R4.1. Reiterating the centrality of fair public goods provision

Our account of the coalitional choice mechanisms underlying the cognitive appeal of national categories addresses the point, raised by many commentators, that historical myths are not the only cultural technology that can be used for nation-building purposes. For instance, Wimmer noted that historical narratives have been used in a wide diversity of formats across social contexts, like “imperial stories of superior civilizational origins” that do not necessarily fit our definition of historical myths. Likewise, Akers emphasized the diversity of societal “meta-narratives” that structure group identities across the world but do not match with our description of historical myths: “meta-narratives” often emphasize the nation's shared beliefs (religious or secular) and shared goals, while our target article only addressed the rhetoric of shared roots. This focus makes it difficult to account for the varieties of nationalism that are not based on the belief in a shared ancestral history – like American nationalism.

We certainly agree that our target article is nowhere near explaining every aspect of nationalistic rhetoric. There are probably dozens of cultural technologies involved in the formation of national categories. In fact, this idea is consistent with our account of coalitional choice psychology: group commitment is the product of a flexible psychological mechanism which assesses the fitness benefits associated with membership in different coalitional arrangements. As such, any input can fuel national affiliation to the extent that it provides information about its associated fitness benefits. For this reason, we actually expect nationalists to invest in a wide range of cultural technologies beyond historical myths to attract coalitional support. In particular, we certainly expect that they will mobilize information about the present and future of the coalition. For instance, commentators have proposed that coalitional recruiters might advertise the nation's “cooperative prowess” in achieving coordination in the present (Wolf); shared goals and beliefs (Akers); the moral virtue of national heroes (Wildes & Andrews); or the magnitude of external threats (Pietraszwski; Snijder & De Dreu). In our target article, we also noted the existence of political uses of history beyond the scope of historical myths as we defined them and which probably play a substantial role in collective actions – for instance, raising awareness about historical grievances of marginalized groups (see sect. 2).

We also recognize that some of these cultural inputs should be significantly more psychologically compelling than historical myths in their capacity to alter coalitional preferences. In particular, a consistent finding in political science is that one of the most important drivers of national affiliation is the fair provision of public goods – or at least the perception thereof (Wimmer, Reference Wimmer2018). In light of this finding, we certainly agree with Friedman that nationalists aiming to recruit coalitional support should primarily emphasize the quality and fairness of resource distributions across social groups – both in the present and in the past. And they certainly do: as historians have shown, one of the most consistent ideological tenets of nationalism is the belief in a horizontal comradeship between all group members – a rhetoric that is often produced with an aim to conceal domination and inequality (Anderson, Reference Anderson1991).

There is, however, one caveat to the claim that nationalists should advertise egalitarian access to public goods in their coalition – at least if “public goods” are understood in a purely economic sense. Indeed, as shown by Sarkar and Sarkar based on the Indian example, low-status individuals sometimes endorse nationalism even when the nation is highly unequal – presumably to their detriment (see Shayo, Reference Shayo2009). From an evolutionary perspective, this is not necessarily a paradox: individuals might still favor a coalitional arrangement in which they receive less strictly economic benefits if this loss is compensated with non-economic benefits to their fitness. In their commentary, Sarkar and Sarkar emphasize status and protection from (perceived) out-group threats as such non-economic benefits, and argue that this is what motivates low-status Hindus to tolerate high degrees of within-coalition inequality. This explanation is certainly plausible: low-status individuals might endorse an unequal coalitional arrangement if they perceive that they receive status gains and protection in exchange (Klor & Shayo, Reference Klor and Shayo2010). Interestingly, historical myths themselves might serve a similar purpose: not by providing status and protection but information about coalitional productivity. In advertising their coalition as especially productive and difficult to replace, recruiters might aim to convince low-status members that their subaltern social position is compensated by the added efficiency.

