Again and again, teachers, professors and anyone else in the teaching professions will tell you that IQ is not the only difference between their best and worst students. Increasingly, psychologists are finding that the one characteristic that is emerging as a significant predictor of success is not social intelligence, or good looks, or physical health, or IQ. It’s grit. It’s been said that grit is living life like it’s a marathon, not a sprint. But what is grit? And how can it be nurtured?