Moral foundations theory is a social psychological theory intended to explain the origins of and variation in human moral reasoning on the basis of innate, modular foundations. At present, the theory proposes six such foundations: Care, Fairness, Liberty, Loyalty, Authority, and Sanctity; however, its authors envision the possibility of including additional foundations. The theory was first proposed by the psychologists Jonathan Haidt and Craig Joseph, building on the work of cultural anthropologist Richard Shweder, subsequently developed by a diverse group of collaborators, and popularized in Haidt's book The Righteous Mind.
Although the initial development of moral foundations theory focused on cultural differences, subsequent work with the theory has largely focused on political ideology. Various scholars have offered moral foundations theory as an explanation of differences among political progressives (liberals in the American sense), conservatives, and libertarians, and have suggested that it can explain variation in opinion on politically charged issues such as gay marriage and abortion. In particular, Haidt and fellow researchers have argued that progressives stress only two of the moral foundations (Care and Fairness) in their reasoning, and libertarians stress only two (Liberty and Fairness), while conservatives stress all six more equally.
Moral foundations initially arose...