UC Berkeley researchers analyzed the racial preferences and online activity of people from the United States who subscribed between 2009 and 2010 to a major Internet dating service. In their profiles, the online daters stated a racial preference. Some said they preferred to date only within their race, others preferred someone outside their race, and yet others said they were open to dating someone of any race.

Researchers were then able to compare the online daters' stated preferences with whom they actually contacted for a date, and they found profound differences between blacks and whites.

"Those who said they were indifferent to the race of a partner were most likely to be young, male and black," said Gerald Mendelsohn, a UC Berkeley psychologist, professor of graduate studies and lead author of the study, which will soon be submitted for publication.

Overall, he said, "Whites more than blacks, women more than men and old more than young participants stated a preference for a partner of the same race,"

The reluctance of whites to contact blacks was true even for those who claimed they were indifferent to race.  More than 80 percent of the whites contacted whites and fewer than 5 percent of them contacted blacks, a disparity that held for young as well as for older participants.

"Were they hypocritical? Alert to the realities of the social world? Striving for political correctness? Attempting an optimizing strategy of self-presentation? Our data do not permit us to choose among those alternatives," the study authors wrote.

The study's coauthors are Lindsay Shaw Taylor, a postdoctoral researcher at UC Berkeley; Andrew T. Fiore, a graduate of the UC Berkeley School of Information who is currently a visiting assistant professor at Michigan State University and Coye Cheshire, an assistant professor in the School of Information.

An estimated one in five Americans has used an online dating service such as eHarmony or  Match.com, and a growing number of urbanites are finding romance via Facebook and other social networking sites. The percentage of couples who have met online is now nearly equal to that of pairs who met through friends or family, according to researchers.

"As the use of online dating services grows, people whose paths never would have crossed offline now regularly meet and have meaningful exchanges in the virtual world," the UC Berkeley study says.

The last 40 years have seen a dramatic shift in attitudes in America toward black-white intermarriage – from three to one opposed to three to one in favor, said Mendelsohn. Yet, 2000 U.S. Census data shows that black-white couples represent just 1 percent of American marriages, he said.

The main findings of this study parallel the census data on marriage in that blacks are more likely than whites to be in interracial marriages, and that couples in which the husband is black and the wife is white are more common than those in which the husband is white and the wife is black, according to Mendelsohn.

"One theory is that blacks are acting like other minority populations in the history of this country," Mendelsohn said. "They are interested in moving up in the power structure, and one way you do that is through intermarriage with the dominant group."

According to the study, more than 80 percent of the online dating contacts initiated by whites were to other whites, with only 3 percent going to blacks. This trend held for both men and women, young and old. "Although black participants initiated contact to members of their own race more than to whites, they were ten times more likely to contact whites than vice versa, according the study,

The researchers also tracked the rates of reciprocation among the pool of online daters, looking at how they responded once they received a message from an interested potential partner. Again, white men and women were most likely to respond to members of their own race, and only 5 percent of their responses went to blacks.

A major objective of the study was to gauge how changing attitudes about interracial marriage and an increase in dating opportunities have played out in relationships between blacks and whites. Also of interest to researchers was the question of whether the Obama presidency signals that the United States has entered a post-racial era.

"It is clear that we are not yet in the post-racial era, and evidence from studies of online dating suggest that waiting for its arrival will take some patience," the study concludes.