list can substitute ³evolutionary psychology² for ³sociobiology²  in Harris¹ statement.

            Let me here invite Associate Dean Krute---and others---to read one of my easily accessible publications on the overall characteristics of the  Yanomamö---a general monograph, still widely used in college courses all over the US and in Europe, called Yanomamö (6th Edition, 1997).  It can be ordered from Amazon.com or found in most college bookstores. It includes a substantial bibliography of my more detailed publications (and the some 22 documentary films I made) on the recent history of the Yanomamö, especially how much field time and data it took me to develop the argument that the Yanomamö were socially circumscribed---a position I developed from my data and  apparently now adopted by Johnson.  In fact, all of the observations on the Yanomamö Krute attributes to Johnson came from my publications.   These publications cover their demographic characteristics by village, their various ecological niches, how the rates of female abduction, violence and warfare vary in these niches, population densities by general area, and many other topics.

            Finally,  Œbitter¹ manioc is not a Yanomamö food except in a few villages where they are in constant contact with the Carib-speaking Ye¹kwana(or at Catholic mission posts where it has been recently introduced); bitter manioc is also not a wild foodstuff Œyielded¹ by swamps.  It is a cultivated starchy staple crop native to the Americas widely used by native tribesmen throughout the Amazon basin.

[i] Sociobiology: The New Synthesis. Harvard University Press

[ii]  Chagnon, N. and R. Hames, 1979  ³Protein Deficiency and Tribal Warfare in Amazonia: New Data.²  Science, 203: 10-15

[iii]   Chagnon, N.  1974  Studying the Yanomamö.  Studies in Anthropological Method.  New York: Holt, Rinehart, and Winston.

        Chagnon, N. 1975  ³Genealogy, Solidarity and Relatedness: Limits to Local Group Size and Patterns of Fissioning in an Expanding Population² Yearbook of Physical Anthropology, 19; pp 95-110.  American Anthropological Association, Washington, DC

[iv] Hamilton, William D. 1964  ³The Genetical Evolution of Social Behaviour, Parts I and II².  Journal of Theoretical Biology, 7:1-52.

[v] Sahlins, Marshall D.  1976.  The Use and Abuse of Biology: An Anthropological Critique of Sociobiology.  University of Michigan Press: Ann Arbor.

[vi] Sahlins, Marshall D. 2000 ³Jungle Fever.²  Book World.  Washington Post. December 10.

[vii] Chagnon, N.  1996.  Review of R. B. Ferguson¹s Yanomami Warfare. American Anthropologist, Vol. 98, No, 3, pp. 670-72).

Napoleon A. Chagnon, Ph.D.
Professor of Anthropology Emeritus
The University of California at Santa Barbara



6a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Laurence D. Krute" 
lkrute@mville.edu
    Date: Mon Mar 31, 2008 7:24 am ((PDT))

To all,

My apologies; I thought that in my first sentence, I was laying to rest these issues or at least putting them aside and I believe I accepted the *fact* of Yanomami warfare/violence.  Given that fact, it then becomes interesting to look at causation and interesting to this list because some of the explanations are clearly "evolutionary psychological" in nature (among others, Allen Johnson on environmental circumscription and Brian Ferguson on the historical circumstances of contact and colonization.)  Whether these explanations are valid or not is a question that can and should be addressed by empirical data.

My real intention was to counter some of the apparently truly simplistic views, not only of Yanomami, but of "aboriginals" in general, that are sometimes presented by posters (as can be seen by looking at the reference to Yanomami in the post I was responding to and at my earlier post on the Iroquois, who were referred to by that poster as hunters/gatherers.)

On a side note, the bitter manioc point was raised by Allen Johnson, among others.  My understanding was that so-called bitter and sweet manioc is a single species, with the differences caused by local soil composition.  I would be happy to be corrected.

L. Krute


Dr. Laurence Krute
Associate Dean--Graduate Advising
School of Education
Manhattanville College
2900 Purchase Street Purchase, NY 10577
voice:914 323-5366
fax:914 323-5493



7a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "dfry@abo.fi" 
dfry@abo.fi
    Date: Tue Apr 1, 2008 12:28 am ((PDT))

Re: News: Has Science Found a Way to End All Wars?

I read Napoleon Chagnon's comments with interest.  As most other readers of this list are probably well aware, the Yanomamö often come up in discussions of war.  I want to start by saying that I agree with Napoleon Chagnon's comments that we should go to the data.  I agree it is not scientific to banter about hearsay.  I also actually have read many of Napoleon Chagnon’s writings on the Yanomamö and have cited them in my writings.

