John-Dylan Haynes is a neuroscientist and Director of the Berlin Center for Advanced Neuroimaging (BCAN). He has designed and performed modern versions of the classic Libet experiments.
Like Patrick Haggard, Haynes has generally agreed with the claims of Harvard psychologist Daniel Wegner, that "conscious will" is an illusion.
But in his most recent work, appearing in the Publications of the National Academy of Sciences, Haynes has found a little more room for free will, or perhaps only confirmation of what is called a"free won't," Benjamin Libet's claim that we can have veto power over an action that has already been initiated. A recent press release described his new work
How can the unconscious brain processes possibly know in advance what decision a person is going to make at a time when they are not yet sure themselves? Until now, the existence of such preparatory brain processes has been regarded as evidence of 'determinism', according to which free will is nothing but an illusion, meaning our decisions are initiated by unconscious brain processes, and not by our 'conscious self'. In conjunction with Prof. Dr. Benjamin Blankertz and Matthias Schultze-Kraft from Technische Universität Berlin, a team of researchers from Charité's Bernstein Center for Computational Neuroscience, led by Prof. Dr. John-Dylan Haynes, has now taken a fresh look at this issue. Using state-of-the-art measurement techniques, the researchers tested whether people are able to stop planned movements once the readiness potential for a movement has been triggered.
“The aim of our research was to find out whether the presence of early brain waves means that further decision-making is automatic and not under conscious control, or whether the person can still cancel the decision, i.e. use a 'veto',” explains Prof. Haynes. As part of this study, researchers asked study participants to enter into a 'duel' with a computer, and then monitored their brain waves throughout the duration of the game using electroencephalography (EEG). A specially-trained computer was then tasked with using these EEG data to predict when a subject would move, the aim being to out-maneuver the player. This was achieved by manipulating the game in favor of the computer as soon as brain wave measurements indicated that the player was about to move.
If subjects are able to evade being predicted based on their own brain processes this would be evidence that control over their actions can be retained for much longer than previously thought, which is exactly what the researchers were able to demonstrate. “A person’s decisions are not at the mercy of unconscious and early brain waves. They are able to actively intervene in the decision-making process and interrupt a movement,” says Prof. Haynes. “Previously people have used the preparatory brain signals to argue against free will. Our study now shows that the freedom is much less limited than previously thought. However, there is a 'point of no return' in the decision-making process, after which cancellation of movement is no longer possible.” Further studies are planned in which the researchers will investigate more complex decision-making processes.
*Matthias Schultze-Kraft, Daniel Birman, Marco Rusconi, Carsten Allefeld, Kai Görgen, Sven Dähne, Benjamin Blankertz and John-Dylan Haynes. Point of no return in vetoing self-initiated movements. Proceedings of the National Academy of Sciences of the USA, Dec. 2015. doi/10.1073/pnas.1513569112.
The kinds of deliberative and evaluative processes that are important for free will involve longer time periods than those studied by Haynes.
The abrupt and rapid decisions needed to beat the computer bear little resemblance to the kinds of two-stage deliberate decisions for which we can first freely generate alternative possibilities for action, then evaluate which is the best of these possibilities in the light of our reasons, motives, and desires - first "free," then "will."
We can correlate the beginnings of the readiness potential (350ms before Libet's conscious will time "W" appears) with the early stage of the two-stage model, when alternative possibilities are being generated, in part at random. The first 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.
Alfred Mele, in his 2009 book Effective Intentions, the Power of Conscious Will, criticized the interpretation of the Libet results on two grounds. First, the mere appearance of the RP a half-second or more before the action in no way makes the RP the cause of the action. It may simply mark the beginning of forming an intention to act. In our two-stage model, it is the considering of possible options.
We have no evidence that Haynes' "unconscious preparatory brain processes" that are generating the readiness potential are initiating any action, perhaps they just initiate new thoughts.
Libet himself argued that there is enough time after the W moment (a window of opportunity) to veto the action, but Mele's second criticism points out that such examples of "free won't" would not be captured in Libet experiments, because the recording device is triggered by the action (typically flicking the wrist) itself.
Thus, although all Libet experiments ended with the wrist flicking, we are not justified in assuming that the rise of the RP (well before the moment of conscious will) is a cause of the wrist flicking. Libet knew that there were very likely other times when the RP rose, but which did not lead to a flick of the wrist.
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