The Guillotine and Neuroscience

The air was chilly in 19th Century Paris as a criminal was led to his fate. A GuillotineThe man had committed a crime and was sentenced to pay. A crowd gathered to watch his punishment. There standing before him was the fateful Madame, the progeny of a French engineer. This Woman with the acerbic jaw was to seal the criminal’s fate. He faced the crowd wide-eyed and fearful, pleading for his life. His pleas seemed to fall on deaf ears as the frenzied crowd prepared for the spectacle. A German man stood waiting to play his part. Theodor Bischoff was not there to enjoy the public execution, he was there in the name of science. As the executioner led the criminal to the apparatus named after Joseph Guillotin (who by the way did not invent the guillotine), Bischoff approached. The blade fell and the criminal’s head dropped to the ground. Bischoff quickly rushed over to the head to perform his experiment.

Bischoff wanted to know whether or not consciousness was centered in the head – in the brain – and if any awareness resided after the beheading. He quickly thrust his fingers at the poor criminal’s eyes to see if there was any eye-blink. There was none. He placed smelling salts under the nose, with no reaction. Finally he spoke the word, “Pardon!” into an ear. Again, no response. He was satisfied with the results and concluded that consciousness did in fact reside in the brain and that it ended when the head was severed. His early neuroscience experiment was complete.

While this approach seems unorthodox at best today, early researchers had to resort sometimes to interesting techniques in order to investigate the influence of the brain on behavior, emotions, and consciousness. Their research methods were often seriously flawed but the work they did was important. Each new discovery led to our current understanding of the brain. So while we have much better methods to research the brain than antagonizing disembodied heads, our current research as neuropsychologists and neuroscientists is founded on the research of such creative men as Bischoff.

Note: I dramatized the story and as such, it is a bit of historical fiction. I don’t know if Bischoff was in Paris, he might have been in Germany when he did the experiment. However, Bischoff did perform this experiment.

Biological Determinism

Free WillAs someone with a strong neurobiological foundation, I believe that the brain is the center of all behavior. What is the evidence for that belief? Remove someone’s brain and see if they have any behavior (note: I’m not endorsing this behavior, I’m merely postulating a hypothetical situation). Without the brain, there is no behavior. So, the brain is necessary for behavior but is it sufficient?

In psychology we often talk about necessary and sufficient conditions for behavior. That is, you may need a certain factor in order for a behavior to happen but without other factors, the behavior will not occur. For example, you need water to live – it is necessary – but you also need food, so thus not sufficient. So, the brain is necessary for behavior but can all behavior be explained solely by the brain? Another way of phrasing this question is, “Does biology determine all behavior?” The term for this belief is biological determinism.

To answer the question we first have to investigate and uncover other potential influences on (causes of) behavior. If behavior is biologically determined, do people have free will? That is, do people really have the ability to consciously make and choose different behavior? Or are all behaviors simply determined at the neuronal (or genetic) level and free will is only an illusion? This post is an expansion on one of my previous posts concerning alternative assumptions to naturalism in neuroscience.

If you really believe that the brain (and by reductionism, genes) are solely responsible for behavior, then you cannot believe that people have free will. You also cannot believe that the environment is directly responsible for behavior – it can influence it – but at the core, your genes and your neurons create behaviors. Alternatively, you can believe that humans have free will, that we can make choices because of or in spite of our biology. Agency can influence biology and biology can influence agency – they are not mutually exclusive categories. While the brain is a necessary condition for behavior, it is not sufficient; agency is a factor in human behavior.