Morality And Brain: High Levels Of Moral Reasoning Linked To Increased Gray Matter In Prefrontal Cortex

Individuals with high levels of moral reasoning may have increased gray matter in areas of the brain, linked to decision making and conflict processing. The findings are published in the journal PLOS ONE.

"To investigate this question, we employed a sample of MBA students ages 24 to 33, past the age at which structural brain maturation is complete, and tested their moral reasoning, then looked at the level of gray matter in the brains of a subset of subjects," said senior author Hengyi Rao, PhD, a research assistant professor of Cognitive Neuroimaging in Neurology and Psychiatry in the Perelman School of Medicine. "MBA students were ideal candidates for this work, as the Wharton curriculum addresses issues of moral decision-making and reasoning," explained Diana Robertson, PhD, a professor of legal studies and business ethics at the Wharton School and an author of the study, in a news release. "We aimed to investigate whether the stage of moral reasoning is reflected in structural brain architecture."

For the study, researchers administered the Defining Issue Test to 67 MBA students to see which pattern of thought or behavior--or cognitive schema--each student used when reasoning on certain moral issues.

The participants were presented with complex moral dilemmas, including medical assisted suicide, and asked to chose the relevance of 12 given rationales. Based on those results, researchers were then assigned one of seven schema types that represent increasing levels of moral development.

Next, the participants underwent an MRI scan that investigated differences in gray matter volume between those who reached the post-conventional level of moral reasoning when compared to those who had not reached that level yet.

Personality placement put the participants in a range of different categories, including things like neuroticism, openness to experience, agreeableness and/or conscientiousness. For those who had higher levels of moral development, their analysis showed more openness to experience and lower neuroticism. Researchers also discovered increased gray matter in the prefrontal cortex for subjects with increased moral reasoning when compared to others.

"The current findings provide initial evidence for brain structural difference based on the stages of moral reasoning proposed by Lawrence Kohlberg decades ago," Rao concluded. "However, further research will be needed to determine whether these changes are the cause or the effect of higher levels of moral reasoning."

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