(…) this chain-link of concepts and body parts and sensations creates what scientist Antonio Damasio calls a somatic marker—a kind of bookmark, or shortcut, in our brainssum. Sown by past experiences of reward and punishment, these markers serve to connect an experience or emotion with a specific, required reaction. By instantaneously helping us narrow down the possibilities available in a situation, they shepherd us toward a decision that we know will yield the best, least painful outcome. Long after we've passed our sixth year, we "know" whether or not it's right to kiss a hostess we barely know good-bye after a cocktail party, whether it's safe to dive into a lake, how we should approach that German shepherd, or that if we reach into an oven without a mitt on, our fingers will get burned. If someone asks us how or why we know that, most of us shrug—what a funny question—and chalk up our response to "instinct."