Sticks and stones can break my bones but words can never hurt me is an adage we teach our children to insulate them from the cruel remarks of others. As adults, however, it’s often the words that arise spontaneously from within—the self-disparagements, disturbing recollections, and ominous forecasts—that cause us emotional pain and prevent us from living our fullest and most productive lives. The human brain has provided us with the technologies that allow us to dominate our planet, but it is also the source of much unnecessary emotional distress. Even when we have no good reason to be upset, our brains can spontaneously flood our minds with disturbing thoughts of past trauma or future disaster.

Much of our unnecessary emotional distress occurs because our attention is involuntarily drawn to whatever most angers or frightens us even when no immediate action is required and the risk is minimal. Our mood tends to be harmed much more by each negative thought than it is improved by each positive one. These two findings constitute what researchers call the negativity bias, and it’s one of the reasons we often struggle to attain peace of mind: that mental equilibrium in which we accept both ourselves and our circumstances, without experiencing distress about something from the past or that might happen in the future.