This study (Kanai, Feilden, Firth & Rees, in press) is doing the rounds on the blogs. They measured political orientation using a five-point scale of very liberal (1), liberal (2), middle-of-the-road (3), conservative (4), and very conservative (5). Gist: liberals have a bigger anterior-cingulate cortex (ACC) than do conservatives; liberals have a smaller right amydala than conservatives.
There are a bunch of problems interpreting brain volume, e.g., does bigger mean better or does it mean less efficient? Also we know volume can change over time, so finding something in the brain doesn’t imply an initial cause of anything. See more in an earlier post over here.
Interpreting what causes these kinds of correlations is a nightmare. There’s a rather large gap between brain volume and self-reported political orientation. Still, something maybe interesting going on.
First thought about this: hmmm, ACC, that’s to do with dealing with interference which loads on little g. Openness to experience also loads on g. I wonder is this liberal scale tapping into Openness/intelligence?
Here’s a table (from Carney, Jost, Gosling & Potte, 2008) summarising theorized personality correlations.
Lots of high Openness on the liberal side there. Their data also supported the correlation (standardised beta of -.4). Question remains, what causes this? (End of think-aloud for now.)
Carney, D. R., Jost, J. T., Gosling, S. D., & Potter, J. (2008). The Secret Lives of Liberals and Conservatives: Personality Profiles, Interaction Styles, and the Things They Leave Behind, Political Psychology, 29, 807-840.
Kanai, R., Feilden, T., Firth, C., Rees, G. (in press). Political Orientations Are Correlated with Brain Structure in Young Adults. Current Biology.
(Prompted by this.)
The main complaint one hears about the big five is that there’s an absence of theory explaining what’s driving the different dimensions. It’s all descriptive, or at best “finger in the wind” theorizing. At least that’s (my perception of) what the critics go on about (usual disclaimers apply). Oh and the stats can be a bit dodgy (see Borsboom, 2006, for a discussion of misapplications of PCA).
DeYoung and colleagues found a bunch of correlations between personality traits and volume of different brain regions. That there’s a relationship between personality and brain structure is unsurprising. That it can be detected is nice, though. That it can be detected with such a crude measure (bigger is better function – except for one bit of the brain and agreeableness) is perhaps surprising, but has been spotted before in (part of) taxi drivers’ hippocampi in the context of spatial navigation (Maguire et al, 2000).
This work belongs to the genre of trying to work out what cognitive processes are driving personality. The geography is not particularly interesting in itself. But with a spot of detective work linking to other studies, the geography gives clues about what might be going on.
Borsboom, D. (2006). The attack of the psychometricians. Psychometrika, 71, 425-440
DeYoung, C. G., Hirsh, J. B., Shane, M. S., Papademetris, X., Rajeevan, N. & Gray, J. R. (2010). Testing Predictions From Personality Neuroscience: Brain Structure and the Big Five. Psychological Science, 21, 820-828
Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S. and Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences of the United States of America, 97, 4398-4403