One way in which the Westermarck Effect might be conceptualized is in terms of E.O. Wilson and Charles Lumsden’s idea of an epigenetic rule. Such rules are, in their words, “genetically determined procedures that direct the assembly of the mind …[that] comprise the restraints that the genes place on development (hence the name ‘epigenetic’)”. I’ve never taken this idea very serious, in part because they suggest that these are the bridge between human nature and morality in general, and in part because of the “genetically determined” bit. But let’s put that aside for now, and think about the Westermarck Effect as an innate constraint not on the mind per se but on how we direct our behavior. What we have so far is something like this:
if two individuals are intimate childhood associates, having been raised together for a number of years from early in life, then those two individuals will have a psychological aversion to sexual relations to one another and/or will lack erotic feelings for one another, and will, as a result, avoid incestual behaviors with one another when they are sexually mature.
- offspring will show the same resulting aversion to any parent by whom they were raised via the same or a similar childhood association mechanism.
- parents will show the same resulting aversion to any offspring they have raised via an attachment mechanism.
But we want to put this more simply. Maybe:
- If you develop care-related attachment through intimate childhood association with an individual, feel contrasexual aversion towards that individual when you are both sexually mature.
- Felt contrasexual aversion towards an individual inhibits sexual attraction to, and sexual behavior with, that individual.
Westermarck himself also thinks that there is something like the following rule, a rule that he seems to think is built into us as well
- Felt contrasexual aversion & the inhibitions it generates are expressed as moral disapproval of contrary expressed feelings & behaviors in general.
I suspect that it is a mistake to try to group this together with the preceding rule, at least if that rule is conceived as something like a built-in rule that individuals are geared act on. This latter “rule” is more like a generalization about how certain kinds of feelings and aversions give rise to expression in the public realm. As such, they require a lot of social scaffolding, including language, certain kinds of group living, and a range of sophisticated social tracking abilities, none of which are required for the basic Westermarckian rule to take effect.
Compare this to rules that might be in play in the domain of another of the 4 Fs: food:
- If you experience nausea, attach a disgust reaction to something salient that you ate shortly before that illness.
- If you recall feeling disgust about some food item, feel averse to eating that thing in the future.
These rules connect personal experience to emotional reaction, and then a memory of that reaction to future behavior. The Westermarck rules connect care-based attachment (via intimate childhood association) to felt contrasexual aversion, then that feeling to the inhibition of sexual attraction and sexual behavior. Compare this to Wolf’s summary of Westermarck’s view (1995: 506):
“Westermarck’s explanation of the incest taboo can usefully be analyzed as consisting of three propositions:
1. In sexually reproducing species, inbreeding produces offspring with a lower mean fitness than outbreeding.
2. Because of this, these species have been subject to selective pressures favoring a disposition that causes early association to inhibit sexual attraction.
3. In human beings, who are capable of symbolic representation, this disposition gave rise to the moral disapproval we call the incest taboo.”
My focus is chiefly on unpacking and clarifying (2), and on noting that (2) and (3) should be taken to have a very different kind of status. Whatever Westermarck himself might have thought, I think that rather than (1) it is more plausible to postulate (1*) at the head of the following overall summary statement of the view that is defensible:
(1*) Sex-biased dispersal patterns, close parental care, and developing pair-bonding in primates have created a disposition that links care-related attachment to contrasexual aversion.
(2a*) This disposition is a rule with the following content: if you develop care-related attachment through intimate childhood association with an individual, feel contrasexual aversion towards that individual when you are both sexually mature.
(2b*) Felt contrasexual aversion towards an individual inhibits sexual attraction to, and sexual behavior with, that individual.
(3a*) Felt contrasexual aversion and the inhibitions it generates are expressed as moral disapproval of contrary expressed feelings and behaviors in general.
(3b*) This disapproval is strengthened through the external scaffolding that comes with increasing hominidization, eventually creating social conventions about incest that, in turn, reinforce that disapproval and regulate feelings of contrasexual aversion.
The difference between (1) and (1*) is important, since (1*) locates the Westermarck Effect squarely as part of our primate heritage and stays clear of debates over just what role the avoidance of inbreeding plays in the development of that effect. By locating the effect in this space, it makes it clear that we are focused on a psychologically-mediated disposition, and that the rule in hominids is likely a homologous development and extension of a rule in place in some form or other for the past 15-20 million years. For many primates, its scope is restricted to the mother-offspring dyad; for others it extends beyond such dyads to close uterine kin; for primates in which paternity can be recognized (e.g., gorillas, chimpanzees), it extends beyond these to father-daughter dyads and paternal kin.
One thing that this introduces is a base-level case to focus on in debates with those who oppose the positing of all such rules. For now we can consider just a version of the account that applies to mother-offspring dyads, a version which is the phylogenetically deepest and that generates the strongest incest taboo—in terms of felt aversion, level of disapproval, taboo normativity, and contravention rates. Those who reject this rule on the grounds that it’s “incest taboos first, feelings of disgust and aversive behavior later” have no explanation whatsoever of the now robust primate data on mother-offspring inbreeding avoidance. Forget inbreeding avoidance more generally: it’s not relevant here. We’re talking about a specific kind of inbreeding avoidance–one brought on by the changing social opportunities created by lactation, extended dependent care of offspring, corresponding increasing demands on parenting, and increased cognitive capacities—and that is mediated through a cognitive-emotional-behavioral rule that interacts dynamically with the emergence of explicit moral attitudes and sanctions.
How much does this tell us about father-daughter and brother-sister incest of the kind taken to an extreme in the Fritl-like cases discussed in Thinking about Incest 3? That’s something I’ll say more about as this series of posts wraps up. Shortly.