Picture: Gladraeli. As Gilbert and Sullivan had it,

…every boy and every girl
That’s born into the world alive
Is either a little Liberal
Or else a little Conservative!

Now indeed it seems that right-wing brains are measurably different from left-wing ones.

Well, alright, it’s not as simple as that, but as this review (via)of an interesting piece of research reports, in one sample of young adults, self-reported political conservatives tended to have a larger right amygdala, whereas self-reported liberals tend to have a larger anterior cingulate cortex. Strictly speaking we are probably not entitled to deduce anything from this, but if we want to jump to conclusions we can assume that a larger amygdala is associated with greater levels of distrust and hostility, while a larger anterior cingulate cortex is associated with greater tolerance of conflict and uncertainty. It’s easy to imagine that a more distrustful (perhaps we should say ‘sceptical’) personality, with a more pessimistic view of human nature, might be associated with generally more right-wing views. I’m not so sure about the interpretation of the other finding, but I suppose a greater tolerance of conflict and uncertainty might be associated with less support for established authority and traditional mores, and so with a generally more leftish slant. I suppose we would expect, in line with the often-observed tendency to drift to the right as one ages, that the amgydala would swell and the anterior cingulate cortex shrink as time went by?

It’s generally fairly plausible that political views correlate to at least some degree with personality traits. It’s often suggested that introversion tends to go with a more conservative outlook, for example. It’s certainly the case that political leanings are more about direction of travel than about specific policies: pretty well everyone alive now is a raving lefty in terms of the medieval political outlook (though even then there were outbursts of radicalism, of course). Conservative opinion which once would fight to the death defending the divine right of kings finds itself, four hundred years later, defending the mercantile individualist values it once regarded as the enemy. For that matter I’ve just been reading a few of Trollope’s novels, and it seems pretty clear that the Duke of Omnium’s coalition government would find its successor in Westminster today not just unacceptably but almost incomprehensibly left-wing, even though in theory the governments have a broadly similar mixture of conservative and liberal opinion.

It’s strange that Kanai’s research identifies two different measures of political leaning. It doesn’t seem to me that trusting and liking people is exactly the same thing as tolerating conflict. The existence of two independent axes suggests that there are actually four different positions. As well as the die-hard right and the entrenched left, we have on the one hand people who favour hard-nosed policies but attach no value to authority and convention; while on the other hand we have people who prefer generous and supportive systems but want to combine them with traditional and conforming ways of behaving. Neither seems at all hard to imagine: I know people who would fit both those descriptions tolerably well. Perhaps our existing political set-up misses out on the full geometry: if so it might be a little worrying because it would imply that perhaps there are problems and solutions which are really quite important but remain partly invisible to us on our one-dimensional view?

If the normal right-left spectrum is so inadequate (and I think many people would say it is, and that there are really not just two axes involved, but several), how come we’re lumbered with it? It’s not that surprising that when one group is in power many of its opponents band together and sink their differences in the joint project of turning the rascals out; and when the tables are turned it’s the new opposition that benefits from the same effect. Over time it seems plausible this would lead to the crystallisation of two broad groupings; and the theme of those who have established wealth and power, and hence tend to like theoretical arguments against change, versus those who have less and so are predisposed to like reforming and revolutionary sentiments, seems well adapted to be the thread along which the parties ultimately take shape.

Fine for politics, but I can’t see how that would explain a similar dichotomy in the brain, unless there’s something more fundamental going on. Could there be some kind of game-theoretical account, in which, say, big-amygdala people do well out of their hard-nosed attitudes and reproduce successfully up to the point where they become a majority of the population, at which point the level of distrust undermines social cohesion and fully offsets the benefits to new ‘selfish’ entrants, so the advantage begins to accrue to the cingulate cortexers who can cope with a bit of dissent and disorder, who then do better until their generosity and trust begins to be exploited by a selfish minority and so on until some kind of balance is reached?

Maybe it’s not genetic, though: perhaps it has to do with birth order? It is said that first-born children tend to endorse authority and take on the role of parental deputy, while for subsequent children there are more rewards in being the first non-conformist than in being a mere second deputy. Perhaps these influences create differential growth in differing parts of the brain (alas, no data on birth order)?

Having jumped repeatedly from one conclusion to another like an excitable frog, I find myself in an unfamiliar part of the pond, so I shall retreat, taking with me only the wild speculation that much of the theory and rhetoric of politics might in fact resemble the bizarre confabulations produced by some patients to give a superficial appearance of conscious volition to behaviour whose actual origins in deep mental hard-wiring or cognitive deficits are actually quite unknown to them.


  1. 1. calvin says:

    I would say a distrusting “attitude” is a pre-requisite for an us vs them mentality… which we do see displayed in the right wing rhetoric. And a tolerance for conflict and uncertainty sounds just like a wishy-washy liberal and wishy-washy climate science. Which means “nuanced”.

    This article reminds me of another may enjoy that touches on similar points:

    It reviews research that breaks people down along two axis: the first individualist – communitarian and the second is hierarchical – egalitarian. And it examines their views of science.

    What I found interesting were how these axis produce four quadrants that we can make over-simplified but interesting political associations with:

    egalitarian communitarians (left wing)
    hierarchical individualists (right wing)
    hierarchical communitarians (communists?)
    egalitarian individualists (… uh, Emerson’s self-reliance?)

    And thanks for an awesomely good blog.

  2. 2. Doru says:

    This research confirms some of the findings in Ramachandran’s split brain experiments (where brain injury patients with physical separation between portions of the brain can have those portions put to sleep while the other portions are kept awake,,,,).
    The one finding that I found very interesting was when one patient believed in existence of God with one half of the brain but not with the other half, rising the dilemma of splitting the body in two after death bodies: one that goes to Heaven and one that goes to Hell.
    My guess is specialization happens through both: genetic predisposition and cultural up bringing.

  3. 3. instant self hypnosis says:

    I hope my amygdala is not that large! I don’t want to experience high levels of distrust and hostility.

  4. 4. chuck says:

    I wonder if this is something that we already have the data on that can be tracked back to birth so we can separate the environment that we grow up in from the actual size of parts of our brain.

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