In the target article, Fitouchi et al. build a new theory that puritanical morality is developed for promoting cooperation by facilitating self-control (regardless its efficiency). Besides, they cast doubts on an influential disgust-based account of puritanical morality, which considers the function of puritanical morality as avoiding communicable diseases driven by a feeling of disgust. Although Fitouchi et al. have elucidated the cognitive and evolutionary foundations of their cooperation-based theory with sufficient evidence, they leave the emotional foundation of puritanical morality unclear after denying the role of disgust. Are there any emotions underlying puritanical morality? What are they? We would like to extend Fitouchi et al.'s theory by proposing moral emotions such as guilt and shame as characteristic emotions in puritanical morality. Our proposition is based on three reasons: (1) violations of puritanical norms induce guilt and shame; (2) guilt and shame support self-control; and (3) guilt and shame enhance cooperation.

First, it is widely reported that people feel guilty and ashamed for conducting various behaviors that condemned by puritanical morality, including binge eating, masturbation, gambling, neglecting to study, failing to excise, and so on (Baumeister, Reference Baumeister1995; Berg et al., Reference Berg, Crosby, Cao, Crow, Engel, Wonderlich and Peterson2015; Mageau, Vallerand, Rousseau, Ratelle, & Provencher, Reference Mageau, Vallerand, Rousseau, Ratelle and Provencher2005; Mosher, Reference Mosher1979; Ratelle, Vallerand, Mageau, Rousseau, & Provencher, Reference Ratelle, Vallerand, Mageau, Rousseau and Provencher2004; Sharma & Sharma, Reference Sharma and Sharma1998). Notably, behaviors manifesting lack of self-discipline (e.g., failing to excise) that are moralized by puritanical morality seem unrelated to disgust, but are related to guilt and shame (Baumeister, Reference Baumeister1995; Harman & Burrows, Reference Harman and Burrows2019; Markland & Tobin, Reference Markland and Tobin2004). Thus, guilt and shame compared to disgust has closer associations with violations of puritanical norms.

Second, guilt and (maybe) shame are supposed to help people inhibit selfish impulses and hedonic motives (Baumeister, Reference Baumeister1995; Baumeister & Exline, Reference Baumeister and Exline1999). Supporting this opinion, behavioral experiments found that guilt and shame promote behaviors that need self-control, such as costly apology, help, amend, and self-punishment (de Hooge, Zeelenberg, & Breugelmans, Reference de Hooge, Zeelenberg and Breugelmans2007; Ohtsubo & Yagi, Reference Ohtsubo and Yagi2015; Yu, Hu, Hu, & Zhou, Reference Yu, Hu, Hu and Zhou2014; Zhu et al., Reference Zhu, Jin, Shen, Zhang, Mai and Liu2017). Neuroimaging experiments also provided supportive evidence that guilt compared to other emotions (e.g., sadness and shame) produces stronger activation in brain regions implicated in self-control, such as orbitofrontal cortex and lateral prefrontal cortex (Wagner, N'Diaye, Ethofer, & Vuilleumier, Reference Wagner, N'Diaye, Ethofer and Vuilleumier2011; Zhu, Feng, Zhang, Mai, & Liu, Reference Zhu, Feng, Zhang, Mai and Liu2019) and that shame is associated with activity in the dorsolateral prefrontal cortex related to self-control (Bastin, Harrison, Davey, Moll, & Whittle, Reference Bastin, Harrison, Davey, Moll and Whittle2016). Considering Fitouchi et al. highlight that puritanical morality aims to improve self-control and prevent self-control failures, guilt and shame are conducive to achieving the aim of puritanical morality.

