New Finding Offers Neurological Support for Adam Smith’s ‘Theories of Morality’


The part of the brain we use when engaging in egalitarian behavior may also be linked to a larger sense of morality, researchers have found. Their conclusions, which offer scientific support for Adam Smith’s theories of morality, are based on experimental research published in the Proceedings of the National Academy of Sciences.

The study was conducted by researchers from NYU’s Wilf Family Department of Politics; the University of Toronto; the University of California, San Diego; the University of California, Davis; and the University of Nebraska, Lincoln.

Previous scholarship has established that two areas of the brain are active when we behave in an egalitarian manner—the ventromedial prefrontal cortex (vmPFC) and the insular cortex, which are two neurological regions previously shown to be related to social preferences such as altruism, reciprocity, fairness, and aversion to inequality. Less clear, however, is how these parts of the brain may also be connected to egalitarian behavior in a group setting.

To explore this, the researchers conducted an experiment in which individuals played a game to gauge brain activity in decision-making. To get at a more detailed understanding of neurological activity during this game, they also examined whether activations were associated with two specific measures of egalitarian preferences elicited outside of an fMRI.

The researchers found that these two measures of egalitarian preferences were significantly associated with activations in the insular cortex, but not with the vmPFC. This result is a potentially profound one as the insular cortex is also the part of the brain that processes the relationship of the individual with respect to his or her environment. In other words, egalitarian behavior may not exist in isolation, neurologically speaking, but, rather, be part of a larger process that stems from altruism and a sense of the larger social good.

Adam Smith expressed this perspective in his 18th-century essay, The Theory of Moral Sentiments.

“Adam Smith contended that moral sentiments like egalitarianism derived from a ‘fellow-feeling’ that would increase with our level of sympathy for others, predicting not merely aversion to inequity, but also our propensity to engage in egalitarian behaviors,” the researchers write. “The evidence here supports such an interpretation.”

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