Tuesday, August 28, 2007

The Non-conscious

An essay by Chris Frith in New Scientist (11 August 2007, subscribers only) on difficulties with the notion of free will contains a useful list of experiments and thought-provoking findings.

He reminds us of Benjamin Libet’s 1983 experiment indicating that decisions are made in the brain before our consciousness is aware of it:

“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.”
Frith recalls the Hering illusion, where a background of radiating lines makes superposed lines seem curved. Even though one knows “rationally” that the lines are straight, one sees them as curved. Frith uses this as an analogy for the illusion that we feel as if we are controlling our actions. To me, this illusion (and perhaps even more profoundly, the Hermann-grid illusion) points to the way different realities can coexist. There is no doubt that humans experience the Hering lines as curved, and that we see shadows in the crossings of the Hermann grid. Likewise, there is no doubt that many (most?) humans have an experience of the divine. The divine is an experiential reality, even if it mightn’t exist by some objective measures.

Other results mentioned include Patrick Haggard’s findings that the act of acting strengthens belief in causation; Daniel Wegner’s work on how one can confuse agency when another person is involved; and work by various researchers on how people respond to free riders; and Dijksterhuis et al’s work on non-conscious decision making, which I discussed in Don’t think about it.

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