Men's faces, on the other hand, were less likely overall to be sex-typical, although male Republicans did tend to have less masculine faces than male Democrats.They were 98 percent more likely to correctly identify women as Republicans when those women had more typically feminine faces.

The undergrads were able to correctly identify the party affiliation of both men and women at rates significantly higher than chance. As the women's faces became more feminine, the odds of the undergrads correctly identifying them as Republicans increased as well. On the flip side, they were 58 percent less likely to correctly identify more feminine-looking women as Democrats.

CONCLUSION: Republican congresswomen have more feminine faces than Democrats, a phenomenon that observers are able to recognize.

IMPLICATIONS: The researchers see an easy connection between the Republican women's objective femininity and their party's obsession with traditional sex roles. That the correlation wasn't seen in men allows them to expand on the role of gender in politics: political leadership, they suggest, "is a historically masculine endeavor, thus automatically conferring masculine characteristics on male politicians." In other words, male Republicans don't need to look masculine in the way that female Republicans need to look feminine.

In a statement, author Kerri Johnson pointed to research suggesting that people tend to think of competency and femininity as being mutually exclusive in women. "We suspect that conservative constituents demand that their politicians be not just competent but also gender-typical, especially among women," she said -- putting the ladies of the GOP in an unfortunate double-bind.

The full study, "Appearance-based politics: Sex-typed facial cues communicate political party affiliation," will be published in The Journal of Experimental Psychology .

The most and least typically feminine faces pictured above belong to (clockwise from top left): Michele Bachmann (R), Kay Granger(R), Rosa DeLauro (D), Stephanie Herseth Sandlin (D), Cathy McMorris Rodgers (R), Anna G. Eshoo (D).

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