Brain study looks for the location of personality

One recent posting was about the claim of evolutionary psychologists that our basic political orientations are more innate than learned. Today, we take a tangential look at the subject by examining a brain study that indicates that basic personality traits may be tied to neural activity in specific areas of the brain.

Oh, great, some of you must be thinking — evolutionary psychology and brain scans. But patience. I’m not going to advocate anything, just report what the study says.

If people like Jonathan Haidt (whose The Righteous Mind has been reviewed here) are right, and basic moral and political attitudes are “prewired” (not the same thing as “hardwired”), that idea would be consistent with brain studies showing that specific neuronal systems are more or less active in people with different perceived personalities.

If they’re right, and whether they are is not the subject of this article. For some people, the brain study is interesting enough on its own. For others, a naked scan is pretty much useless. That’s a debate for another time and place. I’m not avoiding that debate; I’m just not doing it right now.

The study at hand is “Personality Is Reflected in the Brain’s Intrinsic Functional Architecture,” by Michael Milham and a long list of contributors. The study was brought to my attention by “Personality Traits Correlate with Brain Activity,” published by Scientific American on April 14th.

The SA article reports that the Milham, et al., study shows that “resting brain activity varies with a person’s scores on a well-established personality test. When awake but not engaged in a task, each subject displayed activity patterns distinct from those found in someone with different traits.”

The article continues:

Because the brain activity only correlated with the traits, Milham says it is too soon to tell whether the patterns reflect the neural embodiment of personality. The findings, however, add to mounting evidence that studying the brain at rest may be a way to quickly approximate how an individual brain works and to zero in on circuits disrupted in disease.

The introduction to the source article by Milham, et al., puts it this way:

Despite the varied and dynamic nature of human environments, the patterns of behavior and cognition that constitute personality tend to be enduring and broadly predictable. A fundamental challenge to neuroscience is uncovering how personality is encoded in the brain.

Aware that “interpretations of structure-behavior relationships remain ambiguous,” the researchers decided to take a different, more empirical approach. They used “resting-state functional connectivity (RSFC) analyses to directly examine the brain’s functional architecture.” In other words, they used a brain scan to see which parts of the brain were actively associated with identified personality traits.

Relying on recent studies that showed associations between specific brain areas and behaviours linked to specific personality traits, the researchers focused on general connector areas of the brain. They also relied on data showing that identified personality traits (Neuroticism, Extraversion, Openness to Experience, Agreeableness and Conscientiousness — details are in the study) tend to be “non-overlapping,” that is, they trigger activity in different networks of brain structures.

The study’s results showed that different personality domains were associated with specific, non-overlapping brain activity in the areas studied. The scans also showed that, rather than a single brain structure, a group of interacting structures was associated with each identified personality domain.

The researchers caution that their work has a small sample size, and more important that identifying general patterns of neural activity doesn’t mean that they have found specific brain loci that are hardwired to specific personality traits:

By examining the relationship of these hubs with the areas to which they are functionally connected, this approach emphasizes the degree to which personality traits are associated with unique distributed networks of regions, rather than being localized in a few specific regions.

In their conclusion, the research team states that ” consistent with the neural network model of personality, our results suggest that distinct personality domains are encoded by dissociable patterns of functional connectivity among specific brain regions, despite the presence of modest inter-domain score correlations.”

Translation: Different, specific personality traits are associated with dynamic networks of activity in different, specific brain areas.

It’s worth stating clearly that the researchers are not directly promoting a kind of fMRI phrenology. They’re not pointing to a particular region of a particular brain part and saying, “Here lies agreeableness.”  What they are stating is that different parts of the brain activate when different personality traits are evoked by external stimuli.

As the SA article puts it, “Your personality says a lot about you. To categorize people by their disposition, psychologists have long relied on questionnaires. Now, however, researchers may be closing in on a tangible view of character in the brain.”

And, as I have often insisted here, in almost anything, the empirical trumps the speculative.

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