3.1.1. Reciprocal and reputation-based cooperation require delaying gratification

Cooperation refers to any behavior that benefits another individual (the recipient), and the evolutionary function of which is, at least in part, to benefit the recipient (West, Griffin, & Gardner, Reference West, Griffin and Gardner2007, Reference West, El Mouden and Gardner2011). Some types of cooperation provide immediate inclusive fitness benefits to the actor. This is the case of kin altruism, whereby the actor automatically increases his indirect fitness (Hamiltron, Reference Hamiltron1964). This is also the case of by-product mutualisms (West, El Mouden, & Gardner, Reference West, El Mouden and Gardner2011), or cooperation for “shared interests” (West, Cooper, Ghoul, & Griffin, Reference West, Cooper, Ghoul and Griffin2021), whereby the actor benefits the recipient as a by-product of pursing his own immediate self-interest (e.g., cooperative hunting in social carnivores; Leimar & Connor, Reference Leimar, Connor and Hammerstein2003; Leimar & Hammerstein, Reference Leimar and Hammerstein2010).

When the actor's and the recipient's immediate interests are not fully aligned, however, cooperation requires the actor to invest an immediate cost (to benefit the recipient), that is rewarded only in the future, by greater benefit-provision (or reduced cost-infliction) from the recipient or third parties – such as through direct reciprocity (Axelrod, Reference Axelrod1984; Trivers, Reference Trivers1971), indirect reciprocity (Nowak & Sigmund, Reference Nowak and Sigmund2005; Panchanathan & Boyd, Reference Panchanathan and Boyd2004), or partner choice (Barclay, Reference Barclay2013; Roberts, Reference Roberts2020). In the iterated Prisoner's Dilemma, for example, reciprocal cooperation yields higher payoff than defection only in the long run, by securing partners' willingness to reciprocate in subsequent rounds – in the immediate present of each round, cheating pays more than cooperating (Axelrod, Reference Axelrod1984; Axelrod & Hamilton, Reference Axelrod and Hamilton1981). Using evolutionary simulations, Roberts (Reference Roberts2020) shows that the same holds for cooperation under reputation-based partner choice: Cooperation is adaptive when the cost of renouncing the immediate benefit of cheating is exceeded, in the long run, by the increased probability of being chosen as a partner in subsequent interactions. In other words, because people selectively associate with trustworthy partners, a good reputation can be understood as a capital that yields future benefits at each time step of the rest of an individual's life. Damaging this capital by exploiting others brings immediate benefits (e.g., more resources, sexual opportunities, less effort), yet deprives oneself of all the benefits that a good reputation could have brought at each later time-point, by attracting others' cooperative investments (Lie-Panis & André, Reference Lie-Panis and André2022).

Accordingly, scholars have widely noted that reciprocal and reputation-based cooperation require delaying gratification: Individuals must renounce the immediate, smaller reward of cheating to secure the future, larger benefits of cooperating (Axelrod, Reference Axelrod2006; Frank, Reference Frank1988; Manrique et al., Reference Manrique, Zeidler, Roberts, Barclay, Walker, Samu and Raihani2021; Roberts, Reference Roberts2020; Stevens et al., Reference Stevens, Cushman and Hauser2005). Lie-Panis and André (Reference Lie-Panis and André2022) develop a formal understanding of this idea. In their model, individuals are characterized by a discount rate, and engage in numerous trust games during their lifetime, with a certain probability of being observed by others, who transmit reputational information impacting future partner choice. At equilibrium in their model, individuals who cooperate are those who are sufficiently future-oriented, that is, who discount the future benefit of having a good reputation in the rest of their life little enough for this benefit to outweigh the immediate cost of cooperation.

3.1.2. Cooperation and self-control at the proximate level

In line with the fact that reciprocal and reputation-based cooperation ultimately require delaying gratification, psychologists have long noted that self-control – the ability to resist temptations of immediate rewards – is likely involved in cooperative decision making (Ainslie, Reference Ainslie2013; Hofmann et al., Reference Hofmann, Meindl, Mooijman and Graham2018; Manrique et al., Reference Manrique, Zeidler, Roberts, Barclay, Walker, Samu and Raihani2021; Stevens et al., Reference Stevens, Cushman and Hauser2005). For example, when faced with an attractive mating opportunity, avoiding cheating one's partner requires resisting temptations of immediate sexual pleasure (see Gailliot & Baumeister, Reference Gailliot and Baumeister2007). By renouncing this immediate reward, one secures the long-term benefit of preserving one's pair-bonding relationship – a particular type of cooperative interaction (Gurven, Winking, Kaplan, von Rueden, & McAllister, Reference Gurven, Winking, Kaplan, von Rueden and McAllister2009) – as well as one's reputation as a trustworthy partner. Meeting obligations to share resources with others, similarly, requires resisting the immediate reward of consuming these resources for oneself (Hofmann et al., Reference Hofmann, Meindl, Mooijman and Graham2018; Sebastián-Enesco & Warneken, Reference Sebastián-Enesco and Warneken2015). By resisting this temptation, one secures the larger, future benefits of ensuring reciprocal help, as well as a good reputation. Similarly, avoiding interpersonal conflicts sometimes requires overriding aggressive impulses (see Barton-Crosby & Hirtenlehner, Reference Barton-Crosby and Hirtenlehner2021); and doing one's part in collaborative work requires renouncing immediate leisure or procrastination. We call (1) “temptations to cheat” these impulses for immediate rewards (e.g., food, sex, rest) that conflict with prosocial obligations, and (2) “moral self-control” the resistance to these temptations to cheat (following Hofmann et al., Reference Hofmann, Meindl, Mooijman and Graham2018).

