The Woman With No Fear
- Science Holic
- May 29
- 3 min read
Author: Ella Chen
Editor: Hwi-On Lee
Artist: Felicia Chen
When you think of snakes and spiders, the first emotion that pops up is probably fear. This is the case for most people, as these creatures inspire fear in many. For an American woman known as SM, however, these creatures aren’t scary at all. In fact, not even the scariest haunted house in the world induces any fear in her. SM doesn’t experience any fear, nor does she know what fear even feels like.
Through extensive observation of SM’s brain, scientists have discovered that she suffers from a rare condition called Urbach-Wiethe disease, which is caused by a mutation in the ECM1 gene on chromosome 1. ECM1 is important for maintaining the extracellular matrix, a network of proteins that provides structural support to cells and tissues. The mutation causes a build-up of calcium and collagen, eventually leading to cell death. In the case of SM, Urbach-Wiethe disease has caused two black holes in the brain where the amygdala should be — a small almond-shaped mass located in both brain hemispheres, responsible for processing emotions, particularly fear. The amygdala is part of the first step of the fear response, so without it, other regions of the brain do not receive the message of fear and cannot carry out an appropriate response. Thus, SM has no sense of fear and is essentially fearless.
When scientists were first studying SM’s fearlessness, they exposed her to various environments in which the average human being would experience fear, including the “most haunted” place in the world: Waverly Hills Sanatorium. Not only did SM fail to exhibit a fear response, but she even approached the scare actors with excitement and curiosity, laughing at them and approaching them. She showed a similar reaction to live snakes and spiders, and was also able to sit through every horror movie shown to her without being startled. Along with her inability to experience fear, she also cannot recognize facial expressions of fear, though she can identify expressions of joy and sadness.
At first glance, this may seem like a beneficial trait to have. But, in reality, having absolutely no fear at all poses some dangers as well. SM is unable to recognize and escape from dangerous environments, which has led her to be the victim of life-threatening situations multiple times. Even when held at gunpoint, she did not respond with any urgency and simply stayed calm. These instances demonstrate the risks that come with a lack of fear.
However, the more studies are done on SM, the more is revealed on the actual role of the amygdala in the fear response, showing that fear is not as simple as it seems to be. For instance, an experiment in which SM was asked to breathe in carbon dioxide, which normally triggers a feeling of suffocation in people, resulted in an intense panic attack. These results suggested that there are multiple fear pathways in the brain: an internal one, and an external one. External threats, such as a burglar or insects, are received by the amygdala and sent to the hypothalamus and the pituitary gland, which evoke the fear response — this is the pathway that SM lacks. On the other hand, internal threats like exposure to carbon dioxide are detected by the brainstem, a region that controls unconscious functions like breathing and heart rate, which then results in the feeling of panic. The amygdala usually prevents the brainstem from carrying out this response, so without it, the feeling of panic is escalated, which explains why SM had such a strong response to inhaling carbon dioxide. The results of this experiment uncover the amygdala’s true role in fear, showing that there are other pathways in which fear can be expressed.
Since SM is just a single case of this fearlessness, the findings from experiments done on her cannot always be applied to the general public. However, these results push research in a promising direction, potentially leading to therapies for those with anxiety and post-traumatic stress disorder. It’s important to remember that fear is an essential emotion, though, and without it, we could potentially face dangerous situations.
References:
December 2010, J. B. 16. (2010, December 16). Woman With No Fear Intrigues Scientists.
Fox-Skelly, J. (2025, September 25). The rare disease that stops people from feeling fear. Bbc.com;
Willyard, C. (2010, December 16). Fearless Woman Lacks Key Part of Brain. Science.
Yong, E. (2010, December 16). Meet the woman without fear. Discover Magazine.
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