Imagine walking through a dark sanatorium, handling tarantulas, and being held at gunpoint without experiencing a single drop of fear. For an American woman known to the scientific community as Patient S.M., this is her everyday reality. Born in 1965, S.M. has a rare condition called Urbach-Wiethe disease, which caused the complete bilateral destruction of her amygdala during her late childhood.
This brain damage physiologically reduced her ability to feel fear. Dubbed by the media as the “woman with no fear,” her unique neurological makeup has made her the subject of extensive scientific research since 1994.
Haunted Houses and Deadly Spiders
Researchers have tested S.M.’s unique brain function through multiple real-world experiments. When scientists handed her snakes and tarantulas, she showed zero fear. Instead, she displayed curiosity and excitement. The research team also took her to the Waverly Hills Sanatorium, a well-known haunted attraction, and showed her intense horror films like The Silence of the Lambs, The Shining, and The Blair Witch Project.
S.M. experienced no fear during these activities. She did, however, show appropriate emotions, such as happiness and disgust, when viewing non-fear-inducing film clips. She also exhibits impairments in processing scary or sad music.
Missing Social Cues and Personal Space
S.M. is highly outgoing, friendly, and uninhibited. She approaches strangers easily and exhibits a flirtatious personality. Due to her amygdala damage, she cannot recognize fear in the facial expressions of other people and struggles to judge whether a face looks trustworthy.
Furthermore, S.M. lacks a physical sense of personal space. She experiences no discomfort standing nose-to-nose with a stranger while making direct eye contact. While she intellectually understands the concept of personal space, her brain simply does not enforce a physical boundary for her own body.
Real-World Danger and Crime
Her inability to detect looming threats has led to numerous life-threatening encounters. Living in a poverty-stricken area, S.M. has been held up at knifepoint and gunpoint. She was nearly killed in a domestic violence incident and has received explicit death threats.
During these extreme situations, she exhibited no signs of urgency or desperation. Despite facing alienation, hardship, and abuse throughout her life, the mother of three boys maintains a highly positive affect and experiences very little negative emotion. Her memory also processes information differently, as she lacks the memory consolidation typically triggered by emotionally arousing stimuli.
The One Trigger for Panic
While immune to external threats, researchers discovered one specific method that bypassed her brain damage. When scientists administered carbon dioxide inhalation to simulate the physical experience of suffocation, S.M. experienced an intense panic attack. She reported this internal sensation of fear as completely novel.