White Matter Matters

Tales from the science trenches

Axons & Axioms, Episode 2: Judgment Day

The neurophilosophical dilemma of free will.

Welcome to the sophomore edition of Axons & Axioms, a podcast on philosophy and cognitive neuroscience by myself and Derek Leben (Assistant Professor in Philosophy at University of Pittsburgh, Johnston). We have moved on from consciousness to the tricky issue of “free will.” Since Derek contributed equally to this post, as well as to the podcast, from here on out I’m going to refer to myself in the third person to indicate the joint contribution

Are we really free?

A growing body of research in cognitive neuroscience seems to be suggesting that the concept of free will may be nothing but an illusion.  Researchers can manipulate choices using brain stimulation and even predict your future choices well before you make them using brain imaging.

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That’s the rub of this edition of Axons and Axioms.  Does all this neuro-mumbo-jumbo mean that free will is a myth?

It’s fair to say that both Tim and Derek think neuroscience might one day show that human actions, much like other events, are caused by nothing more than previous events and the laws of nature. This is the philosophical position known as ‘determinism.’ Where the A&A hosts disagree is whether this kind of determinism is threatening to free will (at least to the kinds of free will we are usually concerned with) or if the two might be compatible.

“It’s not my fault your honor.  My anterior cingulate cortex is broken.”

Tim starts by discussing the recently published study showing how brain activity can predict the recidivism rate of criminals.  The main result of this research was that criminals with lower activity in an area called the anterior cingulate cortex, during a task designed to measure inhibitory control, tended to have higher recidivism rates than those with higher amounts of activity.  The main conclusion here is that this brain signal reflects a reduction in the ability to control our impulses and those with lower impulse control are more likely to engage in detrimental behavior that will eventually land them back in jail.

The implications for this would be profound if this were true.  Can we hold individuals responsible for their actions if their brains predispose them for impulsivity that leads to poor behavioral regulation?  Does this mean that when faced with an impulsive act (e.g., punching the guy who cuts in line) versus a more socially appropriate action (e.g., having the bouncer remove the line cutter), these individuals aren’t making a free choice?

Well to be clear, we can’t infer diddly-squat from a single fMRI study.  But these are tantalizing questions.

But this somewhat flashy study isn’t the first to suggest that we may not be completely in control of our own actions.  Here’s a list of just a few other findings:

Put them together and the neurobiological evidence sure does point to determinism.

“It depends on what you mean by the word ‘free’.”

On the philosophy-side Derek defends his belief in the compatibility of determinism and free will by proposing a theory about the core meaning of the word ‘free,’ following a linguistic theory called ‘Force Dynamics.’ This theory says that the meanings of many words are based in spatial representations of forces, motions, and tendencies.

Derek’s proposal is that the word ‘free’ corresponds to two force dynamics: (1) not being prevented from moving, and (2) not being forced to move. This core meaning of ‘free’ is then filled-in by context, so you might mean that your action is prevented by other people, or by morality, or rationality, or laws of nature. Derek’s argument for “compatibilism” is that people generally recognize that our actions are ‘blocked’ by things like rationality, morality, and the laws of nature, but nobody takes this to be threatening to the freedom of our actions.

So then why should being ‘forced’ by the laws of nature be threatening to the freedom of our actions? Just showing that there are other forces ‘pushing’ behind us doesn’t take away the metaphorical ‘pushing’ that our own reasoning, attention, memories, and beliefs are doing behind an action. Now, if neuroscience were to show that what’s causing our actions is something outside of the cognitive systems we identify as ‘us,’ then THAT would be a threat to free will!

Check out the full argument on the fate of free will in the podcast titled “Judgment Day.”

(Apologies for the occasional microphone errors… we’re just academics, not sound engineers.)

 

Tim Verstynen, Ph.D., is an assistant professor of psychology at Carnegie Mellon. He is interested in sensorimotor systems, plasticity, and zombie brains.

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