Converging lines of evidence demonstrate this importance of self-control for a wide range of cooperative behaviors. Performance on a delay-of-gratification task predicts children's propensity to share resources with others, after controlling for age (Sebastián-Enesco & Warneken, Reference Sebastián-Enesco and Warneken2015). Focusing on the future rather than immediate consequences of their behaviors makes participants more likely to share with others (Sjåstad, Reference Sjåstad2019), and less likely to behave unethically (Hershfield, Cohen, & Thompson, Reference Hershfield, Cohen and Thompson2012; van Gelder, Hershfield, & Nordgren, Reference van Gelder, Hershfield and Nordgren2013; Vonasch & Sjåstad, Reference Vonasch and Sjåstad2021). Consistent with a trade-off between the immediate benefit of cheating and its future reputational cost, these associations between cooperation and future-orientation are mediated by reputational concern (Sjåstad, Reference Sjåstad2019; Vonasch & Sjåstad, Reference Vonasch and Sjåstad2021). Disrupting participants' right lateral prefrontal cortex – implied in the self-control of impulses for instant rewards (Kober et al., Reference Kober, Mende-Siedlecki, Kross, Weber, Mischel, Hart and Ochsner2010) – makes participants more likely to cheat in cooperative interactions (Knoch & Fehr, Reference Knoch and Fehr2007; Knoch, Schneider, Schunk, Hohmann, & Fehr, Reference Knoch, Schneider, Schunk, Hohmann and Fehr2009; Ruff, Ugazio, & Fehr, Reference Ruff, Ugazio and Fehr2013; Soutschek, Sauter, & Schubert, Reference Soutschek, Sauter and Schubert2015; Strang et al., Reference Strang, Gross, Schuhmann, Riedl, Weber and Sack2015). Following 1,000 children from birth to age 32, Moffitt et al. (Reference Moffitt, Arseneault, Belsky, Dickson, Hancox, Harrington and Caspi2011) show that children with poor self-control are more likely to be convicted of a criminal offense as adults, after controlling for social class origins and IQ. Meta-analytic evidence confirms that low self-control is associated with criminal behaviors (Vazsonyi, Mikuška, & Kelley, Reference Vazsonyi, Mikuška and Kelley2017), lower propensity to forgive others and refrain from retaliation (Burnette et al., Reference Burnette, Davisson, Finkel, Van Tongeren, Hui and Hoyle2014; Liu & Li, Reference Liu and Li2020), and poorer interpersonal functioning (e.g., loyalty) (de Ridder, Lensvelt-Mulders, Finkenauer, Stok, & Baumeister, Reference de Ridder, Lensvelt-Mulders, Finkenauer, Stok and Baumeister2012). Low self-control predicts greater propensity to deceive others to obtain more benefits (Fan, Ren, Zhang, Xiao, & Zhong, Reference Fan, Ren, Zhang, Xiao and Zhong2020), lower likelihood to keep promises in relationships (Peetz & Kammrath, Reference Peetz and Kammrath2011), as well as uncooperative behaviors in the workplace (e.g., low accommodation of coworkers' needs) (Cohen, Panter, Turan, Morse, & Kim, Reference Cohen, Panter, Turan, Morse and Kim2014; Restubog, Garcia, Wang, & Cheng, Reference Restubog, Garcia, Wang and Cheng2010). Regarding sexual cheating, low conscientiousness – a construct related to self-control (Duckworth & Seligman, Reference Duckworth and Seligman2017) – predicts greater likelihood of infidelity in men and women across 52 countries of 10 world regions (Schmitt, Reference Schmitt2004; see also Pronk, Karremans, & Wigboldus, Reference Pronk, Karremans and Wigboldus2011). And studies suggest that intensity of sexual desire, as well as tendencies to notice attractive alternative partners, predict greater infidelity among people with low, but not high dispositional self-control (Brady, Baker, & Miller, Reference Brady, Baker and Miller2020; McIntyre, Barlow, & Hayward, Reference McIntyre, Barlow and Hayward2015).

Despite this wealth of evidence, the self-control requirement of cooperation has been questioned by results from economic games, where meta-analytic evidence finds no association between self-control and cooperation (Thielmann, Spadaro, & Balliet, Reference Thielmann, Spadaro and Balliet2020). Studies also found that American participants cooperate more when forced to decide quickly than when forced to delay their decision – suggesting that cooperation in economic games, rather than requiring self-control, may be spontaneous and effortless (Rand, Reference Rand2016, Reference Rand2017; Rand, Greene, & Nowak, Reference Rand, Greene and Nowak2012). However, this “intuitive cooperation” effect failed to replicate in several, highly powered replications (Bouwmeester et al., Reference Bouwmeester, Verkoeijen, Aczel, Barbosa, Bègue, Brañas-Garza and Wollbrant2017; Camerer et al., Reference Camerer, Dreber, Holzmeister, Ho, Huber, Johannesson and Wu2018; Fromell, Nosenzo, & Owens, Reference Fromell, Nosenzo and Owens2020; Isler, Yilmaz, & John Maule, Reference Isler, Yilmaz and John Maule2021). Recent evidence indicates that, although cooperating in economic games may be prosocial individuals' spontaneous impulse, the reverse is true for more selfish individuals, in which deliberation increases cooperation – consistent with a role of self-control (Alós-Ferrer & Garagnani, Reference Alós-Ferrer and Garagnani2020; Andrighetto, Capraro, Guido, & Szekely, Reference Andrighetto, Capraro, Guido and Szekely2020; Nockur & Pfattheicher, Reference Nockur and Pfattheicher2021; Yamagishi et al., Reference Yamagishi, Matsumoto, Kiyonari, Takagishi, Li, Kanai and Sakagami2017). As Thielmann et al. (Reference Thielmann, Spadaro and Balliet2020) note, this moderation by prosocial disposition may have obscured the relationship between self-control and cooperation in their meta-analysis of economic games (pp. 62–63). Field experiments also suggest that economic games underestimate the involvement of self-control in real-life cooperative decisions. Studying Brazilian fishermen living from their catch from a common lake, Fehr and Leibbrandt (Reference Fehr and Leibbrandt2011) found that, while impulsivity was not associated with lower cooperation in an economic game, it did predict likelihood to free-ride on the common-pool resource in real life.

