Alcohol dependence associated with increased utilitarian moral judgment: a case control study

Abstract

Recent studies indicate that emotional processes, mediated by the ventromedial prefrontal cortex (VMPC), are of great importance for moral judgment. Neurological patients with VMPC dysfunction have been shown to generate increased utilitarian moral judgments, i.e. are more likely to endorse emotionally aversive actions in order to maximize aggregate welfare, when faced with emotionally salient personal moral dilemmas. Patients with alcohol dependence (AD) also exhibit impairments in functions mediated by the prefrontal cortex, but whether they exhibit increased utilitarian moral reasoning has not previously been investigated. The aim of this study was to investigate moral judgment in AD patients (n = 20) compared to healthy controls (n = 20) matched by sex, age and education years. Each subject responded to a battery of 50 hypothetical dilemmas categorized as non-moral, moral impersonal and moral personal. They also responded to a questionnaire evaluating explicit knowledge of social and moral norms. Results confirmed our hypothesis that AD patients generated increased utilitarian moral judgment compared to controls when faced with moral personal dilemmas. Crucially, there was no difference in their responses to non-moral or impersonal moral dilemmas, nor knowledge of explicit social and moral norms. One possible explanation is that damage to the VMPC, caused by long term repeated exposure to alcohol results in emotional dysfunction, predisposing to utilitarian moral judgment. This work elucidates a novel aspect of the neuropsychological profile of AD patients, namely a tendency to generate utilitarian moral judgment when faced with emotionally salient moral personal dilemmas.

Figure 1. Moral judgments of three classes of dilemmas: non-moral, impersonal moral and personal moral dilemmas.

The proportion of ‘yes’ responses are shown for the two groups. Alcohol dependent patients were more likely than healthy controls to respond ‘yes’, i.e. endorsing the proposed utilitarian action, when faced with moral personal dilemmas (P = 0.024). However, no such difference was found for non-moral (P = 0.377) or impersonal moral dilemmas (P = 0.161). Error bars indicate 95% confidence intervals.

Figure 2. Moral judgments of the personal moral dilemmas, further subdivided into low- and high-conflict respectively.

The proportion of ‘yes’ responses are shown for the two groups. Alcohol dependent patients were more likely than healthy controls to respond ‘yes’, i.e. endorsing the proposed utilitarian action, when faced with the high-conflict dilemmas (P = 0.036), while the difference was less pronounced for the low-conflict dilemmas (P = 0.063). Error bars indicate 95% confidence intervals.

Figure 3. Moral judgment on each moral personal dilemma.

The proportion of ‘yes’ responses are shown for the two groups for each of the 21 moral personal dilemmas. The dilemma numbers are directly adapted from Koenigs et al. (2007) and sorted according to increasing proportion of ‘yes’ responses, i.e. endorsing the proposed utilitarian action, by the healthy controls. Dilemmas labelled 1–8 and 9–21 are low-conflict type and high-conflict type respectively. Alcohol dependent patients responded equally or more utilitarian than healthy controls for all personal moral dilemmas except one, and the difference in response was more pronounced for the high-conflict dilemmas (P = 0.036) compared to low-conflict dilemmas (P = 0.063).