Barking up the wrong free: readiness potentials reflect processes independent of conscious will.

In the early 1980s, Libet found that a readiness potential (RP) over central scalp locations begins on average several hundred milliseconds before the reported time of awareness of willing to move (W). Haggard and Eimer Exp Brain Res 126(1):128-133, (1999) later found no correlation between the timing of the RP and W, suggesting that the RP does not reflect processes causal of W. However, they did find a positive correlation between the onset of the lateralized readiness potential (LRP) and W, suggesting that the LRP might reflect processes causal of W. Here, we report a failure to replicate Haggard and Eimer's LRP finding with a larger group of participants and several variations of their analytical method. Although we did find a between-subject correlation in just one of 12 related analyses of the LRP, we crucially found no within-subject covariation between LRP onset and W. These results suggest that the RP and LRP reflect processes independent of will and consciousness. This conclusion has significant implications for our understanding of the neural basis of motor action and potentially for arguments about free will and the causal role of consciousness.