9/20/16

This is your brain

But this is your brain on politics...

The Brain Blog

Or

Brain Anatomy for the Innocent, the Eager and the Doomed…

CAVEAT: The human brain is the single most complicated structure on the planet. Just because a part of the brain seems bigger in liberals or more active in conservatives doesn't mean that "Liberal" or "Conservative" is directly encoded in the brain. It's usually more involved than that. Just keep that in mind as you read.

We know from lots of different research that liberals and conservatives respond differently to different things. It makes sense, then, to think that there might be differences in their brains, in the size of different parts or maybe which parts get turned on under different circumstances. And that's what the research actually shows. (You're remembering that part about most-complicated-structure-on-the-planet, right? Carry on.)

For example, when faced with disturbing images, conservatives respond more strongly (they sweat more) than liberals and pay more attention to the pictures of spiders or dead bodies or whatever. Moreover, they are more vigilant and cautious than liberals and can respond more aggressively when threatened. So is there a part of the brain that helps monitor fear and aggression? Why yes, there is!  It’s called the amydgala, and it’s part of a really cool network called the limbic system.  Here’s the amygdala in red:

The Amygdala

You can see there’s one on each side of the brain. That’s true for almost all brain structures, with the exception of the pineal gland, beloved of crystal gazers and pseudoscientists alike. Anyway, the amygdala is significantly bigger in conservative brains than liberal brains. It’s also much bigger in men than women and explains part of why male brains are bigger than female brains, even controlling for differences in body mass. And possibly why men are generally more aggressive than women.

But I digress.

So what does this mean in general? Can we use this as an explanation for why conservatives respond differently to threats? Why they respond so much more strongly to disgusting images? Is it a cause or an effect of that behavior?  Chicken or egg? Stay tuned.

We also know that liberals can process conflicting information and changes in patterns more efficiently than conservatives. For example, if you have to tap a keyboard when the letter M shows up on the screen but not when the letter W shows up, liberals do better. This requires the activation of a part of the brain that monitors conflict. It’s called the anterior cingulate cortex, and here’s what it looks like:

 

Anterior Cingulate Cortex

The ACC is bigger in liberal brains than conservative brains. And given conflicting information, liberals are generally better at figuring out what’s happening and responding more efficiently than conservatives. (There's another part of the brain that does similar things but is more active in conservatives than liberals.  Obvious this still needs to be worked out.)

But the ACC is also involved when we have to think hard about something. That's actually important for political thinking as well. If we don't allow people to think thoroughly about politics and force them to use easier, low-effort means of thinking, then they tend to arrive at conservative viewpoints rather than liberal ones.  Being a liberal can take work.

So on to the chicken and egg thing.  Those of us who are interested in why folks do the things they do often bring up the nature/nurture argument. Is this behavior or that trait inborn or is it learned? And the best answer is yes, it’s both.  That may be what’s working here, though I’m just guessing. Since we know that for many of us, political affiliation runs in families (like intelligence and musical talent and so on), then maybe people inherit a brain structure that’s primed to absorb the family politics. An inclination, as it were, to be a liberal or a conservative.

Having pulled this theory out of, ahem, I went in search of studies to see what people might have actually found.  And, happy day, the Pew Research Center published a study several years ago that compared political attitudes between identical twins (same brains) and fraternal twins (raised at the same time with some similarities but not the same brain). And they concluded that more than half (56%) of the differences in political orientation between identicals and fraternals could be accounted for by genetics. More than half! They also found that about half of the trait of authoritarianism (much stronger in conservatives than liberals) seems to be inherited as well as half the trait of egalitarianism (stronger in liberals than conservatives). You can find the whole report here.  It’s written for real people instead of scientists, so I can recommend it to you.

Is biology destiny?  No. Genetics may supply the paper and pen, but life itself does the writing.  People are highly, though not infinitely, malleable. However, when we encounter those of the opposite political persuasion, it would probably be helpful to remember that some of what they have to say may come from hard wiring in the brain and childhood experiences and not lend itself to rational debate. Sadly.

Finally, this is your brain on Election Day.