“I felt like a coward, the kind Ernest Hemingway wrote about with contempt, while my husband, the real target, slept soundly and went to work, unfazed. Yet it turns out that the difference between us is not moral but fiercely biological, the result of the well-known fight and flight response, which revs the hormone epinephrine, increasing blood flow in the body and focus in the brain.” Aeon’s Caren Chesler: Are some brains wired for courage and others for fear? (I’d like to think so, but honestly, I wouldn’t say it to your face.)