I have long been interested in the question of free will and back in 2010 even wrote a 16-part series (!) looking into what was known about it. Many people are Cartesian dualists where they view the brain and mind as distinct, the former being a physical organ while the latter is an immaterial entity, dubbed the ‘Ghost in the Machine’ by Gilbert Ryle, that controls the cognitive processes of the former, though how that actually happens has not been made clear.
Back in 1983, Benjamin Libet used a technique to measure brain activity that was called Bereitschaftspotential (readiness potential) that had been discovered nearly twenty years earlier by two German scientists Hans Helmut Kornhuber and Lüder Deecke who concluded that there was brain activity prior to the decision to tap one’s finger. Libet did more measurements and found that the brain activity started about 500 milliseconds before the action but that the participants were conscious of making a decision only 150 milliseconds before the action. This seemed to suggest that the action was decided upon 350 milliseconds before the person became conscious of making it, throwing the idea of free will into serious doubt. (You can read more about Libet’s experiments here.)
A new experiment has revisited Libet’s experiment and has suggested an alternative explanation, that the brain has random rises and falls of the readiness potential and that the correlation between that activity and the decision to act may not be a strictly causal one.
In a new study under review for publication in the Proceedings of the National Academy of Sciences, Schurger and two Princeton researchers repeated a version of Libet’s experiment. To avoid unintentionally cherry-picking brain noise, they included a control condition in which people didn’t move at all. An artificial-intelligence classifier allowed them to find at what point brain activity in the two conditions diverged. If Libet was right, that should have happened at 500 milliseconds before the movement. But the algorithm couldn’t tell any difference until about only 150 milliseconds before the movement, the time people reported making decisions in Libet’s original experiment.
In other words, people’s subjective experience of a decision—what Libet’s study seemed to suggest was just an illusion—appeared to match the actual moment their brains showed them making a decision.
The issue of whether we have free will is far from settled because there are still other studies that suggest that we do not.
There is a lot riding on this question because not only does the question of whether we have free will have moral, ethical, and legal implications, there is something deeply unsettling in the idea that we do not have free will, thus losing our sense of agency, and that we are not responsible for our actions. People tend to desperately want to hold on to the idea that they consciously control their decisions. As Isaac Beshevis Singer said, “We must believe in free will, we have no choice.”
Where does a lack of free will leave the idea of culpability and the insanity defense in criminal cases? Anthony Cashmore takes a close look at that question.
Here is a video discussing the implications of brain science and the lack of free will for the law.