Belief Updating in Moral Dilemmas

Moral psychologists have shown that people’s past moral experiences can affect their subsequent moral decisions. One prominent finding in this line of research is that when people make a judgment about the Trolley dilemma after considering the Footbridge dilemma, they are significantly less likely to decide it is acceptable to redirect a train to save five people. Additionally, this ordering effect is asymmetrical, as making a judgment about the Trolley dilemma has little to no effect on people’s judgments about the Footbridge dilemma. We argue that this asymmetry is the result of a difference in how each dilemma affects people’s beliefs about the importance of saving lives. In two experiments, we show that considering the Footbridge dilemma disconfirms these beliefs, while considering the Trolley dilemma does not significantly affect them. Consistent with predictions of sequential learning models, our findings offer a clear and parsimonious account of the asymmetry in the ordering effect. A growing body of research in moral psychology has shown that people’s past moral experiences can affect their subsequent moral decisions (Liao et al. 2011; Lombrozo 2009; Sinnott-Armstrong 2008; Wiegmann et al. 2008; Wiegmann and Okan 2012). One prominent finding in this line of research is that when people make a judgment about the Trolley dilemma after considering the Footbridge dilemma, they are significantly less likely to decide it is acceptable to redirect a train in order to save five people. Additionally, this ordering effect is asymmetrical. Whereas making a judgment about Rev.Phil.Psych. (2013) 4:705–714 DOI 10.1007/s13164-013-0159-y In the Trolley dilemma, participants are told they are at the wheel of a runaway train that will cause the deaths of five workmen if it proceeds on its present course. The only way to avoid the deaths of these workmen is to hit a switch, redirecting the train to a side track where it will kill a single workman instead. This dilemma is often contrasted with another famous moral dilemma, the Footbridge dilemma, which asks participants to consider a situation in which they are on a footbridge, in between a runaway trolley and five workmen who will be killed if nothing is done. Participants are then told that the only way to save the lives of the five workmen is to push a stranger off the bridge and onto the tracks below where his large body will stop the trolley. Z. Horne (*) : J. Spino Department of Philosophy, University of Illinois Urbana-Champaign, Urbana, USA e-mail: [email protected] D. Powell Department of Psychology, University of California Los Angeles, Los Angeles, USA Author's personal copy