Beauty is not just in the eye of the beholder—it is also in the eyes of the beholder’s friends. A study published in April in Psychological Science found that men judge a woman as more attractive when they believe their peers find that woman attractive—supporting a budding theory that groupthink is not as simple as once thought.

Researchers at Harvard University asked 14 college-age men to rate the attractiveness of 180 female faces on a scale of 1 to 10. Thirty minutes later the psychologists asked the men to rate the faces again, but this time the faces were paired with a random rating that the scien­tists told the men were averages of their peers’ scores. The men were strongly influenced by their peers’ supposed judgments—they rated the women with higher scores as more attractive than they did the first time. Functional MRI scans showed that the men were not simply lying to fit in. Activity in their brain’s pleasure centers indicated that their opinions of the women’s beauty really did change.

The results fit in with a new theory of con­formity, says the study’s lead author Jamil Zaki. When people conform to group expect­ations, Zaki says, they are not concealing their own preferences; they actually have aligned their minds. In addition, the likelihood of someone conforming depends on his or her place within the group, according to a study in the December 2010 issue of the British Journal of Sociology. Members who are central are more likely to dissent because their identities are more secure. Those at the edges, who feel only partially in­volved or are new to the group, may have more malleable opinions.