The Libet Experiments. Does brain activity before a decision make the decision? Maybe it’s just thinking about alternative possibilities?

One commentator (planksip®) asked: How do you reconcile Benjamin Libet’s EEG experiments (readiness potential) et al, which detected a brain’s motor cortex response 300 milliseconds prior to a person being consciously aware of said response?

The neurologist Benjamin Libet performed a sequence of remarkable experiments in the early 1980’s that were enthusiastically, if mistakenly, adopted by determinists and compatibilists to show that human free will does not exist.

His measurements of the time before a subject is aware of self-initiated actions have had an enormous, mostly negative, impact on the case for human free will, despite Libet’s view that his work does nothing to deny human freedom.

Since free will is best understood as a complex idea combining two antagonistic concepts – freedom and determination, “free” and “will,” in a temporal sequence, Libet’s work on the timing of events can also be interpreted as supporting our “two-stage model” of free will.

Indeed, Libet himself argued that there was still room for a veto over a decision that may have been made unconsciously over 300 milliseconds before the agent is consciously aware of the decision to flex a finger, but before the action of muscles flexing.
The original discovery that an electrical potential (of just a few microvolts – μV) is visible in the brain long before the subject flexes a finger was made by Kornhuber and Deecke (1964). They called it a “Bereitschaftspotential” or readiness potential.

As shown on Kornhuber and Deecke‘s RP diagram, the rise in the readiness potential was clearly visible at about 550 milliseconds before the flex of the wrist (blue arrow).

We can correlate the beginnings of the readiness potential (350ms before Libet’s conscious will time “W” appears) with the early stage of our two-stage model of free will, when alternative possibilities are being generated, in part at random. The early stage may be delegated to the subconscious, which is capable of considering multiple alternatives (William James‘ “blooming, buzzing confusion”) that would congest the single stream of consciousness.

One thought on “The Libet Experiments. Does brain activity before a decision make the decision? Maybe it’s just thinking about alternative possibilities?

  1. 32:28 – Alfred Mele’s criticism is key to refuting the Libet Experiments. Leaving the throttle of thinking or considering the action out of the data means that data capturing the veto isn’t included in the study. Very interesting indeed!


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