How many love songs have you heard that mention the brain? Heartache and heartbreak are the shorthand for romantic unhappiness, a racing heart indicates excitement, but no English expression I am aware of links the emotions to the brain. On the contrary, language assigns emotions to almost any organ except the one that is actually responsible for them. The heart gets assigned this responsibility most frequently, but common usage also credits the intestines for producing a person’s courage. After all, we say that a courageous person has guts, not that he or she has a powerful prefrontal cortex, which would be the physiologically correct statement. It’s not just English either. Spanish proverbs on courage center on the person’s kidneys, and a Russian, when annoyed, is likely to say, “You have touched my liver.” Why is our language so out of touch with a basic scientific fact? One reason is history. In his treatise “On the Sacred Disease” dated to 400 B.C., Hippocrates (1), the father of modern medicine, states “Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations.” And the excellent website for the PBS documentary titled The Secret History of the Brain (2) states that Galen, an eminent Roman physician, wrote of the brain as the source of temperament and emotion in 170 B.C. The ancient Greeks and Romans already knew about the role of the brain in causing emotions, but, like so much of the knowledge of antiquity, this was forgotten in the Middle Ages, especially because the Christian Church banned anatomical studies. And, by the way, until real-time imaging of the brain with fMRI came along, anatomical comparisons of the brain across different species provided some of the best evidence for the functions of the different organs. As Paul D. MacLean wrote in his 1967 article “The Brain in Relation to Empathy and Medical Education” in the Journal of Nervous and Mental Disease (3), the similarity of the limbic lobe across all mammals and its absence in reptiles led to the hypothesis that it is involved in emotion. This similarity also permitted anatomical experiments on animals that in conjunction with clinical data on human psychiatric patients provide the bulk of the evidence for the contemporary scientific understanding of emotion. However, all this occurred within the past two centuries, too recently to affect our language. Therefore, the modern European languages came into existence at a time when their speakers were ignorant of the true cause of emotions.
Also, our language reflects our intuition whereas many scientific findings, even basic ones, are counterintuitive. Your heart does race when you’re excited. It is easy to assume that this correlation is causation and much harder to understand the real neurobiology involved. Perhaps, there will one day be a time when there will be as many sayings about the limbic system as there are about the heart now. But for that to happen, the limbic system would need to be thoroughly investigated and explained to all people, so that it is as concrete and tangible as a heartbeat.
- On the Sacred Disease, Hippocrates - Source
- The Secret History of the Brain, PBS - Source
- Maclean (1967). The Brain in Relation to Empathy and Medical Education. Journal of Nervous and Mental Disease, 144 (5): 374-382. Source (warning: paywall)