heh. several of you were grossed out at the thought — and that’s good! that is as it should be.
i don’t have a brother, so i don’t know what the westermarck effect feels like, but apparently it feels like … ewwwwwwww! and it doesn’t just work for sibilings, but any kids that are raised together. i’ve read many accounts of muslim couples who have been made to marry their first-cousins who complain that they’re not attracted to each other and very often they were raised together (in an extended family household), so they feel like … ewwwwwwww!
robin fox had a lot of interesting stuff to say about the westermarck effect in “The Tribal Imagination” (chapter 6 — and also presumbaly in his book on incest, but i haven’t read that). here’s an excerpt for ya [pgs. 128-31]:
“Taboos on sexual relationship between close kin, between the members of the immediate family, were long thought to be a purely human invention. Animals, it was maintained, had no such inhibitions and mated incestuously. Thus the taboos on such animalistic behavior were thought to be the very foundation of human society; they were the ultimate Drumbeat of humanity, by which, in the immortal words of Levi-Strauss, culture said ‘No!’ to nature….
“The move from nature to culture represented by the imposition of the taboos was seen as precarious and counter to natural motives, which were ineradicable. In consequence, the taboos had to be stern and enforced by constant vigilance. In this traditional view, we all wanted to make love to our nearest kin, but once the momentous leap into culture had been taken, it would have been disastrous to go back into the maelstrom of incestuous animality. Our societies were built on the presumption of mating outside the family, it was the very definition of humanity itself, and so stern taboos, laws, and punishments were needed to keep incest at bay.
“This was a plausible view because societies did almost universally ban sex and marriage within the immediate family, and punishments for breaches of this rule were often severe, including torture and death. In their mythologies, primitive tribes and ancients societies often portrayed incest, and the results of it were usually disastrous. There were exceptions to the rule (and we shall return to these), but they were almost always royal exceptions, and royal persons, as gods on earth, were allowed behavior that was not allowed to ordinary mortals. On the whole, then it was agreed, there was a ‘grisly horror’ of incest (Freud) that universally afflicted people and led them to impose and enforce the taboos, often extending them beyond the family to members of the clan, variously defined. Why, the question went, would we have such strong taboos if we did not have the strong desire in the first place?
“Both popular opinion and the collective voice of the behavioral sciences echoed this orthodoxy. But there was always an undercurrent of skepticism. Why, the objectors asked in turn, do we seem, by and large, not to want to have sex with our closest relations? This would be the common-sense observation. Incest happens, but in proportion to non-incest, it does not happen very often. And most of this avoidance of incest does not seem to result from fear of punishment; there seems to be a genuine aversion to incest. This aversion seems to vary according to the relationship: strongest between mother and son, weakest between father and daughter, variable between brother and sister. But it is there, and usually only breaks down in unappetizing circumstances.
“The orthodox view said that left to our own devices we would immediately resort to incest and so we have to be reined in by strong taboos and sanctions…. The skeptical view says that, on the contrary, left to our own devices we would probably mostly avoid incest spontaneously. The orthodox view asks why, then, if this is so, are there the universal strong taboos?
“The skeptic answers that we often taboo the things that we are averse to, not because we secretly want to do them, but because we disapprove of people doing things that are generally obnoxious to us. We strongly taboo murder, not because we are all given to implacable murderous impulses, but because we are averse to it, so that even if only a few people do it, it offends us. We do, however, understand the temptation to do it; we have all perhaps felt it momentarily. So the subject fascinates us and permeates our legends and stories from the beginning. Sex and violence, incest and murder — often linked in our fantasy productions — persist in our imaginative attempts to interpret ourselves to ourselves….
“[I]n looking at animal behavior under natural conditions, indeed at the behavior of all sexually reproducing organisms, outbreeding seemed to be the rule and incest was rare. This was especially true in our primate relatives, and so by implication in our ancestors during the long haul through the savannas and the ice….
“The origin of this sexual reproduction is still a mystery, but whatever the reason, this new form of reproduction won out over its rival (which is still around) by virtue of its ability to produce instant genetic variability for natural selection to work on. Close inbreeding results in a loss of such variability, hence mechanisms evolved to avoid it. At the same time, if inbreeding becomes too random, then any beneficial genes will be dissipated rather than concentrated and preserved. It is this loss of variation that seems to be at the heart of sexual strategies, not the bad genetic effects of close inbreeding. In small bands these effects would quickly be bred out, and even scattered bouts of outbreeding would reestablish a healthy stock.
“So nature aims for a middle ground: organisms breed out to avoid losing variability, but not so far out that they dissipate genetic advantages. In human terms this means that the immediate family is taboo, but that marriage with cousins should be preferred. This is exactly what we find in human history until the dramatic growth and disruption of human populations upset the natural balance of the traditional society.”
actually, this is exactly what we find in human history until the roman catholic church started fiddling with mating patterns in europe in the early middle ages (see Inbreeding in Europe series down below ↓ in left-hand column).
“[I]f inbreeding becomes too random, then any beneficial genes will be dissipated rather than concentrated and preserved.”
think about that in terms of altruism genes.
(note: comments do not require an email. don’t panic!)