Free Will, Illusion, and Neuroscience
by Abdul-Kareem Ahmed
“Give me liberty or Give me death!” demanded Patrick Henry at the 1775 Virginia Convention, swaying the vote to deliver Virginia troops to participate in the Revolutionary War. It is a well-known cry, but perhaps its antiquity does it injustice. Sentimental cries for freedom usually conjure images of men in stockings and wigs, men usually only seen on the likes of coins and dollar bills.
Even if it is not as apparent to us today, we are just as passionate about the idea of freedom. We assure ourselves that we have the inherent right to self-determination and the ability to choose freely. Free will is, after all, of the very essence of being human.
Yet, neuroscientists have momentarily left their laboratories to inform us we do not even have that. Free will is an illusion. Not surprisingly, some philosophers are tickled by the very notion. They’ve been arguing over free will’s definition for millennia. Others are nervous, as they sense the now unavoidable presence of brain science in the academic realm they used to command.
John-Dylan Haynes, a neuroscientist at the Bernstein Center for Computational Neuroscience in Berlin published a study he led in Nature Neuroscience in 2007. The study, “Unconscious determinants of free decisions in the human brain,” was a venture to determine if supposedly ‘free’ decisions are preempted in the brain, and if so, by how long. To understand his study requires some neuroscience knowledge.
The prefrontal cortex lies just beneath your forehead. It is implicated in executive function: mediating conflicting decisions, determining right and wrong, better and best, and other relations. This part of your brain is the bottleneck decisions must go through, including motor decisions: to move or to not. Many decisions are filtered, so maladaptive actions can be inhibited.
The parietal cortex is the superior (top) portion of your brain. This cortex is somatotopically organized, where senses from different parts of the body are integrated and represented in exact parts of the cortex. This map will eventually correlate to another cortex, your motor cortex. Sensory information from your hand goes to the parietal cortex which will relay to the hand section of the motor cortex. Thus, the parietal cortex is implicated in relaying motor activities, like picking up a hot cup of coffee.
These are two of many parts of the brain. But how do scientists know which part of our brain we are using and when? A neuron firing is an energy expensive process. Oxygen is absolutely necessary. You have probably heard of Magnetic Resonance Imaging (MRI), a radiological technique used to visualize the internal body. Functional MRI (fMRI) is a type of MRI that scans for oxygenated blood. The basic tenet of this technique is that active brain regions require more oxygenated blood. During an experiment, a participant performs an activity. A concurrent fMRI scans for oxygenated blood in the brain, and thus reveals brain regions used during that activity.
Haynes’s study of free will used fMRI to examine motor decisions. Participants were presented with a letter stream on a screen, where letters changed every 500ms. These letters would flash one by one. The participant was required to press a left or right button to choose a letter. This choice was spontaneous and represented an impulsive motor decision.
In a second experiment, the participant had to make a voluntary decision. The requirement was to press the left or right button at a time indicated by the investigators. Thus, this was a conscious decision. The determination to press a button was developed far ahead of the motor decision.
The imaging shows that two main regions are involved in such rapid decisions. These were the frontopolar cortex, a part of the prefrontal cortex, and the area between the precuneus and posterior cingulate cortex, parts of the parietal cortex. Activity in these areas is subconscious and precedes activity in regions indicative of conscious awareness of decisions by up to 10 seconds. In the second experiment, activity in the frontopolar cortex preceded that in the precuneus. So, the frontopolar cortex could be responsible for the origination of the decision, and the precuneus the storage. Thus, both impulsive and conscious decisions require activity in these areas before the motor act of pressing a button.
Participants are physically performing the action, but do not have awareness of the decision to start doing so. They click a button after they decide to choose a letter, but the initiation to do so is not represented in areas considered conscious.
Does that mean free will is an illusion? Well, the results certainly pose this question, but perhaps the waters are a little murkier than we think. Let’s think like a philosopher for a minute. To answer this question we need to define what we mean by “self,” “conscious,” and “free will.” Scholarship on these definitions alone can fill tomes. But at least for now we can consider this; if you possess the neural substrate, the cortices through which an action is initiated, but that neural substrate is unconsciously used, is that substrate still part of “you”? Does a cortex have to be consciously used for you to claim control over it? If not, then to whom does that neural substrate, those two cortices, belong? Who is responsible for actions they initiate?
Thus, claiming free will an illusion is premature. Purporting these results undermine the notion of free will assumes free will is defined by our conscious decisions only. Our unconscious decisions are our own, whether we are aware of it or not. Maybe there is a reason behind having unconscious decisions. Being aware of every mundane decision you make is a waste of resources. Some must be relegated to the unconscious.
This is not the first time an issue that philosophers have historically dominated has been questioned by the empirical sciences. Take morality for example. Up until the 20th century, certain human values were taken to be truths of intuition. These were grand truths one simply could not deny, like utilitarianism: one should act in a way to maximize a good outcome. However, in recent years neuroscience challenged the very idea of morality. Behaviors like morality are instead manifestations of levels of neurotransmitters like serotonin, a measly chemical in the brain. What then will happen to the idea of free will?
Neuroscience has yet to shatter the idea of free will. And perhaps such human qualities cannot be reduced to cells and molecules. In history, science has often replaced folk wisdom with hard facts and lucid explanations. But what science cannot explain, man will always ponder. Philosophy can rest easy on this one, at least for now.
The Founding Fathers had a grand idea in mind when they started this country. Freedom. Perhaps it is fitting that the current argument of free will was not had in the late 18th century. It might have been difficult to develop the American philosophy had the Founders been neuroscientists and philosophers.