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Brain structure linked to personality

June 28, 2010
Courtesy of the Association for Psychological Science
and World Science staff

Sci­en­tists have found that the size of dif­fer­ent parts of peo­ple’s brains cor­re­spond to their per­son­al­i­ties. For ex­am­ple, con­sci­en­tious peo­ple tend to have a big­ger lat­er­al pre­fron­tal cor­tex, a brain re­gion in­volved in plan­ning and con­trol­ling act­ions.

Psy­chol­o­gists com­monly break down all per­son­al­ity traits in­to five fac­tors: con­sci­en­tiousness, ex­tra­ver­sion, neu­rot­i­cism, agree­a­ble­ness, and open­ness/in­tel­lect. Re­search­ers Col­in De­Young at the Uni­vers­ity of Min­ne­so­ta and col­leagues wanted to know if these fac­tors cor­re­lat­ed with the size of struc­tures in the brain.

The me­di­al or­bi­to­front­al cor­tex, whose act­iv­ity is high­light­ed in the brain scan ab­ove, was found to be sig­nif­i­cantly larg­er in very extro­verted peo­ple. (Im­age cour­tesy J. O'Doh­erty et al., Cal­tech)


The scientists gave 116 vol­un­teers a ques­tion­naire to de­scribe their per­son­al­ity, then gave them a brain im­ag­ing test that meas­ured the rel­a­tive size of dif­fer­ent parts of the brain. Sev­er­al links were found be­tween the size of cer­tain brain re­gions and per­son­al­ity. The re­search ap­pears in the jour­nal Psy­cho­log­i­cal Sci­ence.

For ex­am­ple, “ev­ery­body, I think, has a com­mon sense of what ex­tro­ver­sion is – some­one who is talk­a­tive, out­go­ing, brash,” said De­Young. “They get more pleas­ure out of things like so­cial in­ter­ac­tion, amuse­ment parks, or really just about an­y­thing, and they’re al­so more mo­ti­vat­ed to seek re­ward, which is part of why they’re more as­sertive.” That quest for re­ward is thought to be a lead­ing fac­tor in ex­tro­ver­sion. 

Ear­li­er stud­ies had found parts of the brain that are ac­tive in con­sid­er­ing re­wards. So DeY­oung and his col­leagues rea­soned that those re­gions should be big­ger in ex­tro­verts. In­deed, they found that one of those re­gions, the me­di­al or­bi­to­front­al cor­tex – just above and be­hind the eyes – was sig­nif­i­cantly larg­er in very extro­verted study sub­jects.

The study found si­m­i­lar as­socia­t­ions for con­sci­en­tiousness, which is as­sociated with plan­ning; neu­rot­i­cism, a ten­den­cy to ex­pe­ri­ence neg­a­tive emo­tions that is as­sociated with sen­si­ti­vity to threat and pun­ish­ment; and agree­a­ble­ness, which re­lates to parts of the brain that al­low us to un­der­stand each oth­er’s emo­tions, in­ten­tions, and men­tal states. Only open­ness/in­tel­lect did­n’t as­sociate clearly with any of the pre­dicted brain struc­tures, the re­search­ers found.

“This starts to in­di­cate that we can ac­tu­ally find the bi­o­log­i­cal sys­tems that are re­spon­si­ble for these pat­terns of com­plex be­hav­ior and ex­pe­ri­ence that make peo­ple in­di­vid­u­als,” said De­Young. He points out, though, that this does­n’t mean your per­son­al­ity is fixed from birth; the brain grows and changes as it grows. Ex­pe­ri­ences change the brain as it de­vel­ops, and those changes in the brain can change per­son­al­ity.


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Personalities come in all kinds. Now scientists have found that the size of different parts of people’s brains correspond to their personalities; for example, conscientious people tend to have a bigger lateral prefrontal cortex, a region of the brain involved in planning and controlling behavior. Psychologists have divided all personality traits into five factors, commonly called the Big Five: conscientiousness, extraversion, neuroticism, agreeableness, and openness/intellect. Colin DeYoung at the University of Minnesota and colleagues wanted to know if these personality factors correlated with the size of structures in the brain. For the study, 116 volunteers answered a questionnaire to describe their personality, then had a brain imaging test that measured the relative size of different parts of the brain. A computer program was used to warp each brain image so that the relative sizes of different structures could be compared. Several links were found between the size of certain brain regions and personality. The research appears in the journal Psychological Science. For example, “everybody, I think, has a common sense of what extraversion is – someone who is talkative, outgoing, brash,” said DeYoung. “They get more pleasure out of things like social interaction, amusement parks, or really just about anything, and they’re also more motivated to seek reward, which is part of why they’re more assertive.” That quest for reward is thought to be a leading factor in extraversion. Earlier studies had found parts of the brain that are active in considering rewards. So DeYoung and his colleagues reasoned that those regions should be bigger in people who are more extraverted. Indeed, they found that one of those regions, the medial orbitofrontal cortex – it’s just above and behind the eyes – was significantly larger in study subjects with a lot of extraversion. The study found similar associations for conscientiousness, which is associated with planning; neuroticism, a tendency to experience negative emotions that is associated with sensitivity to threat and punishment; and agreeableness, which relates to parts of the brain that allow us to understand each other’s emotions, intentions, and mental states. Only openness/intellect didn’t associate clearly with any of the predicted brain structures, the researchers found. “This starts to indicate that we can actually find the biological systems that are responsible for these patterns of complex behavior and experience that make people individuals,” said DeYoung. He points out, though, that this doesn’t mean that your personality is fixed from birth; the brain grows and changes as it grows. Experiences change the brain as it develops, and those changes in the brain can change personality.