Per­son­al­ity traits linked to brain size, study says

sci­en­tists com­pare re­gions that con­trol key char­ac­ter­is­tics

Austin American-Statesman - - WORLD & NATION - By Leslie Ta­mura

Does the size of your brain — or, more specif­i­cally, dif­fer­ent re­gions of it — say any­thing about your per­son­al­ity? Ac­cord­ing to a new study, maybe.

Us­ing mag­netic res­o­nance imag­ing and per­son­al­ity ques­tion­naires, Colin DeYoung, a Uni­ver­sity of Min­nesota psy­chol­ogy pro­fes­sor, and his col­leagues in­ves­ti­gated the bi­o­log­i­cal ba­sis of what psy­chol­o­gists know as the Big Five per­son­al­ity traits: ex­tro­ver­sion, agree­able­ness, con­sci­en­tious­ness, neu­roti­cism and open­ness/in­tel­lect.

Their three years of re­search showed that cer­tain brain re­gions had sig­nif­i­cantly dif­fer­ent sizes depend­ing on the self-re­ported strength of a par­tic­u­lar per­son­al­ity trait.

Re­searchers used MRIs to com­pare the brains of the 116 healthy adults to the “ref­er­ence brain” of a per­son whose per­son­al­ity traits seemed av­er­age, ac­cord­ing to an ar­ti­cle pub­lished in the jour­nal Psy­cho­log­i­cal Sci­ence. Us­ing com­puter soft­ware, DeYoung said re­searchers “stretched or squished” in­di­vid­ual brain scans to match them with the ref­er­ence im­age, and then noted the size of the dif­fer­ent re­gions of each brain.

MRI scans of self-de­scribed ex­tro­verts re­vealed a sig­nif­i­cantly larger me­dial or­bitofrontal cor­tex, the area just above and be­hind the eye socket. This area is in­volved with keep­ing track of re­wards, re­searchers said.

The pos­te­rior cin­gu­late cor­tex and su­pe­rior tem­po­ral sulcus were larger in peo­ple who iden­ti­fied them­selves as hav­ing many char­ac­ter­is­tics as­so­ci­ated with agree­able­ness. That area is as­so­ci­ated with un­der­stand­ing the ac­tions and mental states of oth­ers, re­searchers said. Above-av­er­age con­sci­en­tious­ness was as­so­ci­ated with a larger re­gion of the lat­eral pre­frontal cor­tex, which is in­volved in plan­ning and vol­un­tary con­trol of be­hav­ior.

Self-de­scribed neu­rotics, who tended to ex­pe­ri­ence neg­a­tive emo­tions, had smaller brain vol­umes in ar­eas known to reg­u­late emo­tion. Neu­rotics also had a sig­nif­i­cantly larger mid-cin­gu­late gyrus, a re­gion that de­tects pain and er­ror.

The only trait with­out a sig­nif­i­cant neu­roanatom­i­cal re­la­tion­ship, ac­cord­ing to the re­port, was open­ness/in­tel­lect, which re­searchers said re­flects imag­i­na­tion, cu­rios­ity, and artis­tic and in­tel­lec­tual in­ter­ests.

De­spite find­ing a cor­re­la­tion be­tween brain struc­ture and per­son­al­ity, DeYoung said that genes and the en­vi­ron­ment play im­por­tant roles. “Per­son­al­ity doesn’t change eas­ily, but it can change,” he said. “When it does, that change is ac­com­pa­nied by changes in the brain.”

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