Personality Traits and Trolley Cases : A Correlational Study

“Trolley cases” have been debated by moral philosophers for many years, and have more recently become the subject of experimental psychological research. Joshua Greene (2007), in particular, argues that Trolley Case fMRI results (Greene et al. 2001) support consequentialist (i.e. consequence-based) moral reasoning over deontological (i.e. principle-based) moral reasoning. According to Greene, whereas consequentialist reasoning correlates with evolutionarily newer, distinctly human “higher” cognitive processes, deontological reasoning correlates with evolutionarily older, cruder, and “morally confabulated” emotional processing. We believe that our study – which examined correlations between personality traits and Trolley Case judgments – undermines Greene’s argument. 160 participants (90 male, 69 female, 1 transgendered; median age 31) were recruited online through Mechanical Turk and Yale Experiment Month web advertisements. Participants completed the BFI-44, a measure of the “Big Five” personality traits; the Short D3, a personality survey measuring the “Dark Triad” of Machiavellianism, narcissism, and psychopathy; a Moral Intuition Survey, which included two famous trolley cases; and a demographic survey. We found consequentialist reasoning in one crucial trolley case – a case that most people judge deontologically and (according to Greene’s fMRI results) emotionally – to correlate significantly with psychopathy, as well as with dispositions to cruelty, taking revenge on authorities, disagreeableness, and carelessness. Our results thus suggest that the emotional processing that Greene criticizes as “morally confabulated” is instead a critical and legitimate part of human moral personality and reasoning