Biological differences between the liberal brain and the conservative brain

CC-licensed image, courtesy of Mr. Physics, via Flickr

An excellent post today on the Dangerous Minds blog, and an ensuing discussion on Facebook got me to thinking about the differences between the minds of conservative folks and liberal folks.

Namely, why should it be that so many conservatives have such a hard time changing their opinions when presented with bald facts that contradict those opinions?

We normally think of humans as rational agents.  That is, we expect the beliefs we each hold are based on some sort of evidence and argument, and as more data becomes available to a person, they should update their model of how the world works.  But often, in practice, it doesn’t seem to work out that way.

(This is going to turn out to be a long post.)

Even though biological evolution through the mechanism of natural selection is a fact, there are still people who deny that reality.  Even though there is overwhelming evidence that global warming is actually happening, and is being exacerbated by the actions of humans, there are still people who shout and scream and stomp their feet and demand it isn’t true.

It’s clear to me, based on my own observations, that people of a conservative bent tend to be particularly susceptible to this effect, but we are, each of us, guilty of paying more attention to the evidence that confirms our pre-existing beliefs than we pay to evidence that contradicts it.

So what’s going on here? Are conservatives just “dumber” than average?  Maybe, it turns out:

“Young adults who subjectively identify themselves as “very liberal” have an average IQ of 106 during adolescence while those who identify themselves as “very conservative” have an average IQ of 95 during adolescence.”

From, adapted from the American Sociological Association’s press release and

Kanazawa et al. Why Liberals and Atheists Are More IntelligentSocial Psychology Quarterly, 2010; DOI:10.1177/0190272510361602

Of course, IQ is one of those funny things that means different things depending on how you measure it.  As Christopher Badcock writes in Psychology Today,

The implication is that rising mechanistic intelligence is all very well but goes with declining mentalistic intelligence which—as is so clearly evidenced in autism—carries serious social costs. Conservatives, in other words, may score lower on adaptation to a modern technological style of intelligence, but may score higher on traditional social intelligence whose loss we may well live to regret.

So, maybe conservatives are “smart” in a different way from liberal folks.

There are a number of other ways that conservative brains seem to work differently from liberal brains.  For instance, conservatives tend to experience “disgust” more strongly than liberals:

To test whether disgust sensitivity is linked to specific conservative attitudes, the researchers then surveyed 91 Cornell undergraduates with the DSS, as well as with questions about their positions on issues including gay marriage, abortion, gun control, labor unions, tax cuts and affirmative action.

Participants who rated higher in disgust sensitivity were more likely to oppose gay marriage and abortion, issues that are related to notions of morality or purity. The researchers also found a weak correlation between disgust sensitivity and support for tax cuts, but no link between disgust sensitivity and the other issues.

Conservatives are more likely than liberals to avoid large urban centers, according to one 2005 study.

Conservatives tend to be immune to gaze cues, while liberals tend to follow the eyes of others.

A study in 2007 at NYU demonstrated that liberals break out of habituated responses more readily than conservatives.

Surely, surely there is something other than chance underlying these sorts of differences?  It’s not just that we have different opinions, or access to different knowledge, or that one side is RIGHT while the other is WRONG.  There’s something more fundamental than that at work here.

It all adds up to the simple fact that liberals and conservatives are biologically different from one another.

Now, I’m not saying we’re different species, or anything.  But I do believe there are underlying physiological foundations for the reasons we don’t see eye to eye on so many issues.

As it turns out, there’s a fair amount of evidence that seems to confirm this is the case. Scientists in London have recently found that a conservative brain correlates with a larger amygdala, and a smaller smaller anterior cingulate than a liberal brain.  The researchers in London were quoted in the Daily Mail as saying:

“The anterior cingulate is a part of the brain that is on the middle surface of the brain at the front and we found that the thickness of the grey matter, where the nerve cells of neurons are, was thicker the more people described themselves as liberal or left wing and thinner the more they described themselves as conservative or right wing.”

“The amygdala is a part of the brain which is very old and very ancient and thought to be very primitive and to do with the detection of emotions. The right amygdala was larger in those people who described themselves as conservative.”

Interestingly enough, there was a study published in January of this year which found a similar correlation between the size of the amygdala and the complexity of one’s social network:

The authors found that individuals with larger amygdala reported larger and more complex social networks. This link was observed for both older and younger individuals, and for both men and women.

Barrett noted that the study findings are consistent with the “social brain hypothesis,” which suggests that the human amygdala might have evolved partially to deal with an increasingly complex social life.

Ergo, one would expect that conservatives tend to have more complex social networks than liberals, overall.  This would probably be an interesting research topic for some sociology or anthropology grad student to do for a dissertation; the only relevant information I could find was from a study at Harvard in 2007, which is so old as to be practically useless today (because it only examines blog links), and which doesn’t directly speak to this hypothesis.

