Readers responded to my last post with lots of theories and personal reports on people’s preferences in interracial dating. Also some complaints that I seemed to be asking for comments about only whites and blacks — an impression I didn’t mean to give. Researchers have been studying other races, too. They’ve found that theories and anecdotal evidence aren’t a very reliable guide to these questions: some of the common stereotypes don’t match the data.

Some of you did get it right, like Dan, who hypothesized that Asians are relatively more willing to date outside their race. David predicted that black men are more likely to date white women than white men are to date black women — which is right, although not for the reason many people think. It’s not that white men are more reluctant to date non-whites; it’s that black women are less willing to date someone of another race.

At least that’s the picture that emerges from studies of online daters and speed daters. Men are generally willing to date someone of another race, but women are more reluctant, especially African-American women.

Consider “Racial Preferences in Dating,” a study of more than 400 graduate and professional students who participated in speed dating sessions at Columbia University organized by Raymond Fisman, Sheena S. Iyengar, Emir Kamenica and Itamar Simonson. The researchers conclude: “Even in a population of relatively progressive individuals who have self-selected into participation in a multi-cultural Speed Dating event, we observe strong racial preferences.”

There’s also a clear gender divide, as the researchers note: “Women of all races exhibit strong same race preferences, while men of no race exhibit a statistically significant same race preference.” You might think the gender gap is the result of different dating goals: perhaps the men are more interested in short-term flings, whereas the women are looking for a lasting relationship and are concerned about potential complications from cultural differences. But the researchers conclude otherwise after looking at the data:

“Since older subjects (who are more likely to attend the Speed Dating sessions in hope of starting a serious relationship) have a weaker same race preference, this gender difference is unlikely to result from differential dating goals between men and women.”

The researchers found that most women speed daters said yes (meaning they’d like to see a man again after the four-minute speed date) less often to men of another race than they did to men of their own race. Here’s how much less interested they were in the other races, as compared with their enthusiasm for men of their own race:

African-American women said yes about 30 percent less often to Hispanic men; about 45 percent less often to white men; about 65 percent less often to Asian men. White women said yes about 30 percent less often to black or Hispanic men, and about 65 percent less often to Asian men. Hispanic women said yes about 20 percent less often to black or white men, and 50 percent less often to Asian men. Asian women didn’t discriminate much by race (except for showing a very slight preference for Asian men over black or Hispanic men).

After noting who said yes to whom, the researchers analyzed a confounding factor: the men’s physical attractiveness. They found that the women of different races generally agreed with one another in rating the various men’s attractiveness — and that they were less willing to date a man of another race even when he was just as attractive as a man of their own race. When the researchers controlled for the men’s attractiveness, they found that white, Hispanic and Asian women generally showed about the same level of same-race preference, while black women showed a significantly higher preference.

These results from the speed dating experiment roughly jibe with the study I cited in the earlier post about height-income tradeoffs. In that analysis of more than 20,000 online daters, split roughly evenly between Boston and San Diego, men didn’t show much preference for same-race partners. Women did, and African-American women showed the most pronounced preference.

The researchers, after controlling for all other attributes (height, weight, attractiveness, etc.), calculated how much extra income (relative to the income of the average online male dater, $62,500) a man would need to overcome the racial barrier. Here are some of the estimates (there weren’t enough data to do all the interracial permutations) of how much each extra income a man would need to be equally appealing to a woman as would a man of her own race:

For equal success with an African-American woman, a Hispanic man needs to earn an extra $184,000; a white man needs to earn an additional $220,000. For equal success with a white woman, an African-American needs to earn an additional $154,000; a Hispanic man needs $77,000; an Asian needs $247,000. For equal success with a Hispanic woman, an African-American man needs to earn an additional $30,000; a white man needs to earn an additional $59,000. For equal success with an Asian woman, an African-American needs no additional income; a white man needs $24,000 less than average; a Hispanic man needs $28,000 more than average.

I’ll leave you with two questions: Why do women have these preferences? And what might prompt them to pay less attention to a man’s race?