| 15 Nov 2003 @ 00:01, by Letecia Layson|
14:32 01 October 03
Early female-dominated societies lost their power to men as they acquired cattle, a new study demonstrates.
The idea that early communities became "patrilineal", with male status and inheritance being most important, when they gained cattle has been debated since the beginning of modern anthropological studies in the nineteenth century. However, no one had been able to convincingly demonstrate a causal link.
Now Clare Janaki Holden and Ruth Mace at University College London, UK, believe they have produced some of the firmest evidence yet to back the theory.
They made a linguistic tree of the evolution of 68 African Bantu languages, which include modern day Swahili and Zulu, and correlated this with the acquisition of cattle herds by those language speakers and the type of society they lived in.
The researchers then used a clever mathematical model to infer what had happened in the past to produce the pattern of languages seen today. "At an early stage these populations were more matrilineal than today," Holden told New Scientist. "They then adopted cattle and became patrilineal."
"I think this study is very important," says Mark Pagel, an evolutionary biologist at the University of Reading, UK. "What they are trying to show is that human mating patterns, wealth inheritance and dominance systems respond to ecological variation in the same way that we would expect animal populations to behave."
Holden believes reason the acquisition of cattle led to a switch to male-dominated societies is most probably linked to the system of "bridewealth". This tradition, in which a bridegroom gives cattle to a bride's family, is particular to the Bantu speaking regions of sub-equatorial Africa.
"If a man's got lots of cattle he can have lots of wives. So if you have cattle it makes sense to give it to sons rather than the daughters," she says. The fundamental reason for this is that wealthy, and therefore attractive, sons are likely to have more children than daughters, because while women must bear each child a man need only impregnate a woman.
Holden believes that the acquisition of wealth may generally causing a shift in power to men: "If you have valuable resources they are probably going to become monopolised by men because men can use them to acquire more wives or women."
Another factor that could be important, Holden says, is cattle raiding, with men better able to defend against marauders.
The Bantu linguistic tree created by Holden and Mace charts the divergence of the languages from a common starting point about 3000 years ago. They then added data about each population's ownership of cattle and their type of society, matrilineal or patrilineal.
The pair then applied the mathematical model, developed by Pagel, to find the "maximum likelihood" historical scenario that would have produced the modern day situation. They found that acquiring cattle did indeed cause a shift to a man's world, or one of "mixed descent" where both sexes are important for inheritance.
Crucially, they were able to account for the fact that the cultures were related. Cultural traits tend to be passed down generations in the same way as genetic ones.
Pagel, who is also Mace's husband, says the study shows the cultural phenomenon arose independently a number of times and "greatly strengthens" the belief that the cattle ownership and patrilineal societies have a causal connection and are not observed together for some other reason.
Journal reference: Proceedings of the Royal Society B (DOI 10.1098/rspb.2003.2535)
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