Disentangling Weirdness from Moral Purity: A Test of Two Competing Theoretical Perspectives

Abstract

Past investigations indicate that harm-based moral violations are judged to be worse when greater in magnitude or frequency, but purity-based moral violations are relatively insensitive to variations in magnitude and frequency. While some psychologists argue that this is evidence that harm and purity violations are rooted in different psychological mechanisms, others contend that all moral judgments are rooted in harm and point to confounding issues such as the association between weirdness and purity-based moral violations. The current study addresses these criticisms by experimentally varying weirdness as a feature of harm-based moral violations. A sample of 314 participants judged the wrongness of moral violations in the harm, purity, and weird-harm domains. Each violation was either low or high in magnitude, varying the frequency or amount of transgression occurring. If harm and purity moral judgments have distinct psychological mechanisms, moral evaluations of weird-harm violations low versus high in magnitude should resemble those of harm-only violations by showing sensitivity to action magnitude while also demonstrating different patterns from purity violations that instead are relatively insensitive to magnitude. In contrast, the perspective arguing for a single psychological mechanism rooted solely in perceived harm would predict that moral evaluations of weird-harm violations low versus high in magnitude should resemble those of purity violations and deviate different from harm-only violations by showing insensitivity to action magnitude. Results indicated a sensitivity to action magnitude for both weird-harm and harm-only violations but not for purity violations. These findings support a pluralistic understanding of morality suggesting the use of distinct psychological mechanisms in moral judgment dependent upon the type of moral transgression that has occurred.