Sacrificial dilemmas, especially trolley problems, have rapidly become the most recognizable scientific exemplars of moral situations; they are now a familiar part of the psychological literature and are featured prominently in textbooks and the popular press. We are concerned that studies of sacrificial dilemmas may lack experimental, mundane, and psychological realism and therefore suffer from low external validity. Our apprehensions stem from three observations about trolley problems and other similar sacrificial dilemmas: (i) they are amusing rather than sobering, (ii) they are unrealistic and unrepresentative of the moral situations people encounter in the real world, and (iii) they do not elicit the same psychological processes as other moral situations. We believe it would be prudent to use more externally valid stimuli when testing descriptive theories that aim to provide comprehensive accounts of moral judgment and behavior.Research on morality has experienced a major resurgence over the past decade. A shift away from rationalist theories that dominated the literature for many years created new theoretical space, prompted new questions, and called for new empirical methods. New stimuli created for laboratory studies have spurred research activity and led to many contributions to our understanding of morality. However, we believe it is now important to revisit the methodological principle of external validity. We question whether behavioral scientists who study morality should be concerned that they have become desensitized to potential limitations of stimuli that have risen in prominence over the past several years. To the extent that researchers seek to develop general theories of morality, their study stimuli must engage the same psychological processes that operate in everyday situations (Aronson, Wilson, & Brewer, 1998;Mook, 1983).The scholarly literature on moral judgment increasingly features studies that examine people's reactions to "sacrificial dilemmas" (Bartels & Pizarro, 2011), or brief scenarios where the only way to prevent a calamity from affecting a group of people would be to harm someone else or some smaller group. The trade-off in sacrificial dilemmas is not problematic in and of itself. Researchers can learn a great deal from the way people approach tough choices that put different moral considerations in conflict. Our concern, however, is that many sacrificial dilemmas are set in fanciful, sometimes absurd, contexts, and these artificial settings may affect the way people approach the situation and decide what to do. Moral psychology has developed a sophisticated understanding of how people respond to sacrificial dilemmas (Bartels, Bauman, Cushman, Pizarro, & McGraw, in press;Waldmann, Nagel, & Wiegmann, 2012), but we worry that the judgment and decision-making processes people use in these unusual situations may not External Validity in Moral Psychology 537 accurately reflect moral functioning in a broader set of situations. To be clear, our focus in the current paper is on...