Abstract
A key challenge in the field of behavior intervention technology is to help people address habit-related issues such as depression, diet, exercise, and smoking. For these issues, theories suggest that small behavioral prompts delivered on a daily basis might be one effective way to motivate incremental shifts that accumulate into sustainable change. However, while this approach is appealing, we still know very little about how to design effective behavioral prompts that work in the context of everyday life. To fill this gap, we have developed a mobile intervention that sends people one sustainable lifestyle challenge every day. In a 20-day field trial with 139 participants, we collected logs from our mobile app, surveys, and post-study interviews. Participants completed a total of 1,921 daily challenges. In this paper, we report on participants' feelings and reactions to this daily challenge approach. This feedback suggests new design opportunities for mobile behavior interventions that use daily prompts.