3.1.3. People perceive that cooperation requires self-control

Our account of puritanism assumes that people intuitively perceive this self-control requirement of cooperation – a premise that is well supported. Lie-Panis and André (Reference Lie-Panis and André2022) show that, because ability to delay gratification enables higher levels of cooperation, it can evolve into a credible signal of trustworthiness. Psychological evidence confirms that, in interaction with strangers as well as in established relationships, people infer others' self-control from their behavior, and expect individuals they perceive as more self-controlled to behave more cooperatively (Buyukcan-Tetik & Pronk, Reference Buyukcan-Tetik and Pronk2021; Buyukcan-Tetik, Finkenauer, Siersema, Vander Heyden, & Krabbendam, Reference Buyukcan-Tetik, Finkenauer, Siersema, Vander Heyden and Krabbendam2015; Gai & Bhattacharjee, Reference Gai and Bhattacharjee2022; Gomillion, Lamarche, Murray, & Harris, Reference Gomillion, Lamarche, Murray and Harris2014; Koval, VanDellen, Fitzsimons, & Ranby, Reference Koval, VanDellen, Fitzsimons and Ranby2015; Peetz & Kammrath, Reference Peetz and Kammrath2013; Righetti & Finkenauer, Reference Righetti and Finkenauer2011). People's intuitions about a good moral character include traits arguably related to self-control, such as being principled or responsible (Goodwin, Reference Goodwin2015; Goodwin, Piazza, & Rozin, Reference Goodwin, Piazza and Rozin2013). And many societies consider self-control, self-discipline, or self-restraint, as key virtues inherent to a good moral character (e.g., Lybian Bedouins: Abu-Lughod, Reference Abu-Lughod2016, pp. 90–93; Buddhism: Clark, Reference Clark1932, pp. 86–88; Goodman, Reference Goodman and Zalta2017; Confucianism: Csikszentmihalyi, Reference Csikszentmihalyi and Zalta2020; Tiwald, Reference Tiwald and Zalta2020; Sunni Islam: el-Aswad, Reference el-Aswad and Leeming2014; Wolof: Irvine, Reference Irvine1974, pp. 126–127; Zanzibar: Beckmann, Reference Beckmann2010, p. 620; Christianity: Spiegel, Reference Spiegel2020).

3.2.1. Lay theories of modifiers of state-self-control

Some behaviors of the puritanical constellation, we argue, are perceived as altering self-control as a state – that is, the ability to resist temptation in a given moment. We call them “modifiers of state-self-control.”

Intoxicants. A first perceived modifier of state-self-control is intoxicant use. Psychological evidence shows that people widely believe alcohol to cause loss of self-control (Brett, Leavens, Miller, Lombardi, & Leffingwell, Reference Brett, Leavens, Miller, Lombardi and Leffingwell2016; Critchlow, Reference Critchlow1986; Leigh, Reference Leigh1987). Studies similarly suggest that people perceive drug use as enhancing short-term sexual impulses (Quintelier et al., Reference Quintelier, Ishii, Weeden, Kurzban and Braeckman2013). These lay theories likely stem from observation of intoxicants' objective psychological effects. Alcohol actually impairs the inhibition of impulses (Heatherton & Wagner, Reference Heatherton and Wagner2011), narrows attention to cues of immediate rewards – an effect known as “alcohol myopia” (Giancola, Josephs, Parrott, & Duke, Reference Giancola, Josephs, Parrott and Duke2010) – , and fuels a range of impulsive behaviors (e.g., reactive aggression: Duke, Smith, Oberleitner, Westphal, & McKee, Reference Duke, Smith, Oberleitner, Westphal and McKee2018; Gan, Sterzer, Marxen, Zimmermann, & Smolka, Reference Gan, Sterzer, Marxen, Zimmermann and Smolka2015; Parrott & Eckhardt, Reference Parrott and Eckhardt2018; sexual impulsivity: Rehm, Shield, Joharchi, & Shuper, Reference Rehm, Shield, Joharchi and Shuper2012; economic impulsivity: Schilbach, Reference Schilbach2019). Consumption of drugs is similarly associated with impulsivity (Duke et al., Reference Duke, Smith, Oberleitner, Westphal and McKee2018; Nemoto, Iwamoto, Morris, Yokota, & Wada, Reference Nemoto, Iwamoto, Morris, Yokota and Wada2007; Weafer, Mitchell, & de Wit, Reference Weafer, Mitchell and de Wit2014).

The moral disciplining theory thus posits that intoxicants are moralized because they are perceived as favoring uncooperative behaviors, such as aggression, infidelity, and general negligence of obligations, by leading people to lose control over immediate impulses, and fueling disregard of future consequences. This hypothesis contrasts with existing accounts, which ignore cooperative concerns in the moralization of intoxicants, by arguing that their moralization stems from disgust-based concerns for the “purity of the soul” (Clifford et al., Reference Clifford, Iyengar, Cabeza and Sinnott-Armstrong2015; Henderson & Dressler, Reference Henderson and Dressler2019; Horberg et al., Reference Horberg, Oveis, Keltner and Cohen2009; Silver, Reference Silver2020), or from exclusively selfish attempts of monogamous strategists to limit sexual promiscuity specifically (Kurzban et al., Reference Kurzban, Dukes and Weeden2010).

Immodesty as cue exposure. Beside intoxicants, people perceive that self-control is also threatened by exposure to stimuli triggering short-term-oriented impulses – an effect called cue exposure (Heatherton & Wagner, Reference Heatherton and Wagner2011). Animal brains evolved reward systems tracking stimuli contributing to reproductive success (e.g., food items, sexual opportunities). Environmental cues predicting such items' availability in the immediate environment (e.g., sexual cues, appetizing smell) are thus rapidly learned and imbued with “wanting” properties (Duckworth, Gendler, & Gross, Reference Duckworth, Gendler and Gross2016a; Hyman, Reference Hyman2007; Kringelbach & Berridge, Reference Kringelbach and Berridge2009). Exposure to these cues thus generates strong urges to consume the reward in the here and now, pushing individuals toward immediate gratification at the expense of long-term goals (Boswell & Kober, Reference Boswell and Kober2016; Demos, Heatherton, & Kelley, Reference Demos, Heatherton and Kelley2012; Fujita, Reference Fujita2011; Heatherton & Wagner, Reference Heatherton and Wagner2011).

