Philosophers, psychologists and researchers from other fields have created various methods for studying topics in moral psychology, with empirical studies dating back to at least the 1890s.[27] The methods used in these studies include moral dilemmas such as the trolley problem,[24][37] structured interviews and surveys as a means to study moral psychology and its development, as well as the use of economic games,[39] neuroimaging,[40] and studies of natural language use.
Interview techniques[edit]
In 1963, Lawrence Kohlberg presented an approach to studying differences in moral judgment by modeling evaluative diversity as reflecting a series of developmental stages (à la Jean Piaget). Lawrence Kohlberg's stages of moral development are:[42]
Obedience and punishment orientation
Self-interest orientation
Interpersonal accord and conformity
Authority and social-order maintaining orientation
Social contract orientation
Universal ethical principles
Stages 1 and 2 are combined into a single stage labeled "pre-conventional", and stages 5 and 6 are combined into a single stage labeled "post-conventional" for the same reason; psychologists can consistently categorize subjects into the resulting four stages using the "Moral Judgement Interview" which asks subjects why they endorse the answers they do to a standard set of moral dilemmas.[30]
Survey instruments[edit]
Between 1910 and 1930, in the United States and Europe, several morality tests were developed to classify subjects as either fit or unfit to make moral judgments.[27][43] Test-takers would classify or rank standardized lists of personality traits, hypothetical actions, or pictures of hypothetical scenes. As early as 1926, catalogs of personality tests included sections specifically for morality tests, though critics persuasively argued that they merely measured intelligence or awareness of social expectations.[27]
Meanwhile, Kohlberg inspired a new series of morality tests. The Defining Issues Test (dubbed "Neo-Kohlbergian" by its constituents) scores relative preference for post-conventional justifications,[44][45] and the Moral Judgment Test scores consistency of one's preferred justifications.[46][47] Both treat evaluative ability as similar to IQ (hence the single score), allowing categorization by high score vs. low score.
Among the more recently developed survey measures, the Moral Foundations Questionnaire[48] is a widely used survey measure of the five moral intuitions proposed by Moral Foundations Theory: care/harm, fairness/cheating, loyalty/betrayal, authority/subversion, and sanctity/degradation. The questions ask respondents to rate various considerations in terms of how relevant they are to the respondent's moral judgments. The purpose of the questionnaire is to measure the degree to which people rely upon each of the five moral intuitions (which may coexist). The new and improved version of this instrument (i.e., Moral Foundations Questionnaire-2; MFQ-2) was developed in 2023. In this version, Fairness was split to Equality and Proportionality. Hence, the MFQ-2 measures Care, Equality, Proportionality, Loyalty, Authority, and Purity.[49] In addition to survey instruments measuring endorsement of moral foundations, a number of other contemporary survey measures exist relating to other broad taxonomies of moral values,[50][51][52] as well as more specific moral beliefs,[53][54] or concerns.