Digital nudging leverages behavioral science and information technology to provide a new set of tools for designers to change behavior and create habits. Examples of digital nudges include smart feedback and reminders and technology defaults. I study the role of design and data in digital nudging and applications in the domains of consumer choices, health behavior, and daily work. To help expand research and practice, I propose three principles for the design of digital nudging solutions: choice of technology, use of data, and digital experimentation.

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Chapter on Digital Nudging

Online Choice Architecture: The Good, the Bad, and the Complicated

Insufficient engagement represents a major barrier that limits the scientific yield from mobile health studies and undermines the effectiveness of digital interventions. There is a growing interest in the science of engagement in digital and mobile health, with research seeking to gain better understanding of how to conceptualize, measure and intervene to promote engagement in mobile health studies and digital interventions. 

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Paper on Micro-randomized Trial for Headspace Engagement

Time-varying Model of Engagement

Digital technology has the potential to transform healthcare in general, and mental healthcare in particular. By redefining illness identification and management, digital and mobile health provide novel opportunities to measure disease and therapeutic response in ways that matter most to patients and clinicians. Although much clinical research is being done in these areas, there have been almost no successful attempts to integrate multiple technological tools in a personalized fashion within specific real-world clinical settings.

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HEATLHI Workshop

Digital biomarkers are the physiological and behavioral measures collected via connected digital devices or wearable and mobile computing systems. A set of accurately and reproducibly measurable digital biomarkers can be used to predict and influence various health conditions, outcomes, and to generate actionable insights. In recent years, we observed a rapid growth in adoption of digital biomarkers in the medical literature, computer science research, and digital health industry. Advancing the translational science of digital biomarkers requires the continuous integration of key technological innovations from the areas of mobile computing, machine learning, health sciences and medicine. 

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Digital Biomarkers Paper

Digital Biomarkers Workshop

The goal of this study is to evaluate effectiveness of scalable, tailored text- messaging programs for alcohol use among older adults. This study focuses on gain and loss framing of behavior change goals (i.e., the positives of change and the negatives of remaining with the status quo), critical components of behavioral science and health behavioral interventions.

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Clinicaltrials.gov Registration

This study examine cognitive training through gaming (PolyRules! mobile app) and walking (Fitbit Charge 5). The goal is to evaluate the feasibility of gamified inhibitory control training and/or leisure-time physical activity on cognitive functioning among healthy adults.

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PolyRules! App

Walk and Play Preprint

This 30-day pilot study examines whether real-time, contextual data about parents’ daily states (behaviors, feelings, or experiences) can guide the delivery of stress-regulation prompts. Parents with children under 18 are micro-randomized each day to receive either a mobile prompt recommending a mindfulness or stress-management exercise, or no prompt. The study aims to determine when and for whom such prompts are most effective in promoting engagement with mobile stress-regulation activities and reducing daily stress. It builds on evidence that mindfulness-based interventions improve psychological and physiological outcomes but often face low engagement in mobile formats.

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Paper on Micro-randomized Trial for Headspace Engagement

This study developed and validated the Digital Marshmallow Test (DMT), a mobile app for assessing and monitoring impulsivity on iOS and Android platforms. Built using Apple’s ResearchKit and Android’s ResearchStack, the app includes self-report, ecological momentary assessment, and behavioral task modules. In a 21-day study (N=116), the DMT demonstrated its ability to capture both trait and state impulsivity in daily life and clinical contexts. The app offers a scalable tool for studying impulsive behavior and developing digital interventions.

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Digital Marshmallow Test (DMT) Paper

mPulse Mobile Sensing Paper

Many people want to reduce their smartphone usage to increase productivity and well-being, but fail to accomplish this goal. We conducted a randomized control trial with a student population (N=112) over three weeks to test the effectiveness of two widely available digital nudges for screen time reduction. Along with a tracking-only control condition, a passive digital nudge (i.e., grayscale mode) was compared to an active digital nudge (i.e., time limits). The passive nudge led to an immediate, significant reduction of objectively measured screen time compared to the control condition. Conversely, the active nudge led to a smaller and gradual screen time reduction. Those in the control condition, who simply tracked their usage, did not lower their screen time. As opposed to the popular belief that reducing screen time is beneficial, we found no immediate causal effects of reducing screen time on subjective well-being and academic performance.

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PsyArXiv Preprint

The widespread adoption of intelligent voice assistants (IVAs), like Amazon’s Alexa or Google's Assistant, presents new opportunities for designers of persuasive technologies to explore how to support people's behavior change goals and habits with voice technology. In this work, we explore how to use planning prompts, a technique from behavior science to make specific and effective plans, with IVAs. We design and conduct usability testing (N=13) on a voice app called Planning Habit that encourages users to formulate daily plans out loud. We identify strategies that make it possible to successfully adapt planning prompts to voice format. We then conduct a week-long online deployment (N=40) of the voice app in the context of daily productivity. Overall, we find that traditional forms of planning prompts can be adapted to and enhanced by IVA technology.

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Planning Habit and Alexa Paper