Anyway, I digress…

So the amygdala, eh? Any other differences in the liberal and conservative brains?  Yep.  Turns out, conservatism strongly correlates with high levels of left-hemisphere activation, and liberalism strongly correlates with high levels of right-hemisphere activation.  See also this very interesting study by Neuropolitics from back in 2005.

Not only that, but it turns out certain neurotransmitters are asymmetrically distributed in the brain.  For instance, that left hemisphere has lots more dopamine floating around, and that right hemisphere has lots more noradrenaline.  Once again, Neuropolitics has some interesting information:

“No other neurochemical would leave its signature on the American Revolution quite like dopamine, due primarily to the goal-seeking nature of the highly active dopaminergic system.

Conservative mental attributes are more closely associated with highly active dopaminergic systems, and the Conservative advantages in semantic language processing and arithmetic calculation are a natural result.

The unambiguous cognitive styles of Conservatives are firmly rooted in the higher signal-to-noise neural communication of dopaminergic networks. Conversely, Liberals exhibit more ambiguous cognitive styles, consistent the noradrenergic activation system which is distributed asymmetrically in the right hemisphere.”

What’s more, it turns out that you get more activity going on with your dopamine system when you’re older, and more in your noradrenaline system when you’re younger, reinforcing the notion that younger folks tend to be more liberal, and older folks tend to be more conservative.

So, yeah.  There’s biological differences between liberals and conservatives.  Which brings us back around to the question of why it’s so hard for conservatives to change their minds.

It comes down to feeling threatened, I think.  It’s that enlarged amygdala which is processing the fear associated with being mistaken.  The ancient lizard-brain amygdala activates a strong emotional response, and that interferes with rationality.  By threatening the beliefs of a conservative by correcting misinformation, it may be you are making them temporarily less rational, instead of more.

This seems to be a plausible opinion:

The apocalyptic reaction of many conservatives to the Obama Presidency has traces of the left amygdala written all over it. The amygdalar reactivity to opposite-race faces is the trigger for the fear that many conservatives have for Obama, and subsequently induces the fight or flight responses associated with amygdalar activation.

Further, the amygdala can induce negative emotional states for long periods of time, particularly if prefrontal cortical activity is not sufficient to attenuate amygdalar activation. The left brain is especially susceptible to verbally communicated threat, given its strong language orientation and the left amygdala’s elevated reactivity to threats communicated via language.

The threats communicated by conservatives are typically quite simple, avoid activation of the higher cognitive processing areas of the prefrontal cortex in favor of ventral PFC and temporal activation, and based on simple one or two-word phrases, such as death panels, socialism, communism, fascism, Hitler, Stalin, etc. These are also words that have been introduced as threatening words early in life.

Glenn Beck has become extraordinarily effective at communicating threat to conservatives, via classroom blackboards, word analysis, and threatening symbols. He is no doubt charging the mesolimbic dopamine system among his many devoted fans, which works to increase the level of their bonding to him (analogous to romantic bonding brain mechanisms), and ironically, increasing the experience of reward in their brains.

I think the takeaway lesson from all of this is to remember, the next time you find yourself arguing with someone of the opposite political persuasion:  They’re not stupid. They’re not evil. They may not even be wrong. Their brain is just working much differently from yours, and that’s not necessarily a bad thing.  There’s a reason we have diverse neurological styles.  Variation throughout the species strengthen us as a whole, and provide the basis for new evolution to occur.

1 thought on “Biological differences between the liberal brain and the conservative brain”

  1. Keep looking for a good site on this topic and not finding one. Keep finding only those written by Liberals, for Liberals, but contradicting each other back on forth as two who is left brained and who is right brained. The only common denominator I can find is that the author will assign whatever traits he thinks are negative to the conservatives.

    Former extreme Liberal/Leftist, raised to be that way, began to become centrist/conservative in 20s. Current IQ, post head injury a in mid 30s 122, top measured IQ while becoming more conservative 147. Problem with being smart is that you can talk yourself, and others, into whole loads of rational sounding rubbish. And yes, all the people coming back to religion and more traditional conservative ways that I know are all very highly intelligent as well. Doctoral students, authors, people who travel widely and engage the new routinely. When I visited a mosque it was the Left wing/liberal peace and social justice types that all asked me if I wasn’t terrified to go then and get my head cut off. Not really sounding much like your idealized liberals, are they?

    And, by the way, it’s been shown that Libertarians, often the scariest of the right-wingers and most prone to conspiracy theories about freedom and oppression, share far more of their mental and moral processing with liberals than with traditional conservatives. Liberals think in two spheres morally care vs harm and liberty vs oppression, Libertarians think in only one liberty/oppression. By contrast conservatives, and almost everyone else in the world thinks in 6 moral spheres.
    Why don’t you ask the extreme Leftists about their mad delusions and beliefs about groups that control the world. They may have good IQs, but the just use them to confirm their own biases, more than to explore.

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