People have a folk-understanding of cue exposure. Early in development, children understand that distracting their attention away from tempting cues (e.g., the marshmallow in front of them) allows them to delay gratification more easily (Carlson & Beck, Reference Carlson, Beck, Winsler, Fernyhough and Montero2001; Mischel & Mischel, Reference Mischel and Mischel1983; Peake, Hebl, & Mischel, Reference Peake, Hebl and Mischel2002). Also witnessing this folk-understanding, people develop “situational” strategies for self-control, rearranging their environment upstream (e.g., by not storing tempting snacks at home) to prevent short-term impulses to be triggered by cue exposure (Duckworth et al., Reference Duckworth, Gendler and Gross2016a; Duckworth, White, Matteucci, Shearer, & Gross, Reference Duckworth, White, Matteucci, Shearer and Gross2016b; Milyavskaya, Saunders, & Inzlicht, Reference Milyavskaya, Saunders and Inzlicht2021). This folk-understanding, we argue, has moral consequences when cue exposure is perceived as endangering, not personal self-control (e.g., resisting sugar to preserve health), but moral self-control (resisting impulses to refrain from cheating).

This allows explaining another part of the puritanical constellation – the condemnation of immodesty. Behaviors condemned as immodest by puritanical standards typically involve emission of stimuli likely perceived as triggering impulses, thus favoring harmful self-control failures. Immodest clothing reveals cues of female fertility or sexual interest, such as body curves, skin, hair, or eyes (Pazhoohi, Reference Pazhoohi2016; Pazhoohi & Hosseinchari, Reference Pazhoohi and Hosseinchari2014). Exposure to these cues is known to alter males' state-self-control, by triggering their reward systems and sexual appetite (Platek & Singh, Reference Platek and Singh2010; Spicer & Platek, Reference Spicer and Platek2010; Symons, Reference Symons, Ambramson and Pinkerton1995), and increasing their preference for immediate over delayed rewards (Kim & Zauberman, Reference Kim and Zauberman2013; Wilson & Daly, Reference Wilson and Daly2004). Studies also suggest that exposure to sexual cues increases males' propensity to engage in manipulative and coercive behaviors to obtain sexual gratification – and thus to facilitate, not only self-control failures in general, but also moral self-control failures (Ariely & Loewenstein, Reference Ariely and Loewenstein2006).

Prescriptions of modesty, we thus argue, are another strategy – besides prohibition of intoxicants – for preventing self-control failures with socially harmful effects. Immodest clothing and behaviors are moralized because, by increasing cue exposure, they are seen as increasing the probability that people – especially males – lose control over impulses, thereby favoring antisocial behaviors such as sexual aggression, conflicts, adultery, or premarital sex.Footnote ³ Just as people remove tempting snacks from their environment when feeling unable to resist them, societies can deem mutually beneficial, when fearing the fragility of their members' self-control (see sect. 5), to remove tempting stimuli from their environment to prevent uncooperative behaviors.

This hypothesis contrasts with existing accounts of modesty norms, which mainly regard them as selfish attempts of males to guard their mates (Dickemann, Reference Dickemann, Alexander and Tinkle1981; Pazhoohi et al., Reference Pazhoohi, Lang, Xygalatas and Grammer2017a). Although males' mate-guarding interests likely contribute to these norms' attractiveness, we propose that moralization of modesty also emerge from more widely shared concern for the general social harm (e.g., conflicts, aggressions, infidelity) that may result from failures to control sexual impulses.

3.2.2. Lay theories of modifiers of trait-self-control

Other behaviors of the puritanical constellation, we argue, are perceived as altering self-control as a trait – that is, as the stable psychological disposition to resist temptations across situations. We term them “modifiers of trait-self-control.”

Immoderate indulgence in bodily pleasures. Moralizations of victimless bodily pleasures, we argue, stem from perceptions that excessively or too frequently indulging in bodily pleasures would decrease trait-self-control. Such beliefs may be grounded in experience: The bodily pleasures typically condemned by puritanical standards generate common addictions, such as food addictions (Volkow, Wang, & Baler, Reference Volkow, Wang and Baler2011, Reference Volkow, Wise and Baler2017), sexual addictions (Farré et al., Reference Farré, Fernández-Aranda, Granero, Aragay, Mallorquí-Bague, Ferrer and Jiménez-Murcia2015; Karila et al., Reference Karila, Wery, Weinstein, Cottencin, Petit, Reynaud and Billieux2014), alcohol addictions (Vengeliene, Bilbao, Molander, & Spanagel, Reference Vengeliene, Bilbao, Molander and Spanagel2008), drug addictions (Baler & Volkow, Reference Baler and Volkow2007), or gambling disorders (Farré et al., Reference Farré, Fernández-Aranda, Granero, Aragay, Mallorquí-Bague, Ferrer and Jiménez-Murcia2015) – addiction being widely viewed as a disruption of self-control (Baler & Volkow, Reference Baler and Volkow2007; see also Vonasch, Clark, Lau, Vohs, & Baumeister, Reference Vonasch, Clark, Lau, Vohs and Baumeister2017). Researchers have long noted the potent reinforcement learning associated with consumption of bodily pleasures or intoxicants. Past experience with such a reward (e.g., energy-rich food) increases the motivational drive (“wanting”) elicited by future exposure to it, making harder the future self-control of the associated impulse (e.g., food craving; Baler & Volkow, Reference Baler and Volkow2007; Story, Vlaev, Seymour, Darzi, & Dolan, Reference Story, Vlaev, Seymour, Darzi and Dolan2014; Volkow, Wise, & Baler, Reference Volkow, Wise and Baler2017).

