One big misinterpretation of Libet’s findings, and of appreciating the true nature of the self in general, is that one cannot passively wait for an urge to occur while at the same time monitoring when one becomes conscious of bringing it about. We cannot step outside of our mind and say, ‘Yes, that’s when I felt the urge to move, and that’s when I actually started to do so.’ You cannot have your mental cake and eat it. As the philosopher Gilbert Ryle12 pointed out, in searching for the self, one cannot simultaneously be the hunter and the hunted. Such reasoning reflects our inherent dualist belief that our mind is separate from our body.
We may think that our mind controls our body but that is an illusion of free will and control. This illusion arises when our subjective conscious intention precedes the actual execution of the movement with little delay. We know this timing is critical because, if you disrupt the link between when you experience the intention to act and the execution of the act, we experience a loss of willed action. This is when we feel that we are not in control of our bodies.
Being in Two Minds
Most of the time we feel we have control over our actions. There are exceptions such as reflexes that do not involve conscious control and, as discussed, some behaviours are surprisingly infectious such as laughing and yawning when in a crowd, but for the most part our normal daily actions seem under our control. However, brain damage can change all of that. When we damage our brain, we can lose control over our bodies. Paralysis is the most common example. Our limbs may be perfectly fine but if we damage the brain centres for movement then, irrespective of our strongest will, our paralysed limbs cannot move. Sometimes, though, parts of our body can move by themselves. For example, ‘alien hand syndrome’ is a condition in which patients are not in control of one of their hands and experience the actions as controlled by someone else or that the hand has a will of its own.13 This is also known as the ‘Dr Strangelove syndrome’, a nod to Stanley Kubrick’s 1964 movie in which Peter Sellers plays a wheelchair-bound nuclear war expert and former Nazi whose uncontrollable hand makes Nazi salutes and attempts to strangle him. Strange as Dr Strangelove syndrome might seem, there is a perfectly reasonable explanation based on the discovery that each hand is under relatively independent control from the opposite side of the brain.
For reasons that Mother Nature knows best, much of processing and output in the brain is lateralized to the opposite hemisphere. If you were to draw an imaginary line down the centre of the human body then all the information coming from the left side of the world goes to the right hemisphere. Likewise, all the information from the right side is processed in the left hemisphere. The same is true for actions. The left hemisphere controls the right side of the body and the right hemisphere controls the left. If you severely damage the left hemisphere then you can be left paralysed down the right side of the body and vice versa.
Some skills tend to be lateralized. For example, the left hemisphere controls language whereas the right hemisphere is better at the visual processing of the space around us. That’s why brain damage to the left hemisphere disrupts language and patients become aphasic (unable to produce speech) whereas damage to the right hemisphere leaves language intact but often disrupts the patient’s awareness of objects especially if they are in the left side of space.
We are not aware of these divisions of labour as the two hemispheres work together to produce joined-up thoughts and behaviours. This is because the two sides of the brain are connected together through the large bundle of fibres of the corpus callosum that enables the exchange of information. This exchange also enables the abnormal electrical activity of epilepsy, which can originate in one hemisphere, and spread to both sides of the brain causing major seizures. Epilepsy can be extremely debilitating but by severing the corpus callosum fibres that connect the two hemispheres, the electrical brainstorm can be contained and prevented from transferring from the original site to the rest of the brain. This containment alleviates the worst of the symptoms.
The consequence of this operation is to produce a ‘split brain’ patient. The two halves of the brain continue to work independently of each other but you would be hard pressed to notice any difference. Spilt-brain patients look and behave perfectly normally. This begs the question of why we need the two halves of the brain connected in the first place. In fact, it turns out that split-brain patients are not normal. They are just very good at compensating for the loss of the exchange of brain activity that is normally passed backwards and forwards between the two hemispheres of the intact brain.
Neuroscientist Michael Gazzaniga has shown that these split-brain patients can effectively have each half of the body thinking and acting in a different way. One of his most dramatic observations sounds very similar to the Dr Strangelove syndrome.14 He gave one of his split-brain patients a puzzle to solve using only his right hand (controlled by the language-dominate left hemisphere). However, this was a spatial puzzle in which where the blocks had to be put in the correct position (something that requires the activity of the right hemisphere). The right hand was hopeless, turning the blocks over and over until, as if frustrated, the left hand, which the patient had been sitting on, jumped in and tried to take the blocks away from the patient’s right hand. It was if the hand had a different personality.
Sometimes this lack of control takes over the whole body. French neurologist François Lhermitte reported a bizarre condition that he called ‘environmental dependency syndrome’ in which patients slavishly copied the doctor’s behaviour.15 Like the Tourette’s patient who had to mimic every other person’s behaviour, Lhermitte’s patients were similarly compelled to copy every action the doctor made. At one point, the French neurologist got down on his knees in his office as if to pray, whereupon the patient copied him with her head bowed and hands clasped in prayer. Other patients exhibited a related behaviour known as ‘utilization’ in which the sight of an object triggered an involuntary associated response.16 Such patients will pick up cups in their vicinity and start drinking from them, even when the cup is empty or not theirs. They will feel the compulsion to flick light switches and pull handles. In all of these examples, the patients’ actions are triggered by external events and not their own voluntary action, although some may reinterpret their unusual behaviour as if it arose of their own free will. They will justify their actions as if they willed them when, in fact, it was something in the environment that had taken control over their actions.
‘The Great Selfini’
When not bedevilled by strange neurological disorders, most of us feel we are in control because the coupling between the mental state of consciousness and initiated actions in everyday experience confirms our belief that we have willed our actions freely and in advance of their initiation. But if the reality of free will is an illusion, then why do we experience it so strongly? Why do we need the experience of free will? Why did it evolve?