Third, looking at the bigger picture, the social function of guilt and shame (particularly guilt) is maintaining and repairing cooperative relationships (Chang, Smith, Dufwenberg, & Sanfey, Reference Chang, Smith, Dufwenberg and Sanfey2011; Sznycer, Reference Sznycer2019). As moral violations induce guilt and people are guilt averse, people usually act in a moral way that trying to minimize their anticipated guilt regarding their decisions, which promotes greater levels of cooperation (Battigalli & Dufwenberg, Reference Battigalli and Dufwenberg2007; Bellemare, Sebald, & Suetens, Reference Bellemare, Sebald and Suetens2019; Charness & Dufwenberg, Reference Charness and Dufwenberg2006). Guilt avoidance is a crucial mechanism that prevents moral violations, motivates cooperative behavior, and maintains cooperative relationships (Chang et al., Reference Chang, Smith, Dufwenberg and Sanfey2011). Guilt and (maybe) shame not only can maintain cooperative relationships, but also help to restore jeopardized relationships. After violating moral norms, people are faced with blame, punishment, and even exclusion from future cooperation (Boyd, Gintis, Bowles, & Richerson, Reference Boyd, Gintis, Bowles and Richerson2003; Fehr & Gächter, Reference Fehr and Gächter2002; Tomasello & Vaish, Reference Tomasello and Vaish2013). To cope with this problem, guilt and shame urge people to conduct behaviors (e.g., apology, compensation, and self-punishment) that require sacrificing short-term interests (e.g., body pleasure and monetary reward) and weighting long-term benefits (cooperative relationships) (Ghorbani, Liao, Çayköylü, & Chand, Reference Ghorbani, Liao, Çayköylü and Chand2013; Nelissen, Reference Nelissen2011; Nelissen & Zeelenberg, Reference Nelissen and Zeelenberg2009; Watanabe & Ohtsubo, Reference Watanabe and Ohtsubo2012; Yu et al., Reference Yu, Hu, Hu and Zhou2014; Zhu et al., Reference Zhu, Shen, Tang, Ye, Wang, Mai and Liu2017). Studies have found that guilt- and/or shame-induced behaviors (e.g., apology, compensation, and self-punishment) can facilitate forgiveness from others and restore jeopardized relationships (Hechler, Wenzel, Woodyatt, & de Vel-Palumbo, Reference Hechler, Wenzel, Woodyatt and de Vel-Palumbo2022; McCullough, Kurzban, & Tabak, Reference McCullough, Kurzban and Tabak2013; Zhu et al., Reference Zhu, Shen, Tang, Ye, Wang, Mai and Liu2017). Given Fitouchi et al. advocate that the ultimate function of puritanical morality is boosting cooperation, the functions of guilt and shame and puritanical morality coincide well with each other.

It is difficult to judge whether guilt or shame plays a more important role in puritanical morality at the current stage. One problem is that some researchers construed “guilt” as a synonym for “shame” or vice versa. Another problem is that many studies measured only guilt or only shame. Still another problem is that guilt and shame tend to co-occur after moral violations (e.g., Nelissen & Zeelenberg, Reference Nelissen and Zeelenberg2009). We note that guilt and shame have conceptual, theoretical, and neural differences (e.g., Bastin et al., Reference Bastin, Harrison, Davey, Moll and Whittle2016; Tangney & Dearing, Reference Tangney and Dearing2003; Tangney, Miller, Flicker, & Barlow, Reference Tangney, Miller, Flicker and Barlow1996). To distinguish the influences of guilt and shame on puritanical morality, we encourage future studies to (1) measure both guilt and shame feelings (e.g., Ghorbani et al., Reference Ghorbani, Liao, Çayköylü and Chand2013) and (2) create both guilt and shame conditions, in which guilt and shame are respectively the dominant emotion (e.g., Wagner et al., Reference Wagner, N'Diaye, Ethofer and Vuilleumier2011; Xu et al., Reference Xu, Zhu, Zhang, Zhang, Liang, Mai and Liu2022).

Additionally, we keep an open mind about whether other moral emotions are involved in puritanical morality. For instance, several studies have demonstrated a link between gratitude and self-control (Desteno, Li, Dickens, & Lerner, Reference Desteno, Li, Dickens and Lerner2014; Dickens & DeSteno, Reference Dickens and DeSteno2016). Thorough explorations on the associations between various moral emotions and puritanical morality are needed in the future.

Moral emotions are vital elements of moral apparatus linking moral norms and moral behaviors (Tangney, Stuewig, & Mashek, Reference Tangney, Stuewig and Mashek2007). A moral theory without any concern about emotion is probably incomplete. We propose that moral emotions such as guilt and shame are characteristic emotions underlying puritanical morality, especially within the theoretical framework constructed by Fitouchi et al. We clarify the close associations among moral emotions, puritanical morality, self-control, and cooperation. Our extension contributes to filling in the missing part of Fitouchi et al.'s theory (i.e., the emotional foundation of puritanical morality) and setting a new direction for future research.