The Physiology of Moral Sentiments

44 Pages Posted: 13 Jun 2009

See all articles by Paul J. Zak

Paul J. Zak

Claremont Graduate University - Center for Neuroeconomics Studies

Date Written: June, 12 2009


Adam Smith made a persuasive case that moral sentiments are the foundation of ethical behaviors in his 1759 The Theory of Moral Sentiments. This view is still controversial as philosophers debate the extent of human morality. One type of moral behavior, assisting a stranger, has been shown by economists to be quite common in the laboratory and outside it. This paper presents the Empathy-Generosity-Punishment model that reveals the criticality of moral sentiments in producing prosocial behaviors. The model's predictions are tested causally in three neuroeconomics experiments that directly intervene in the human brain to turn up and turn down moral sentiments. This approach provides direct evidence on the brain mechanisms the produce prosociality using a brain circuit called HOME (Human Oxytocin-Mediated Empathy). By characterizing the HOME circuit, I identify situations in which moral sentiments will be engaged or disengaged. Using this information, applications to health and welfare policies, organizational and institutional design, economic development, and happiness are presented.

Keywords: Neuroeconomics, Law, morality, emotions, Adam Smith

JEL Classification: C9

Suggested Citation

Zak, Paul J., The Physiology of Moral Sentiments (June, 12 2009). Journal of Economic Behavior and Organization, Forthcoming, CELS 2009 4th Annual Conference on Empirical Legal Studies Paper, Available at SSRN:

Paul J. Zak (Contact Author)

Claremont Graduate University - Center for Neuroeconomics Studies ( email )

160 E. 10th St.
Claremont, CA 91711-6165
United States

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