We all know that liberals and conservatives are far apart on health care. But in the way their brains work? Even in automatic reflexes, like blinking? Or the way their glands secrete moisture?
That's the suggestion of some recent research. It hints that the roots of political judgments may lie partly in fundamental personality types and in the hard-wiring of our brains.
Researchers have found, for example, that some humans are particularly alert to threats, particularly primed to feel vulnerable and perceive danger. Those people are more likely to be conservatives.
One experiment used electrodes to measure the startle-blink reflex, the way we flinch and blink when startled by a possible danger. A flash of noise was unexpectedly broadcast into the research subjects' earphones, and the response was measured.
The researchers, led by Kevin B. Smith of the University of Nebraska-Lincoln, found that those who had a stronger blink reflex at the noise were more likely to take conservative positions like favoring gun rights, supporting warrantless searches, and opposing foreign aid.
That makes intuitive sense: If you are more acutely sensitive to risks and more fearful of attack, you also may be more aggressive in arming yourself and more wary of foreigners.
Scholars also measured changes in the electrical conductance of research subjects' skin, after they were shown images meant to trigger disgust -- like a person eating a mouthful of worms. Our bodies have evolved so that when we're upset, glands secrete moisture to cool us down, and that increases conductance.
Liberals released only slightly more moisture in reaction to disgusting images than to photos of fruit. But conservatives' glands went into overdrive.
(Interestingly, women say that they feel more disgusted on average when they see such images, but they do not secrete more skin moisture than men do. One possibility is that women are raised to affect more revulsion than they feel, because it is considered feminine, while men are socialized to pretend that they are never grossed out.)
This research is tentative and needs to be confirmed, but it fits into a fascinating framework of the role of personality types in politics, explored in a recent book, "Authoritarianism and Polarization in American Politics," by two political scientists.
Marc J. Hetherington of Vanderbilt University and Jonathan D. Weiler of the University of North Carolina start by exploring data showing a remarkably strong correlation between state attitudes toward spanking children and voting patterns.
Essentially, spanking states go Republican, while those with more timeouts go Democratic.
Hetherington and Weiler contend that the differences stem from profound differences in cognitive styles.
Spankers tend to see the world in stark, black-and-white terms, perceive the social order as vulnerable or under attack, tend to make strong distinctions between "us" and "them," and emphasize order and muscular responses to threats.
Parents favoring timeouts feel more comfortable with ambiguities, sense less threat, embrace minority groups -- and are less prone to disgust when they see a man eating worms.
We shouldn't take this too far. It's not as if people in rural America, who overwhelmingly favor gun rights, invariably have a greater startle reflex than city dwellers. And the electorate undergoes big political shifts over time, even if human reflexes don't.
Hetherington says that electoral shifts sometimes reflect shocks, like Sept. 11, that leave middle-of-the-roaders feeling vulnerable and more authoritarian in their worldview.
I moaned to the scholars that their research was utterly dispiriting for those of us in the opinion business.
After all, it's extra-challenging to try to change people's minds if they may not even share our hard-wiring. Are people who are "wrong" on the issues beyond redemption, because of their physiological inability to help themselves?
Hetherington and Smith dismissed my whining and were more sanguine.
For starters, they note that physiological differences are probably found among the extremes on each side, while political battles are fought in the middle.
Indeed, these studies may be useful in determining what arguments to deploy against the other side.
"What research like ours may help with is in figuring out how to construct an argument in a way that is going to meaningfully connect with those on the other side," Smith said.
Conservatives may be more responsive to health reform, he suggested, if it is framed as a national security argument. For example, American companies complain about the difficulty of competing with foreign companies that don't have to pay for employee medical coverage. In that sense, our existing health care system leaves us vulnerable.
That foreign threat might make conservatives sweat so much that maybe, just maybe, they'd consider revisiting the issue.
NEW YORK TIMES