" But to me, the most profound discovery this new generation of neuroscientists has made is the powerful connection between infant brain chemistry and adult psychology. Lying deep beneath these noble, complex human qualities we call character, these scientists have found, is the mundane, mechanical interaction of specific chemicals in the brains and bodies of developing infants. Chemistry is not destiny, certainly. But these scientists have demonstrated that the most reliable way to produce an adult who is brave and curious and kind and prudent is to ensure that when he is an infant, his hypothalamic-pituitary-adrenal axis functions well. And how do you know that? It's not magic. First, as much as possible, you protect him from serious trauma and chronic stress; then, even more important, you provide him with a secure, nurturing relationship with at least one parent and ideally two. That's not the whole secret to success, but it is a big, big part of it. "

― Paul Tough , How Children Succeed: Grit, Curiosity, and the Hidden Power of Character