In 1983, Benjamin Libet asked people to flick their wrist whenever they felt like it, and to note the moment they felt the urge. Brain activity linked to the movement began about half a second before the act. The feeling of deciding came only about 200 milliseconds before it.
Truth label: Debated. Serious people disagree. You get both sides.
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Free won't
Libet himself did not think this ruled out free will. He suggested we still have a brief window to veto an action once we become aware of it.
The pushback
In 2012, Schurger and colleagues argued that the early brain signal may be random background noise building up, not a hidden decision. A 2019 study found the signal for arbitrary choices but not for deliberate ones.
Still open
There is no majority agreement on what Libet's results mean for free will.
Learn
- Readiness potential. This is the slow build of electrical activity over the brain's motor areas before a voluntary movement. It was first described in 1965.
Test yourself
Roughly when did people report feeling the urge to move?
200 milliseconds before. On average about 200 milliseconds before the movement, after the brain signal had already begun.
Sources
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