As one approach to examining the way ethical decisions are made, we asked experts (i.e., ethicists, regulatory officials, and experienced researchers) and novices (i.e., inexperienced graduate students) to review a set of scenarios that depict some important ethical tensions in research. The method employed was "protocol analysis," a talk-aloud technique pioneered by cognitive scientists for the analysis of expert performance. The participants were asked to verbalize their normally unexpressed thought processes as they responded to the scenarios, and to make recommendations for courses of action. We found that experts spent more time working through the decision-making process than novices and also raised substantially more concerns than novices. Differences also exist among the three groups of experts.