Consciousness Blog 09 January 2016
Ever since Benjamin Libet demonstrated in the 1980s that movements originate in the brain 350 milliseconds before there is conscious awareness of the intention to move, there has been extensive debate as to whether free will exists, or is a mere sham, constructed as an illusion by the conscious brain as a part of the 'I' that allows a person to feel in charge of their world.
New research carried out at the Bernstein Center for Computational Neuroscience, Charité–Universitätsmedizin Berlin, led by Prof. Dr. John-Dylan Haynes, in conjunction with Prof. Dr. Benjamin Blankertz and Matthias Schultze-Kraft from Technische Universität Berlinin, has clarified the sequence of neurological events that leads up to movement or its abandonment, showing that voluntary abandonment (cancellation) of a movement is possible up to 200 ms before actual initiation of the movement, but no later.
In the experiment, subjects were asked to press a floor-mounted button in response to an instruction given by a computer, but to arrest the movement if a further, countermanding instruction was shown on the screen. The computer was programmed to give the instructions at varying intervals, and the participant was encouraged to play against the computer as in a game. Electroencephalography (EEG) was used to monitor the player's brain waves throughout the duration of the game. The process was manipulated in favor of the computer as soon as brain wave measurements indicated that the player was about to move.
"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. "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."
The problem with any such experiment, or, rather, with the conclusions drawn from it as regards free will, is that the latter is supposed to operate on one side of a dividing line between unconscious and conscious processes. This idea originates in the supposition that consciousness is somehow a free-standing and self-sufficient space within which mental events can take place. This could loosely be called a 'dualist' position, a heresy that has afflicted many writers on consciousness, and it flies in the face of massive amounts of neurological evidence linking consciousness (whatever that weasel word may mean) with the continuing non-conscious brain activity that underpins and generates it.
From the perspective of an onlooker, the behaviour of another person who kicks them, or halts a kick before it is delivered, has all the qualities of free will. What does it matter whether the action originates in one part of the brain or another, or in multiple regions (what is in fact the case)? Lawyers may split hairs over whether a piece of behaviour was 'intended' (i.e. was driven by free will) or displayed mental incapacity (thought to be involuntary and hence somehow less culpable); but they are being dualist when they do that. This is not to argue for equality of punishment regardless of mental state, but merely to point out that the concept of criminal responsibility is built on a misunderstanding of how consciousness works.
Read more in Chapter Eight of Agent Human by Michael Bell, The Con Of Consciousness; The Illusion of Individuality.