538 CHAPTER 13
How odd, then, that a study by Dr. Colin DeYoung and colleagues (DeYoung et al.,
2010) seems to suggest that there are indeed certain areas of the brain associated with
certain personality traits. Specifically, DeYoung and colleagues believe they have evidence
for the biological seat of four of the Big Five: extraversion, neuroticism, agreeableness, and
conscientiousness.
In their study, 116 volunteers answered a questionnaire about their Big Five per-
sonality traits. The participants were then subjected to a structural magnetic resonance
imaging technique for identifying the volume of specific areas of the brain. One partici-
pant was found to be near the group average for personality traits, and that individual’s
brain image was used as a reference image to which the other participants’ scans were
compared.
The trait of extraversion was associated with a higher volume in the medial orbi-
tofrontal cortex (underside of the frontal lobe, directly above the eyes). This area of the
brain is associated with recognizing the value of rewarding information. Neuroticism
was associated with lower brain volume in several areas responding to threat, pun-
ishment, and negative emotions. Reduced volumes were found in the dorsomedial
prefrontal cortex (toward the top and middle of the prefrontal cortex) and in the left
posterior hippocampus. Neuroticism was also associated with higher brain volume
in the middle cingulate cortex (cortical component of limbic system), associated with
error detection and response to pain. Areas of the brain associated with the inten-
tions of actions and mental states of others were correlated to agreeableness, with the
area of the posterior cingulate cortex showing a greater volume in individuals high in
that trait and a lesser volume in the left superior temporal sulcus. Conscientiousness
seemed associated with the left lateral prefrontal cortex, an area located on the side of
the frontal lobes involved in planning, working memory, and voluntary control of behav-
ior. (The researchers did look at areas that might be associated with the fifth of the Big
Five traits, openness, but failed to find any significant differences.)
The advances in personality neuroscience, coupled with better understanding of
brain function and brain processes, have also led to new and revised theories of per-
sonality. For example, Dr. DeYoung has developed the Cybernetic Big Five Theory
(DeYoung, 2015). This theory looks at personality through traits that are related to vari-
ations in brain structure and also through characteristic adaptations, or how someone’s
life circumstances influence their individual goals, strategies, and personal interpretations
(DeYoung, 2015).
Despite the advances offered through personality neuroscience, some research-
ers urge caution. Some studies have been with small samples. To counterbalance this,
researchers need to take advantage of meta-analysis techniques to attempt to synthesize
the results of hundreds of smaller studies, as well as conduct studies with larger sample
sizes (Yarkoni, 2015). Additional studies and meta-analyses will continue to help us under-
stand the links between personality and the physical structure and functioning of the brain.
No skull bulges needed!
Questions for Further Discussion
- We use personality assessments to make predictions about employment, marriage,
and stability, among other things. What might it mean for the future if a brain scan
becomes part of personality assessment?
- If personality traits are so closely linked with brain structure, what does that say about
the plasticity of personality? Are people able to change their traits? Their behavior?
