Where in the brain is morality? Everywhere and maybe nowhere

Abstract

The neuroscience of morality has focused on how morality works and where it is in the brain. In tackling these questions, researchers have taken both domain-specific and domain-general approaches—searching for neural substrates and systems dedicated to moral cognition versus characterizing the contributions of domain-general processes. Where in the brain is morality? On one hand, morality is made up of complex cognitive processes, deployed across many domains and housed all over the brain. On the other hand, no neural substrate or system that uniquely supports moral cognition has been found. In this review, we will discuss early assumptions of domain-specificity in moral neuroscience as well as subsequent investigations of domain-general contributions, taking emotion and social cognition (i.e., theory of mind) as case studies. Finally, we will consider possible cognitive accounts of a domain-specific morality: Does uniquely moral cognition exist?

Keywords:

• Moral
• Emotion
• Theory of mind
• Domain-specificity
• fMRI

Acknowledgments

Thanks to Jesse Prinz for his helpful comments on an earlier draft of this paper.

Notes

¹ Throughout this review, we take moral neuroscience and psychology to address only descriptive and not prescriptive questions. The empirical project is to characterize the nature of the moral domain, the proper description of moral content and computation, not normative moral truths. Thus, we make no normative evaluation of patient populations, with cognitive deficits, whose moral judgments differ from judgments delivered by neurotypical individuals.

² We take fMRI activations within VMPC, including the medial portions of the orbitofrontal cortex (BA 11 and 12) as well as the medial prefrontal cortex from the ventral surface to around the level of the genu of the corpus callosum (BA 25 and portions of BA 10 and 32), to suggest the engagement of emotional processing.

³ The VMPC projects to limbic, hypothalamic, and brainstem regions that execute visceral and autonomic components of emotional responses (Ongur & Price, 2000); neurons within the VMPC encode the emotional value of sensory stimuli (Rolls, 2000).

⁴ We do not take the evidence to suggest that all moral judgments are emotionally mediated. Instead, moral cognition depends on multiple inputs from multiple cognitive systems—emotional appraisals are one such input for certain kinds of moral judgments.

⁵ The term “social brain” is sometimes used more generally to describe brain regions involved in any form of social cognition, including emotion. Here, we use “social brain” to refer to the brain regions involved specifically in how we reason about the minds, or mental states, of other social agents, including their beliefs and intentions (theory of mind).

⁶ Could nonmoral inputs (e.g., cause, intent) be combined in such a way that they are systematically transformed for moral judgment (Knobe, 2005)(F. Cushman, personal communication)? If so, this might provide support for a putative moral faculty.