Trolley dilemmas from the philosopher’s armchair to the psychologist’s lab

Trolley dilemmas were first developed by moral philosophers engaged in reflection on the ethics of permissible harm. But they have since become central to psychological research into morality. One reason why psychologists have paid so much attention to trolley dilemmas is that they see them as a key way to investigating the contrast between deontological and utilitarian approaches to ethics. This framing, however, departs from the original philosophical purpose of trolley dilemmas, and can lead psychological research astray. In this chapter, we question the assumption that trolley dilemmas can shed general light about the psychological bases of utilitarian decision-making. Some lay responses to trolley dilemmas that psychologists routinely classify as ‘utilitarian’ in fact have little meaningful relation to what philosophers mean by this term. Even when what underlies lay responses to trolley dilemmas partly echoes aspects of a utilitarian approach to ethics, this doesn’t generalise to other moral domains, and tells us little about the psychological roots of other aspects of utilitarianism. Properly used, trolley dilemmas have a useful role to play in psychological research. But once we get clear about what we can, and cannot, learn from them, the current centrality of the trolley paradigm in moral psychology will seem overblown.