Overall, we easily recognize that historical myths activating perceived fitness interdependence through cues of repeated interaction over time are not the sole element with the potential to generate affiliation with large groups. Cultural evolutionary processes can generate a variety of technologies to achieve the same objectives while targeting the same human minds. For instance, fictions with imaginary worlds target specific cognitive mechanisms which explain why they have recurrent design features – yet they exist in an impressive variety of formats (Dubourg & Baumard, Reference Dubourg and Baumard2022). Likewise, the cultural technologies for nation-building that become prevalent in a given context might vary to some extent with ecological and cultural constraints: for instance, as suggested by Wimmer and Akers, historical myths might be more prevalent in countries that have an ancient history that they can exploit, but less so in countries like the United States, where European-Americans could not rely on ancient historical material.

What we do argue however is that historical myths are cross-culturally recurrent, and most importantly, that they are especially puzzling. The combination of these two factors is how we justify the focus of our main article. It is unsurprising that nationalists emphasize the present and future benefits that can be derived from national commitment; or that social movements use history to highlight historical grievances; but it is puzzling that nationalists care so much about their nation being ancestral and continuous (see sect. 2 for a discussion of this point).

R5.1. Proximate mechanisms add interesting descriptive layers, but do not necessarily improve explanatory power

The coalitional choice psychology framework can also address concerns regarding the relationship between the ultimate logic of group affiliation and its proximal manifestations. Indeed, several commentaries proposed alternative of complementary accounts to our theory of historical myths by emphasizing proximal mechanisms. We recognize that our target article was focused on the ultimate logic and cognitive mechanisms driving the cultural evolution of historical myths while leaving out important proximal mechanisms at play.

Generally, we agreed with the authors who proposed proximal complements to our theory. Some of them discussed possible phylogenetic pathways that might have contributed to the human ability to produce historical myths. Benitez-Burraco stressed the decisive role of the human ability for language and storytelling in the evolution of large-scale cooperation and proposed two evolutionary pathways to account for it. Similarly, Maryanski and Turner suggested that “Machiavellian” social manipulation – similar to coalitional recruitment in humans – is found in chimpanzees, suggesting that this trait might date back to early hominoid ancestors. Both accounts are plausible, although more research is needed to establish these hypotheses. Other commentators focused on psychological proximal accounts: Kaufman, Kashdan and McKnight and Kardos suggest that the appeal of historical myths stems from psychological needs (e.g., for meaning, belonging, continuity, or entitativity). Drawing on Social Identity Theory, Kardos links these needs to social identification, which ultimately fosters within-group cooperation. Similarly, Pelletier and Fay, Wildes and Andrews and Oatley and Wu insist that historical myths do not merely provide information about the fitness interdependence of group members, but also elicit emotions or “affective states” that also play an important role in nationalist rhetoric. In particular, Pyszczynski, Solomon and Grenberg stress the role of death anxiety in motivating social identity. We certainly acknowledge the fundamental role of psychological needs and emotions on decision-making, especially when it comes to group affiliation.

Finally, we agree with Elster and Glowacki that historical myths activate cues of self-concept and thus help group members represent their group as a “quasi-coherent self with distinct characteristics, goals and desires.” As suggested by these authors, representing social groups in this way is likely beneficial and might serve as a basis for more complex computations (e.g., representing stereotypes, group “goals” or “desires,” see Tooby et al., Reference Tooby, Cosmides and Price2006). It is less clear, however, how representing the group as a coherent entity leads specifically to coalitional preferences. The authors propose that this is because the perception of a coherent group-self might increase individuals' interest in group-level benefits but this causal mechanism is underspecified. One possible answer is that the perception of a coherent group-self actually reflects perceived fitness interdependence between group members – which is why it motivates coalitional affiliation. More research is needed to test this hypothesis.

Overall, while we agree that these accounts add interesting layers to our theory, it is unclear whether they alter the main predictions of our model. Proximate mechanisms are certainly indispensable for evolutionary theories, but only to the extent that they yield novel predictions that would not be expected by sole reliance on the theoretical tools of evolutionary biology – the “phenotypic gambit” of human behavioral ecologists (Nettle, Gibson, Lawson, & Sear, Reference Nettle, Gibson, Lawson and Sear2013). For instance, evolutionary psychologists are interested in the evolved cognition of humans because it can explain why humans sometimes engage in maladaptive behaviors in industrial environments (Li, Van Vugt, & Colarelli, Reference Li, Van Vugt and Colarelli2018). Similarly, considering phylogenetic or neurobiological constraints can explain why apparently sub-optimal traits evolve (Nettle et al., Reference Nettle, Gibson, Lawson and Sear2013). In our case, the contribution of proximal accounts beyond the cognitive processes we describe in the main article is less clear. More research is needed to investigate whether the study of storytelling capacities (Benitez-Burraco), emotions (Pelletier & Fay, Wildes & Andrews, Oatley & Wu) or psychological needs (e.g., Kaufman, Kashdan & McKnight, Kardos) can make new predictions about the cultural success of historical myths.

