On the Epidemiology of Sexual Norms

Shaun Nichols has suggested that social norms with "affective resonance" -- norms, that is, forbidding actions that are emotionally upsetting -- are more likely to persist than "affect neutral" norms. In particular, Nichols proposes that norms against harming people and norms pertaining to "core disgust" (especially involving bodily fluids) are more likely to endure the centuries than norms related to non-harmful, non-bodily-fluid-involving behavior, such as norms governing posture and the position of silverware. We'll let go of norms about elbows on the table; norms against slander and urinating in public we're more attached to.

(Studying, in this way, the "epidemiology" of norms can give us insight into the basis of our moral judgments. And that, of course, is near the core of ethics and moral psychology. Nichols' idea of getting at such questions by looking at the history of etiquette manuals stands among the most intriguingly creative uses of empirical evidence I've ever seen by a philosopher.)

Now, it does seem very plausible on its face that affect-backed norms would survive better than affect-neutral ones. Yet a student of mine, Beth Silverstein, has persuaded me that Nichols hasn't struck to the core of it. Silverstein suggests that norms that have a functional basis are the ones most likely to survive. Thus, affect-backed norms tend to survive because they typically have a functional basis. Disgust-backed norms are functionally grounded in health concerns; harm norms are functionally grounded in the conditions for the smooth operation of society. Non-affect-backed norms that have a functional grounding, such as avoiding pork (which used to be more likely to carry disease) or putting the fork on the left, knife and spoon on the right (in accordance with the traditional left-handed use of the fork), do tend to survive.

I doubt Nichols would want to disagree with the claim that functional norms are more likely to survive. The question is how much of a role is left over for affect as the basis of norms, once those driven by function are taken account of. Perhaps not much? Looking at the history of norms against flatulence and body odor might be relevant here. But the example that I find most interesting is the evolution of sexual norms.

We live in a society of relatively low sexual disgust (at least by recent European standards). Nichols points out our increasing sensitivity over time to hygiene, and our increasingly refined sense of disgust in that domain; but the opposite seems to be occurring with respect to sexual norms: What is counted as "pornography", what bodily exposures are seen as "disgusting", and how disgusting they seem -- in such matters we have become more lax, rather than more restrictive, especially over the last several decades.

I hypothesize that this has to do with the change in the functionality of sexual restrictions: With the advent of birth control of sexual disease prevention and cure, sexuality became functionally less dangerous, and our norms responded. In the 80's there was something of a reversal with the advent of AIDS, but as AIDS is coming more under control (in the middle-class U.S.), norms are liberalizing again. In large, traditional civilizations, sexual norms had to be restrictive because of the threat of the spread of disease; less so, perhaps, in small, traditional tribes. (I don't claim novelty for this hypothesis, though I can't now recall a source.)

So in the sexual domain at least, I'd suggest that Silverstein fares better than Nichols: The evolution of norms is driven more by function than by affective disgust. The sense of disgust comes after, shifting to match our function-driven norms.