We all have bad habits - things we eat, drink, do or say that cause us unhappiness. We repeat these behaviours over and over again - almost as if we are on autopilot. But we can break free from them, and use the mechanics of habit formation to make doing good things feel effortless.

Dr Laurie Santos meets a scientist who sleeps in her running gear and a former army doctor who went to Vietnam to fight a wave of heroin abuse in the military and discovered something startling about habits.

For an even deeper dive into the research we talk about in the show visit happinesslab.fm