Rational choice or evolved preferences? How do Israeli men and women select their mates?

How do young Israeli men and women choose their mates? Do they make carefully calculated decisions on the basis of the present conditions of the marriage market? Or do they simply follow their evolved preferences designed for conditions that prevailed hundreds of thousands of years ago?

That is the question that Yaarit Bokek-Cohen of Ariel University, Yochanan Peres of Tel Aviv University, and I pursue in our recent paper “Rational Choice and Evolutionary Psychology as Explanations for Mate Selectivity” published in the May 2008 issue of the Journal of Social, Evolutionary, and Cultural Psychology. There are two major theories of mate selectivity (how selective one is in choosing mates). The rational choice theory, derived from the work of Gary S. Becker and Shoshana Grossbard-Shechtman in economics, posits that economic forces of supply and demand operate in the marriage market. What determines the supply and demand of men and women is the operational sex ratio (how many available men there are for each available woman).

If the sex ratio is high (more men than women), then the “supply” of men is high, but the “demand” for them is low, and thus men’s “value” drops and they must command lower “price.” In contrast, if the sex ratio is low (more women than men), then the “supply” of men is low, “demand” for them is high, and their “value” therefore soars and they can command higher “price.” Exactly the opposite happens to women in each condition; their value is higher if there are more men than women, and their value is lower if there are more women than men. As a result, rational choice theory predicts that women become more selective and men become less selective in their mate selection when sex ratio is high and there are more men; conversely, it predicts that women become less selective and men become more selective in their mate choice when sex ratio is low and there are more women.

In contrast, evolutionary psychology predicts that men’s and women’s evolved preferences are adapted to and designed for the conditions that prevailed during the course of human evolution. These evolved psychological mechanisms are relatively impervious to the fluctuations of conditions in recent human history. These evolved preferences include mate selectivity. Because women have much higher obligatory parental investment than men (they must carry the baby for nine months and nurse it for several years afterwards while it takes men only 15 minutes to produce a baby), and because women have much lower fitness ceiling (women can have many fewer babies in their lifetimes than men can), evolutionary psychology predicts that women are always more selective in their mate selection than men; mistakes are much costlier for women than for men so women have to be more cautious. Evolutionary psychology further predicts that this evolved sex difference in mate selectivity largely will not respond to fluctuations in the current environment, such as the operational sex ratios.

Contemporary Israel provides an excellent site for testing rational choice and evolutionary psychological predictions for mate selectivity. Until the 1970s, the sex ratio in Israel was close to parity. Since then, however, due to a combination of factors such as selective emigration, where a large majority of single Israelis who emigrate are men, and differential mortality, where many more men die than women, the sex ratio in Israel has steadily declined. In 2000, the sex ratio among singles in their 30s was extremely low. For unmarried men age 35-39 and unmarried women age 30-34, it was .646. It means that there are fewer than two unmarried men in their 30s for three unmarried women. This is a perfect condition for what Grossbard-Shechtman calls “marriage squeeze for women.” Rational choice theory would predict that women would become less selective, and men become more selective, under marriage squeeze for them. Evolutionary psychology, in contrast, would predict that women would continue to be more selective than men even under marriage squeeze for them.

To establish the baseline sex difference in mate selectivity, we rely on David M. Buss’s landmark international study of mate selection, which includes data from 37 cultures in 33 countries on six continents and five islands. The international sample includes 10,047 individuals of all races and all major world religions throughout the globe. Buss’s data demonstrate two major sex differences in mate selectivity. First, women are overwhelmingly more selective in their mate selection than men are throughout the world; they typically list three times as many criteria for selecting mates than men do. Second, there is a singular exception to greater female selectivity. Men are more selective than women when it comes to physical features (age, physical attractiveness, body shape).

We collected data from a large national commercial computer dating service in Tel Aviv in 2000, to see what criteria contemporary Israeli men and women list as important for their mates. Upon subscription to this dating service, each new member must fill out a self-administered questionnaire about what traits they deem to be important in their mates. We have nearly 3,000 individuals in our sample.

When we examine the criteria that these Israeli men and women list as important, a remarkable result emerges. Despite the extreme marriage squeeze for women, where one out of every three women is likely to be left mateless, the pattern of sex difference in mate selectivity in Tel Aviv in 2000 is virtually identical to what Buss found throughout the world in the 1980s. Israeli women list more than three times as many criteria as important in their mates as Israeli men do. And the only area where Israeli men are more selective than Israeli women is physical (physical attractiveness, body build, eye color, hair color, facial skin condition, etc.)

In other words, despite the extreme condition in which the Israeli men and women find themselves today, their mate preferences do not seem to be any different from those expressed by men and women everywhere and always. Women are much more selective in their mate selection than men are, except when it comes to physical features. Despite facing a very bleak one in three chances of not finding a mate, Israeli women still maintain much higher standards in mate selection than Israeli men do. Rather than making rational decisions in response to the prevailing market conditions, as rational choice theory predicts, men and women appear to carry out their evolved psychological mechanisms under most circumstances.