The extent of liberalism in people may be linked to their bodies and deep seated psychology and not just results of conscious decision-making or upbringing as commonly thought, says a study.
Physiological responses and deep-seated psychology are at the core of political differences, the findings showed.
"Politics might not be in our souls, but it probably is in our DNA," said political scientists John Hibbing and Kevin Smith of University of Nebraska-Lincoln and John Alford of Rice University in the US.
Across research methods, samples and countries, conservatives have been found to be quicker to focus on the negative, to spend longer looking at the negative, and to be more distracted by the negative, the researchers noted.
Using eye-tracking equipment and skin conductance detectors, the three researchers observed that conservatives tend to have more intense reactions to negative stimuli, such as photos of people eating worms, burning houses or maggot-infested wounds.
This so-called "negativity bias" may be a common factor that helps define the difference between conservatives, with their emphasis on stability and order, and liberals, with their emphasis on progress and innovation, the researchers proposed.
The study appeared in the journal Behavioral and Brain Sciences.