"We showed pictures of familiar and unfamiliar political leaders to voters in two different samples and found that familiarity and partisanship each significantly influenced how candidates were perceived," said the study's lead researcher, Kevin M Kniffin, a postdoctoral research associate at Cornell University's Dyson School of Applied Economics and Management.
"For example, Democrats rated Barack Obama as more physically attractive, and Republicans tended to rate Sarah Palin as better looking," Kniffin said.
"In both of the studies, people were viewing the pictures through partisan-coloured lenses," said Kniffin.
The results for those unfamiliar candidates showed no favouritism based on political affiliation.
"There's no 'Republican look' or 'Democrat hairdo'. If you don't recognise political leaders and can't view them through partisan lenses, they don't have the halos or horns that influence perceptions of familiar leaders," Kniffin said.
The study was published in The Leadership Quarterly.