My skeptics group is getting together on Wednesday night to discuss this topic, among other things.
Personally, as an atheist, I take issue with the concept of “free will.” The phrase is connected too closely to religion, from Eve in Eden and her (problematic?) decision to take the snake at his word, all the way to Calivinist predestination and the justification for caste systems that existed in many societies and still exist in some countries.
A better question skeptics should ask would be, is choice an illusion?
Haynes updated a classic experiment by the late Benjamin Libet, who showed that a brain region involved in coordinating motor activity fired a fraction of a second before test subjects chose to push a button. Later studies supported Libet’s theory that subconscious activity preceded and determined conscious choice — but none found such a vast gap between a decision and the experience of making it as Haynes’ study has.
In the seven seconds before Haynes’ test subjects chose to push a button, activity shifted in their frontopolar cortex, a brain region associated with high-level planning. Soon afterwards, activity moved to the parietal cortex, a region of sensory integration. Haynes’ team monitored these shifting neural patterns using a functional MRI machine.
Taken together, the patterns consistently predicted whether test subjects eventually pushed a button with their left or right hand — a choice that, to them, felt like the outcome of conscious deliberation. For those accustomed to thinking of themselves as having free will, the implications are far more unsettling than learning about the physiological basis of other brain functions.
That said, they were only measuring button pushing, a task where doing so with the right hand or left hand isn’t going to make any difference to the outcome. No real thought was necessary to determine the best course of action, unlike contemplating the purchase of a house or whether you should run into traffic to grab a kid before he gets hit. And there’s a flaw in this study probably, since people are typically geared from birth toward favouring one side of the body over the other. I don’t tend to consciously choose to pick a pen up with my right hand. I just do it. I don’t consciously choose not to include my right-index finger in the picking up of said pen. That’s a leftover reaction my brain has to a couple major finger injuries in my childhood that rendered it unusable for a while. My brain compensated for my bandaged finger then and still does, even though the finger has been fine for 28 years. And yet I type with it all the time. It’s a funny old brain.
Now quoting New Scientist, the nature of “readiness potential,” and what Libet’s study had determined back in the 1980s:
Long sceptical of Libet’s interpretation, Jeff Miller and Judy Trevena of the University of Otago in Dunedin, New Zealand, attempted to tease apart what prompts the RP using a similar experiment, with a key twist.
They also used scalp electrodes, but instead of letting their volunteers decide when to move, Miller and Trevena asked them to wait for an audio tone before deciding whether to tap a key. If Libet’s interpretation were correct, Miller reasoned, the RP should be greater after the tone when a person chose to tap the key.
While there was an RP before volunteers made their decision to move, the signal was the same whether or not they elected to tap. Miller concludes that the RP may merely be a sign that the brain is paying attention and does not indicate that a decision has been made.
Why would there be a difference in timing between choices of tap/no tap? I also wonder why they assumed there would be a difference in timing between tapping at a random moment and waiting for a tone first. Oh, because possibly people would be deciding long before the tone if they’d push a key or not. But it doesn’t read as if that’s what they were measuring and looking for to prove their theory. Wouldn’t that have been a better test of Libet’s theory, though? And I also wonder if the timing would vary depending on what people got to choose with their key stroke: the fruit or the chocolate, a wooden block or a soft ball, tickets to a movie or the opera. heh. Would the RP be different with a bigger incentive and reward?
I dunno. Thoughts? Do you think we have much say in what we’re going to do with ourselves, or are we at the mercy of our neurons?