Moral conviction interacts with metacognitive ability in modulating neural activity during sociopolitical decision-making

The extent to which a belief is rooted in one’s sense of morality has significant societal implications. While moral convictions can inspire positive collective action, they can also prompt dogmatism, intolerance, and societal divisions. These negative effects may be exacerbated by poor metacognition. There has been extensive research in social psychology about the characteristics of moral convictions, but their neural mechanisms and how they are incorporated into the valuation and decision-making process remain unclear. This study was designed to examine the neural mechanisms of decision-making on sociopolitical issues that vary on moral conviction, as well as how metacognitive abilities relate to these mechanisms. Participants (N = 44) underwent fMRI scanning while deciding on each trial which of two groups of political protesters they supported more. As predicted, stronger moral conviction was related to faster response times. Hemodynamic response in the anterior insula (aINS), anterior cingulate cortex (ACC), and lateral prefrontal cortex (lPFC) were elevated during decisions with higher moral conviction level, supporting both the emotional and cognitive dimensions of moral conviction. Functional connectivity between lPFC and vmPFC was also higher on trials higher in moral conviction, elucidating mechanisms through which moral conviction is incorporated into valuation. Support for protesters was positively associated with brain activity in regions involved in valuation (particularly vmPFC and amygdala). Metacognitive sensitivity, measured in a separate perceptual task, negatively correlated with parametric effects of moral conviction in the brain, providing new evidence that metacognition modulates responses to morally convicted issues.