Moral foundations and political orientation: Systematic review and meta-analysis.

We investigate the relationship of morality and political orientation by focusing on the influential results showing that liberals and conservatives rely on different moral foundations. We conducted a comprehensive literature search from major databases and other sources for primary studies that used the Moral Foundations Questionnaire and a typical measure of political orientation, a political self-placement item. We used a predefined process for independent extraction of effect sizes by two authors and ran both study-level and individual-level analyses. With 89 samples, 605 effect sizes, and 33,804 independent participants, in addition to 192,870 participants from the widely used YourMorals.org website, the basic differences about conservatives and liberals are supported. Yet, heterogeneity is moderate, and the results may be less generalizable across samples and political cultures than previously thought. The effect sizes obtained from the YourMorals.org data appear inflated compared with independent samples, which is partly related to political interest and may be because of self-selection. The association of moral foundations to political orientation varies culturally (between regions and countries) and subculturally (between White and Black respondents and in response to political interest). The associations also differ depending on the choice of the social or economic dimension and its labeling, supporting both the bidimensional model of political orientation and the findings that the dimensions are often strongly correlated. Our findings have implications for interpreting published studies, as well as designing new ones where the political aspect of morality is relevant. The results are primarily limited by the validity of the measures and the homogeneity of the included studies in terms of sample origins. (PsycInfo Database Record (c) 2021 APA, all rights reserved).