An important controversy not mentioned by Chagnon in his posting involves his widely reiterated report from "Science" magazine from 1988 that unokais (Yanomamö men who have undergone a purification ritual after having participated in a killing) have over three times the number of offspring as non-unokais.  There has been controversy over this finding.  It has been challenged by various authors, and Chagnon has defended his interpretations.

I became interested in this unokai controversy a few years ago.  After much  investigation, I have concluded that there are several reasons that make Chagnon's  conclusion that unokais have more kids highly questionable.  This is not merely ‘an opinion.’ It is not because I am a student of Marvin Harris (I am not).  It is not because I am anti-evolutionary (I am not).  It is because the original math does not hold up under scrutiny.  I have calculated how the original analysis is flawed and thus the interpretations based on it are highly questionable.

Most striking is the fact that Chagnon’s own data show that unokais as a group are  substantially older than non-unokais.  Despite his claims that unokais and non-unokais are of comparable ages, mathematics show that they are not.  From carefully examining Chagnon’s own published data, it can be determined that 55% of the unokais are over 41 years of age, whereas 56% of the non-unokais are younger than age 31.  I calculate, again using Chagnon's own published data, that the age differences between these two groups of men is at least 10.4 years.  Older Yanomamö men have more offspring than younger Yanomamö men, whether or not they are unokais Chagnon’s published data show this clearly.  What this means is that huge age differences between unokais and non-unokais throw the whole finding that ‘killers have more kids’ into serious doubt, because older men have more kids than younger men.

There are other problems with the analysis as well, which I explain in detail in Chapter 15 of ‘The Human Potential for Peace’ (Oxford University Press, 2006).  The detailed mathematical reanalysis of Chagnon’s data is presented in the endnotes.

Why should members of this list care about the fact that this unokai reproductive success interpretation is highly suspect’ First of all, Chagnon’s widely cited claim that Yanomamö men who have killed have over three times the RS as those who have not killed is reiterated in almost every evolutionary psychological discussion of warfare.  It is treated as gospel.  At best this interpretation is greatly exaggerated, at worst it is totally wrong.  If we are scientists and objective, we should want to report and reiterate accurate findings, not erroneous ones.  I would hope that we are looking for truth, not gospel.  Second, as someone who is favorable to evolutionary interpretations of human behavior, I think this finding has helped to lead evolutionary thinking about warfare and violence off in a rather unproductive direction.  It is hard to find justification for a ‘killers-out-reproduce-non-killers’ model of human aggression from either data on the simplest human societies, nomadic bands, or from animal models of human aggression.


--
Douglas P. Fry, PhD
Åbo Akademi University
& University of Arizona



7b. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Napoleon Chagnon" 
chag99@charter.net
    Date: Tue Apr 1, 2008 5:24 pm ((PDT))

On 4/1/08 2:32 AM, "dfry@abo.fi" <dfry@abo.fi> wrote:
[Hide Quoted Text]
Re: News: Has Science Found a Way to End All Wars?

<snip>

I became interested in this unokai controversy a few years ago.  After much investigation, I have concluded that there are several reasons that make Chagnon's conclusion that unokais have more kids highly questionable.  This is not merely Œan opinion.¹ It is not because I am a student of Marvin Harris (I am not).  It is not because I am anti-evolutionary (I am not).  It is because the original math does not hold up under scrutiny.  I have calculated how the original analysis is flawed and thus the interpretations based on it are highly questionable.
        <snip>
CHAGNON:

