Fear . What’s your biggest fear? Snakes? Planes? Snakes on planes . . . ? Most of us can think of a couple things that send shivers down the spine. But have you ever stopped to wonder where the fear came from initially? It all starts in the brain. The same circuit that jolted humans to fight or flee from a woolly mammoth now gets activated when you're nervous about a first date. Long long ago, humans were probably more in tune to their fear circuits . . . because danger was a real, immediate thing with a very clear resolution. The whole process was much simpler—rustling in bushes . . . fear circuit activated . . . muscles ready. Then, after a quick check of the surroundings, our cave-dwelling ancestors would have either taken flight, gotten into a fight, or realised it was just the wind. If it was the wind, the fear response immediately dissipated. Fear didn't linger . . . nor did it leave subtle traces of self-doubt. But somewhere along the timeline, th