Damage to the ventromedial prefrontal cortex is associated with impairments in both spontaneous and deliberative moral judgments

Abstract

Implicit moral evaluations—spontaneous, unintentional judgments about the moral status of actions or persons—are thought to play a pivotal role in moral experience, suggesting a need for research to model these moral evaluations in clinical populations. Prior research reveals that the ventromedial prefrontal cortex (vmPFC) is a critical area underpinning affect and morality, and patients with vmPFC lesions show abnormalities in moral judgment and moral behavior. We use indirect measurement and multinomial modeling to understand differences in implicit moral evaluations among patients with vmPFC lesions. Our model quantifies multiple processes of moral judgment: implicit moral evaluations in response to distracting moral transgressions (Unintentional Judgment), accurate moral judgments about target actions (Intentional Judgment), and a directional tendency to judge actions as morally wrong (Response Bias). Compared to individuals with non-vmPFC brain damage and neurologically healthy comparisons, patients with vmPFC lesions showed a dual deficit in processes of moral judgment. First, patients with vmPFC lesions showed reduced Unintentional Judgment about moral transgressions, but not about non-moral negative affective distracters. Second, patients with vmPFC lesions showed reduced Intentional Judgment about target actions. These findings highlight the utility of a formal modeling approach in moral psychology, revealing a dual deficit in multiple component processes of moral judgment among patients with vmPFC lesions.