The document discusses how storytelling can be used in health apps to promote behavior change. It provides examples of apps that have used storytelling effectively, such as Talkspace which uses framing, Carrot Fit which uses memorable stories, and Zombies Run! which uses engaging stories. The document also discusses different ways stories can be integrated into apps, such as telling traditional stories, letting data tell stories, or enabling users to tell their own stories. Overall, it argues that storytelling is an effective technique because it is how humans naturally make sense of their experiences.