         I forgot to mention that in addition to other controversial facts I  have published, I also published the lead article in one of the issues of Science in 1988 on some 25 years of my field studies on Yanomamö warfare, differential reproduction, and marital success.  Scientists seem to have few quibbles with my findings, but cultural anthropologists have generally been outraged by them.  Fry responds to my recent posting by saying that he ³Šbecame interested in this unokai controversy a few years ago.²  My findings are not Œcontroversial¹ to scientists like biologists and animal behaviorists.
         There have been a number of attempts, some of them quite spirited, by cultural anthropologists to repudiate and debunk my 1988 Science paper, ³Life Histories, Blood Revenge, and Warfare in a Tribal Population² (Science, Vol 239, pp. 985-992).  Most of these challenges appear to emanate from cultural anthropologists who, like Fry, want to emphasize the Œhuman potential for peace¹ lest the world lose appreciation for the Noble Savage view of Man, or like Sahlins who simply finds violence, war and evolution so repugnant that he denounces it like a vehement Ayatollah, or like Ferguson
who refuses, as a matter principle, to consider as relevant psychological, biological, and, presumably any human characteristic that evolved by a process of natural selection in explanations of human violence and warfare.
         Ferguson, for example, initially reacted to this article by arguing that since the unokai category (roughly translated as known Œkillers of humans¹) contained all the headmen and since I had also published that headmen had more wives and offspring than other men, he seemed to be sure that my data were Œbiased¹ in favor of the marital and reproductive accomplishments of headmen.  I responded to Ferguson¹s concerns in the American Ethnologist (1989, Vol. 16, No. 3, pp 565-69) and reanalyzed the data I produced in my 1988 Science article with all of the headmen removed. The results were almost identical to what I had presented in my original Science article.
         I carefully read the lengthy endnote in Fry¹s 2006 publication at about the time it appeared and concluded that with some shaky but creative assumptions about my age estimates for the Yanomamö males in my study---both unokai and non-unokai---one could try to make the case Fry just posted today on the Ev-Psych list.  He alludes to his research into ŒChagnon¹s other published data¹ that supports his interpretations and his claim that I Œmisrepresented¹ the real situationŠand my misrepresentation is now Œgospel¹ in lots of evolutionary circles.  Good Lord, let us hope that this news is not widely known to others....I want to point out two things that are pertinent to Fry¹s claims. First, in my Science paper I separated the relevant Yanomamö populations into four age categories and then compared the marital and reproductive performances of unokais and non-unokais within each of these four categories.  Fry says: ³I calculate, again using Chagnon¹s own published data, that the age difference between these two groups of men is at least 10.4 years.²  Second, I have never published data that would enable someone to determine who specifically was a Œkiller¹, his name, his village, his age, how many wives he had, and how many offspring.  In short, the data needed to make the criticisms that Fry makes can not be gleaned from my published data. I have attempted to protect the identities of yet living unokais because prominent people in Venezuela have threatened to apprehend, try, convict, and punish Yanomamö who kill othersŠincluding women identified as having committed infanticide.
         If Fry disagrees with my above remarks, perhaps he should write a technical paper that clearly shows how he came to his conclusions about my published data on the marital and reproductive accomplishments of Yanomamö unokais compared to same-age Yanomamö non-unokais and submit it to a reputable refereed journal in one of the natural sciences.


Napoleon A. Chagnon, Ph.D.
Professor of Anthropology Emeritus
The University of California at Santa Barbara



5a. News: Has Science Found a Way to End All Wars?
    Posted by: "dfry@abo.fi" 
dfry@abo.fi
    Date: Wed Apr 2, 2008 2:26 am ((PDT))

Re: Has Science Found a Way to End All Wars?

I thank Napoleon Chagnon for taking the time to respond to my posting about questioning the accuracy of the unokai reproductive success finding published in the prestigious journal ?Science.? Chagnon characterizes my mathematical calculations of age estimates as ?shaky.? Since it does not take much space to show how I used the published data in Chagnon?s 1988 ?Science? article to calculate age
interval midpoints, I would like to let each reader have the opportunity to decide whether I know how to calculate averages or not. Here is part of the endnote 55 for Chapter 15 from ?The Human Potential for Peace? (Oxford University Press, 2006).

"The average age for each age-bracket can be estimated by multiplying the mid-point value of the age-bracket by the number of men within the age bracket. (This is a conservative approach given the pattern of within age-bracket variation suggested by Figures 15.1 and 15.2). Separate estimates of the average age of the unokais and non-unokais can then be obtained by adding up the respective four age bracket products and dividing each sum by the number of men in the relevant group--the usual way to calculate averages in other words.

?The age calculations are as follows:
20-to-24 year age-interval midpoint value = 22 years
25-to-30 year age-interval midpoint value = 27.5 years
31-to-40 year age-interval midpoint value = 35.5 years
estimated > 41 year age-interval midpoint  = 50.7 years
Unokais
22 x 5 men =        110
27.5 x 14 men =     385
35.5 x 43 men =  1,526.5
50.7 x 75 men  = 3,802.5
110 + 385 + 1,526.5 + 3,802.5 = 5,824
5,824/ 137 unokais = 42.5 years as the estimated average age for unokais
Non-unokais
22 x 78 men =    1,716
27.5 x 58 men =  1,595
35.5 x 61 men =  2,165.5
50.7 x 46 men =  2,332.2
1,716 + 1,595 + 2,165.5 + 2,332.2 = 7,808.7
7,808.7 / 243 non-unokais = 32.1 years as the estimated average age for non-unokais.

The difference in estimated average ages therefore is 42.5 - 32.1  = 10.4 years."

I must add a couple of comments. First, the 10.4 year estimate is almost certainly too small since it does not attempt to adjust for within interval age variation. It is a conservative. Second, this is
basic mathematics. Either the math is correct or not. I have explained in detail what I am doing at every step, cite the sources of Chagnon?s data I am using, present explicitly what assumptions I am making and why, and present all the calculations in black and white. Even more details are in the book, such as how the demographic data published in one of Chagnon?s 1979 sources provide the Yanomamö population age pyramid for use in my calculations. I don?t think the adjective ?shaky? applies to my age estimates, but what do other readers think?

