‘Disgust is thought to have originated in distaste, a food-rejection impulse or motivation triggered by the ingestion of unpleasant-tasting substances, prototypically those that are bitter (Chapman, Kim, Susskind, & Anderson, 2009; Rozin & Fallon, 1987). Because many bitter substances are toxic (Garcia, Hankins, Denton, & Coghlan, 1975), the role of distaste in food rejection has a clear and concrete adaptive function. Distaste appears to have very ancient origins: Even sea anemones, which first evolved some 500 million years ago, will expel bitter foods from their gastric cavity (Garcia et al., 1975)’ (Chapman & Anderson, 2013, p. 300).
There’s also a bit of a puzzle about the postulation of this foundation. Roughly, Iyer et al. (2012) found a group of people where the foundations do not appear to work (and we’ll see later that others have found further groups; in particular, Davis et al. (2016)). On the face of it, this looks like an objection to the theory. Why is postulating an additional foundation a good response to that objection?
Haidt et al’s own answer to this question does not appear convincing:
‘MFT’s five moral foundations appeared to be inadequate in capturing libertarians’ moral concerns, but the approach that gave birth to these foundations served us well in examining this new group, and stimulated us to consider Liberty/oppression as a candidate for addition to our list of foundations’ (Graham et al., 2013, p. 87).
I do think there might be more compelling answers to the question of why postulating an additional foundation is a good response to the objection. But I would not start from the view that the foundations should include Liberty — the case for that is quite different from the case for the other foundations.
Chapman, H. A., & Anderson, A. K. (2013). Things rank and gross in nature: A review and synthesis of moral disgust. Psychological Bulletin, 139(2), 300–327. https://doi.org/10.1037/a0030964
Chapman, H. A., Kim, D. A., Susskind, J. M., & Anderson, A. K. (2009). In Bad Taste: Evidence for the Oral Origins of Moral Disgust. Science, 323(5918), 1222–1226. https://doi.org/10.1126/science.1165565
Davis, D., Dooley, M., Hook, J., Choe, E., & McElroy, S. (2017). The Purity/Sanctity Subscale of the Moral Foundations Questionnaire Does Not Work Similarly for Religious Versus Non-Religious Individuals. Psychology of Religion and Spirituality, 9(1), 124–130. https://doi.org/10.1037/rel0000057
Davis, D., Rice, K., Tongeren, D. V., Hook, J., DeBlaere, C., Worthington, E., & Choe, E. (2016). The Moral Foundations Hypothesis Does Not Replicate Well in Black Samples. Journal of Personality and Social Psychology, 110(4). https://doi.org/10.1037/pspp0000056
Doğruyol, B., Alper, S., & Yilmaz, O. (2019). The five-factor model of the moral foundations theory is stable across WEIRD and non-WEIRD cultures. Personality and Individual Differences, 151, 109547. https://doi.org/10.1016/j.paid.2019.109547
Graham, J., Haidt, J., Koleva, S., Motyl, M., Iyer, R., Wojcik, S. P., & Ditto, P. H. (2013). Moral Foundations Theory: The Pragmatic Validity of Moral Pluralism. In P. Devine & A. Plant (Eds.), Advances in Experimental Social Psychology (Vol. 47, pp. 55–130). Academic Press. https://doi.org/10.1016/B978-0-12-407236-7.00002-4
Graham, J., Haidt, J., Motyl, M., Meindl, P., Iskiwitch, C., & Mooijman, M. (2019). Moral Foundations Theory: On the advantages of moral pluralism over moral monism. In K. Gray & J. Graham (Eds.), Atlas of Moral Psychology. New York: Guilford Publications.
Graham, J., Haidt, J., & Nosek, B. A. (2009). Liberals and conservatives rely on different sets of moral foundations. Journal of Personality and Social Psychology, 96(5), 1029–1046. https://doi.org/10.1037/a0015141
Graham, J., Nosek, B. A., Haidt, J., Iyer, R., Koleva, S., & Ditto, P. H. (2011). Mapping the moral domain. Journal of Personality and Social Psychology, 101(2), 366–385. https://doi.org/10.1037/a0021847
Iyer, R., Koleva, S., Graham, J., Ditto, P., & Haidt, J. (2012). Understanding Libertarian Morality: The Psychological Dispositions of Self-Identified Libertarians. PLOS ONE, 7(8), e42366. https://doi.org/10.1371/journal.pone.0042366
Miller, L., Murphy, R., & Buss, A. (1981). Consciousness of body: Private and public. Journal of Personality and Social Psychology, 41(2), 397–406.
Schnall, S., Haidt, J., Clore, G. L., & Jordan, A. H. (2008). Disgust as Embodied Moral Judgment. Personality and Social Psychology Bulletin, 34(8), 1096–1109. https://doi.org/10.1177/0146167208317771
Sinnott-Armstrong, W., Young, L., & Cushman, F. (2010). Moral intuitions. In J. M. Doris, M. P. R. Group, & others (Eds.), The moral psychology handbook (pp. 246–272). Oxford: OUP.