Ross Douthat's recent New York Times piece claiming that monogamy leads to, or causes, happiness, has stirred up quite the critical commentary, most recently from Dr. Maryanne Fisher on her Psychology Today blog. As she explains, causality does not imply correlation, and any possible causal link between monogamy and happiness could go either way (or both). Also, a third factor could be influencing both: for instance, depression could influence a person's happiness and his or her sexual behavior, making it look like one causes the other. As Dr. Fisher writes, Tracy Clark-Flory's Salon article nicely points these out things as well, and recommends that people read Mark Regnerus and Jeremy Uecker's book Premarital Sex in America: How Young Americans Meet, Mate, and Think about Marrying before jumping on distortionary soundbites.
I confess that I have not read the book (though I have ordered it!), but this whole discussion has me thinking (dangerous, I know, but what else do I have to do?). Here are some thoughts of mine on monogamy, happiness, and adultery:
1. As we all know (and about which I've written before), happiness is a slippery concept; even positive psychologists and "happiness economists" that purport to measure it do so with a good amount of humility (well, most of them, at least). But it doesn't take much to see that monogamy and promiscuity can each give a person happiness, albeit likely two different kinds. Promiscuity—not to be taken in any pejorative or judgment-laden sense, but merely as "nonmonogamy"—brings the excitement of variety, the thrill of the unknown, and the pure physical bliss of sex, untethered by any emotional attachment or anxiety. On the other hand, monogamy brings a deeper, longer-lasting, and more fulfilling type of happiness that enhances any other aspects of one's life. So merely linking monogamy and happiness, without specifying which type of happiness is meant, is somewhat facile.
2. Recognizing these two types of happiness may help explain the appeal to some of adultery: in the adulterer's mind, he or she may be trying to retain the security and deeper type of happiness with his or her spouse, while enjoying the sheer animality and thrill of uncommitted sex with someone else. Of course, the ideal would be to find the more hedonic, animalistic pleasure with his or her spouse or partner instead of looking for it outside the marriage or relationship, and to a certain extent that can be done. But if the thrill of casual sex comes from variety and the unknown, the person you've been lying next to every night for years is unlikely to provide that. (This is not to say adultery is excused in such cases, mind you—I'm merely acknowledging its possible appeal.)
3. This leads to another, more scientific problem with such comparisons: comparing monogamy and promiscuity is not just a matter of changing the number of partners like a variable in an equation. As mentioned before, monogamy often includes emotional ties—or entanglements, depending on how you look at it—that have a strong, if not stronger, effect on happiness than does the simple fact of having only one sexual partner. By the same token, promiscuity usually does not have the same intensity of emotional ties with a single person, but may also have a wide range of emotional attachments with one's multiple partners, some of whom may be friends, colleagues, or co-workers rather than casual hook-ups, and the emotions involved with those relationships will have their own effects on happiness.
4. Finally, flowing from the last two points, a true scientific test on the number of sexual partners and happiness would have to control for all other factors can try to vary only the number of sexual partners—of course, this would be controlled adultery! We would need to take people in monogamous relationships and introduce new sexual partners without the knowledge of their significant others. (Somehow I don't see this experiment getting past the research ethics boards—never mind the self-selection bias involved in getting volunteers!) Researchers could also look at people in open relationships and vary their numbers of sexual partners, but once again, they choose to be in that type of relationship, so there is self-selection again—presumably, they would be less happy in a monogamous relationship.
But it would seem that we have a natural experiment testing the other direction, from promiscuity to monogamy: marriage (and other commitment ceremonies). However, this has self-selection problems too, since the couple have chosen (at least, we assume they have) to get married, therefore signaling that they are (or will be) happier in a monogamous relationship. Again, a researcher would have to perform "shotgun weddings" (without the traditional motivation behind them), forcing promiscuous people to be monogamous.
Sounds absurd, right? No one would be happier after being forced into a monogamous relationship, which just reinforces my earlier point: what makes people more or less happy is not simply the number of sexual partners they have, but the reasons they have them, including the emotions involved in the relationship(s). Linking monogamy with "happiness" makes for nice headlines, but as Dr. Fisher points out, the connections between people's relationships, sex lives, and well-being are much more complex than some people consider.