Third, if Napoleon Chagnon thinks that my calculation of age interval averages is wrong, well let?s not forget the obvious. He is the guy that holds the individual age data for each man in this own sample. All Chagnon has to do is to tell us readers the actual age averages for the unokais and non-unokais. He collected this data, so if he thinks my estimates are ?shaky,? then let?s hear what the actual age figures are. We will then see how accurate my estimate is of at least 10.4 years in age difference between the unokais and non-unokais. At the same time we will also see if Chagnon is correct in his assertions that the unokais and non-unokais are of comparable ages. We both can?t be right. Instead of taking pot-shots at my estimates, why not come up with the actual figures? We will then have actual numbers regarding the age differences between unokais and non-unokais for the first time.

Turning to headmen, first, let us establish that according to Chagnon himself, in 1979, the headmen in his study population average 8.6 offspring compared to a non-headman average of 4.16 (with only men 35 years and older included). In his posting, Chagnon cites his own response to Ferguson in ?American Ethnologist? in 1989 and states that he did a  re-analysis with ?all of the headmen removed.? I am very curious about this point because we are presented with a contraction in Chagnon?s own writings. Does he really remove all the headmen? I will paste in endnote 71 from Chapter 15 of ?The Human Potential for Peace,? which explains this contradiction:

"Chagnon et al. 1979 list 20 Yanomamö headmen in 13 villages. They explain on page 318 (italics added) that ?in some villages there are several ?headmen? as described above, a situation that often emerges when a village?s composition includes several large descent groups.? Separately, Chagnon 1979a:385 (italics added) states ?If there are two comparatively large lineages in the village, it is common to find two headmen, one from each descent group, and quite common for most of the village social activities to reflect the interests and desires of the two leaders.? Similarly, nine years later and related to the same Yanomamö population that he has most intensively studied, Chagnon 1988:988 (italics added) states that if a ?village has two descent groups of approximate equal size it will have two (or more) leaders?."

"Chagnon 1988:988 also states that ?all headmen in this study are unokai.? In writing a rebuttal one year later to Ferguson?s 1989b commentary on his 1988 Science article, Chagnon 1989, in note 2,
reports that his statement about all headmen being unokai was wrong, and so he removes one non-unokai headman along with 12 headmen from the unokai group (as part of his argument that the headman effect does not compromise his reported findings). This, of course, amounts to removing a total of 13 men from the analysis to adjust for a headman effect, not the 20 headmen from the earlier reports. Chagnon 1989 does not explain why only 13 headmen, instead of 20, are removed (nor does
he offer any information about the implied loss of seven headman positions as descent group leaders)."

I remain very curious why only 13, not 20, headmen were removed for the 1989 reanalysis. This decision invalidates Chagnon?s 1989 reanalysis, it seems to me. (The reanalysis is also problematic in
that it retains the same four age categories as in the previous analysis, but see ?The Human Potential for Peace? on this problem). In other words, I am questioning the accuracy of saying that ALL headmen
were removed for the 1989 reanalysis when only 13 of 20 headmen were removed. What happened to the other seven headmen? And how did one headman change groupings? Napoleon Chagnon has never explained why he removed only 13 headmen. In my calculations, I run the estimates both
ways: With 13 headmen removed and again with 20 headmen removed. Readers can compare the two analyses, but both have an impact on the results. Both, to different degrees, diminish further the supposed effect that unokai might have higher RS.

Finally, since Napoleon Chagnon seems to assume I belong to the evolution-despising cultural anthropology tribe, I will reveal that I actually hold my academic degrees in biological anthropology. The very first paper I presented in my professional career was called ?From Ik to Kamikaze: The Sociobiology of Selfishness and Altruism.? I am not Sahlins. I am not Rousseau.

--
Douglas P. Fry, PhD
Åbo Akademi University
& University of Arizona



10a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Napoleon Chagnon" 
chag99@charter.net
    Date: Thu Apr 3, 2008 6:49 am ((PDT))

On 4/2/08 5:01 AM, "dfry@abo.fi" <dfry@abo.fi> wrote:
[Hide Quoted Text]
Re: Has Science Found a Way to End All Wars?

