Fear is a fundamental emotion, a survival mechanism designed to protect us from danger. But what if someone couldn’t experience fear? This is the reality for two individuals, one in Britain and another in the United States, due to rare medical conditions.
Jordie Sarnik of the UK developed Cushing’s syndrome in 2005. The condition causes the body to produce too much cortisol, a stress hormone. Treatment required removal of his adrenal glands. The successful procedure came with an unexpected consequence – the disappearance of fear. He rode rollercoasters, jumped out of planes, and abseiled down from heights, experiencing no fear response. His heart rate remained consistent, without any indicators of anxiety or distress.
S.M., an American woman, is another example. She has Urbach-Wiethe disease, a rare genetic disorder, also known as lipoid proteinosis. This disease damages the amygdala, the part of the brain that processes fear. Researchers tested S.M. by exposing her to scary movies, haunted houses, snakes, and spiders. Despite these frightening stimuli, she showed no fear; instead, she was often drawn to them.
S.M.’s behavior is distinct. She approaches people very closely, even strangers. When asked how close she was comfortable being to someone, she said 0.34 meters (about a foot), much less than the average person. This shows that fear helps regulate social behavior.
S.M. has been threatened with weapons on multiple occasions, yet she never perceived danger. This lack of fear sometimes led her into dangerous situations.
Scientists say fear works in two ways: in response to external threats (like an animal attack) and internal threats (like suffocation). The amygdala is vital for recognizing external dangers, but internal anxieties are handled by the brainstem. When exposed to carbon dioxide, S.M. experienced extreme fear, showing that fear doesn’t depend solely on the amygdala.
Feinstein argues that without an amygdala, an animal would likely die quickly in the wild, as it cannot recognize danger. However, S.M. has lived for over 50 years without it. These cases show that fear protects us and deeply influences our social and emotional behavior.