April 20, 2024

Free will resides in the parietal cortex

French study shows that neural activity precedes “free will”
"Possible site of free will found in brain" was one of the more intriguing headlines in New Scientist
this month. Angela Sirigu, of the CNRS Cognitive Neuroscience Centre in
Bron, France, says that there is a specific brain region, the parietal
cortex, involved in the consciousness of movement. When it was
stimulated with an electrical probe during surgery, patients felt a
desire to, say, wiggle their
finger, roll their tongue or move a limb. Stronger electrical pulses
convinced them that they had actually performed these movements, even
they had been motionless.

In the rather dry words of her team’s article in Science,
"Our study suggests that motor intention and awareness are emerging
consequences of increased parietal activity before movement execution."
In other words, the sensation that we will to do something is
illusory.  What really happens is that first of all the neurons crackle
and fire and then we feel like doing it. As the article points out, free will is "appealing from a spiritual point of view", but contemporary research has all but disproved it.

Patrick Haggard,
a British neuroscientist, told New Scientist
that the experiment pinpoints volition in a specific part of the
brain. "That’s extremely interesting, because up to now it has been
very difficult for neuroscientists to deal with the idea of intentions
or wishes or will," he says. No one should be surprised, says Haggard,
that the experience of volition
can be linked to specific brain areas. "I can’t think of any way you can
have conscious experience other than as a result of neurons in your
brain firing."

So, if there is no free will, is there really any
role for ethics at all? That is the intriguing question which
neuroscience is posing more stridently every year.~ New Scientist, May 7; Science, May 8