Perhaps more important, our wiring—whether fixed or not—tells only part of the story. Research suggests a 50-40-10 formula for happiness: About 50 percent of our happiness is wired in. Another 40 percent can be attributed to how we interpret and respond to what happens to us, and 10 percent is driven by our circumstances—where we live and with whom, where we work and with whom, the state of our health, and so forth.