R5.2. Proximate accounts are not alternatives to ultimate accounts

Conversely, we disagree with commentaries that presented proximal accounts as alternatives to our ultimate model (e.g., Kardos). Most of the proximal mechanisms cited in the commentaries are not alternatives to our account but are likely the proximal manifestation of the ultimate logic we described. We have no doubt that people experience visceral and measurable emotions and psychological needs related to their social identity – for example, need for belonging, need for continuity, etc. What we propose is that most of these visceral affective states might be design features of cognitive mechanisms that motivate individuals to engage in behaviors that are beneficial to their reproductive success – just like the visceral desire for an attractive mate is a feature of our mating cognition. For instance, the “need for belonging” is likely the proximate psychological mechanism that motivates humans to secure membership into a reliable group of social partners and “need for continuity” might be the proximal motivation that pushes people to attend to cues of repeated interactions over time and commit to more interdependent groups. Likewise, successful historical myths might indeed reduce anxiety, not by providing an abstract sense of permanence, but by showing the group as a cohesive entity that is able to provide valuable fitness benefits. This account is compatible with the evidence provided by Pyszczynski, Solomon and Grenberg – much of which we cited ourselves and analyzed in light of our account in the target paper (see sects. 4 & 5).

The same line of reasoning applies for emotions. From an evolutionary perspective, emotions are a coordinated adaptive response to adaptive challenges in our environment – for instance, fear coordinates coherent physiological and perceptual responses to the presence of imminent threats (Al-Shawaf, Conroy-Beam, Asao, & Buss, Reference Al-Shawaf, Conroy-Beam, Asao and Buss2016). Thus, some of the emotions elicited by historical myths, like “security” or “intimacy” (Wildes and Andrews) might represent a psychological response to the recipients' perception of fitness interdependence with other group members. However, in light of our theory, we believe that the emotions that might play the most important role in national affiliation were not mentioned in the commentaries. First, previous research suggests that empathy is the emotional marker of perceived interdependence (Fitouchi, André, & Baumard, Reference Fitouchi, André, Baumard, Al-Shawaf and Shackelford2024). For this reason, we expect that successful historical myths – and more generally, successful nation-building – should elicit empathy toward other group members. Similarly, because coalitional choice psychology can lead to moral representations about what constitutes a mutually beneficial coalitional arrangement, national affiliation might elicit a sense of moral duty – or, in cases where individuals are imposed a coalitional arrangement that is not perceived as mutually beneficial, anger (André et al., Reference André, Fitouchi, Debove and Baumard2022; Fitouchi, André, & Baumard, Reference Fitouchi, André and Baumard2023). Overall, this discussion shows the limitations of traditional philosophical divides between rationality and emotion (“Logos” and “Pathos,” following Pelletier & Fay). Emotions and other psychological needs are instincts that are felt viscerally, but they are also “rational” – in the sense that have evolved to solve adaptive problems, and result from complex computations of fitness costs and benefits (Al-Shawaf et al., Reference Al-Shawaf, Conroy-Beam, Asao and Buss2016).

Ultimate and proximal explanations are therefore complementary: ultimate theories provide the evolutionary logic for the existence of a trait, while proximal theories uncover how this trait manifests. However, proximate theories that rely on psychological needs and emotions without considering ultimate-level mechanisms run the risk of producing almost tautological explanations – equivalent to claims like: people eat because they have a need for food and have sex because they have a need for pleasure. These accounts also tend to raise more questions than they solve: why do people have such needs and emotions in the first place? In the absence of first principles from which needs can be inferred, psychological needs might become ad-hoc explanations of human behavior.

