People of all ages seek to experience the feelings of joy, engagement, and meaning that define a happy life. A positive side-effect of happiness is its beneficial effects on physical health. Yet, some people consistently experience positive emotions more easily, suggesting that genetic factors are at play. This project will identify whether genetic variants underlie a predisposition toward positive emotions, which would have positive health implications. Candidate genes will be tested in a large sample of young adults. Emotions and physical health will be measured using innovative mobile techniques to track feelings in daily life. Analyses will test for relationships among genes, emotions, and health. This project will lead to a better understanding of why emotional wellbeing is more readily attainable for some, despite its universal pursuit. Greater understanding of the link between emotions and daily health will also be elucidated.