I may regret this...
Human evolution
A book came across my desk yesterday, containing the following paragraph:
Mating consortships are also sometimes seen in chimpanzees and are particularly common in bonobo. In fact, a male and female bonobo may spend several weeks primarilly in each other's company. During this time, they mate often, even when the female isn't in estrus. But these relationships of longer duration aren't typical of chimpanzee [...] males and females.Esentials of physical anthropology / Robert Jurmain, Lynn Kilgore [and] Wendy Trevathan. 6th. ed. Belmont, CA : Thomson Wadsworth, 2006. ISBN 0495030619.
I only loked at it coz of the cute chimps on the cover. Anyway - that paragraph jumped out at me because of my recent discussions with Stuart. Basically, it suggested something that seems to me to drive a coach and horses through Knight's theories.
If consortship/pair bonding type relationships are imminent within our nearest evolutionary cousins, then we could well infer that such a practise was in existence within human evolution at some point - bonobo style relationships. If then we further consider that all it would take would be selective pressures (and benefits) to extend this kind of relationship, then we can begin to see modern human sexual relations emerging through a simple evolutionary process quite easilly.
The lack of oestrus Knight notes could in fact just be a consequence of bonobo sex - if oestrus stops being important we may simply have stopped selecting for it.
That is, I'd suggest, there is no need for a sex strikle theory to account for observable features.
Stuart asked for a rival theory - there's one. Hominids were engaging in consortships, those who had more solid consortships which lasted longer produce more succesful offspring, passing on the tendency for consortship and long term relationships we see in human history.
posted by Bill at 08:30
4 Comments:
I wonder why only humans have evolved in the way we have if what we have could emerge "quite easily"? I beleive pair-bonding is actually quite prevelent in nature, even if not necessarilly among primates. However, lets not forget, it wasn't just us, there were several co-existing species of hominid around, it's just only ours survived.
Why don't bonobos have it? the good Darwinian answer is that the right mutations haven't come along at the right moments. Maybe bonobos are only just setting off on the course that our ancestors took off on, maybe they'll be human in 5 million years...
What were those selection pressures you talk about? Selecting for what? What benefits? What about the costs and the conflicts? Well, the pressures would be such that consortship leads to a likely increase in child survival - ranging from the early stage protection from predators to later stage assistance in food gathering.
Chimpanzees have been evolving for as long as humans. I wonder why their oestrus signals haven't withered away? I beleive they use their oestrus as part of their reproductive baheviour - my point was once you get to consortships that last before and after oestrus is ceases to be teh mechanism by which mates are attracted and ceases to be selected for.
I wonder why the consortship patterns you mention "aren't typical" among chimpanzees?
No mutation at the right time? Counterveilling genetic make-up/behaviour that millitates against success of such a gene? I know Chimps and Bonobos are our cousins, but their cousin=s we haven't talked to since great aunt silverback's funeral 5 million years ago, at best they can be indicative...
I note that bonobo chimpanzees form female coalitions to challenge male dominance. That they offer sexual favours in order to get meat. That's pretty extraordinary, isn't it? I wonder if this could tell us anything more convincing about human origins?
They tell us Knight's theory could be right, and is a possible model, but not the only model, and not necessarilly the best model.
Stuart, it wasn't a complete rival theory (if that) merely a rival to one premise (an important premise) of Knight's theory.
As for a rival theory of language - random mutation, for no good reason a language gene appeared that did not conflict with our survival chances and it stayed resident.
It could all be fluke.
Primates pass on learned behaviors also. Its not all mutation and genetics.
Adam Buick forwarded me the following, by Chris Harman, which I reproduce here without further comment:
is\knight
REVIEW FOR IS JOURNAL
BLOOD RELATIONS: MENSTRUATION AND THE ORIGINS OF CULTURE
CHRIS KNIGHT, YALE UNIVERSITY PRESS, 40
EVERY generation of Marxists has to fight its battle against those who produce the latest proofs_strangely enough, always the same old proofs_that Marxism is finished. But we have also had, repeatedly, to fight another, even more tiresome battle against people who claim to be on our own side. Ever since HErr Professor Durhing beguiled half the intellectuals of the German socialist movement with his ''revolution in science'' in the 1880s, Marxists have had to expose a series of intellectual quacks who have tried to present their pet systems of myths and half truths as the latest thing in scientific advance.
Chris Knight's book about the origins of human culture falls straight into the same tradition of quackery.
Every chapter is headed by a quote from Marx. But the intellectual basis of the book owes little to Marx's insistence that the social production is the key to the development of humanity.
