Mick Hartley

Marcus du Sautoy, in his unfortunately-named Sexy Science column in the Times, is full of enthusiasm and wild claims, as befits a science populariser:

I’m sure that you had the impression you were asserting your free will in your choice to read The Times today. That it was a conscious decision to stop on this page and start reading the Sexy Science column. But before you read on, let me warn you that the story I am about to tell could fundamentally change your perspective on whether you are freely making decisions or not. Because recently I took part in an experiment which has rocked my sense that I am consciously making the decisions I take. Free will it appears is just an illusion.

If you thinking that some dramatic new neurological breakthrough is about to be revealed – well it isn't. What he's doing (as part of yesterday's Horizon programme) is revisiting the famous experiments of Benjamin Libet – though the name doesn't feature anywhere – but using a  functional magnetic resonance imaging scanner (fMRI) in place of the more primitive equipment that was available to Libet back in the 70s. He's very impressed with the fMRI:

This extraordinary piece of equipment has done for neurophysiology what Galileo’s telescope did for astronomy 400 years ago. Just as the far reaches of our galaxy have come into view with ever more sophisticated telescopes, the fMRI scanner has allowed scientists such as [John-Dylan] Haynes to peer inside our heads and see what the brain is doing.

Well…there are good reasons not to get too carried away with all this, but I don't want to dig up those arguments again. The point here is that Libet's findings are replicated:

[W]hat he [Haynes] discovered is that, by analysing my brain activity, he is able to predict which button I am going to press six seconds before I am consciously aware of which one I choose. Six seconds is a huge length of time. My brain decides which button I am going to press. Left or right. Then one elephant, two elephant, three elephant, four elephant, five elephant, six elephant. Now my brain throws the decision into my conscious brain and gives me the feeling that I am consciously making the decision.

Haynes can see which button I will press because there is a region in the brain that is lighting up six seconds earlier preparing the motor activity. A different region of the brain lights up according to whether the brain is preparing my left finger to press the button or my right finger. Haynes is not able to predict with 100 per cent certainty yet but the predictions that he is making are clearly above the hit-rate that you’d get if you were trying to guess. And Haynes believes that with more accurate imaging it might be possible to get close to 100 per cent accuracy.

I've posted about this before, both in response to a piece by Sue Blackmore on Libet's death two years ago, and earlier, in a more general look at moral responsibility and free will. Here's what I argued then:

This [Libet's] result depends on the accurate reporting of the conscious experience of making a decision, which is always going to be unreliable. But then why assume that your free will is always conscious? Yes, you may report that the decision took place, as far as you were aware, after the neurological activity appeared – but what prompted that neurological activity? What else but a decision of yours? Otherwise why doesn't your arm keep moving all the time, randomly? The cause of your arm moving was your decision to move your arm. The fact that your awareness of that decision follows on from the neurological activity doesn't change that. All it shows is that (perhaps) a part of your decision-making is pre-conscious, or unconscious. That's not an uninteresting finding, but it certainly doesn't show that you have no free will.

The assumption behind Du Sautoy's belief here that free will has been shown to be illusory is that free will is always a conscious activity. But it isn't. The overwhelming majority of our daily decisions never reach that conscious state of wondering whether to do A or to do B – with chin, as it were, cupped in hand. We just do things. We're still acting freely, even if we're not conscious of all the intricacies of the decision-making process.