Accordingly, a widespread belief seems to be that the more one indulges in bodily pleasures, the more their temptations become hard to resist. A significant share of people believes that pornography (Grubbs, Grant, & Engelman, Reference Grubbs, Grant and Engelman2018a; Grubbs, Kraus, & Perry, Reference Grubbs, Kraus and Perry2019), fatty and sugary foods (Ruddock & Hardman, Reference Ruddock and Hardman2017), and intoxicants (Edelstein et al., Reference Edelstein, Wacht, Grinstein-Cohen, Reznik, Pruginin and Isralowitz2020; El Khoury, Noufi, Ahmad, Akl, & El Hayek, Reference El Khoury, Noufi, Ahmad, Akl and El Hayek2019) can be addictive – and people likely associate addiction with loss of self-control (see Vonasch et al., Reference Vonasch, Clark, Lau, Vohs and Baumeister2017). In vignette studies, we found that participants judged individuals increasing their indulgence in bodily pleasures over several months (e.g., pornography, alcohol, fatty and sugary foods) as altering their trait-self-control as a result of this lifestyle change (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022). Surveying religious attitudes toward pleasure, Glucklich (Reference Glucklich2020, pp. 13–27) concludes that the addictive character of food, sex, alcohol, or gambling, is a major concern across world religions. Reviewing attitudes toward sex in European history, Dabhoiwala (Reference Dabhoiwala2012) highlights that “It was a Christian commonplace that anyone who succumbed to this impure appetite [lust], even just once, risked developing a fatal addiction to it” (p. 33). In Hinduism, similarly, “Ancient Indian texts often call the four major addictions that kings were vulnerable to ‘the vices of lust,’ sometimes naming them after the activities themselves – gambling, drinking, fornicating, hunting” (Doniger, Reference Doniger2014, p. 365). Table 1 summarizes selected cases of such folk-psychological beliefs in various cultural contexts.

Table 1. Examples of folk-psychological beliefs about modifiers of trait-self-control

If people perceive that cooperation requires self-control (sect. 3.1.3), and that overindulgence in bodily pleasures reduces self-control, they may moralize bodily pleasures as indirectly facilitating uncooperative behaviors. For example, if indulgence in sexual pleasure in victimless situations (e.g., masturbation, frequent sex within marriage), is perceived as making people addict to sex, it becomes responsible for impeding the control of sexual urges in cooperative situations as well, where these impulses are socially harmful (e.g., when resisting them is necessary to avoid adultery). If victimless gluttony is perceived as making people addict to food, it becomes responsible for fueling uncontrollable urges which, in other situations, will prove socially harmful (e.g., when resisting food cravings is necessary to respect others' property). Repeated indulgence in bodily pleasures may be perceived, more generally, as decreasing self-control across domains, thus decreasing people's cooperativeness in general. This would be consistent with the lay theory we discuss next: That repeatedly practicing self-control would train self-control.

Self-control training, daily self-discipline, and ritual observance. Another recurrent lay theory seems to be that self-control can be trained by repeated practice – although the objective efficacy of such training is scientifically debated (Berkman, Reference Berkman, Vohs and Baumeister2016; Friese, Frankenbach, Job, & Loschelder, Reference Friese, Frankenbach, Job and Loschelder2017; Miles et al., Reference Miles, Sheeran, Baird, Macdonald, Webb and Harris2016). Field experiments on parents suggest a widespread belief that children's self-control can be improved, associated with self-control-training practices, such as giving children unhealthy snacks less often, or bringing them less frequently to fast-food restaurants (Mukhopadhyay & Yeung, Reference Mukhopadhyay and Yeung2010). In vignette studies, participants judged that sustained self-discipline over several months (e.g., exercising regularly, reducing indulgence in bodily pleasures) would likely improve a target's trait-self-control (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022). This is consistent with cross-culturally recurrent beliefs that investment in ascetic practices or effortful activities allow to “build character” and improve people's self-control (see Table 1).

If people perceive both that cooperation requires self-control (Righetti & Finkenauer, Reference Righetti and Finkenauer2011), and that regular self-discipline trains self-control, they may moralize effortful activities (e.g., waking up early, spiritual disciplines, needless hard work), as means to “build character” – that is, to improve the self-control required to honor prosocial obligations. This helps explaining another component of the puritanical constellation: The moralization of constant self-discipline, needless hard work, and unproductive effort, even when the latter are devoid of direct benefits to other people (Celniker et al., Reference Celniker, Gregory, Koo, Piff, Ditto and Shariff2023; Tierney et al., Reference Tierney, Hardy, Ebersole, Viganola, Clemente, Gordon and Uhlmann2021).

This also allows explaining the moralization of pious ritual observance. Indeed, psychologists have extensively argued that rituals of world religions, such as fasting, meditation, regular prayer, or effortful pilgrimages, appear specifically geared toward training self-control (Geyer & Baumeister, Reference Geyer, Baumeister, Paloutzian and Park2005; Koole, Meijer, & Remmers, Reference Koole, Meijer and Remmers2017; McCullough & Carter, Reference McCullough and Carter2013; McCullough & Willoughby, Reference McCullough and Willoughby2009; Tian et al., Reference Tian, Schroeder, Häubl, Risen, Norton and Gino2018; Wood, Reference Wood2017). These rituals require sustained restrictions of bodily desires (e.g., fasting), commitment to regular practice (e.g., praying five times a day, at fixed hours), cognitive effort (e.g., reading and memorizing the scriptures), and repeated inhibition of spontaneous tendencies (McCullough & Willoughby, Reference McCullough and Willoughby2009). We argue that these activities, as the rest of the puritanical constellation, are ascribed a moral disciplining function: Cultivating the self-control perceived necessary to honor prosocial obligations. This allows explaining why moralizations of diligent ritual observance cluster with other puritanical values (sect. 1.1) – so that “piety” is commonly listed, alongside temperance and restraint from bodily pleasures, among the core virtues of the “purity” morality (Graham et al., Reference Graham, Haidt, Koleva, Motyl, Iyer, Wojcik and Ditto2013; Haidt, Reference Haidt2012; Haidt & Joseph, Reference Haidt and Joseph2007).

