In the grand tapestry of human thought, few debates have endured with as much vigor and complexity as the discussion surrounding moral judgments. Philosophers, psychologists, and neuroscientists have passionately grappled with the fundamental question: Do moral judgments share a unique essence that sets them apart from non-moral matters? This intricate discourse has given rise to two opposing camps: moral monists, who argue for a unified moral essence centered around concerns of harm, and pluralists, who contend that moral judgments are a diverse landscape of human cognition.
Venturing into the heart of this age-old debate, a team of researchers, under the leadership of René Weber from UC Santa Barbara, embarked on a journey to dissect the very nature of morality. Employing a multifaceted approach that combined surveys, interviews, and cutting-edge brain imaging technology, they probed the intricacies of moral judgments and their neurological underpinnings.
Their discoveries unveiled a remarkable revelation: a general network of brain regions engaged when passing judgment on moral violations, contrasting starkly with the mental processes involved in assessing mere social norm infractions, such as an unconventional approach to coffee consumption. What is even more intriguing is that this neural network exhibited a striking overlap with regions implicated in the theory of mind—a key facet of human social cognition. However, delving deeper into the neural landscape revealed distinct activity patterns, indicating that the human brain navigates various moral issues through distinct pathways, lending credence to the pluralist perspective of moral reasoning. Astonishingly, these findings even highlighted disparities in how liberals and conservatives evaluate moral issues, underscoring the profound impact of moral judgments on political ideology.
Frederic Hopp, the study’s first author and a doctoral student in UC Santa Barbara’s Media Neuroscience Lab, offered an insightful perspective, stating, “In many ways, I think our findings clarify that monism and pluralism are not necessarily mutually exclusive approaches. We show that moral judgments of a wide range of different types of morally relevant behaviors are instantiated in shared brain regions.”
A remarkable breakthrough emerged as a machine-learning algorithm demonstrated the ability to discern the specific moral category or “foundation” being assessed by an individual based on their brain activity. Hopp explained that this achievement became possible because distinct moral foundations provoke unique neural activations.
The research was rooted in Moral Foundations Theory (MFT), a framework devised to elucidate the origins and variations in human moral reasoning. This theory classifies human moral foundations into six categories:
- Issues of care and harm
- Concerns of fairness and cheating
- Liberty versus oppression
- Matters of loyalty and betrayal
- Adherence to and subversion of authority
- Sanctity versus degradation
These foundations are further categorized into two broad moral domains: “individualizing” foundations, comprising care/harm and fairness/cheating, primarily safeguard individual rights and freedoms, while “binding” foundations—loyalty/betrayal, authority/subversion, and sanctity/degradation—operate predominantly at the group level.
The researchers devised a model based on MFT to investigate whether this framework and its nested categories manifested in neural activity. Participants rated brief descriptions of behaviors that transgressed specific moral foundations and behaviors contravening conventional social norms, serving as a control group. An fMRI machine meticulously tracked brain activity across various regions as participants contemplated these scenarios.
Crucially, specific brain regions consistently distinguished between moral and non-moral judgments. The medial prefrontal cortex, temporoparietal junction, and posterior cingulate, among others, were found to be pivotal in this distinction. Additionally, participants took longer to evaluate moral transgressions than non-moral ones, suggesting a more profound evaluation of actions in the context of one’s values.
Senior author René Weber emphasized this complexity, stating, “Although moral judgments are intuitive at first, deeper judgment requires responses to the six ‘W questions’: Who does what, when, to whom, with what effect, and why. And this can be complex and takes time.” This deeper level of moral reasoning recruited brain regions associated with mentalizing and theory of mind.
The study also illuminated that breaches of loyalty, authority, and sanctity elicited heightened activity in brain regions related to perceiving others’ actions, rather than self-centered processing. Weber remarked, “It was surprising to us how well the organization into ‘individualizing’ versus ‘binding’ moral foundations is reflected on the neurological level in multiple networks.”
Furthermore, the researchers crafted a decoding model capable of accurately predicting the specific moral foundation or social norm under scrutiny based on finely detailed activity patterns in the participants’ brains. This achievement shattered the notion of a unified neurological basis for all moral categories, bolstering the idea that distinct moral categories, as proposed by Moral Foundations Theory, have unique neurologic underpinnings.
This insight revealed that moral reasoning operates akin to other cognitive tasks, evoking characteristic brain activity patterns that vary based on specific details. Hopp likened this to the activation of the ventral temporal cortex when viewing pictures of houses or faces. In moral reasoning, distinct activation patterns in specific brain regions underscore the non-unified nature of moral judgments.
Beyond its academic significance, Moral Foundations Theory provides a robust framework for comprehending group identity and the phenomenon of political polarization. A growing body of evidence from surveys and behavioral experiments suggests that liberals emphasize the care/harm and fairness/cheating categories, which protect individual rights and freedoms, while conservatives prioritize loyalty/betrayal, authority/subversion, and sanctity/degradation, which operate at the group level.
Weber expounded on this point, stating, “Indeed, our results provide evidence at the neurological level that liberals and conservatives have complex differential neural responses when judging moral foundations.” This implies that individuals across the political spectrum may emphasize entirely different values when assessing a given issue.
This study is a vital contribution to the ongoing research efforts of the Media Neuroscience Lab, which embarked on this journey in 2016 to unravel the intricacies of moral judgments and their variation across different scenarios. As Hopp mused, “the observation that we can reliably decode which moral violation an individual is perceiving also opens exciting avenues for future research: Can we also decode if a moral violation is detected when reading a news story, listening to a radio show, or even when watching a political debate or movie?” These questions hold the promise of shaping the future of moral neuroscience.
The study’s co-investigators included distinguished neuroscientist and moral philosopher Walter Sinnott-Armstrong from Duke University, as well as Scott Grafton, a professor in UC Santa Barbara’s Department of Psychological and Brain Sciences. Jacob Fisher and Ori Amir, respectively a Ph.D. student and a postdoctoral fellow in Weber’s Media Neuroscience Lab during the study, also contributed as co-authors.
Ultimately, the research underscores that our capacity to cooperate within groups is intricately guided by systems of moral and social norms, along with the rewards and penalties that stem from adhering to or flouting these norms. As Weber aptly summarized, “For millennia, fables and fairy tales, nursery rhymes, novels, and even ‘the daily news’ all weave a tapestry of what counts as good