I thank Napoleon Chagnon for taking the time to respond to my posting about questioning the accuracy of the unokai reproductive success finding published in the prestigious journal ?Science.? Chagnon characterizes my mathematical calculations of age estimates as ?shaky.? Since it does not take much space to show how I used the published data in Chagnon?s 1988 ?Science? article to calculate age interval midpoints, I would like to let each reader have the opportunity to decide whether I know how to calculate averages or not. Here is part of the endnote 55 for Chapter 15 from ?The Human Potential for Peace? (Oxford University Press, 2006).
<snip>
         Let me first address one of the last items raised by Douglas Fry¹s posting yesterday.  The differences in most of my Yanomamö demographic statistics, such as numbers of children by headmen between the 1979 and 1989 publications Fry cites has to do with a somewhat novel aspect of my field research.  I frequently returned to the Yanomamö many times between 1964, when my field work started, and 1997 when it ended.  In 1987/8 I updated my demographic data base for the Œcore villages¹ in my sample---some dozen or so villages that were very widely scattered and not easy to reach by canoe and on foot in the same Œcensus year¹---or, for that matter, to reach at all in any year.
         Because of this the data that Fry cites from one of my 1979
publications was from an earlier demographic data base than the data I used (and he cites) in my response to Ferguson¹s article in 1989.  People die, new babies are born, headmanship changes (including sometimes the number of headmen per village), lineage composition of villages change as a result of village fissioning, and even the number of politically separate villages changes.  Consequently there are bound to be differences in some statistics that I reported in early publications compared to more recent publications, but I try to inform the reader of this in major publications, like my 1988
Science article for example.

         Now to Fry¹s comments about age differences between unokais and non-unokais:

A.         Fry¹s method for re-calculating ages from my data assumes that ages are relatively evenly distributed within each of my four age groupings. This is probably not true.  The Yanomamö are illiterate and have no idea of their ages in years and I have to estimate their ages by Œon-site inspection¹---looking them over in person (and taking a photograph of them). Estimating ages is easier for the youngest people but difficult for adults. Consequently when I first census a village many people are estimated to be 20, 30, 40; a few are estimated be 25, 35, 45, etc. and none are estimated to be 22, 29, 33, etc. Also, some age estimates of individuals might be off more than others---I might estimate someone to be 25 when he might be in fact be 33---if that could be known. I am more confident of my age estimates for individuals in villages I either visit frequently or whose members I have known for upwards of 25 or 30 years. Perhaps I should have just made two age groups in my Science article: males from 10 to 30 and males over 30.

B.         I have not claimed that ³..unokais and non-unokais² are of comparable ages in general:  I put them into four different age groups and said that men within each of these groups were of comparable age.  It is unlikely that there are Œhuge¹ age differences within these categories.

C.       It seems that Fry has ignored the data in Table 3 of my Science article, which shows marital success of unokais vs. non-unokais for each of the four age categories I used.  Unokais have more offspring because they marry earlier, stay married longer, and have more wives than non-unokais in the same age category as I make explicit in both the text and the tables of that article. It is not true that the offspring production of unokais and non-unokais is simply a function of age, i.e., that men of the same age category will have the same number of children independent of their unokai
status, which was one of the major points of my article.

         Let me end, as Fry¹s last posting ended, by inviting the statistically proficient among the contributors to this list to look at the data in my 1988 science article and Fry¹s  challenge to some of my conclusions.  My 1988 Science article is now some 20 years old.  It was given very rigorous scrutiny by science¹s statisticians---who challenged me on several issues not related to what Fry is contesting, and, after its publication, it was presumably scrutinized by some of the many of the scientists who cite it.


Napoleon A. Chagnon, Ph.D.
Professor of Anthropology Emeritus
The University of California at Santa Barbara



Messages in this topic (18)
________________________________________________________________________
10b. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "dfry@abo.fi" 
dfry@abo.fi
    Date: Thu Apr 3, 2008 4:17 pm ((PDT))

Re: News: Has Science Found a Way to End All Wars?

In response to H. M. Hubey suggestions, modeling the demography of the Yanomami unokais and non-unokais is an interesting endeavor, and I encourage it. But before we get wrapped up in this particular
theoretical challenge, let?s return to the actual numbers that are presently available to us. We can see from Napoleon Chagnon?s (1988) data that 56 percent of the non-unokais are less than 31 years old,
whereas 55 percent of the unokais are 41 plus years of age. This is a fact derivable from Chagnon?s (1988) Tables 2 and 3 (see the end of this posting for some of his data). Therefore, there is no doubt that the unokais as a group are substantially older than the non-unokais.

Chagnon has never published the actual average ages for the unokais (n = 137) and the non-unokais (n = 243), but he has claimed repeatedly that the unokais and non-unokais he compares are the same age (e.g., Chagnon 1990 p. 95; Chagnon 1992a p. 205; Chagnon 1992b pp. 239-240; see Fry 2006, p. 289, note 11.) Mathematically, the unokais and the non-unokais cannot be the same age when they have these extremely different age distributions. Chagnon's four age categories does not adequately control for age distributions that are really different from each other.

