We feel like our intentions drive the decisions we make and the actions we take. But has science revealed that 'free will' is an illusion? A thread on the neuroscience of intentional action

Some suggest a tension between free will & the general scientific picture of the universe. If every piece of matter (including you) behaves according to physical laws all your future behaviour is determined by past conditions. There's no room for intentions to change anything.

This metaphysical question is perhaps too slippery for scientists to answer. Instead, cognitive science has focused on a more specific question about free will - do conscious intentions play a causal role in driving action?

In an influent 1983 study Benjamin Libet & co probed this question by giving participants a simple task. "Watch a rotating clock and press a button when you feel like it." Participants had to tell the experimenter where the clock hand was when "they first felt the urge to move".

At the same time, participants had electrical brain activity recorded using a technique called electroencephalography (EEG). This allowed the researchers to record the build up of motor activity before the button was actually pushed.

The key result was that 'readiness potentials' in the brain precede the conscious intention to move by hundreds of milliseconds. Since causes must precede effects, Libet & co concluded that conscious intentions can't be causing the movement. The feeling of 'will' is epiphenomal.

If you'd like to learn more about Libet's experiments on conscious intentions, you can read this
@TrendsNeuro piece by @cdfrith and @PatrickHaggard
charting the impact of these findings on the study of human volition https://www.cell.com/trends/neurosciences/fulltext/S0166-2236(18)30112-7

You can see how neuroscientists have used other techniques to identify neural precursors to conscious intention in this thread https://twitter.com/iamscicomm/status/1290652141930110980?s=20