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Activation of brain region found to predict altruism

Jan. 21, 2005
Courtesy Duke University Medical Center
and World Science staff

Re­search­ers say they have found that ac­ti­va­tion of a par­tic­u­lar brain re­gion pre­dicts wheth­er peo­ple tend to be self­ish or al­tru­is­tic.

Figur­ing out how this brain area works “may give clues to the ori­gins of im­por­tant so­cial be­hav­iors like al­tru­ism,” said Scott A. Huet­tel, a neu­ro­sci­en­tist at Duke Uni­ver­si­ty Med­i­cal Cen­ter in Dur­ham, N.C., though he added, it “may not nec­es­sar­i­ly iden­ti­fy what drives peo­ple like Moth­er The­re­sa.”

Volunteers clean a park. (Courtesy King County DNR, Wash.)
The study, by Huet­tel and others, is to ap­pear in today’s ad­vance on­line edi­tion and the Feb­ru­ary print is­sue of the re­search jour­nal Na­ture Neu­ro­science.

In 2005, re­search­ers reported seeing the ef­fects of em­pa­thy in the brain: its “pain” cen­ters awak­en­ing in re­sponse to some­one else’s suf­fer­ing. Yet it’s unclear how altruism—the de­sire to help—takes root, according to Dha­rol Tan­ker­s­ley, a grad­u­ate stu­dent in Huet­tel’s lab and lead in­ves­ti­ga­tor in the new study.

His team scanned 45 peo­ple’s brains while they ei­ther played a com­put­er game or watched the ma­chine play it on its own. Ei­ther way, suc­cess­ful play­ing earned mon­ey for a char­i­ty of the par­ti­ci­pant’s choice.

The re­search­ers scanned the par­ti­ci­pants’ brains us­ing a tech­nique called func­tional mag­net­ic res­o­nance im­ag­ing, which uses mag­net­ic pulses to meas­ure changes in ox­y­gen lev­els that in­di­cate brain cell ac­tiv­i­ty.

The scans re­vealed that a re­gion of the brain called the pos­te­ri­or su­pe­ri­or tem­po­ral sul­cus was ac­ti­vat­ed more when peo­ple per­ceived an ac­tion—that is, when they watched the com­put­er play—than when they acted them­selves, Tanker­s­ley said. This re­gion, which lies in the top and back por­tion of the brain, is gen­er­al­ly ac­ti­vat­ed when the mind is try­ing to fig­ure out so­cial re­la­tion­ships.

The re­search­ers then char­ac­ter­ized the par­ti­ci­pants as more or less al­tru­is­tic, based on their re­sponses to ques­tions about how of­ten they en­gaged in dif­fer­ent help­ing be­hav­iors, and com­pared the par­ti­ci­pants’ brain scans with their es­ti­mat­ed lev­el of al­tru­is­tic be­hav­ior. The scans showed that in­creased ac­tiv­i­ty in the pos­te­ri­or su­pe­ri­or tem­po­ral sul­cus strongly pre­dicted a per­son’s like­li­hood for al­tru­is­tic be­hav­ior, they said.

Ac­cord­ing to the re­search­ers, the re­sults sug­gest that al­tru­is­tic be­hav­ior may orig­i­nate from how peo­ple view the world, rath­er than how they act in it. Al­tru­ism seems to depend on an abil­i­ty to per­ceive oth­ers’ ac­tions as “mean­ing­ful,” Tanker­s­ley said.

The sci­en­tists sug­gest that stu­dying the brain sys­tems that al­low peo­ple to see the world as a se­ries of mean­ing­ful interac­tions may ul­ti­mate­ly help fur­ther un­der­stand­ing of dis­or­ders, such as au­tism or antiso­cial be­hav­ior, char­ac­ter­ized by deficits in interper­sonal interac­tions. The re­search­ers are now ex­plor­ing ways to study the de­vel­op­ment of this brain re­gion ear­ly in life, Tanker­s­ley said, adding that such in­for­ma­tion may help de­ter­mine how the ten­den­cies to­ward al­tru­ism de­velop.

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Researchers say they have discovered that activation of a particular brain region predicts whether people tend to be selfish or altruistic. “Although understanding the function of this brain region may not necessarily identify what drives people like Mother Theresa, it may give clues to the origins of important social behaviors like altruism,” said study invest igator Scott A. Huettel, a neuroscientist at Duke University Medical Center in Durham, N.C. The results are to appear Jan. 21 in the advance online edition of the research journal Nature Neuroscience and the February print issue. Why some people choose to act altruistically is unclear, said lead study invest igator Dharol Tankersley, a graduate student in Huettel’s laboratory. Researchers have seen the effects of empathy in the brain, such as when its “pain” centers awaken in response to someone else’s suffering. But how a person develops altruism, the desire to help, remains unknown, according Tankersley’s group. In the study, researchers scanned the brains of 45 people while they either played a computer game or watched the computer play the game on its own. In both cases, successful playing earned money for a charity of the partici pant’s choice. The researchers scanned the partici pants’ brains using a technique called functional magnetic resonance imaging, which uses magnetic pulses to measure changes in oxygen levels that indicate nerve cell activity. The scans revealed that a region of the brain called the posterior superior temporal sulcus was activated more when people perceived an action—that is, when they watched the computer play—than when they acted themselves, Tankersley said. This region, which lies in the top and back portion of the brain, is generally activated when the mind is trying to figure out social relationships. The researchers then characterized the partici pants as more or less altruistic, based on their responses to questions about how often they engaged in different helping behaviors, and compared the partici pants’ brain scans with their estimated level of altruistic behavior. The scans showed that increased activity in the posterior superior temporal sulcus strongly predicted a person’s likelihood for altruistic behavior, they said. According to the researchers, the results suggest that altruistic behavior may originate from how people view the world rather than how they act in it. It seems “the ability to perceive other people’s actions as meaningful is critical for altruism,” Tankersley said. The scientists suggest that studying the brain systems that allow people to see the world as a series of meaningful interactions may ultimately help further understanding of disorders, such as autism or antisocial behavior, that are characterized by deficits in interpersonal interactions. The researchers are now exploring ways to study the development of this brain region early in life, Tankersley said, adding that such information may help determine how the tendencies toward altruism are established.