One of the few exceptions to the old saying “everybody is afraid of something” is a 44-year-old woman known to psychologists as patient SM. She suffers from a rare case of brain damage to an almond-shaped region of her brain called the amygdala that, according to a paper published online December 16 in Current Biology, makes her incapable of experiencing fear.

For three months researchers did everything they could to scare SM. “We tried to use stimuli common in Western society,” says Justin Feinstein, a University of Iowa graduate student who worked on the study. They showed her horror movies, walked her through haunted houses and exposed her to all kinds of other situations that the average person would consider frightening. They dug through her past, questioning her about times when she had been held up at knifepoint and gunpoint and nearly killed in a domestic dispute. Not once in any of these situations did they find evidence that SM felt afraid, by her report or via observation.

They found instead that situations that would terrify most people evoked in SM an intense feeling of fascination. At one point they took SM to a pet store to see how she would behave around snakes, an animal she had earlier told them she hated. When she saw the snakes, she was immediately drawn to them. She even picked one up and began playing with its tongue. When asked to explain her behavior, she said that she was overwhelmed with curiosity.

These findings suggest that our emotional response to danger involves elements of both fear and fascination. When we find ourselves in potentially threatening situations, Fein­stein explains, “the amygdala helps us navigate the fine boun­dary between approach and avoidance.” If the amygdala is functioning properly, these emotions work together to get us out of trouble—and enable us to enjoy the occasional grue­some movie. When it is damaged, however, our response can actually work against our survival, attracting us to the very things we should be avoiding. As the researchers concluded, “the evolutionary value of fear is lost.”