In my previous posting, I invited Napoleon Chagnon to share with us the actual average ages for the 137 unokais and the 243 non-unokais. Presenting the means and standard deviations for these two groups would help to clarify the situation. (By the way, sharing the mean ages for these two groups of men does not compromise confidentiality, an important ethical concern previously mentioned by Chagnon, but not applicable to the publication of aggregate statistics such as means and standard deviations for groups of men.)

I have already published a set of mathematical corrections related to this unokai issue that take into consideration both the age difference between the two groups and also the headmanship problem (as discussed in my previous posting), since neither age nor headmanship were adequately controlled for in Chagnon?s original (1988) study.

The central conclusion, simply put, is that Chagnon?s claims that the unokais have over three times more offspring as non-unokais of the same age is wrong.  Although erroneous, this claim has proliferated in the literature. I pointed out that it has become gospel, by which I mean that it is accepted as truth and fervently defended against any one who would question its veracity. This type of reaction is reminiscent of faith-based religion, not science. I expect more from evolutionary psychology.

PS: Here are the age category figures for unokais and non-unokais from Chagnon (1988) Tables 2 and 3. It may be useful to turn the two age distributions into bar charts to see visually what the distributions look like. Again, 55% of the unokais are over 41 whereas 56% of the non-unokais are under 31 years of age.

Age Intervals in Years        Unokais                Non-Unokais
20 to 24                        5                        78
25 to 30                        14                        58
31 to 40                        43                        61
Over 41                        75                        46

--
Douglas P. Fry, PhD
Åbo Akademi University
& University of Arizona



19a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "dfry@abo.fi" 
dfry@abo.fi
    Date: Fri Apr 4, 2008 5:48 pm ((PDT))

Re: Has Science Found a Way to End All Wars?

Professor Chagnon writes:
        “Because of this the data that Fry cites from one of my 1979 publications was from an earlier demographic data base than the data I used (and he cites) in my response to Ferguson's article in 1989.  People die, new babies are born, headmanship changes (including sometimes the number of headmen per village), lineage composition of villages change as a result of village fissioning, and even the number of politically separate villages changes.  Consequently there are bound to be differences in some statistics that I reported in early publications compared to more recent publications, but I try to inform the reader of this in major publications, like my 1988 Science article for example.”

As I understand the situation based on Dr. Chagnon’s articles, the material published in his 1979 publications is based on a census conducted in 1975, whereas the material presented in his 1988 Science article reflects a 1987 census. The number of villages in his study population did not change dramatically. Obviously some demographic changes would be expected over a 12 year interval between these two censuses. However, my question for Dr. Chagnon is what happened to 7 lineage headman positions (not the men themselves) in 12 years? Did 7 lineages really just disappear, along with their headman positions? This seems highly unlikely, and no such disappearance is mentioned in Chagnon’s reports that I am aware of. I’m not just nit-picking here. There were 20 headmen in the population consisting of 13 villages, for the same study population, and then Chagnon reports that all the headmen, 13 of them, were removed for a reanalysis.
Sure individual headmen could have died in the 12 years between the two censuses, but they would have been replaced by new lineage heads. So to go specifically to the point, what happened to the 7 headmen positions? Why were only 13 headmen removed for the reanalysis, not the originally reported 20 headmen for the same study population? These are specific question that the demographic generalities offered above by Chagnon do not address.

  Professor Chagnon also writes:
“A.         Fry's method for re-calculating ages from my data assumes that ages are relatively evenly distributed within each of my four age groupings.   This is probably not true.  The Yanomamö are illiterate and have no idea of their ages in years and I have to estimate their ages by 'on-site inspection'---looking them over in person (and taking a photograph of them).    Estimating ages is easier for the youngest people but difficult for adults.  Consequently when I first census a village many people are estimated to be 20, 30, 40; a few are estimated be 25, 35, 45, etc. and * none* are estimated to be 22, 29, 33, etc. Also, some age estimates of individuals might be off more than others---I might estimate someone to be 25 when he might be in fact be 33---if that could be known. I am more confident of my age estimates for individuals in villages I either visit frequently or whose members I have known for upwards of 25 or 30 years. Perhaps I should have just made two age groups in my Science article: males from 10 to 30 and males over
30. B.         I have not claimed that "..unokais and non-unokais" are of comparable ages *in general*:  I put them into four *different* age groups and said that men *within each of these groups* were of comparable age.  It is unlikely that there are 'huge' age differences within these categories.”

