Think of the last time you told yourself something critical or negative. Then think of the last compliment you gave yourself.

Which is easier to remember?

Many of us—whether due to genetics, brain chemistry, our experiences or coping skills—tell ourselves way too many negative thoughts. We ruminate, thinking the same negative, unproductive thoughts over and over.

Each thought is made up of a complex pattern of activity between proteins and other chemicals, gene expressions and neural connections in our brain. The more we have a thought, the stronger this circuit grows. A well-developed thought “is like a ski track in the snow. The more you ski down a path, the easier it is to go down that path and not another,” says Alex Korb, a neuroscientist and author of “The Upward Spiral: Using Neuroscience to Reverse the Course of Depression, One Small Change at a Time.”

With intent and practice, you can create another path. Psychologists call the technique cognitive reappraisal. The result will be stronger neural networks devoted to positive thoughts, or a happier brain.