| Happiness is the ultimate goal for individuals worldwide, yet mood disorders affect more people than ever and many are unhappy. To support people in achieving happiness, the subfield of positive psychology was formed around the development of positive interventions, or activities that encourage people to reflect on positive aspects of their lives. These interventions are effective, but a key challenge for them in real-world practice is promoting access to and sustained engagement with intervention activities so they can benefit those in need.;Positive psychologists suggest that interactive technologies can address these challenges, yet technology design is not within their realm of expertise. However areas of Human-Computer Interaction (HCI) specifically study ways that technologies support people in reflecting on their lives and changing their behaviors. This dissertation brings together these lines of research, suggesting and evaluating ways that technologies can be used to improve engagement with positive interventions. A key insight drawn from HCI research is the use of social media content as a record of people's experiences, which can then be used as inspiration in positive intervention activities, injecting variety into otherwise redundant exercises.;We first present a pilot intervention to better understand questions around the design of such technologies. We then present the design and preliminary evaluation of Positivity, an intervention technology that leverages social media content and persuasive strategies to support completion of intervention activities. We do not find that Positivity is effective in increasing happiness, but through mixed-methods analysis we find partial success with respect to our design goals and specific system features.;Our work contributes to positive psychology by presenting the design and evaluation of an intervention technology that leverages HCI research, suggesting features to support engagement and highlighting challenges in evaluating real-world intervention technologies. We also contribute to the small body of work studying persuasive technology interventions to support psychological, instead of physical, well-being. Finally, we heed critiques of personal informatics as focusing too heavily on data capture and show that by defining the purpose of reflection and selecting data that facilitates this purpose, personal informatics systems can effectively use data archives for reflection. |
