Tuesday, September 11, 2007

Liberal and Conservative Preferences Run Deep -- Brain Deep

Some political bloggers are having fun with a study published Sunday in the journal Nature Neuroscience.

The study finds evidence the brains of liberals and conservatives function differently. It appears liberals have brains that adapt to sudden changes a bit more readily than do the brains of conservatives. Naturally, liberal bloggers are spinning the study one way while conservatives are spinning it the other. Each side wants to show how the study "proves" folks on their side of the fence are superior thinkers. But neither the liberal nor the conservative bloggers that I read are discussing one of the most interesting implications of the study -- that humans may have evolved innate perspectives or prejudices.

The study was conducted by political scientist David Amodio and his colleagues at New York University. They recruited 43 subjects for the experiment and began by asking each subject to rank his or herself on a scale for political views. One end of the scale was "extremely liberal" while the other end was "extremely conservative".

After the recruits ranked themselves, they were directed to sit before a computer screen and press one of two buttons depending on whether they saw an "M" or a "W". Each time they saw a letter, they had only half a second in which to respond -- nothing like a little pressure to think fast.

Eighty percent of the time (400 out of 500 instances) they saw the same letter. This was to encourage them to expect that letter. "You keep seeing the same stimulus over and over, so when the opposite stimulus comes on it's always a surprise," said Amodio.

When the less common letter appeared on the screen, the people who identified themselves in the conservative half of the scale pressed the "usual" button 47% of the time instead of switching to the correct button. In comparison, the "liberals" achieved the slightly lower error rate of 37%.

Up until this point, nothing about the study was surprising: There have been dozens of studies showing a strong link between political persuasion and certain personality traits. "Conservatives tend to crave order and structure in their lives, and are more consistent in the way they make decisions. Liberals, by contrast, show a higher tolerance for ambiguity and complexity, and adapt more easily to unexpected circumstances (Source)." But Amodio's study is unique because he performed electroencephalogram (EEG) scans on the brains of his subjects while they were performing their task -- thus discovering significant differences in the way the brains of liberals and conservatives were operating.

Liberals had slightly over twice as much activity as conservatives in a region of the brain called the anterior cingulate cortex. Some scientists think that area of the brain acts as a mental brake by helping the mind recognize "no-go" situations where it must refrain from the usual course of action. They refer to that function of the anterior cingulate cortex as "conflict monitoring".

According to Amodio, "The neural mechanisms for conflict monitoring are formed early in childhood," and are probably rooted in part in our genetic heritage. "But even if genes may provide a blueprint for more liberal or conservative orientations, they are shaped substantially by one's environment over the course of development."

It seems to me Amodio's overall take on his experiment is in line with what most other scientists are saying these days: Genes may predispose us to certain thoughts and behaviors, but environment still plays a major role in how we think and act. But if genes predispose us to certain inclinations, then how and why did those genes evolve?

As luck would have it, Ed Yong has a post on the evolution of personality differences over at Not Exactly Rocket Science that sheds considerable light on the question of how and why personality differences (and by extension, political preferences) might have evolved in us. Basically, it turns out that certain personality traits most likely evolved as ways of answering the age-old question, "Should I have kids now or later?" At first blush, there might not seem to be much of a relationship between reproduction, personality differences, and political preferences, but do check out Ed's article for insight into how those things might be linked.

I think the important thing to realize here is that "liberal" and "conservative" tendencies evolved in us because both tendencies increase our biological fitness -- depending on the circumstances. If one or the other were inherently superior, then natural selection, working over millions of years, would have resulted in that one particular tendency being the only tendency humans have. Either we would all be "liberals" or we would all be "conservatives". But that didn't happen because both liberal and conservative personalities have advantages.

UPDATE: Cognitive Daily has an illuminating critique of the study here. I think it should be read in conjunction with Ed's article, however, because I don't think Cognitive Daily's critique of the "Left-wing/Right-wing" study amounts to an refutation of the notion there may be significant and inherent differences in the way liberal and conservative brains operate.


Homo Politicus: Brain Function of Liberals, Conservatives Differ

Political Affiliation Could All be in the Brain (New Scientist)

Study Finds Left-Wing Brain, Right Wing Brain (L.A. Times)

1 comment:

Mahendra said...

Paul, thanks for this insightful and informative post!

I had read about the personality/political relationship before. But the Not Exactly Rocket Science article on how different evolutionary behavior may have caused personality traits in the first place, was new and very insightful.