Rather Knight's acknowledges his debt to: ''sociobiology's achievements'' in seeing that ''what animates ... the flesh and blood individual...are...genes...whose only law is to survive..'' to the mystical poets Peter Redgrove and Penelope Sharp, whose ''style and tone'', he tells us, is ''Jungian'' to those ''involved in the Greenham Common anti-missile campaigns of the early 1980s'' who refused ''to collaborate in the whole masculinist political set up...'' and to his ''political friends'' which include prominent Labour MP Ken Livingstone and two lesser known luminaries of the London Labour left, Keith Veness and Graham Bash.
His politics are those of the Labour left of a decade ago_when Knight himself edited the ''personal politics'' section of the Labour Briefing, mixing Greenham Common feminism with municipal socialism_ and his methodology is a similarly eclectic. The resulting confusion leads to absurdities like speaking of a ''class conflict...between genders'' among ''monkeys and apes''.
Most pop sociobiologists do not go beyond the 17th century mechanical materialist, Thomas Hobbes, who described life for humans in the ''state of nature'' as ''nasty, brutish and short'', with a ''war of all against all'' making impossible the development of civilisation impossible until people were forcibly compelled to behave themselves. Knight is no exception.
He argues ''genetic imperatives'' necessarily caused continual, bitter, bloody competition among our primate ancestors. Their behaviour, like that of present day primates, he describes as like ''primitive capitalists'', their battles with each other reminiscent ''of some of Lenin's descriptions of inter-imperialist rivalry''. And this prevented any real development of culture until among our ancestors until about 50-60,000 years ago when cooperation replaced conflict.
His ''theory'' is a ''Just So'' story about how such a change could have occurred_instead of telling how the elephant got its trunk, it claims to tell how humans got culture.
It depends on adding a number claims to the initial postulate of endless conflict'
1. Males and females of all species have different ''genetic imperatives'' . Males can have innumerable offspring if they can squirt their sperm around widely enough, while females are restricted to those they carry inside their own bodies. So the genetically successful male will always be the one that fights others males for ''dominance'' over as many females as possible and does nothing to help in the upbringing of progeny, but the genetically successful female will pay attention to rearing her offspring. In this way the motherly women and the philandering male are genetically fixed, and males, given the chance, will behave as parasites and oppressors, a ''leisured class'', lording over an exploited class of female reproducers. These, suffering from the incessant competition of animal society and have an interest in bringing about its revolutionary overthrow.
2. Human beings differ biologically from other primates in a way that alters the balance of power between the sexes, without changing the fundamental genetic disposition of either sex. The oestrus cycle, in which the female is only ''on heat'' and of sexual interest to the male at the time of ovulation, is replaced by the menstrual cycle, with sex possible at all times_except, according to Knight, at the time of menstruation itself, when it is a fairly bloody business.
3. Late on in human evolution women discovered how to take advantage of this by synchronising their periods so as to deny men sex until they went out hunting and returned to share the catch with them. Such a ''sex strike'' forced the innately competitive males to cooperate to the benefit of the females and of humanity in general.
4. This all triggered off the development of culture and language some 50-60,000 years ago.
5. The myths and taboos of ''traditional societies'' bear witness to this today.They reenact elements of the sex strike by forbidding sex or cooking during menstruation, by banning hunters from eating their own kill, and by extolling the moon. Their tales of wondrous snakes or dragons are a celebration of women's power and solidarity, even if this has since has been usurped by men. ''Such beliefs are in essence good science.''
But this equation of myth with science is based on linking together of half truths, false generalisations, unproven assertions and the occasional fact.
Take his initial presupposition, the alleged, state-of-nature, bloody competition between male primates over food and females. Knight justifies himself by reference to Solly Zukerman's study of the chimps in London Zoo in the early 1930s. But there have been scores of further studies since, many based in the wild, which give a very different picture[i]. They reveal differences of social behaviour between different ape species as great as those between any of them and modern humans[ii]. And in many cases there are far more instances of cooperation between individuals that conflict.
The social life of chimps, and still less gorillas, is certainly not one of endless battles by males to dominate females[iii]. Cases of aggressive behaviour do occur among chimps_but they are not all pervasive and only occasionally end in fights.[iv]
Nor are there continual fights over food. When common chimpanzees make ''occasional forays into meat eating'' they ''share out morsels among individuals who beg persistently enough..'' [v]
With pygmy chimpanzees ''Food and feeding are a focus for social interactions...Plant food is frequently shared.''[vi]
And any hunting of other animals is, itself, likely to involve cooperation between different members of the chimp group_and not only the males. It involves action that ''implies a lot of restraint, a good deal of cooperation, and not a little communication''.[vii]
So much for Knight's most basic sociobiological postulate, the cooperation was impossible until the ''sex strike''! With it his whole construction collapses.
