Kevin Smith, professor of political science, has published findings that people can choose liberals or conservatives by viewing a person's photo or video.

Liberals show more emotion in their facial expressions than conservatives, according to a study done by a team of University of Nebraska-Lincoln political scientists.

Past research found political ideology can be identified by looking at someone’s face, but the research did not indicate why.

In a paper recently published in the academic journal Politics and the Life Sciences, UNL professor and political science chair Kevin Smith and his teammates found it is in part because liberals express more facial emotion than their political counterparts.

“We did four studies for this paper, and they all triangulate on the same thing,” Smith said in a Nebraska Today article. “People can, with greater-than-chance accuracy, figure out whether you’re liberal or conservative just by looking at your face, and emotional expressivity seemed to be driving it in our analysis.”

Smith said this finding suggests facial emotional expressivity is another biological difference in conservations and liberals, with his previous research showing that there are biological predispositions in political beliefs.

In Smith’s first study, participants took a survey where they rated themselves on their own emotional expressivity.

“Liberals reported being less able to stop from expressing emotions, while conservatives were a little more buttoned-down,” he said.

In his next study, Smith recorded facial reactions using the corrugator supercilii muscle. The muscle, which sits above the eye and is involved in many facial expressions, was monitored while participants viewed positive and negative images.

The study found liberals used the muscle more in their reactions than conservatives did.

Smith and his colleagues conducted two more studies to determine if emotional expressivity is in fact identified and perceived as liberal.

In the third study, participants watched silent videos of unidentified congressional representatives giving speeches. The videos were stripped of obvious body movements and facial expressions. Participants were then asked to rate the speakers on emotional expressivity and political ideology. Results displayed emotional expressivity correlates not only with perceived ideology but actual ideology as well.

“We deliberately picked video without overt emotional cues,” Smith said. “But sure enough, people could pick out who the liberal one was and who the conservative one was.”

In the final study, participants were shown images of four German lawmakers — two with neutral expressions, two with clearly emotional expressions — and asked to rate them on a political spectrum.

Just as before, the results showed that those with emotional expressivity were deemed more liberal than those without.

“The real clincher for us was when the conservative person was smiling, the conservative was rated as more liberal,” he said. “He was still rated as conservative, but he was rated less conservative when he was smiling.”