One commentary explicitly addressed this critique: Pyszczynski, Solomon and Grenberg propose that historical myths are appealing because they alleviate death anxiety; and they justify this psychological need with anxiety's presumed deleterious effect on “diverse biological and psychological systems that facilitate individual survival.” We raise several concerns about this interpretation. First, the proposed evolutionary mechanism is underspecified. The authors mention that historical myths “enable people to view themselves as valuable contributors to something great that stretches far into the past and that will endure indefinitely,” but it remains unclear why people should perceive this information as reducing the “inevitability of death.” Second, the authors wrongly assume that anxiety is systematically detrimental to survival and reproduction. In contrast, evidence shows that anxiety is an adaptive mood that is triggered by threatening environments and generates adapted physiological and cognitive responses (e.g., higher threat sensitivity) – which does not mean that there cannot be pathological forms of anxiety (Nettle & Bateson, Reference Nettle and Bateson2012). Relatedly, the authors claim that people might feel anxious because of the inevitability of death. But from an evolutionary perspective, it would make no sense to react to a threat that is so general and, by definition, inevitable (Kirkpatrick & Navarrete, Reference Kirkpatrick and Navarrete2006). Rather, evidence shows that threat-detection mechanisms react to specific and avoidable threat with adaptive responses, like pathogens, predators or coalitional rivals (Neuberg & Schaller, Reference Neuberg and Schaller2016). Cognitively, humans do not fear “death” but fear specific features of their environment that may compromise their fitness. Thus, if it is indeed true that historical myths alleviate death anxiety, a compelling theory must provide an evolutionarily plausible reason for why information about the ancient history of one's group can lead to fitness gains.

R6.1. Uncertainty reduction

Several commentators suggested alternative ultimate accounts for the cultural success of historical myths. One recurrent proposal was that historical myths might serve an epistemic function, providing a shared framework for interpreting social interactions. For instance, Moser suggested that they serve as “meta-heuristics for ensuring that members of a common group follow the same norms, envision the world with a shared ontology, and respond to new problems in the same way.” Similarly, Grüning and Krueger proposed that myths “provide[s] a behavioral framework for the world that reduces the cognitive load of decision making.” This account is convincing but might not explain the same types of historical narratives as the ones we emphasized in the target article. Uncertainty-reduction theories are well-suited to explain myths that provide information about the distinct customs and values of group members – like the myths described by Oatley and Wu – but are less suited to explain historical myths that emphasize cooperative events and long histories. Future research might disentangle the two accounts by testing how relevant psychological constructs (e.g., uncertainty aversion and national identification) predict the endorsement of historical narratives.

R6.2. Cultural group selection and arbitrary group norms

Other commentators rejected our claim that the cultural evolution of historical myths could be explained in the absence of group-level processes and proposed alternative accounts based on cultural group selection theory. First, Smaldino and Zefferman proposed that group boundaries reflect the scale of cultural variation – because this is the scale at which parochial behavior is favored by group-level cultural selection. As a result, the function of historical myths might be to “clarify the scale of existing cultural variation.” However, this idea does not account for the immense malleability of group boundaries – far beyond the constraints of cultural similarity – that we detailed in section 3. As political scientists have repeatedly shown, ethnic and national group boundaries are malleable and often reflect contextual incentives more than sincere attachment to cultural homogeneity (Habyarimana, Humphreys, Posner, & Weinstein, Reference Habyarimana, Humphreys, Posner and Weinstein2007). This is well illustrated by a seminal paper showing that the Chewa and Tumbuka ethnic groups are allies in Zambia but rivals in Malawi – despite being culturally similar across borders, and reflecting different incentives for alliances in both countries (Posner, Reference Posner2004). Cultural (especially linguistic) similarity can certainly play an important role in coalitional preferences, to the extent that sharing culture reduces transaction and coordination costs, but other incentives (e.g., shared goals, common threats, efficient institutions) can substantially reduce and sometimes cancel preferences based on cultural similarity (e.g., Habyarimana et al., Reference Habyarimana, Humphreys, Posner and Weinstein2007). Finally, this account does not explain the design features of historical myths. Per Smaldino and Zefferman, nationalists should simply advertise the cultural homogeneity of their nation – which they often do – but not advertise the nation's long history of cooperation.