Every other point of his argument is similarly flawed.
1. ''Genetic success'' for individual males does not, in all situations and at all times, depend upon males ignoring the interests of everyone else. To say the most successful genetic strategy will be to fertilise as many females as possible, rather than to helping one female rear her offspring, is rather like saying a successful gambling strategy always involves put small sums of money on many horses rather than the lot on a near certainty. Of course it doesn't. It all depends on the odds.
If material conditions mean an unaided female will almost certainly lose her offspring to predators or through starvation, then any male fails to help with child rearing will not be able to pass on his genes. ''Survival of the fitted'' will then be the survival of the most fatherly.
As Gigliari tells:
''In many species of mammals, the parental investment by males
is considerable, and apparently enhances the reproductive potential of both sexes''. He refers to Callicebus monkeys, white handed gibbons, wild dogs, wolves, and Hartman Zebras.[viii] I don't think KNight would want to argue a sex strike had to take place in all these cases!
2. Human females are not unique in the replacement of the oestrus cycle, with its ''on heat'' phase, by the menstrual cycle nor in their readiness for sex at any point in the cycle. ''The menstrual cycle is a process common to old world monkeys, apes and men''[ix] and, as a result, ''In anthropoid apes the sexual cycle is not expressed nearly as markedly as in other animals''.[x]
Among chimps ''mating may occur at any time during the female's cycle'' although ''significantly more sexual behaviour occurs during the follicular phase'',[xi], ''orang utangs mate throughout the female's menstrual cycle without pronounced cyclical changes in behaviour''[xii], and gorilla ''Females may present themselves to males throughout the cycle, but males accept a greater proportion when the female's labia are fully swollen''[xiii]. Among both chimps and gorillas, the it can be either males or females who take the initiative sexually.[xiv]
Knight's picture of the philandering male, driven by an overpowering instinct to fight other males to fertilise as many females as possible, hardly matches up with the facts!
3. Sychronisation of periods among females in close contact with each other is not, as Knight claims, as an adaptive mechanism specific to humans and which can explain some sudden invention of culture a few thousand years ago. It occurs among rats, gelada baboons, hamadryas baboons, rhesus monkeys and chimpanzees[xv].
What is more, it is certainly not a conscious mechanism, as is implied by talk of women can choosing to synchronise periods to go on ''sex strike''. It is a completely unconscious process, arising as physical stimuli, probably of an olfactory nature, cause changes in hormonal balances.[xvi]
4. There is overwhelming evidence for the existence of culture and language long before Knight's 50 to 60,000 years ago. Stone implements have been found that are more than two million years old[xvii] and by half a million years ago there were being designed according to common patterns. By the time of the neanderthals, 200,000 years ago, there is evidence of ritual burial. There was already a marked growth of the parts of the brain responsible for speech in modern man_Broca's and Wernicke's_in homo erectus 500,000-1,000,000 years ago (and possibly in homo habilis more than a million years before this) [xviii], while the vocal organs of the neanderthals would have been able to make most of the sounds we can[xix].
All this suggests there was a long drawn out development of symbolic culture and language out of rudimentary sounds and gestures similar to those used by chimps and gorillas today. There would have been all sorts of quantitative changes and qualitative leaps at different points during the two million years of this development, as humans evolved larger brains and learnt new ways of using them_archaeologists have long distinguished between the different ''cultures'' that characterise tools to be found at different times in this long history. But this does not at all means that humans accidentally managed to quadruple the size of the primate brain over a three or four million years period, suddenly 50-60,000 years discovering how to use it.
5. Among many surviving hunter gatherer societies_those closest their lifestyle to our ancestors of 50-60,000 years ago, myths and taboo are not all what Knight's model demands. He himself admits, ''It is certainly not the case that [Australian] Aboriginal women everywhere synchronised their periods with one another or with the moon in the recent pre-contact period'', and that ''we have little hard evidence for either the present or absence of real menstrual synchrony among the hunter-gatherer peoples of Africa''.
N or as menstrual taboos by any means universal in such societies. The Mbuti pygmies of the central African rain forest ignore the strict menstrual taboos that prevail among their agricultural bantu neighbors[xx], while the Kung regard menstruation as a relatively minor event.[xxi]
So desperate is Knight fo evidence that he claim painting the body red has menstrual significance. Does he apply that to all women who use makeup?
