Does Brain Size Predict Who You Vote For?

Political season is here again, and it's time for the quadrennial re-emergence of the neuropundits. It starts earlier every time, and this time it started in April of this year, with a new paper in Current Biology by Ryoto Kanai and colleagues.

The paper received attention because its third author is a movie star, Colin Firth, who played the King of England, won an Academy Award AND had a paper published in Current Biology. So he's having a good year.

But the content of the paper is interesting too. The authors compared the sizes of several brain structures in liberal and conservative students (in the UK, so we still have to wait for the most interesting results: brain size in tea party members).

Oh and no students were injured in the collection of these data. Thanks to fMRI, you can measure brains in living people, and you don't have to remove anyone's skull.

Anyhow, the authors learned that liberals have larger anterior cingulate cortex than conservatives and that conservatives have a larger amygdala.

I have big no gripes with this paper, which is quite judicious in its conclusions. But I do have a gripe with the media coverage of the study, and with other neuropolitics studies more generally. The media like to pretend that we know what these effects mean. But neuroscience just doesn't really know. Like, we have no idea what an enlarged anterior cingulate implies.

Time magazine says, for example, that an enlarged anterior cingulate means you are "better at managing conflicting information," which kind of fits with positive stereotypes about liberals. Like, you could say that liberals are better at managing conflict, so they willing to accept compromise and be more flexible (about premarital sex, abortions, drug use, money distribution). The problem is that you could make the same facts could go the opposite way. You could also say, for example, that since liberals have a larger anterior cingulate, they feel conflict more intensely, so that they are less willing to accept compromise and be more dogmatic (about the death penalty, eating meat, hunting, economic tradeoffs associated with fighting global warming, etc). All we really know is that anterior cingulate has something to do with feelings of conflict. The rest is pure speculation.

Oh and actually, many researchers (myself included) think that anterior cingulate has nothing to do with conflict. That idea is like so 2003. So, uh, let's think of a new theory.

What is anterior cingulate activated by? I'll tell you, and then show you how easy it is to come up with silly just-so stories: just combine a brain fact with an unrelated stereotype.

• It's activated by marijuana. Maybe that's why liberals are more likely to support legalization.
• It's activated by anxiety, maybe that's why liberals are anxious about the environment.
• It monitors rewards and money, so maybe that's why democrats are so good a keeping the deficit down.
• It controls error detection, so liberals are more likely to be oversensitive to small slights. That's why they love political correctness.
• It plays a central role in learning. That's why teachers' unions are overwhelmingly democratic.
• It controls blood pressure and rational cognition, maybe that's why liberals are more calm and rational.

See? It's trivially easy to do neuropolitics. That's why Mr. Darcy and friends were smart to avoid both pride and prejudice in their interpretation of the data. Unfortunately, most media coverage of neuropolitics does not.