Free will · Quiz question 26/35
The Libet Experiment (Readiness Potential)
Your brain starts moving before you "decide" — did neuroscience disprove free will? The Libet experiment and how it's been reinterpreted.
A neuroscience experiment found that brain activity linked to a movement starts a few hundred milliseconds before people consciously decide "I'll move my hand now".
That feeling of "I decided" is more like a late report on something that already happened.
Neuroscientist Benjamin Libet and colleagues published it in Brain in 1983. Participants flexed their wrist whenever they felt like it and reported when they first felt the urge, using a spot on a rotating clock. The brain's "readiness potential" began several hundred milliseconds before that reported moment (around 350 ms when the movement wasn't pre-planned).
Libet's result became famous as "conscious decisions are just late notices of what the brain already started." If you agreed with this line, you're with that reading. Interestingly, Libet himself kept a role for consciousness: a last-moment "veto."
Later work changed the picture a lot. Schurger and colleagues (2012) modeled the readiness potential not as a "decision" signal but as the averaged shape of random neural noise drifting toward a threshold. Philosophers also asked whether a random wrist flick is anything like the deliberate choices we hold people responsible for, and whether anyone can accurately report when they "felt" an intention. Daniel Dennett argued the whole idea of a conscious decision as a single instant is mistaken.
Consciousness doesn't make decisions, it reports them. Neuroscience shakes the commonsense picture of free will.
Key names: Daniel Wegner, Sam HarrisThe readiness potential may be background noise building up, and a spontaneous wrist flick isn't a model of real choice.
Key names: Schurger, Alfred MeleEven if decisions start in unconscious processes, those processes are still part of you.
Key names: Daniel Dennett, Paul Churchland