4.1.1. Moralizations of bodily pleasures should be most robustly associated with perceptions that they facilitate social harm

As a cooperation-based theory of puritanism, MDT predicts that moralizations of victimless bodily pleasures, and lack of self-discipline, should be most robustly associated with the perception that they facilitate uncooperative behaviors and cause social harm. In line with this idea, Schein et al. (Reference Schein, Ritter and Gray2016) show that moralizations of sexual indulgences (e.g., oral sex) are most strongly associated with perceptions that these behaviors are “dangerous” or “harmful.” Associations between disgust (or disgust-sensitivity) and moralizations of sexual indulgences disappear when perceptions of harm are controlled for (Schein et al., Reference Schein, Ritter and Gray2016; see also Gray et al., Reference Gray, Schein and Ward2014; Gray & Schein, Reference Gray and Schein2016). In the General Social Survey, support for legal restrictions of pornography is associated with the belief that “sexual material lead people to commit rape” (Sherkat & Ellison, Reference Sherkat and Ellison1997). In two vignette studies (N > 1,100), we presented participants with a target led to increase their indulgence in bodily pleasures, such as gluttony and masturbation (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022). Participants judged that, as a result of this lifestyle change, the target had likely become more prone to uncooperative behaviors, such as refusing to help a friend, free-riding on colleagues' work, and cheating his partner if he had the chance (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022). The more participants perceived that bodily pleasures would decrease the target's cooperativeness, the more they morally condemned victimless indulgence in those pleasures (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022).

At a more general level, MDT predicts that moralizations of victimless excesses should relate to cooperation-based moral concerns. By contrast, moral foundations theory (MFT) argues that moralizations of self-discipline are part of disgust-based concerns unrelated to cooperation. Thus, as per MFT, condemnations of victimless excesses should relate more strongly to “purity” concerns – putatively independent of cooperation – than to other moral concerns unambiguously related to cooperation (e.g., loyalty). Across four studies using the Moral Foundations Questionnaire (N > 3,000), participants' tendency to moralize victimless excesses (e.g., snacking on junk food, getting high on drugs, failing to exercise) is predicted not only by concerns for “purity” – which MFT assumes to be independent of cooperation – , but also, and to a similar extent, by moral concerns uncontroversially related to cooperation, such as loyalty/betrayal, and authority/respect (Mooijman et al., Reference Mooijman, Meindl, Oyserman, Monterosso, Dehghani, Doris and Graham2018). This suggests that self-discipline is moralized because it is seen as necessary to ensure within-group cooperation and social order.

These findings are consistent with historical evidence. Historians and social scientists have argued that puritanical moral campaigns of early modern Europe – variously labeled “disciplinary revolutions” (Gorski, Reference Gorski1993, Reference Gorski2003), “social disciplining” (Oestreich et al., Reference Oestreich, Oestreich and Koenigsberger1982), “civilizing offensives” (Eisner, Reference Eisner2014; Powell, Reference Powell2013), or “reform of popular culture” (Burke, Reference Burke1978) – condemned undisciplined indulgence in bodily pleasures to “foster forms of socialization that would promote cooperation and harmony and result in a well-disciplined and well-ordered society” (Martin, Reference Martin2009, p. 9; see also Burke, Reference Burke1978; Eisner, Reference Eisner2014; McIntosh, Reference McIntosh2002). Similarly, ancient ascetic spiritualities (e.g., Late Stoicism, Platonism, early Christianity, Pythagoreanism), prescribed an “overall habituation to temperance” with the explicit aim to prevent bodily appetites to fuel antisocial behaviors (Gaca, Reference Gaca2003). As Platonism contended, for example,

4.1.2. The more people perceive bodily pleasures as altering self-control, the more they should moralize bodily pleasures

MDT posits that people perceive bodily pleasures as degrading cooperativeness because they perceive bodily pleasures as degrading self-control, for example because of their addictive character. Thus, the more people perceive victimless bodily pleasures as addictive, or as altering self-control more generally, the more they should moralize bodily pleasures. In line with this idea, studies consistently find that the moralization of pornography is associated with the perception that it is addictive for the self (Grubbs et al., Reference Grubbs, Exline, Pargament, Hook and Carlisle2015, Reference Grubbs, Grant and Engelman2018a; Grubbs, Wilt, Exline, Pargament, & Kraus, Reference Grubbs, Wilt, Exline, Pargament and Kraus2018b). The perception that pornography is addictive is also more prevalent among religious people (Droubay & Butters, Reference Droubay and Butters2020), who are known to moralize pornography more strongly (Droubay, Butters, & Shafer, Reference Droubay, Butters and Shafer2021; Grubbs et al., Reference Grubbs, Exline, Pargament, Hook and Carlisle2015). In vignette studies, the more participants perceive indulgence in gluttony, masturbation, and harmless laziness, as reducing an individual's self-control, the more they morally condemn victimless indulgence in those pleasures (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022).

4.1.3. The perception that bodily pleasures alter self-control should mediate the perception that they affect cooperation

Experimental evidence suggests that the perceived effect of bodily pleasures on self-control mediates their perceived effect on cooperativeness. In the above-mentioned studies, the effect of indulgence (vs. restraint) on a target's perceived change in cooperativeness was 100% mediated by the perceived deleterious effect of indulgence (vs. restraint) on the target's self-control (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022). In other words, participants perceived indulgence in bodily pleasures, as opposed to restraint, as increasing an individual's propensity to uncooperative behaviors almost exactly to the extent that they perceived indulgence (vs. restraint) as altering this individual's self-control.

