The debate over whether gender plays a role in color preference has raged since the late 1800s, with some arguing sex doesn't make a shade of difference and others insisting that it does. One universal preference: blue appeals to all. But new research shows that girls really do prefer pink—or blue with a splash of red (think purple).

"We can only speculate about the universal preference to blue … from an evolutionary point of view," says Yazhu Ling, a research associate in psychology at Newcastle University in England and co-author of the new study published in Current Biology. "A clear blue sky signaled good weather, clear blue also signals a good water source—these would benefit us," she notes, "especially in our 'savanna' days" when people lived in hunter-gatherer societies.

Ling, and Anya Hurlbert, a psychology professor at the university, had 208 volunteers—98 men and 110 women—take computer-based tests during which they were asked to pick between two rectangles of different colors. The researchers concluded that there are two fundamental continuums underlying color preference: blue-yellowness and red-greenness. Whereas both sexes leaned toward blue on the blue-yellow scale, women showed a more profound preference than men for red to green on the second measure. Thirty-seven of the subjects had recently immigrated to the U.K. from mainland China. Although the Chinese men and women both showed a stronger preference for red than the British group, with the women still favoring it more, Ling says the male preference for red among the Chinese population is likely linked to cultural differences. "Red in China indicates happiness and luckiness," she says, "and is the prime color we use for festivals."

But why the overall female preference for, "redder blues." Ling speculates it harks back to hunter-gatherer societies. "The female, as gatherer, had to pick reddish fruits against green leafy backgrounds, therefore a preference for red against green may have benefited their food gathering and thus gained them evolutionary advantage," she says. "Evolution may also drive females to prefer redder faces (male faces are ruddier than female faces across all races). A reddish face often [means] good health; this may be a good cue to help the females to select mates."

Hurlbert and Ling plan to repeat their experiment in different age ranges of subjects of British and Chinese lineage. (In the current study they were 20 to 26 years of age.) They are also considering surveying other ethnic groups as well as babies to determine whether color preference is more a matter of nature or nurture.