Purity is not a distinct moral domain

Abstract

Purity violations overlap with other moral domains. They are not uniquely characterized by hypothesized markers of purity – the witness's emotion of disgust, taint to perpetrator's soul, or the diminished role of intention in moral judgment. Thus, Fitouchi et al.'s proposition that puritanical morality (a subset of violations in the purity domain) is part of cooperation-based morality is an important advance.

A recent development in moral psychology with important theoretical consequences is the division of morality into distinct domains (Rozin, Lowery, Imada, & Haidt, 1999). One such hypothesized moral domain has become the focus of intense research: purity. Purity was theorized to be distinct from other moral domains, such as autonomy for example. Autonomy violations occur when a perpetrator intentionally harms another person and thereby elicits anger in a witness, whereas purity violations occur when the perpetrator, intentionally or not, defiles his or her own body or soul and thereby elicits disgust in a witness (Rozin et al., 1999). However, more recent research questions whether purity is distinct from autonomy (Gray, DiMaggio, Schein, & Kachanoff, 2022; Kollareth, Brownell, Durán, & Russell, 2023).

Consistent with the recent questioning of purity as a distinct moral domain, Fitouchi et al. raise the question whether a subset of violations in the purity domain, what can be called puritanical morality (condemnation of lust, gluttony, drinking, drugs, gambling, etc.) is an exception to the cooperative function of moral cognition. They propose moral disciplining theory (MDT) and argue that at least some acts featured in puritanical morality are cooperation-based moral concerns. If so, such acts, allegedly understood as violations in the domain of purity, lack distinct psychological foundations and evolutionary concerns said to characterize that domain.

That violations of purity are characterized by a unique emotion, disgust, is also questionable. Fitouchi et al. argue that puritanical moral acts such as lust, gluttony, intemperance, lack of self-discipline, and impiety are unrelated to disgust. Furthermore, much of the research offered in support of the claim that purity violations are disgusting confounds the violation with a pathogen. Examples include: thinking of scriptures while expelling excrement (Haidt, 2003) or cleaning a bathroom with the national flag (Haidt, 2012; Haidt, Koller, & Dias, 1993). When studies de-confound purity violations from pathogens, those alleged purity violations are not perceived as disgusting (Kollareth & Russell, 2019; Kollareth et al., 2023; Royzman, Atanasov, Landy, Parks, & Gepty, 2014).

Fitouchi et al. also note that the word disgust is polysemous. Thus, there is a problem using the word disgust to measure the emotional reaction of disgust. The word disgust is synonymous with “grossed-out” when the target includes a pathogen. However, in other contexts, a witness may use the word disgust to indicate anger or even dislike. In studies that used the word gross or phrase grossed-out in the response format, purity violations free of pathogens were more angering than gross (Kollareth & Russell, 2019; Kollareth et al., 2023; Royzman et al., 2014).

A similar confound occurs with the use of an emotional facial expression as a measure of disgust. The standard disgust face (nose-scrunch, raised upper lip) is associated with both disgust and anger (Pochedly, Widen, & Russell, 2012; Rozin, Lowery, & Ebert, 1994; Widen & Russell, 2010). However, the face of someone about to vomit (open mouth, lowered bottom lip, cheeks raised), which we call the “sick face,” was more reliably associated with pathogen disgust (Widen, Pochedly, Pieloch, & Russell, 2013). Studies have shown that the standard disgust face is commonly interpreted as angry rather than disgusted (Pochedly et al., 2012; Rozin et al., 1994; Widen & Russell, 2010). Ekman (1972) found what he called a “confusion” of anger and disgust when Papua New Guineans selected faces for basic emotions. Opposing the view that purity violations (free from pathogens) elicit genuine disgust, Ritter, Preston, Salomon, and Relihan-Johnson (2016) found that religious thought violations were not associated with the standard “disgust face” that was elicited by physically disgusting stimuli.

Yet another question raised by Fitouchi et al. in relation to disgust is whether behaviors that degrade the elevated nature of the human soul or remind humans of their animal nature are disgusting. Empirical studies have examined this specific hypothesis and conclude: Animal reminders per se are not disgusting (Kollareth & Russell, 2017). Some disgusting things may remind us of our animal nature, but they are not disgusting because they do so (Kollareth & Russell, 2018).

Consistent with the idea of purity violations degrading one's spiritual self, Rottman, Kelemen, and Young (2014) offered “taint to soul” as a marker of a purity violation. However, studies show that purity violations are not the only type of moral violation that a witness believes taints or degrades the soul (Kollareth et al., 2023). Witnesses find that murder, a hypothesized autonomy violation, taints the soul of the perpetrator more than does suicide, a hypothesized purity violation (Allam, Kollareth, & Russell, 2022).

Yet another hypothesized marker of a purity violation is related to the role of intention. According to Young and Tsoi (2013), “mental states, in fact, matter less, specifically, in cases of ‘purity’ violations” (p. 586). Initial research provided some support for this hypothesis (Barrett et al., 2016; Chakroff et al., 2016). However, more recent studies emphasize the role of the perpetrator's intention in the judged morality of various violations including those of purity. Context rather than domain governs the role of the perpetrator's intention (McHugh, McGann, Igou, & Kinsella, 2022). When context is taken into account, intention plays a significant role in the judged immorality of purity violations just as it does for autonomy violations (Kupfer, Inbar, & Tybur, 2020; Parkinson & Byrne, 2018). In the purity domain, the perpetrator's intention is significant and substantial: It is used to judge whether an impure act is moral or immoral (Kollareth & Russell, 2022).

In short, although every moral violation is distinct, empirical evidence does not support the claim of a distinct moral domain of purity. Indeed, violations characterized as purity overlap in many ways with other hypothesized moral domains – a claim consistent with Fitouchi et al.'s interesting and important hypothesis that puritanical morality is part of cooperation-based morality.