WASHINGTON, Sept 18, 2008 (AFP) - Calm people tend to be liberals and those who react strongly to sudden noises and threatening images tend to be political conservatives, US researchers said in a study published Thursday.

'Individuals with measurably lower physical sensitivities to sudden noises and threatening visual images were more likely to support foreign aid, liberal immigration policies, pacifism, and gun control,' said the study in Science Magazine.

'Individuals displaying measurably higher physiological reactions to those same stimuli were more likely to favor defense spending, capital punishment, patriotism, and the Iraq war,' it said.

Participants in the study were selected randomly by phone and screened to determine if they held strong political beliefs, regardless of which way they leaned.

Forty-six people who were retained for the study were then asked to fill out a questionnaire asking them, among other things, about their political beliefs.

Later, two common physiological reactions to a perceived danger, blinking and skin moisture levels, were measured after the participants had heard a sudden noise and seen threatening images -- a large spider on a frightened person's face, a person with a bloody face, and a maggot-infested wound.

Those who supported conservative policies such as military spending, school prayer, and the death penalty reacted strongly to the stimuli, while people who backed liberal policies such as foreign aid, pacifism, gay marriage and abortion rights were calmer.

The researchers were unable to say whether political attitude causes the physiological reaction or vice versa.

But the link that the study suggests exists between the two traits 'provides one possible explanation for both the lack of malleability in the beliefs of individuals with strong political convictions and for the ubiquity of political conflict,' they said.

The study was conducted by researchers from Rice University in Texas, the University of Nebraska-Lincoln, the University of Illinois, and the Virginia Institute for Psychiatric and Behavioral Genetics.