From brain science, new questions about free will

July 1, 2010
Courtesy of Science
and World Science staff

Phi­loso­phers since an­cient times have strug­gled with the ques­tion of wheth­er hu­mans have any free will. With forc­es such as God or mo­lec­u­lar in­ter­ac­tions—de­pend­ing on whom you asked and when—said to ul­ti­mately con­trol eve­ry­thing, can hu­mans really make any de­ci­sions “in­de­pen­dently”?

Some sci­en­tists say re­cent re­search val­i­dates such con­cerns, cast­ing doubt on the com­mon hu­man feel­ing that we are able to make up our own minds, at least in the way we like to think.

In the July 2 is­sue of the re­search jour­nal Sci­ence, Ruud Cus­ters and Henk Aarts of Utrecht Uni­vers­ity in The Neth­er­lands dis­cuss re­search sug­gest­ing our sub­con­scious thoughts can ma­ni­pu­late our goals and mo­tiva­t­ions much more than sci­en­tists have ev­er im­ag­ined.

“Although it is of­ten tak­en for granted that goal pur­suit orig­i­nates in con­scious de­ci­sions, it can al­so arise from un­con­scious sources,” the pair wrote.

Re­cent find­ings show that the hu­man brain is of­ten steps ahead of its own­er, Cus­ters and Aarts ex­plained: the brain pre­pares the ac­tion well be­fore any con­scious thoughts in­struct it to do so.

The sci­en­tists cit­ed work by re­search­ers such as John Bargh at Yale Uni­vers­ity and Pe­ter Goll­witzer at New York Uni­vers­ity start­ing in 2001. Bargh and col­leagues showed how mo­tiva­t­ion to­ward a goal could arise with­out con­scious aware­ness, Cus­ter and Aarts wrote. “S­tu­dents were seated at a ta­ble to work on two seem­ingly un­re­lat­ed lan­guage puz­zles. For some stu­dents, the first puz­zle in­clud­ed words re­lat­ed to achieve­ment (such as win or achieve), and for oth­ers it did not. Stu­dents who were ex­posed to achieve­ment words were found to out­per­form the oth­ers on the sec­ond puz­zle.”

Cus­ter and Aarts pre­s­ent a the­o­ry based on the idea that the hu­man brain is de­signed for ac­tion, con­tin­u­ously and sub­con­sciously pro­cess­ing in­forma­t­ion rel­e­vant to our be­hav­ior, so that it is con­stantly ready to “in­struct” its own­er how to deal with the op­por­tun­i­ties and chal­lenges posed by our en­vi­ron­ments.

The frame­work the au­thors pro­pose for this sub­con­scious decision-making pro­cess, they said, helps re­veal just how thor­oughly these un­con­scious thoughts per­me­ate our ev­eryday lives.

“Ear­lier re­search has shown that ac­tion goals, such as mov­ing a fin­ger, that were in­i­tially con­sciously set are un­con­sciously pre­pared be­fore they are acted on,” they wrote. “The lit­er­a­ture re­viewed here sug­gests that the un­con­scious na­ture of the will has an even more per­va­sive im­pact on our life. Goals far more com­plex than fin­ger move­ments, can guide be­hav­ior with­out be­ing con­sciously set first, when they them­selves are ac­ti­vat­ed out­side con­scious aware­ness.”