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August 31, 2007

Frith free will froth:

The letters page of this week's New Scientist contains a lively debate about the neuroscience of free will, inspired by neuropsychologist Chris Frith's recent article on the topic.

Frith's article (sadly, closed-access) was discussing a classic experiment in neuroscience that seems to suggest that our brains generate an action before we're consciously aware of making the choice to move, suggesting our experience of having complete conscious control over our actions may be mistaken:

Curiously, considering it is over 20 years old, a single experiment dominated our discussions. Reported in 1983 (and replicated variously) by Benjamin Libet at the University of California, San Francisco, the experiment is crucial because it seems to show we don't have free will. Using an electroencephalogram, Libet and his colleagues monitored their subjects' brains, telling them: "Lift your finger whenever you feel the urge to do so." This is about as near as we get to free will in the lab.

It was already known that there is a detectable change in brain activity up to a second before you "spontaneously" lift your finger, but when did the urge occur in the mind? Amazingly, Libet found that his subjects' change in brain activity occurred 300 milliseconds before they reported the urge to lift their fingers. This implies that, by measuring your brain activity, I can predict when you are going to have an urge to act. Apparently this simple but freely chosen decision is determined by the preceding brain activity. It is our brains that cause our actions. Our minds just come along for the ride.

In response, two of the correspondent's question the appropriateness of the experimental task (is finger lifting a good example of free will?) and whether the result equally applies to the situation where we can stop an intended action.

Another draws parallels between our concept of free will and the influence of peer pressure and conformity, while two letters discuss how compatible free will is with a model of a physical deterministic universe.

In other words, if physics can, in principle, mathematically model the interaction of every atom to predict what will happen, how can we influence this process if we're nothing more than a collection of atoms?

Finally, two other correspondents highlight some weakness in Frith's ideas, and indeed many current theories of free will, that arise out of more fundamental problems in understanding fully the best way of linking mind- and brain-level theories.

Just reading the letters gives a good overview of some of the major problems when trying to understand both the concepts and science of conscious control of action.


Link to excellent Wikipedia page on free will.

—Vaughan.

Posted at August 31, 2007 11:30 AM

Comments

Cecilia Abadie says:

I think we are in a pre-Copernican view of the human mind, thinking that unconsciousness (Sun) revolves around consciousness (Earth). The way I'd interpret Libet's experiment is that un-consciously the will to move the finger is there before it gets to be conscious, therefore the brain registers unconscious activity before the individual is aware of wanting to do something. I predict as we have more tools to interpret the unconscious life we'll move into a more Copernican-like view of the mind, where unconscious is the real thing and consciousness is just a little part of our selves.

Comment posted at September 1, 2007 10:48 AM

Anibal says:

Since the seminal investigations and papers of Libet (1983), then rlefected in a full-length book published in 2003 (Mind Time: Temporal factor in consciousness), have been many disscusions about the implications of Libet´s finding in relation to the traditional conception of cartesian philosophical free will, that is, that human agency is totally a prime mover encapsulated form the rest of the cuasal chains of the world.

Its bacward refering to sensory experiences or its 0.5 sec of time since the first "readiness potential" recorded in the scalp of the subect, while he is only conscious of the itention to move later, have been critisized by many in terms of its flaw methodological construal (how the movement of finger is necessary to dertermine free will and not the consequences of of an action in the context of an interaction with others)or that this time (o.5 sec) before the subject becomes aware of his intention to move, is just only a reflection of the process of neural consolidation.

I think Libet is credited by being the first author to tackle the problem of free will in a modern scientifically manner but the the problem of free wil is constrained by many factors not yet captured by today neuroscientific experimental designs. There are many cultural, individual, societal... factors necessary to explain free will and the conceptual clarification of philosphers is still needed before we have clear picture of how the brain could create movemnts "de novo" (true free will) or only a movement that is preceed by other (illusion of free will).

Comment posted at September 1, 2007 05:35 PM

Conscious Robots says:

Interesting study. It's peculiar to see science entering the philosophical arena for a change. It is a really weird thought though to imagine your body auto-managing decisions while you sit back and observe. I wonder how we can define our conscious mind if even decision making is relegated to the unconscious brain.

Ian from www.consciousrobots.org

Comment posted at July 14, 2008 11:33 AM

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