Justin Feinstein is one of the few scientists who have been able to study a woman who has zero fear response. To protect the woman’s identity, this subject is known only as “S.M.”, and Feinstein has had the opportunity to work with her under laboratory conditions and in real world scenarios (e.g. coffee meeting, sporting event, professional conference etc.) for the past 15 years as of 2018. S.M.’s lack of fear has had unexpected consequences within her life, as she displays no sense of typical fear induced scenarios (e.g. personal space, feeling completely comfortable being nose to nose with a complete stranger as the concept of personal space and discomfort has no meaning), heightened by the fact that S.M. does not produce typical signals of distrust when interacting with a novel person. S.M. lacks fear because she is without her amygdala, a physical trait observed in very few human beings, making S.M. one of the only people in the world to produce this physiology. S.M. has no amygdala because she has been diagnosed with Urbach-Wiethe Disease (pronounced “urr-bock vee-they”). The underlying etymology of Urbach-Wiethe Disease is still unknown but in patients with the condition, specific portions of the brain, in both hemispheres, can become subject to selective calcification which erodes the ability to function as designed. The amygdala acts as a sentry for potential fearful stimuli, and produces a response accordingly. The removal of or inability of the amygdala to work correctly results in a complete and total lack and/or loss of fear. This condition has caused S.M. considerable difficulty during her life as she has experienced dangerous interactions with those participating within the illicit drug trade. Upon one occasion, a stranger ran up to S.M., placed a firearm against her temple, and yelled “bang!”. Neighbors witnessed this event and notified law enforcement which puzzled S.M. as she did not view the event as dangerous or alarming and therefore did not expect to be contacted by the police. When the human body detects the intake of too much carbon dioxide, it can become pushed into a state of alarm. Feinstein wanted to better understand what would occur if he interfered with S.M.’s respiratory system, using 35% carbon dioxide during the first trial run. Feinstein found that S.M. was immediately fearful after a single intake breath, despite his original hypothesis of no fear response being observed. S.M. displayed an immediate and dramatic fear response with S.M. herself describing it as the “most intense fear ever felt” during her entire life. This single breath was revolutionary for neurology as it definitively proved that the amygdala is not the only region of the brain which controls and is related to fear