As the public ask questions about the power of technology in society and wonder how to create change, many people mistrust the technology industry to develop answers. How can we advance a world where digital power is guided by evidence and accountable to the public? Citizen science currently plays a central role in the governance of complex systems involving powerful corporate actors, including the environment, product safety, and consumer protection. In this conversation, J. Nathan Matias will describe how citizen scientists collect data and test causal questions for change in our digital lives–on topics including harassment, pro-social behavior, misinformation, and algorithmic accountability. Designing citizen behavioral science requires advances in computer science and can lead to fundamental discoveries about human and algorithm behavior. Nathan will also present the work of the Citizens and Technology Lab at Cornell University (formerly CivilServant), which works alongside communities of tens of millions of people in citizen behavioral science for a flourishing internet.