(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