New experimental and big data research have generated unexpected ethical challenges for social scientists. Historically, these disciplines have been largely observational—involving the passive collection of existing information and data. More recently, social scientists have embraced experimental methods to study a wide variety of social, policy, and political questions. This experimental revolution has created a new set of ethical problems and a backlash against social science experiments. Especially challenging are the popular field experiments—experiments conducted on a massive scale, without any informed consent, often affecting larger societies or systems. Scott Desposato, professor of political science at UC San Diego, looks at these new issues, examines the perspective of subjects and societies, and discusses the way social scientists are working to build new norms of research.