In her book My Stroke of Insight, brain scientist Jill Bolte Taylor explains that the natural life span of an emotion—the average time it takes for it to move through the nervous system and body—is only a minute and a half, a mere ninety seconds. After that, we need thoughts to keep the emotion rolling. So, if we wonder why we lock into painful emotional states like anxiety, depression, or rage, we need look no further than our own endless stream of inner dialogue.

Modern neuroscience has discovered a fundamental truth: Neurons that fire together, wire together. When we rehearse a looping set of thoughts and emotions, we …