Female Republican politicians look more feminine than their Democratic counterparts, according to a study published Thursday based on facial features of US women lawmakers.
Tea Party favorite Michele Bachmann is a good example of the correlation, said the study by two Californian psychology graduates, which looked at features including cheek bones and fullness of lips.
Perhaps counter-intuitively, however, Republican male lawmakers tend to look less typically masculine than their Democratic counterparts, according to the University of California Los Angeles (UCLA) research.
The study, compiled by feeding portraits of 434 members of the House of Representatives into a computer modeling program, took no account of hairstyles, jewelry or makeup.
"Female politicians with stereotypically feminine facial features are more likely to be Republican than Democrat," said lead author Colleen Carpinella.
What's more, "the correlation increases the more conservative the lawmaker's voting record," she added of the study, to be published online in the peer-reviewed Journal of Experimental Social Psychology.
"I suppose we could call it the 'Michele Bachmann effect,'" added Kerri Johnson, the study's senior author and an assistant professor of communication studies and psychology at UCLA.
The model compared faces based on more than 100 features, including the shape of the jaw, the location of eyebrows, the placement of cheek bones, the shape of eyes, the contour of the forehead and the fullness of the lips.
"We weren't looking at hairstyle, jewelry or whether a person was wearing make up or not," Carpinella said. "We wanted to get an objective measure of how masculine or feminine a face is."
For men, Republicans perhaps surprisingly are have less stereotypically masculine faces than Democrats.
But the researchers said they did not think this difference was particularly revealing.
"It may be unnecessary for Republican men to exhibit masculinity through their appearance," Carpinella said. "Their policy advocacy and leadership roles may already confer these characteristics on them."