Does Free Love Promote or Impede Successful Marital Search?

Listening to satellite radio while driving, I occasionally come across the Cosmo channel. The target audience appears to be women engaged simultaneously in the search for a long-term partner — a "keeper" — and a good deal of casual sex. That raises an interesting question: does casual sex make success in marital search more or less likely, for them in particular or for women more generally? It is an old question but the sexual revolution may provide new evidence.

There are two obvious arguments against the pattern. The first is that in a society where sex is readily available without marriage the incentive to engage in a protracted search for a long-term partner, costly in time, effort, and emotion, is much lower than in a society with more traditional mating patterns. The second is that sex has emotional consequences — you feel differently about someone afterwards. Arguably one of the consequences is to reinforce emotional bonds that promote long term pairing, plausible on both subjective evidence and evolutionary grounds, since human infants require extended care. The bonds forged with your fiftieth sex partner might be weaker than the ones forged with your first or second, making marital stability, when the keeper is finally found, less likely.

There are two obvious arguments in the other direction. The first is that if individuals very much desire sex and cannot get much of it outside of marriage there is an incentive to marry the first moderately acceptable partner willing to say yes. The second is that a successful sexual relationship makes a successful marriage more likely, so the parties are less likely to regret their choice if they try before they buy. Seen from that point of view, cohabitation is a trial run for marriage rather than a substitute.

It is not enough to observe that divorce rates have gone up along with rates of non-marital sex, since that might be due to other causes, most obviously legal changes that made divorce easier. Better evidence is that the probability that a woman’s marriage will end in divorce increases, although not monotonically, with the number of sex partners she has had prior to marriage, as shown below. That may mean that prior partners result in a weaker marital bond but it could be a selection effect, evidence that the sort of woman who chooses to have little or no premarital sex is the sort likely to end up in a stable marriage

Was the Sexual Revolution a Mistake?

Even aside from the effect on mate search, it is possible that the sexual revolution has made the world a worse place. The argument has two parts.

Babies

When legalized abortion and readily available contraception first became hot political issues, a major argument for both was preventing the birth of unwanted children, meaning children born to unmarried mothers. Both legalized abortion and readily available contraception, which now exist in most developed societies, have been accompanied by the opposite of the predicted effect. In 1940, about four percent of all births in the U.S. were to unmarried mothers. Currently, about 40% are.

One possible explanation starts with the effect of the changes on the opportunities available to women who want children. In a world without contraception, sex comes with a risk of pregnancy — in the jargon of economics, sex and children are joint products. Since rearing a child by yourself is hard, women are reluctant to have sex without at least a commitment to marriage if a pregnancy results. Men want sex (as do women, though perhaps on average less). Men do not get pregnant and are arguably less interested in producing children than women are. The result is that men are willing to commit to support children if, in some cases only if, it is the only way they can get a reliable source of sex.

Contraception and abortion break the link between sex and pregnancy. Now women who do not want children and do enjoy sex provide an alternative for men who do not want to support children. Their competition drives down the price in commitment that women who want children can charge to men who want sex; some find that no suitable man is willing to commit to support them and end up as single mothers.¹ Seen from that standpoint, the mistake in the conventional view was the assumption that the children of unmarried women were all unwanted, born due to contraceptive failure or the unavailability of contraception rather than deliberate choice.

As long as we only consider effects on adults there is no obvious reason to regard the change as a bad thing; some people are better off, some worse off. Conventional economic analysis would show it to be a transfer plus a net gain; I leave the demonstration as an exercise for the reader.

But the adults are not the only ones concerned. It is widely believed, may well be true, that children brought up in a single parent household have worse lives than those brought up by a married couple. If so, the gains to (some) adults may have been purchased at a cost to many children — and to adults whom those children affect.

That is one possible explanation of the sharp increase in the number of single mothers, but there are others. A woman who wants to reproduce faces a choice between two alternative mating strategies. The long-term strategy is to pair up with the most desirable man she can get and jointly rear their children. The short-term strategy is to get pregnant by the most desirable man she can get to sleep with her and rear the child herself. Both women and men are equipped for their roles in both strategies, with different preferences for potential mates according to which is being followed.²

In a society sufficiently poor that a woman cannot afford to bring up a child by herself, it is long term or nothing. As a society gets richer more women can choose the short-term strategy, which may appeal to women who cannot find a suitable husband or do not want one. That, allowing for substantial time lags in social institutions, might help explain the large changes in observed behavior in developed societies over the past fifty years.

Nests

So far I have treated the purpose of marriage as sex and children. It is also about a complicated set of emotional and material benefits, a nest. For a lot of  men and women the world is mostly a cold and lonely place. It is nice to have somewhere you belong, with someone who loves you and whom you love.

In a world where non-marital cohabitation was for most people not an option — roughly speaking, the U.S. prior to the 1960's — the usual way of satisfying those desires was marriage. In the current world, cohabitation provides many of the short-term benefits without the long-term commitment. Once in such a relationship, both search and exit become harder. With a nest to come home to it can be hard to abandon it for the cold world and a renewed search. If you are fond of your partner, breaking up is hard to do — even if objective consideration persuades you that it is in the long-term interest of both parties. Cohabitation may be continued, converted into marriage or a near equivalent, even if the parties are not as well suited to each other as would have been required for mutual assent to marriage under the old system.

Sufficiently rational partners would understand all this and choose between cohabitation and search accordingly, but rationality in this context is under pressure from two directions. Many of us are poor at making tradeoffs between short term and long term, as the state of my weight long demonstrated. And the emotions associated with love, sex, and cohabitation are not entirely conducive to rational thought. The option of an attractive short-term substitute for marriage may result, in the long term, in your ending up with the wrong person.

"Women have simple tastes. They get pleasure out of the conversation of children in arms and men in love."

(H.L. Mencken)

1. For a formal economic version of the argument, see Akerlof, G. A., Yellen, J. L., & Katz, M. L. (1997). “An analysis of out-of-wedlock childbearing in the United States.” The Quarterly Journal of Economics, Vol. 111, No. 2, pp. 277-317.

2. David Buss, The Evolution of Desire: Strategies of Human Mating.