The Poison Geek

He's fearless. She's totally without fear. They showed no fear. Yes, they are fearless.

She is fearless.

Um, actually, yeah, she is. Literally.

A woman with a rare genetic disorder, Urbach-Wiethe disease, isn't frightened by anything – haunted houses, spiders, snakes, movie monsters, death threats, being attacked or robbed, the Live Science website reports.

Researchers at the University of Iowa have done their best to scare the 44-year-old woman, identified only as "SM" for confidentiality reasons.

And they failed.

SM has a damaged amygdala, an almond-shaped portion of the brain strongly linked to feelings of fear in animals - and, SM's case indicates, in humans as well.

"On no occasion did SM exhibit fear, and she never endorsed feeling more than minimal levels of fear," the experts wrote.

They indicated that, over a three-month period of investigation "and a life history replete with traumatic events, SM repeatedly demonstrated an absence of overt fear manifestations."

Which, as they note, has clear drawbacks:

"She is aware that she does not have appropriate or normal responses to situations that would normally induce fear," University of Iowa researcher Daniel Tranel said.

A lack of response that could easily lead her into danger by being unaware of - or, more accurately, unresponsive to - conditions and situations that others would recognize as potentially threatening.

But here's Einstein's "difficulty - opportunity" thing again: Justin Feinstein, one of the researchers, has worked with veterans who suffer from PTSD. He described them as having lives "marred by fear," sometimes so great they can't even leave their homes. SM can help us to better understand how fear functions in the brain and thereby to develop better treatments.