In past few posts in this series, I have tried to stay close to the view of what the Westermarck Effect is that focuses on sexually mature sibling incest avoidance and the idea that intimate childhood association produces it, but that also suggests that Westermarck himself flips between that view and one that is much broader in its range, applying to other family dyads as well. Time now to step back from micro-details to take a look at the larger cluster of views of which this “effect” is a part.
There are at least five such views in play here. The first of these, a claim about certain kinds of rules and practices—taboos—has been long accepted. It says that
incest taboos are universal across cultures, even though the content of those taboos varies.
Incest taboos result in pairwise restrictions on who can have sex, marry, or have children, with whom, based on the kinship relations between the members of the pair. The claim about their universality is often taken to pick out a phenomenon to be explained by cultural anthropologists in discussions of kinship, sexual practices, taboos more generally, or cross-cultural variation. It allows that incest sometimes occurs, but that it is normatively proscribed, and a proscription that is followed for the most part.
The most influential explanations of incest taboos offered by anthropologists–from Tylor and McLennan in the 19th-century through to the Freudian-drenched 20th-century accounts of Murdock, White, Levi-Strauss, Schneider, and even, more recently, Godelier, have either denied the remaining four claims, or been articulated in ignorance of them.
- incest avoidance is widespread in the nonhuman animal world, including amongst nonhuman primates
- humans and their closest primate relatives alike have a natural psychological aversion to incest that plays a causal role in both incest avoidance and, in the case of humans, incest taboos.
- incest taboos are conventionalized expressions of the natural psychological aversion to incest that humans have
- incest taboos in human societies are, in some sense, derivative from pre-existing incest avoidance in the nonhuman animal world
The first is a view about certain kinds of behaviors and their avoidance, a view for which Westermarck himself had weak evidence, but that evidence has now become sufficiently solid in light of advances in the study of animal sociality that it cannot be reasonably denied. That is not to say that it cannot be ignored, as it has been by many focused on human incest and its avoidance who hold that human incest, our feelings about it, and the rules that exist in all human cultures pertaining to it, make human incest a phenomenon of an entirely different kind from anything that we find in the nonhuman animal world. Westermarck offers a particular version of the second claim about human beings, one according to which the “natural aversion” here is innate and the causal role it plays in both avoidance and incest taboos is direct. Again, the broader claim here has received much support from both human and nonhuman primate studies conducted in the last 30 years. The third claim is what William Durham calls the expression hypothesis; in Westermarck’s hands, it is the claim that the expression of the natural psychological aversion to incest in humans in incest taboos operates via moral disapproval. The fourth claim goes beyond Westermarck’s own views, but I suspect receives support, and articulation, from the preceding four claims. It is the denial of this claim that has characterized the most influential views of incest and incest taboos in cultural anthropology, with incest taboos being a sui generis human cultural phenomenon to be understood, along with other social rules and practices, in their own terms.
What do I think is the status of each of these claims? The first two, at least restricted to the nonhuman primate world, seem to me clearly true and supported by strong evidence, recent denials (Leavitt 2007, Leiber 2006) notwithstanding. The last two, by contrast, remain more open than their proponents have thought, though their denial, as well as the alternatives put in their place, need to be articulated with the first two claims granted, something that few have done. The lynchpin claim, a part of the second claim, is that humans have a natural psychological aversion to incest; this claim is presupposed by the third claim, and its truth would significantly strengthen the case for Westermarck’s hypothesis about the mechanism for incest avoidance in humans.