Bereitschaftspotential

Recently there was an article on The Atlantic reviewing the literature on free will as it is investigated by neuroscience.

Knowing nothing about the subject except the factoids people tell at parties or TED talks, I found it quite interesting.

The most popular factoid is as follows: before we consciously make a decision our brains have already decided it for ourselves. This was based on the research of American Physiologist Benjamin Libet and was all the rage.

This was based on an experiment performed by two Germans: the volunteers were told to tap their fingers whenever they pleased. At the same time, they would record activity in the brain.

The result was what was termed the Bereitschaftspotential, or readiness potential. It’s form reminds one of an inverted Yukawa potential. The rise of the Bereitschaftspotential was interpreted as the brain getting ready to perform the action. When it starts to grow, the action is imminent. Implicit in the interpretation is that the potential causes the action.

Libet actually measured the difference between the potential’s rise and the person consciously deciding to tap his or her finger (by asking him or her).

But quite recently (2010), one Dr. Aaron Schurger realised that the pattern of the Bereitschaftspotential was very similar to the pattern of any cumulative noise in the brain. There was nothing special about it. Pure randomness.

Yet another instance of one being fooled by randomness.

The explanation proposed to the earlier findings is as follows: we gather information about the world — say, from memory or from the outside world — to decide what to do, to judge the information (and so to act). In the absence of such cues when, for instance, we are subjected to an experiment of tapping fingers that tries to reproduce a decision artificially, the taps coincide with some random flow of our neurones.

With this new hypothesis and interpretation many more advances were made to better understand our brain activity vis-à-vis our decision. (One should read the article for a starting point.)

Now, as for me, I’m quite glad this annoying little factoid that people tell at parties is forever debunked (with little resistance from the Neuroscience community).

What does this say about free will? At the very least that we should be more subtle about it.

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