“bad is stronger than good” is an important principle of design by evolution. “Responses to threats and unpleasantness are faster, stronger, and harder to inhibit than responses to opportunities and pleasures.” This is a matter of how our brains are wired: most sense data pass through the amygdala, which helps control our fight-or-flight response, before being processed by other parts of our cerebral cortex. The feeling that a fright can make us “jump half out of our skin” is based on this physical reality—we’re reacting long before we know what it is that we’re reacting to.
This is one of the reasons that human beings make heavy weather of being happy. We have been hardwired to emphasize the negative, and, for most of human history, there has been a lot of the negative to emphasize. Hobbes’s description of life in the state of nature as “nasty, brutish and short” is so familiar we can forget that, for most of the people who have ever lived, it was objectively true. Most humans have had little control over their fate; a sniffle, a graze, or a bad piece of meat, let alone a major emergency such as having a baby—all were, for most of our ancestors, potentially lethal. One of the first people to be given penicillin was an Oxford policeman named Albert Alexander, who, in 1940, had scratched himself on a rose thorn and developed septicemia. After he was given the experimental drug, he began to recover, but the supply ran out after five days, and he relapsed and died. That was the world before modern medicine, and it would have been familiar to Ig and Og in a crucial respect: one false move and you were dead.
more from The New Yorker here.