Antisocial personality traits predict utilitarian responses to moral dilemmas

In the study, Bartels and Pizarro gave participants a set of moral dilemmas widely used by behavioral scientists who study morality, like the following: "A runaway trolley is about to run over and kill five people, and you are standing on a footbridge next to a large stranger; your body is too light to stop the train, but if you push the stranger onto the tracks, killing him, you will save the five people. Would you push the man?" Participants also completed a set of three personality scales: one for assessing psychopathic traits in a non-clinical sample, one that assessed Machiavellian traits, and one that assessed whether participants believed that life was meaningful. Bartels and Pizarro found a strong link between utilitarian responses to these dilemmas (e.g., approving the killing of an innocent person to save the others) and personality styles that were psychopathic, Machiavellian or tended to view life as meaningless.

These results (which recently appeared in the journal Cognition) raise questions for psychological theories of moral judgment that equate utilitarian responses with optimal morality, and treat non-utilitarian responses as moral "mistakes." The issue, for these theories, is that these results would lead to the counterintuitive conclusion that those who are "optimal" moral decision makers (i.e., who are likely to favor utilitarian solutions) are also those who possess a set of traits that many would consider prototypically immoral (e.g., the emotional callousness and manipulative nature of psychopathy and Machiavellianism).

While some might be tempted to conclude that these findings undermine utilitarianism as an ethical theory, Prof. Bartels explained that he and his co-author have a different interpretation: "Although the study does not resolve the ethical debate, it points to a flaw in the widely-adopted use of sacrificial dilemmas to identify optimal moral judgment. These methods fail to distinguish between people who endorse utilitarian moral choices because of underlying emotional deficits (like those captured by our measures of psychopathy and Machiavellianism) and those who endorse them out of genuine concern for the welfare of others." In short, if scientists' methods cannot identify a difference between the morality of a utilitarian philosopher who sacrifices her own interest for the sake of others, and a manipulative con artist who cares little about the feelings and welfare of anyone but himself, then perhaps better methods are needed.