This converges with experimental evidence on the moralization of gluttony. People regularly indulging in fatty and sugary foods (e.g., hamburgers, donuts), compared to people with healthy diets, are seen not only as less moral and less trustworthy (Mankar, Joshi, Belsare, Jog, & Watve, Reference Mankar, Joshi, Belsare, Jog and Watve2008; Merritt, Reference Merritt2013; Oakes & Slotterback, Reference Oakes and Slotterback2004; Steim & Nemeroff, Reference Steim and Nemeroff1995), but also as less self-controlled (Gerrits, de Ridder, de Wit, & Kuijer, Reference Gerrits, de Ridder, de Wit and Kuijer2009; Merritt, Reference Merritt2013; Puhl & Heuer, Reference Puhl and Heuer2010; Steim & Nemeroff, Reference Steim and Nemeroff1995). Experimental evidence indicates that these perceptions of lower self-control mediate the relationship between indulgent (vs. restrained) diet and perceived lower morality and trustworthiness (Fitouchi et al., Reference Fitouchi, André, Baumard and Nettle2022; Merritt, Reference Merritt2013; Steim & Nemeroff, Reference Steim and Nemeroff1995) – more so than other mediators such as a health-related concern or a general halo effect (Steim & Nemeroff, Reference Steim and Nemeroff1995).

These results converge with historical and ethnographic evidence that, in various cultural contexts, overindulgence in food or sex is condemned as causing uncooperative behaviors through the erosion of self-control. Scholars have argued that moral panics over masturbation in Victorian England emerged from the fear that excessive sexual activity “could, and probably would, lead to habits of indulgence in sensual pleasure and thus cause the erosion of self-control” (Hunt, Reference Hunt1998, p. 589; Seidman, Reference Seidman1990). Masturbation, or too frequent marital sexuality, were denounced as

In Muslim Zanzibar, “once tried out, sex is said to dominate a person's thoughts with ever-increasing desire and to make it difficult to refrain from behavior that is classified as immoral, including disrespect of the elders or drug and alcohol abuse” (Beckmann, Reference Beckmann2010, p. 622). In North India, excessive indulgence in sweets is perceived to develop an impulsive character trait, leading to commit antisocial behaviors, “like cheating, stealing and selling daughter” (Vatuk & Vatuk, Reference Vatuk and Vatuk1967, p. 111). As ethnographers report:

In the Amhara peasants (Ethiopia), “there is also the fear that if one indulges in eating and drinking he may become uncontrollably hostile” (Levine, Reference Levine1965, p. 223), because “eating and drinking to full satiation, and maintaining this state over time, makes one thankless, arrogant, unmindful of law and custom, and dangerously impulsive” (Reminick, Reference Reminick1975, p. 29). Surveys of moral attitudes toward food since European antiquity conclude that “[t]he heart of the problem it seems is that food pleasure challenges self-control” (Coveney, Reference Coveney2006, p. xii; Hill, Reference Hill2011). In medieval Christianity, excessive food pleasure – alongside other deadly sins – “represent devilish temptations that challenge the Christian to develop and practice discretion and self-control” (Hill, Reference Hill2011, p. 135). By weakening the will, gluttony “turns humans into dishonest animals, destined for hell” (Hill, Reference Hill2007, p. 68). By seeking “delicious viands,” a man can “do good to fewer others and cannot withhold himself so that he may help a poor man, or two, or more” (Hill, Reference Hill2007, p. 68). As Doniger (Reference Doniger2014) highlights, similar rationales for abstaining from meat recur in Hindu texts: “flesh heats the passions and is, therefore, dangerous for the ideal Hindu person, who is always in control of his emotions” (p. 415).

4.4.1. The more people perceive male self-control as vulnerable to cue exposure, the more they should moralize immodesty

If immodesty is moralized as a risk factor for harmful self-control failures, it should be all the more condemned that people perceive surrounding males as unable to resist sexual urges in the face of cue exposure. Indeed, if males are believed able to remain peaceful and self-controlled even when exposed to tempting cues, immodesty should lose its (perceived) potential to generate social harm, and should therefore not be condemned. In line with this prediction, Moon et al. (Reference Moon, Wongsomboon and Sevi2021) show that the more people stereotype men as unable to control their sexual urges, the more they moralize female immodest clothing and other cue-exposing behaviors (e.g., public breastfeeding). This effect does not generalize to phenomena unrelated to cue exposure, and holds after controlling for participants' reproductive strategy and other potential confounds (e.g., religiosity, conservatism, benevolent or hostile sexism). This suggests that, although inherently harmless, immodesty is moralized because of its perceived potential implications on male moral self-control (Moon et al., Reference Moon, Wongsomboon and Sevi2021).

4.4.2. Modesty norms should be well designed to prevent cue exposure specifically

Second, modesty norms should specifically target behaviors increasing cue exposure. This seems to be the case. Eye-tracking experiments show that Islamic clothing decreases visual access to female body curves (Pazhoohi, Macedo, & Arantes, Reference Pazhoohi, Macedo and Arantes2017b), and accordingly decrease males' rating of female attractiveness (Mahmud & Swami, Reference Mahmud and Swami2009; Pazhoohi & Hosseinchari, Reference Pazhoohi and Hosseinchari2014; Sheen, Yekani, & Jordan, Reference Sheen, Yekani and Jordan2018). Modest clothing across puritanical traditions specifically hide such sexually arousing stimuli (e.g., Puritans’ austere clothing: Bremer, Reference Bremer2009; Islamic veiling: Mernissi, Reference Mernissi2011; Jewish Tznihut dress: Andrews, Reference Andrews2010; Hindu India: Stephens, Reference Stephens1972, p. 4; ancient Christian veiling: Tariq, Reference Tariq2014). Psychological evidence indicates that immodesty is more negatively viewed in public – that is, when its cue-exposing effects are amplified (Acker, Reference Acker2009). The Quran also specifies that elderly women, deemed less attractive, can go unveiled (Mernissi, Reference Mernissi2011), and studies of rural Muslim villages report that demands of modesty apply less strongly to elderly women (Antoun, Reference Antoun1968, p. 683; Belghiti, Reference Belghiti1969).

