Where your eyes don't go

There's a They Might be Giants song with the same title as this post which is a tuneful take on the horror of having an unconscious mind that could be getting up to anything. I've always liked this line:

Every jumbled pile of person has a thinking part that wonders
What the part that isn't thinking isn't thinking of

Brain scientists are still pondering this issue of when the conscious mind become aware of decisions the brain has already made, as a Nature News story tells us. (As usual, this will probably disappear soon, so I need to take out large extracts):

Your brain makes up its mind up to ten seconds before you realize it, according to researchers. By looking at brain activity while making a decision, the researchers could predict what choice people would make before they themselves were even aware of having made a decision....

Haynes and his colleagues imaged the brains of 14 volunteers while they performed a decision-making task. The volunteers were asked to press one of two buttons when they felt the urge to. Each button was operated by a different hand. At the same time, a stream of letters were presented on a screen at half-second intervals, and the volunteers had to remember which letter was showing when they decided to press their button.

When the researchers analysed the data, the earliest signal the team could pick up started seven seconds before the volunteers reported having made their decision. Because of there is a delay of a few seconds in the imaging, this means that the brain activity could have begun as much as ten seconds before the conscious decision. The signal came from a region called the frontopolar cortex, at the front of the brain, immediately behind the forehead.

If you think you heard about this type of experiment before, you'd be right. It is building on some (now) quite old results of Libet, whose experiment was quite similar in design, as the article explains:

Libet's study has been criticized in the intervening decades for its method of measuring time, and because the brain response might merely have been a general preparation for movement, rather than activity relating to a specific decision.

Haynes and his team improved the method by asking people to choose between two alternatives — left and right. Because moving the left and right hands generates distinct brain signals, the researchers could show that activity genuinely reflected one of the two decisions.

But all is not lost for free will yet:

...the experiment could limit how ‘free’ people’s choices really are, says Chris Frith, who studies consciousness and higher brain function at University College London. Although subjects are free to choose when and which button to press, the experimental set-up restricts them to only these actions and nothing more, he says. “The subjects hand over their freedom to the experimenter when they agree to enter the scanner," he says....

But results aren't enough to convince Frith that free will is an illusion. “We already know our decisions can be unconsciously primed,” he says. The brain activity could be part of this priming, as opposed to the decision process, he adds.

Part of the problem is defining what we mean by ‘free will’.

Personally, I like to look in the mirror every morning and say "stop making decisions without me" ten times while I shave.

Gratuitous political postscript: I hope they never include Brendan Nelson in these tests. No ten seconds for him: I reckon he must surely have about about a 10 hour gap between speaking and recognition of what his stream of consciousness has already come up with.