Second, Hoffman and Moya propose a game-theoretical model to claim that large social groups may not “be based on anything “real”” – as long as all group members have a shared understanding of group boundaries. This claim is similar to other commentaries, who stressed the coordination role of historical myths. Wolf points to evidence that shared mental representations stimulate cooperation; and proposes that it is the observation that group members have achieved a shared representation of the past that make historical myths compelling for coalitional choice. Fonagy and Campbell make a similar point when they attribute the appeal of historical myths to their capacity to elicit a “shared cognition” (i.e., shared intentionality, shared goals and mutual recognition).

The coordination of minds and behaviors is certainly an important feature of group formation. As evolutionary psychologists have claimed: “groups do not objectively exist: they only exist to the extent that they are represented in mutually consistent ways in the minds of assorted individuals” (Tooby et al., Reference Tooby, Cosmides and Price2006; p. 111). Accordingly, people are highly sensitive to cues that indicate common knowledge of relevant information among a group of participants – and use these cues to motivate cooperation (De Freitas, Thomas, DeScioli, & Pinker, Reference De Freitas, Thomas, DeScioli and Pinker2019; Deutchman, Amir, Jordan, & McAuliffe, Reference Deutchman, Amir, Jordan and McAuliffe2022). This probably explains why historical myths are often publicly displayed in ostensible rituals – typically in the forms of national commemorations (e.g., Ben-Amos, Reference Ben-Amos2000). Contra Hoffman and Moya, however, we note that this claim does not need to presume any group-level mechanism: a plausible alternative is that elites have an intuitive understanding of human social cognition and have a direct incentive to publicly display historical myths to recruit coalitional support.

More generally, we disagree with the claim that coordination is the sole driver of coalitional choice, and therefore that what individuals decide to coordinate on is arbitrary. Consistent evidence from across the social sciences shows that coalitional choice in humans (including in large natural groups) depends on a variety of variables – all of which are indicators of the potential fitness costs and benefits associated with group membership: shared goals (Noyes & Dunham, Reference Noyes and Dunham2017), common threats (Barclay & Benard, Reference Barclay and Benard2020), expectation of reciprocity (Yamagishi & Kiyonari, Reference Yamagishi and Kiyonari2000), institutional quality (Bartoš & Levely, Reference Bartoš and Levely2021), reputation circulation (Habyarimana et al., Reference Habyarimana, Humphreys, Posner and Weinstein2007), and, we suggest, perceived fitness interdependence (e.g., Swann et al., Reference Swann, Buhrmester, Gómez, Jetten, Bastian, Vázquez and Zhang2014). In psychology, the notion that mere coordination is sufficient to establish group boundaries is reminiscent of the minimal group paradigm – in which researchers found that mere allocation to an arbitrary group was sufficient to elicit in-group favoritism (Tajfel, Reference Tajfel1982). But precisely, subsequent studies have found that in-group preferences in minimal groups readily disappear when other sources of incentives are introduced (e.g., reputational incentives and reciprocal cooperation) (Balliet, Wu, & De Dreu, Reference Balliet, Wu and De Dreu2014). Lastly, there are abundant examples of failed nation-building – cases where people refuse a given coalitional arrangement despite strong coordination cues from state-level public propaganda (see sect. 2).

These elements demonstrate that pure coordination is insufficient to establish group boundaries in individual minds. Our suggestion is that while coordination is important, individuals want to coordinate on coalitional arrangements that are otherwise desirable. This explains why cultural technologies are not arbitrary, but tend to exhibit recurrent cross-cultural (not necessarily universal) patterns – as those of historical myths.

