“Testing Heritability of Moral Foundations: Common Pathway Models Support Strong Heritability for the Five Moral Foundations”, Michael Zakharin, Timothy C. Bates2022-05-26 (genetic correlation, ethics, sociology)⁠:

Moral Foundations Theory (MFT) predicts that moral behavior reflects at least five foundational traits, each hypothesised to be heritable.

Here, we report two independent twin studies (total n = 2,020), using multivariate multi-group common pathway models to test the following 3 predictions from the MFT: (1) The moral foundations will show heritability; (2) The moral foundations will each be genetically distinct and (3) The clustering of moral concerns around individualising and binding domains will show heritability.

Supporting predictions 1 and 3, Study 1 showed evidence for substantial heritability of two broad moral factors corresponding to individualising and binding domains. In Study 2, we added the second dataset, testing replication of the Study 1 model in a joint approach. This further corroborated evidence for heritable influence, showed strong influences on the individualising and binding domains (h² = 49% and 66%, respectively) and, partially supporting prediction 2, showed foundation-specific, heritable influences on Harm/Care, Fairness/Reciprocity and Purity/Sanctity foundations. A general morality factor was required, also showing substantial genetic effects (40%).

These findings indicate that moral foundations have genetic bases. These influenced the individual foundations themselves as well as a general concern for the individual, for the group, and overall moral concern.

[Keywords: morality, moral foundations, Haidt, twin study, heritability]