Theory of mind network activity is associated with metaethical judgment: An item analysis

The theory of mind network (ToMN) is a set of brain regions activated by a variety of social tasks. Recent work has proposed that these associations with ToMN activity may relate to a common underlying computation: processing prediction error in social contexts. The present work presents evidence consistent with this hypothesis, using a fine-grained item analysis to examine the relationship between ToMN activity and variance in stimulus features. We used an existing dataset (consisting of statements about morals, facts, and preferences) to examine the variability in ToMN activity elicited by moral statements, using metaethical judgments (i.e. judgments of how objective/subjective morals are) as a proxy for their predictability/support by social consensus. Study 1 validated expected patterns of behavioral judgments in our stimuli set, and Study 2 associated by-stimulus estimates of metaethical judgment with ToMN activity, showing that ToMN activity was negatively associated with objective morals and positively associated with subjective morals. Whole brain analyses indicated that these associations were strongest in bilateral temporoparietal junction (TPJ). We also observed additional by-stimulus associations with ToMN, including positive associations with the presence of a person (across morals, facts, and preferences), a negative association with agreement (among morals only), and a positive association with mental state inference (in preferences only, across 3 independent measures and behavioral samples). We discuss these findings in the context of recent predictive processing models, and highlight how predictive models may facilitate new perspectives on both metaethics and the nature of distinctions between social domains (e.g. morals vs. preferences).