R6.3. Andreas Wimmer's theory of nation-building

Wimmer wrote an especially detailed critique of our target article. His commentary explores a promising avenue for testing our theory using large cross-country datasets. It also gives us an opportunity to discuss the relevant measures to do so. Indeed, the “foundation year” variable that was used as an outcome variable by Wimmer in his regression model is not suited to test our main hypotheses because it was designed to measure the objective date of birth of an ethnic group. To collect this data, Kaufman asked experts when they thought that an ethnic identity first emerged and explicitly noted that he was not “concerned with the group's own claims, which often stretch back much further than what is warranted by the historical record” (Kaufmann, Reference Kaufmann2015). Yet, it is precisely the “group's own claims” on the antiquity and continuity of their nation that matters for our theory. The target article is very clear that historical myths are mental representations of the past that are likely to diverge from expert opinions. Future studies using large datasets should select an outcome variable that measures group member's subjective rather than objective representations of their history. Collecting subjective data will also shed light on intra-group variability in the endorsement of historical myths – as we expect that not all group members hold the same representation of their past (see sect. 6.1).

We actually provide such data in the main article – despite the commentary claiming otherwise. We cite numerous psychological experiments showing that people readily endorse the belief their nation has an ancient and continuous history; and that this endorsement is significantly higher in people who identify with their nation more, who are exposed to information about the disappearance of their group, and who are more exposed to threat cues (see sects. 4 & 5). However, we agree with Wimmer that this data is imperfect, relies too heavily on Western samples, and needs to be tested outside the lab.

Finally, Wimmer referred us to his own “modernist” account of nationalism (Wimmer, Reference Wimmer2018). We believe that our respective accounts are quite compatible in that they both assume that successful nation-building is premised on the quality of intra-group cooperative exchanges. One key difference in our approaches is that Wimmer (Reference Wimmer2018) emphasizes the relationship between citizens and the state, which we also recognize as an important driver of coalitional choice (see R1 & R2) – whereas our target article also emphasizes the (perceived) horizontal bonds between individuals. Another difference lies in our relative disciplinary focus. As a political scientist, Wimmer (Reference Wimmer2018) is interested in the objective determinants of successful nation-building (i.e., public goods provision), whereas psychologists are interested in individuals' subjectivity (e.g., perceived public goods provision). Integrating the two disciplines in the study of nationalism is crucial as what ultimately drives behavior is what people perceive, and how this information is processed in our minds.

R7.1. Positive and negative historical narratives

Finally, several commentators suggested promising avenues for extending and broadening our research work. A first line of investigation for future studies is to differentiate historical myths and their psychological impact based on their valence. Indeed, some authors questioned our decision to focus on historical myths that describe positive past interactions, when so many national narratives are based on national traumas. For instance, Wimmer cites the historical “tales of victimhood, defeat and injustice” that prevail in Polish nationalism and Zionism. Bilewicz and Bilewicz make a similar point, although they note that myths of shared suffering may in fact reduce national cohesion. These observations are consistent with historical research showing the prevalence of negative themes (e.g., crushing military defeats) in nationalist rhetoric; and with psychological evidence that shared negative experiences are more likely to generate identity fusion than shared positive experiences (Whitehouse et al., Reference Whitehouse, Jong, Buhrmester, Gómez, Bastian, Kavanagh and Gavrilets2017).

Here, we propose a tentative explanation for this apparent paradox, although more research is needed to support our claims. We suspect that, generally, these disastrous narratives are not displayed for their own sake. Rather, they are typically used as a narrative device to highlight the heroic self-sacrifice of ancestors (e.g., Serbian nationalism: Bieber, Reference Bieber2002; Lomonosov, Reference Lomonosov2021; in Israeli nationalism: Ben-Amos, Reference Ben-Amos2003; Gal, Reference Gal, Carvalho and Gemenne2009). A striking example is how the siege of Masada – during which a battalion of Jewish soldiers self-sacrificed to fight Roman oppressors in 73-74 CE – became a central symbol of Israeli nationhood despite being a military defeat. The story of Masada was explicitly used to “inspire many Israelis and Jews to greater heroism and self-sacrifice” (Smith, Reference Smith1999, pp. 179–180). The phrase “Masada shall not fall again” has become a rallying sign for Israeli nationalists, and Masada remains one of the most visited places in Israël, showing the prominence of this narrative (Gal, Reference Gal, Carvalho and Gemenne2009; see also Ben-Yehuda, Reference Ben-Yehuda1996).

