Hardwiring Happiness: The Practical Science of Reshaping Your Brain—and Your Life

Whatever we repeatedly sense and feel and want and think is slowly but surely sculpting neural structure.

the cortisol in your brain overstimulates, weakens, and eventually kills cells in your hippocampus, gradually shrinking it.

If you fail to get a carrot today, you’ll have another chance to get one tomorrow, but if you fail to avoid a stick today—whap!—no more carrots forever.

intense, prolonged, or repeated mental/neural activity—especially if it is conscious—will leave an enduring imprint in neural structure,

Our ancestors could make two kinds of mistakes: (1) thinking there was a tiger in the bushes when there wasn’t one, and (2) thinking there was no tiger in the bushes when there actually was one. The cost of the first mistake was needless anxiety, while the cost of the second one was death.

to help our ancestors survive, the brain evolved a negativity bias that makes it like Velcro for bad experiences but Teflon for good ones.

Inner strengths are the supplies you’ve got in your pack as you make your way down the twisting and often hard road of life. They include a positive mood, common sense, integrity, inner peace, determination, and a warm heart.

As they say in neuroscience: Neurons that fire together wire together. Mental states become neural traits.

Because they lived in small bands, it was uncommon for them to meet people they didn’t know, and often dangerous when they did. While some bands interacted peacefully with each other, on average about one in eight men died in conflicts between bands, compared to one in a hundred men who died due to warfare in the twentieth century.

each person has the power to change his or her brain for the better—what Jeffrey Schwartz has called self-directed neuroplasticity.