I would like to thank Professor Chagnon for the additional clarification regarding age-estimating methodology (point A).  I totally understand the roughness of age-estimating process, from research I have conducted, and the tendency to make age estimates to the seemingly most likely 5 or 10 year mark.

I have imagined that Chagnon’s use of the four age intervals was an attempt to compare unokais and non-unokais of somewhat similar ages (point B). I guess a remaining difference of opinion here, between him and me, is whether or not dividing up the samples into four different age groups really controls for age differences in the sample. Chagnon seems to still defend this analytical choice, whereas I see serious problems with it.

I would tend to agree with Dr. Chagnon that for the youngest three age groups (that span 5 years, 6 years, and 10 years, respectively), the average age differences between the unokais and the non-unokais within each of these groups would probably not be ‘huge.’ And now, as new information from Dr. Chagnon (in point A above), it appears that most men in the 5-year interval 20 to 24 would have been estimated to have been 20 years of age, regardless of whether they are unokais or non-unokais. However, the fourth interval, of an estimated 33 years (that is, males over 41 years to about 74 years) could reflect substantial age differences within this one very substantial age-interval between unokais
and non-unokais. 33 years is a huge age interval.

I hope that Dr. Chagnon will be forthcoming with the actual mean ages and standard
deviations for the 137 unokais and the 243 non-unokais in his sample.

My main point, though, is that the age differences overall between the entire groups of unokais and non-unokais should be more stringently controlled for in order to really eliminate confounding effects of age.  This has not been done. When it is done, I have shown mathematically, that the unokai reproductive success advantage over non-unokais is markedly reduced. Additionally, controlling for a headman effect reduces possible unokais reproductive advantage still further. As fully discussed in The Human Potential for Peace, calculations show that the combined effects of age and headmanship are substantial. Even the most onservative calculation (age alone) cuts the originally unokai reproductive success advantage reported by Chagnon in 1988 by 56 percent whereas the most liberal (yet plausible) calculation, combining corrections for age and headman effects, totally eliminates any unokai reproductive advantage whatsoever.

Recently, I have been examining conflict and aggression in nomadic hunter-gatherer
society. The nomadic hunter-gatherer data take us in a totally different theoretical direction than a paradigm largely derived from Chagnon’s Science article that killers have more children--and by implication, that natural selection has supposedly favored killers over less aggressive men. I go into detail in my recent books (e.g., Beyond War), but I’ll mention just a taste of a different evolutionary model of human aggression based on observable patterns of nomadic forager behavior.

As among various animal species, there is a marked tendency for nomadic foragers to practice a great deal of restraint. Of the Yahgan, Martin Gusinde expresses: “A person will literally foam with rage.”  Nevertheless, he can muster astonishing self-control when he realizes that he is too weak to stand against his opponent."

The widely reported pattern of avoidance--voting with one’s feet--of conflict by nomadic foragers obviously reflects restraint. A second indication of restraint is that a great number of disputes simply never escalate to the level of physical aggression. In evolutionary terms, if a conflict can be handled without incurring the risks associated with physical fighting, so much the better. Animals sometimes employ low-risk threat displays in place of actually fighting. Humans, with language at their disposal, can employ verbal threats in a parallel manner.

Third, the ritualized aggression of various animal species has analogs among nomadic foragers, as illustrated by the song dueling among the Netsilik, the formal pattern of spear-throwing and dodging among the Tiwi, or the ceremonial spear-throwing of the Murngin during a peacemaking ritual called the makarata. Siriono bystanders enforce the cultural rules of fair fighting. Such aggression-limiting rules and ritualized contests are regularly mentioned in the ethnographic literature on simple foragers. A fourth indication of restraint is that even within societies where revenge killing is socially allowed or advocated, as among the Netsilik, nonetheless, many killings simply go unavenged.

A focus on restraint also puts a new spin on tribal Yanomamö aggression, although the Yanomamö, of course, are not nomadic foragers. As among nomadic foragers, Yanomamö men minimize risks, as reported by Chagnon across many of his publications (e.g., 1988, 1992, 1996). Yanomamö often take revenge through sorcery rather than by physically attacking an enemy, many disputes are handled through contests that curtail serious injury and the loss of life, raiding is undertaken in groups instead of individually, men find excuses to drop-out of raiding expeditions, the ambushing a single unsuspecting victim is a favored tactic, women usually are not captured during a raid because they slow down the rate of retreat thus endangering the raiders, villages sometimes simply move away from aggressive neighbors, and so forth. As in many animal species, the use of restraint by humans is apparent across a variety of evolutionarily natural and unnatural environments.
Exercising restraint during aggressive encounters may well be the outcome of strong selective forces operating over evolutionary time.

