Brain scanner predicts your future moves
13 April 2008 - New Scientist.
Long before you decided to read this story, your brain may have already said "click that link".
By scanning the brains of test subjects as they pressed one button or another – though not a computer mouse – researchers pinpointed a signal that divulged the decision between seven and ten seconds before people ever realised their choice. The discovery has implications for mind-reading, and the nature of free will.
"Our decisions are predetermined unconsciously a long time before our consciousness kicks in," says John-Dylan Haynes, a neuroscientist at the Bernstein Center for Computational Neuroscience in Berlin, who led the study. It definitely throws our concept of free will into doubt, he adds.
This is by no means the first time scientists have cast doubt on conscious free will. In the early 1980s, the late neuroscientist Benjamin Libet uncovered a spark of brain activity three tenths of a second before subjects opted to lift a finger. The activity flickered in a region of the brain involved in planning body movement.
But this region might perform only the final mental calculations to move, not the initial decision to lift a finger, Haynes says.