WOMEN often complain that dating is like a cattle market, and a paper just published in Biology Letters by Thomas Pollet and Daniel Nettle of Newcastle University, in England, suggests they are right. They have little cause for complaint, however, because the paper also suggests that in this particular market, it is women who are the buyers.

Mr Pollet and Dr Nettle were looking for evidence to support the contention that women choose men of high status and resources, as well as good looks. That may sound common sense, but it was often denied by social scientists until a group of researchers who called themselves evolutionary psychologists started investigating the matter two decades ago. Since then, a series of experiments in laboratories have supported the contention. But as all zoologists know, experiments can only tell you so much. Eventually, you have to look at natural populations.

And that is what Mr Pollet and Dr Nettle have done. They have examined data from the 1910 census of the United States of America and discovered that marriage is, indeed, a market. Moreover, as in any market, a scarcity of buyers means the sellers have to have particularly attractive goods on offer if they are to make the exchange.

The advantage of picking 1910 was that America had not yet settled down, demographically speaking. Though the long-colonised eastern states had a sex ratio of one man to one woman, or thereabouts, in the rest of the country the old adage “go west, young man” had resulted in a surplus of males. Mr Pollet and Dr Nettle were thus able to see just how picky women are, given the chance.

Rather than looking at the whole census, the two researchers relied on a sample of one person in 250. They then assigned the men in the sample a socioeconomic status score between zero and 96, on a scale drawn up in 1950 (which was as close to 1910 as they could get). They showed that in states where the sexes were equal in number, 56% of low status men were married by the age of 30, while 60% of high status men were. Even in this case, then, there are women who would prefer to remain single rather than marry a deadbeat. When there were 110 men for every 100 women (as, for example, in Arizona), the women got really choosy. In that case only 24% of low-status men were married by 30 compared with 46% of high-status men. As the men went west, then, so did their marriage opportunities.