In summary, the anthropological material on patterns of aggression in nomadic
hunter-gatherer settings is not consistent with an image of killers out reproducing non-killers at every turn. To the contrary and in parallel with studies of aggression in various animal species, a great deal of restraint on aggression is evident in nomadic forager societies. I point out in Beyond War and The Human Potential for Peace that conflicts are handled by toleration, avoidance, and a plethora of safer, non-physical approaches such as verbal harangues, arguments, discussions, reprimands, song duels, and mediations assisted by others. Some nomadic forager groups have developed social rules that help to limit the severity of physical fighting or ritualized contests that allow for the venting of emotions without serious injury. In band level societies, on-lookers, as interested third parties, stand ready to intervene to enforce the rules or pull
contestants apart should fighting escalate. Such interventions are often unnecessary because both contestants simply follow the rules of restraint on their own accord. It is in their interests to do so because following the rules minimizes risks to both of them. As is observable elsewhere in the animal kingdom, the restrained or limited use of aggression among nomadic foragers is readily apparent. This type of data presents us with a very different evolutionary model of aggression than does the unokais model that focuses on killing as a path to reproductive success.

--
Douglas P. Fry, PhD
Åbo Akademi University
& University of Arizona


5a. Re: News: Has Science Found a Way to End All Wars?
    Posted by: "Napoleon Chagnon" 
chag99@charter.net
    Date: Sat Apr 5, 2008 5:37 pm ((PDT))

On 4/4/08 6:18 PM, "dfry@abo.fi" <dfry@abo.fi> wrote:
[Hide Quoted Text]


Re: Has Science Found a Way to End All Wars?

Professor Chagnon writes:

<snip>

³As I understand the situation based on Dr. Chagnon¹s articles, the material published in his 1979 publications is based on a census conducted in 1975, whereas the material presented in his 1988 Science article reflects a 1987 census. The number of villages in his study population did not change dramatically. Obviously some demographic changes would be expected over a 12 year interval between these two censuses. However, my question for Dr. Chagnon is what happened to 7 lineage headman positions (not the men themselves) in 12 years? Did 7 lineages really just disappear, along with their headman positions? This seems highly unlikely, and no such disappearance is mentioned in Chagnon¹s reports that I am aware of. I¹m not just nit-picking here. There were 20 headmen in the population consisting of 13 villages, for the same study population, and then Chagnon reports that all the headmen, 13 of them, were removed for a reanalysis. Sure individual headmen could have died in the 12 years between the two censuses, but they would have been replaced by new lineage heads. So to go specifically to the point, what happened to the 7 headmen positions? Why were only 13 headmen removed for the reanalysis, not the originally reported 20 headmen for the same study population? These are specific question that the demographic generalities offered above by Chagnon do not address.²

Fry misrepresents---or simply does not understand---the social organization and political practices of the Yanomamö.  There are lots of smaller lineages represented in most Yanomamö villages.  Not all of them have Œlineage heads¹; Fry treats this concept as one that occurs as some kind of formal political position in Yanomamö culture.  It does not exist as a formal position.  For example, six or eight lineages might be found in a village, but there are not six or eight Œheadmen¹ in the village.

He also insists on using the sociodemographic characteristics of a set of 13 villages from my 1975 census database to cast doubt on my findings for the 12 villages I considered in my 1988 Science article.  He says he understands that things change over a 12 year period, but then demands to know Œ..what happened to the 7 lineage headman positions?² that he Œdiscovered¹ in my 1979 publicationn.  Well, Fry himself Œcreated¹ these positions (supra) but demands that I explain why they disappeared.

Finally, his somewhat glowing accounts of ethnographies on various
hunters/gatherers that  show how they reportedly manage to constrain and restrain violence is supplemented with lessons from animal species which do the same.  He ends with the hopeful suggestion that ³This type of data presents us with a very different evolutionary model of aggression than does the unokais model that focuses on killing as a path to reproductive success.² I get the feeling that my 1988 Science article MUST be repudiated in cultural anthropology lest it remain a viable Œmodel¹ of aggression, which I did not suggest it was, but a possibility that seems to bother Fry.

Unfortunately, this is my last post on this topic.  I¹m trying to finish a book and I don¹t have time to re-explain basic Yanomamö ethnography---nor is this the forum in which to do it.  I also do not want to be confused with, as Mark Hubey put it in one of in his posting on 4/3, those anthropologists who Œ....prefer doing fourth grade arithmetic and fighting for decades over aproblem that can be solved by undergrads.¹

Napoleon A. Chagnon, Ph.D.
Professor of Anthropology Emeritus
The University of California at Santa Barbara