A preference for physically formidable leaders -- caveman politics -- may have evolved to ensure survival in ancient human history, U.S. researchers suggest.Gregg R. Murray and J. David Schmitz of Texas Tech University said political pundits have long pointed out that voters prefer the taller candidate for president 58 percent of the time from 1789 to 2008, but to test the theory they reviewed the literature to establish concepts of the \"big man\" in tribal leadership of ancient societies, as well as the impact of physical strength on rank and status in the animal kingdoms.Study participants were asked to describe and draw a figure that represented their concept of a \"typical citizen\" and an \"ideal national leader,\" before being asked to draw both figures together. The results showed that 64 percent of students drew the leader as taller than the citizen, the researchers said.In the second test, study subjects were asked to answer a questionnaire about their own leadership attributes to consider how height influences personal perceptions of political leadership and attitudes toward running for office.\"Our research and the literature demonstrate that there is a preference for physically formidable leaders that likely reflects an evolved psychological trait, independent of any cultural conditioning,\" Murray said in a statement. \"So while at 6 feet, 1 inch, Barack Obama towered over the 5-foot-8 John McCain in 2008, perhaps he\'ll meet his physical equal in one of the \'big man\' governors in the 6-1 Rick Perry or the 6-2 Mitt Romney in November 2012.\"The findings were published in the Social Science Quarterly.