Readiness potentials are a controversial areas of research. Brain activity can be measured when laboratory participants decide to make a consciously initiated movement, such as making a movement of their finger. 'Readiness potentials' are spikes of electrical brain activity which have been reliably measured as occuring prior to participants reports of 'deciding' to make the movement. Some researchers have argued that if a freely willed movement is preceded by measurable electrical activity then maybe it wasn't so freely willed after all.

A fascinating article has just been published in Consciousness and Cognition which digs in to this phenomenon a little more. Using post-hypnotic suggestion the authors decoupled the experience of volition from a self-initiated movement. Participants still performed an action, but they didn't have the feeling that they were controlling it.  This allowed the researchers to test whether readiness potentials are really to do with willed actions (free will!). Readiness potentials were still observed in this free-will-absent condition, which supports the argument that readiness potentials aren't indexing free will after all.

Schlegel, A., Alexander, P., Sinnott-Armstrong, W., Roskies, A., Tse, P. U., & Wheatley, T. (2015). Hypnotizing Libet: Readiness potentials with non-conscious volition. Consciousness and Cognition, 33, 196-203.

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