Brains of liberals, conservatives may work differently, study finds

CHICAGO -- The differences between liberals and conservatives may run deeper than how they feel about welfare reform or the progress of the Iraq war: Researchers reported Sunday that their brains may actually work differently.

In a study likely to raise the hackles of some conservatives, scientists at New York University and the University of California, Los Angeles, found that a specific region of the brain's cortex is more sensitive in people who consider themselves liberals than in self-declared conservatives.

The brain region in question helps people shift gears when their usual response would be inappropriate, supporting the notion that liberals are more flexible in their thinking.

"Say you drive home from work the same way every day, but one day there's a detour and you need to override your autopilot," said NYU psychologist David Amodio. "Most people function just fine. But there's a little variability in how sensitive people are to the cue that they need to change their current course."

The work, to be reported today in the journal Nature Neuroscience, grew out of decades of previous research suggesting that political orientation is linked to certain personality traits or styles of thinking. A review of that research published in 2003 found that conservatives tend to be more rigid and closed-minded, less tolerant of ambiguity and less open to new experiences. Some of the traits associated with conservatives in that review were decidedly unflattering, including fear, aggression and tolerance of inequality. That evoked outrage from conservative pundits.

The latest study showed "there are two cognitive styles -- a liberal style and a conservative style," said UCLA neurologist Dr. Marco Iacoboni, who was not connected with the latest research.

Linda Skitka, a professor of psychology at the University of Illinois at Chicago, said it's possible the liberals in the recent study appeared more flexible than the conservatives because the population was skewed.

"We're more likely to find extreme conservatives in the U.S. than extreme liberals," she said.

Participants were college students whose politics ranged from "very liberal" to "very conservative." Scientists instructed them to tap a keyboard when an M appeared on a computer monitor and to refrain from tapping when they saw a W.

M appeared four times more frequently than W, conditioning participants to press a key in knee-jerk fashion whenever they saw a letter.

Each participant was wired to an electroencephalograph that recorded activity in their anterior cingulate cortex, the part of the brain that detects conflicts between a habitual tendency (pressing a key) and a more appropriate response (not pressing the key). Liberals had more brain activity and made fewer mistakes than conservatives when they saw a W, researchers said. Liberals and conservatives were equally accurate in recognizing M.

Researchers obtained the same results when they repeated the experiment in reverse, asking another set of participants to tap when they saw W.

Frank Sulloway of the Institute of Personality and Social Research at the University of California, Berkeley, who was not involved in the study, said results "provided an elegant demonstration that individual differences on a conservative-liberal dimension are strongly related to brain activity."

Analyzing the data, Sulloway said liberals were 4.9 times more likely than conservatives to show activity in the brain circuits that deal with conflicts and were 2.2 times more likely to score in the top half of the distribution for accuracy.

Based on the results, Sulloway said, liberals could be expected to more readily accept new social, scientific or religious ideas.

Amodio said it would be a mistake to conclude that one political orientation was better than another. The tendency of conservatives to block distracting information could be a good thing depending on the situation, he said. Positions on specific issues are influenced by many factors, he noted.