Music and dance, similarly, are often condemned as exposing people to auditory and visual stimuli impeding self-control, thus making antisocial behaviors more likely. Islamic warning against the dangers of music insist on its self-control-impeding effects: “music as an activity is about exciting pleasures that make humans slaves to unruly passions” (Kiyimba, Reference Kiyimba, Nannyonga-Tamusuza and Solomon2012, pp. 93–94); and compare music's psychological effects to those of alcohol: “avoid singing for it decreases shame, increases desire…and verily it takes the place of wine and does what drunkenness does” (Otterbeck & Ackfeldt, Reference Otterbeck and Ackfeldt2012, p. 232). Christian oppositions to dancing often specifically targeted the “mixed” dancing of men and women, exposing people to sexual cues and “lascivious” bodily movements (Wagner, Reference Wagner1997). In early China, Confucius condemned the “immoral, seductive popular music of Zheng,” which “was sung by mixed groups of men and women, and gave rise to sexual improprieties” (Slingerland, Reference Slingerland2014, p. 76). In early modern Europe, “plays, songs and, above all, dances were condemned for awakening dangerous emotions and as incitement to fornication” (Burke, Reference Burke1978, p. 212), whereas festivals were denounced as “occasions of violence” (Burke, Reference Burke1978, p. 212). Tellingly, the very same entertainment – music – can become morally praised when it takes the form of a disciplined, effortful, and patient activity perceived as cultivating people's self-control rather than impeding it, thus facilitating prosociality. For example, although he condemned arousing popular music, Confucius prescribed classical musical performance, precisely because the latter “place[s] limits on appetitive desires” and thus “promote[s] unselfishness…and prepare[s] people to behave morally in different domains of their life” (Csikszentmihalyi, Reference Csikszentmihalyi and Zalta2020, pp. 7, 5).

6.1.1. Hygiene norms

Moral psychologists often define purity as condemning not only bodily pleasures and undisciplined lifestyles, but also dirty and unclean behaviors (Graham et al., Reference Graham, Haidt, Koleva, Motyl, Iyer, Wojcik and Ditto2013; Gray et al., Reference Gray, DiMaggio, Schein and Kachanoff2022; Kollareth et al., Reference Kollareth, Brownell, Duran and Russell2022). Moral prescriptions of hygiene may seem, in line with moral foundations theory (Graham et al., Reference Graham, Haidt, Koleva, Motyl, Iyer, Wojcik and Ditto2013), straightforwardly related to disgust and pathogen-avoidance. Yet recent evidence suggests the fecundity of the moral disciplining framework to explain even this part of purity concerns. In almost 20,000 participants across 56 countries, the restrictiveness of hygiene norms (e.g., against spitting, for handwashing) is more strongly and robustly predicted by the valorization of self-control than by perceived pathogen threat and historical pathogen prevalence – whose effect on the main factor of hygiene norms disappears when self-control values are controlled for (Eriksson, Dickins, & Strimling, Reference Eriksson, Dickins and Strimling2021). This suggests that not only ascetic restraint, but also the conscientious observance of hygienic practices, may be moralized as an exercise of self-discipline.

6.1.2. “Impure thoughts” and the moralization of mental intimacy

Puritanical traditions can go as far as moralizing, not only victimless behaviors and private lifestyles, but also the very mental states individuals experience, such as the “impure” thoughts and desires they may entertain. In psychological experiments, Christians and Protestant participants judge some mental states (e.g., adulterous desire) to be as immoral as the behaviors that could follow them (Cohen, Reference Cohen2003; Cohen & Rozin, Reference Cohen and Rozin2001; Siev & Cohen, Reference Siev and Cohen2007). Early Church fathers (e.g., Paul, Matthew) insisted that a man looking with desire at a woman already commits adultery “in his heart” (Gaca, Reference Gaca2003, pp. 152–153). From the thirteenth century onward, Christians were obligated to confess not only their immoral actions but also their sinful thoughts (Tentler, Reference Tentler2015). In the Muslim tradition, the condemnation of zina (unlawful, non-marital sex) also extends to mental states such as looking at the body curves of a woman (“zina of the eye”) or hearing an unrelated woman's voice (“zina of the ear”) (Bouhdiba, Reference Bouhdiba2012, pp. 38–39; see also Rabbinic Judaism: Hezser, Reference Hezser2018, pp. 15–16).

The moral disciplining account helps explain this phenomenon as a special case of prevention of harmful self-control failures. Picturing oneself enjoying a reward, for example in adulterous or violent thoughts, may be perceived as triggering urges to consume this reward (e.g., sexual pleasure), making people more likely to succumb harmful temptations (e.g., adultery, assault). As written in the most popular Christian devotional book (The Imitation of Christ, fifteenth century), “first there comes into the mind an evil thought: next, a [vivid] picture: then delight, and urge to evil” (Tentler, Reference Tentler2015, p. 156). According to our account, although inherently harmless, mental states and desires are moralized when perceived as critically increasing the probability of harmful self-control failures.

In line with this idea, the puritanical moralization of mental states is often associated with prescriptions of “intra-psychic” self-control techniques (see Duckworth et al., Reference Duckworth, Gendler and Gross2016a, Reference Duckworth, White, Matteucci, Shearer and Gross2016b), aimed at detecting the birth of impulses in one's consciousness to facilitate their self-control. For example, historians have noted that “[i]t was characteristic of puritans to subject themselves to intense self-examination” (Bremer, Reference Bremer2009, p. 38). By meditating frequently, and recording his impulses in moral diaries (Bremer, Reference Bremer2009; Gorski, Reference Gorski1993, Reference Gorski2003), the individual “was to reflect on the sins he was especially prone to commit so that he might guard against those urges” (Bremer, Reference Bremer2009, p. 55). In the Christian tradition more generally, meditation has been construed as a self-control technique that “kills temptation at the root, by producing a mental ‘soil’ that will not sustain the development of illicit desires that lead to vice” (Spiegel, Reference Spiegel2020, p. 12). Neo-Confucian traditions under China's Song, Yuan, and Ming dynasties (tenth to seventeenth centuries) similarly adopted and adapted techniques of meditation used to “detect and undercut selfish inclinations and desires” (Tiwald, Reference Tiwald and Zalta2020). In line with these cases, psychological evidence suggests that the tendency to attribute to others the ability to internally control their mental states and impulses predicts the propensity to moralize mental states (Weiss, Forstmann, & Burgmer, Reference Weiss, Forstmann and Burgmer2021).