I knew I was inferior. I just couldn’t prove it.

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…

Analyzing the data, [Berkeley researcher Frank J.] 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.

Sulloway said the results could explain why President Bush demonstrates a single-minded commitment to the Iraq war and Sen. John F. Kerry, the liberal Massachusetts Democrat who opposed Bush in the 2004 presidential race, was accused of being a flip-flopper for changing his mind about the conflict.

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

“There is ample data from the history of science showing that social and political liberals indeed do tend to support major revolutions in science,” said Sulloway, who has written about the history of science and has studied behavioral differences between conservatives and liberals.

Exit question one: Aren’t these results more easily explained by liberals’ unusual sensitivity to the letter “W”? (Exit answer: No. They tested them with other letters.) Exit question two: How do they manage to shoulder the load of cat-like reflexes and supreme rationality?