Theory-Based and Tailor-Made: Motivational Messages for Behavior Change Technology

Changing behavior is an intricate and difficult process, which requires people to make a conscious decision to change, and stick with it for a long period of time. To really be able to change we need awareness and motivation. Luckily, most people now own technology that can be used for communication, and therefore also for support and motivation, if we can harness the technology to our advantage. Using technologies to motivate people to change their behaviors is increasingly explored. However, developing motivational technology that effectively supports long-term behavior change is a challenge. Solutions offered in the field are: (1) basing motivational strategies on existing behavior change theory and (2) tailoring the strategies to characteristics of the user. But how can we operationalize these theory-based strategies so that we can use them in motivational technology? And what characteristics should one tailor these strategies to?

In this dissertation, we investigate how we can motivate people to inherently change their physical activity behavior through theory-based and tailored interventions in the form of motivational text messages. This involves exploring, evaluating, and documenting ways in which we can operationalize theory-based strategies, researching and evaluating characteristics of the user that can be used to tailor these theory-based strategies to, and finally, testing and comparing the theory-based strategies in a field study.