Ever wonder why your friend is a monster-wave-surfing, plane-jumping junkie and you prefer to quietly stretch in the gravity-bound comfort of a yoga [0] studio? Well, scientists may now have found part of that answer. As reported in January’s Outside [1] magazine, researchers at Seattle’s Fred Hutchinson Cancer Research Center [2] have identified a gene, neuroD2, that may affect the fear response.

Most mice (and humans) are born with two copies of this gene, which affects the amygdala––an almond-shaped part of the brain that is the seat of emotional memory. It’s where things like love, anger, and fear get logged and associated with particular circumstances. For the study [3], recently published in Proceedings of the National Academy of Sciences [4], some mice were engineered to have only one neuroD2; the control group had two. In one experiment researchers played a tone followed by a low shock to the mice’s feet. The double-gened mice crouched low and waited for the next time they heard the tone. The normal-gened mice did not crouch and wanted to go surfing again.

Humans are almost never born with only one of these genes, but, “different people could have different concentrations of the protein that the genes produce,” according to Outside. “Higher levels might lead to safer behavior, while lower levels might lead to more magazine covers.”

So what I want to know is: Following the study’s logic, can you have a compromised “seat of emotional memory” work for you and not against you? Or do people who fearlessly surf 50-foot waves and bungee jump again and again have problems with emotional bonding and intimacy? Think about it and let me know what you come up with in the comment box below.

Illustration by Zohar Lazar via Outside [5]