“Libet, however, draws attention to earlier work according to which a short (300-ms) period of appropriate cerebral activity is required to achieve the “neuronal adequacy” necessary for a conscious experience. He proposes that the same is true of the relationship between the readiness potential, RP, and the decision to act at about -200 ms. This suggests a third role, a more functionally epiphenomenal one, according to which the apparent conscious decision is neither a veto nor a trigger but merely the coming to consciousness of an unconscious process already in progress and indicated by the RP” (Libet, 1985, p.548).

(Libet, 1999, p.51)

References:

Libet, B. (1985). Unconscious cerebral initiative and the role of conscious will in voluntary action. Behavioral and brain sciences, 8(4), 529-539.

Libet, B. (1999). Do we have free will?. Journal of consciousness studies, 6(8-9), 47-57.

Experiment Demonstration