Humans are hardwired to make fast decisions. Our caveperson ancestors needed to work out in an instant if the shadow in the shrubs was a tiger or a friend who had had a hard night on the cider. If we spotted danger, our natural flight response was triggered, and we high-tailed it in the other direction. If we couldn’t identify the danger after a second or so, most of us tended to take to the hills just in case. It was a matter of life or death.