Two evolutionary mechanisms may explain the appeal of tales of heroic self-sacrifice for nationalist coalitional recruiters. First, the public celebration of group members who risk their lives for the nation sends a powerful signal that such behavior is socially valued and will be rewarded. In certain conditions (e.g., when death probability is compensated with even greater potential benefits) these incentives can motivate extreme pro-group behavior (Dessalles, Reference Dessalles2018). This idea was confirmed in a recent model, showing that a propensity to pay tribute to self-sacrificial heroes might coevolve with the presence of heroic acts in a social group (Dessalles, Reference Dessalles2024). A second possibility is that martyrological narratives serve as a hyper-stimulus of costly helping (Barclay, Bliege Bird, Roberts, & Számadó, Reference Barclay, Bliege Bird, Roberts and Számadó2021). By observing costly self-sacrifice from other coalition members, recipients can infer that they are highly valued by other members and therefore, that the fitness interdependence that binds them is high (Barclay et al., Reference Barclay, Bliege Bird, Roberts and Számadó2021). In our target article (sect. 4), we suggested that cues of repeated interactions over time might be perceived as having a greater impact on perceived fitness interdependence if these interactions were especially costly to participants. Thus, by emphasizing heroic acts of costly helping in the past, coalitional recruiters may hope to reinforce the commitment of group members.

R7.2. Are historical myths detrimental to social cohesion?

These hypotheses address Wimmer's observation that nationalism is often founded on tales of victimhood, but do not explain Bilewicz and Bilewicz's remark that endorsing such tales has deleterious effects on social cohesion. In particular, these authors cite evidence that endorsement (or exposure) of traumatic collective memories are associated with more paranoia, conspiratorial beliefs and obsession with treason – which might ultimately damage social cohesion. These observations are consistent with the view of Kaufman, Kashdan and McKnight who also stress the negative psychological effect of historical myths – although their focus is on positive narratives. In strengthening the cohesion of the majority group, these authors argue, positive historical myths might contribute to the stigmatization of marginalized groups and dissenting in-group members – and stifle their creativity.

In fact, these psychological responses to historical myths – positive or negative – are not incompatible with their potential positive effect on national commitment. Recall that the output of coalitional choice psychology is not directly cooperation, but the mental representation that a given coalitional arrangement is desirable – leaving the possibility that people might shirk their national obligation. When the incentives and consequences of cheating are especially high – as it is usually in times of national trauma – we might actually expect that commitment to the nation will translate into a greater motivation to monitor and sanction other group members. This probably manifests psychologically in the form of paranoid thinking, conspiratorial beliefs or exclusionary attitudes toward dissenters (Greenburgh & Raihani, Reference Greenburgh and Raihani2022). In line with this idea, attachment to the homeland and nationalism are positively correlated with Right-Wing Authoritarianism – showing that people who support a given coalitional arrangement also support more stringent social control to maintain its boundaries (Osborne, Milojev, & Sibley, Reference Osborne, Milojev and Sibley2017). Future research might further investigate the negative traits associated with the endorsement of historical myths.

R7.3. Historical myths for attack and defense

Third, Snijder and De Dreu raise an interesting debate on the contextual variability of historical myth prevalence. Our target article predicted that historical myths would spread more in societies engaged in warfare because group members need more costly investment from each other (sect. 5.1), but it remains unclear whether this prevalence should vary between attack and defense situations. Snijder and De Dreu convincingly show that group members are more interdependent in defense than in attack and conclude that historical myths will be more prevalent in attack situations. We generally agree with this logic but introduce a possible caveat. Defense situations are indeed more prone to fitness interdependence between group members, but they also make cooperation failures more costly – and possibly dramatic. The severe cost of losing against invaders might incentivize group members to transmit historical myths. More research is needed to determine which of these two opposite effects trump the other and how this affects the circulation of historical myths.

R7.4. Toward a psychological science of the historical discipline?

Finally, our research might open broader research question related to the psychological appeal of history in general. In their commentary, Pietraszewski and Moncrieff convincingly demonstrated that the cross-cultural interest of humans for history represents a puzzle for social science beyond the study of historical myths. Interest for history, these authors argue, recycles important cognitive templates like the ones involved in retaliatory behavior. We certainly concur with the author's call for an adaptationist cognitive science of history and hope to see future studies addressing these questions.