Tuesday, April 22, 2008

Does the brain have a will of its own?

The belief in free will--that personal choices are not simply determined by fate or forces of a physical or divine nature--is under attack!

John-Dylan Haynes of the Max Planck In­sti­tute for Hu­man Cog­ni­tive and Brain Sci­ences in Leip­zig, Ger­ma­ny has looked into the matter, and published his findings, summarized recently in World Science:

Cer­tain pat­terns of brain ac­ti­vity pre­dict peo­ple's de­ci­sions up to 10 sec­onds be­fore the peo­ple are aware of them... Re­search­ers tracked brain ac­ti­vity while peo­ple viewed a stream of let­ters on screen, and then pressed a but­ton. Each par­ti­ci­pant was asked to de­cide freely which of two but­tons to press and when to press it.

Scan­ning the brains with a tech­nique called func­tion­al mag­net­ic res­o­nance im­ag­ing, the in­ves­ti­ga­tors used a sta­tis­ti­cal meth­od known as pat­tern rec­og­ni­tion to ex­am­ine brain ac­ti­vity as­so­ci­at­ed with each choice. Ac­ti­vity in two brain re­gions, called the pre­fron­tal and pa­ri­e­tal cor­tex, pre­dicted which but­ton the per­son would press, they found... This ac­ti­vity oc­curred up to 10 sec­onds be­fore sub­jects were con­sciously aware of hav­ing made a de­ci­sion, ac­cord­ing to the re­search­ers.

Is it true that our decisions are made before we are even aware of them? Has all the trouble I've taken to choose entrees from menus been wasted time? Have I already decided on the answer to that question? At least the brain appears to be efficient.

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