As for his other great taboo, the ''first kill'' one, Knight himself writes that is ''not always rigidly adhered to'' that ''it is in fact systematically evaded or undermined in a multiplicity of historically determined ways.'' Put more simply: it does not apply universally as he claims!
What we are faced with in this book, then, are a series of phoney facts linked together by a intricate cobweb of speculation and then dressed up as ''Marxism''.
This is particularly regrettable since there has developed, in recent years, a body of evolutionary theory among a minority of archeologists and anthropologists that fits in with what genuine Marxists have long argued[xxii].
The starting point of this approach is to recognise that in certain situations natural selection favours groups whose genetic make up enables them to learn from each other and to cooperate to get a livelihood.
This happened some millions of years ago among the ape-like ancestor we share with the chimps and gorillas. Faced with climactic changes different groups of this species responded differently. While the ancestors of the gorillas and the chimp adapted to forest and woodland life, our ancestors were able to survive in savannah (open grassland dotted with clumps of trees) because three characteristics present in all African apes became more marked in them_the ability to stand upright, the ability to cooperate in gathering food and the ability to make rudimentary tools.
Their mode of existence that gave selective advantage to traits_both biological and cultural_ that only exist in embryonic form in other primates: cooperation, the use of the hand to make and carry tools, the development of communication through gesture and voice, the detailed observation of animals life to be hunted and plant life to be collected, increased concern with the socialisation of the young while they learnt from their elders, the establishment of friendly links with other groups through intermating.
What we have here is the beginnings of a labour theory of human origins and of culture, something which then enables us to begin to explain other epochal changes in human existence, like the rise of agriculture, the growth of a surplus, and the origin of classes, the state, systematic warfare and women's oppression.
A few of those who practice this approach are conscious Marxists. Most are not. But they are driven to materialist conclusions by the desire to explain the factual material they have discovered about the history of humanity. We can learn a lot from them_providing we are not put off the whole topic by Knight's menstrual moonshine.
2,701
[i]. See, for instance, Jane Goodall, The Chimpanzees of Gombe, Cambridge MAss, 1986. For a list of 25 field studies of chimpanzees, see N M Tanner, On Becoming Human, Cambridge 1981, p62. For a summary of other evidence, see V P Alexeev, Origins of the Human Race, Moscow 1986, p275
[ii]. A point made, for instance,by MF GAdika & G Teleki, in Current ANthropology, June 1981
[iii]. Roger E Leakey and Roger Lewin, Origins, London 1977, p64, A F Dixson, The natural history of the gorilla, London 1981, p128, and Tanner, pp93-103
[iv]. See the evidence from Sugiyama and Reynolds & Reynolds, quoted in Tanner, p102
[v]. Leakey and Lewin, p 76
[vi].Adrienne L Zihlman, ''Common Ancestors and uncommon apes'', in JR Durant, Human Origins, Oxford 1989, p98.
[vii]. Leakey and Lewin, p154. See also Leakey and Lewin, p156, and Williams, p155 and Goodall, p304
[viii]. Giglieri, The chimpanzees of Kibale Forest, NY 1984, p179
[ix]. Dixson, p1 41
[x]. Alexeev, p272
[xi]. Dixson, p 148. See also the abstract of JF Dahl's paper, ''Sexual aggression in pygmy chimpanzees'' in the International Journal of Primatology, 1k987, p451, and also Jane Goodall, as above.....
[xii]. Nadler's findings, reported in Dixson, p150
[xiii].m Dixson, as above
[xiv]. Nader, as reported in Dixson, p 145, and Tanner p 97
[xv]. |?|?|? ''The synchrony of oestrus swelling in captive group living Chimpanzees, International Journal of l of Primatology, vol 6 no 4, 1985, pp330 and 342
[xvi]. See the discussion on its causes, in Synchrony, etc
[xvii]. Richard Leakey, ''Recent fossil finds in Africa'', in J R Durant, ed, Human origins, Oxford 1989, p60
[xviii].The archeologist P V Tobias argues that these areas were already developed in Homo Habilis, up to a million years earlier than this
[xix]. According to Lieberman (???)
[xx]. For a full account fo the Mbuti, and the way the;y make fun of the observance of the menstrual taboo among their neighbors, see Colin Turnbull, The Forest People.Knight himself quotes the example, but he then goes on to try to turn the truth on its head by claiming it reinforces his case!
[xxi]. Marjorie Showstack,
[xxii]. See, for instance, Leakey and Lewin, Tanner, Alexeev, ......
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