The human brain is much better than previously thought at discovering and avoiding disease, a new study led by researchers at Karolinska Institute in Sweden reports. Our sense of vision and smell alone are enough to make us aware that someone has a disease even before it breaks out. And not only aware — we also act upon the information and avoid sick people. The study is published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).
The human immune system is effective at combating disease, but since it entails a great deal of energy expenditure, disease avoidance should be part of our survival instinct. A new study now shows that this is indeed the case: the human brain is better than previously thought at discovering early-stage disease in others. Moreover, we also have a tendency to act upon the signals by liking infected people less than healthy ones.
“The study shows us that the human brain is actually very good at discovering this and that this discovery motivates avoidance behavior,” says principal investigator Professor Mats Olsson at Karolinska Institute’s Department of Clinical Neuroscience.
By injecting harmless sections of bacteria, the researchers activated the immune response in participants, who developed the classic symptoms of disease — tiredness, pain and fever — for a few hours, during which time smell samples were taken from them and they were photographed and filmed. The injected substance then disappeared from their bodies and with it the symptoms.
Dr. Stegall’s Comments: Our bodies are fascinating, and the brain is arguably the most incredible organ of all. The level of awareness and control which exists in our brains is truly remarkable! We should all be excited about learning more about how our brains can impact our health and help us prevent disease.