The commentary by Whitehouse draws on evolutionary anthropology and psychology to analyze extreme self-sacrifice through the lens of identity fusion. Surprisingly, given the title, this fascinating theoretical integration lacks a deep consideration of the roles of intergroup processes and normative systems in shaping the expression of fused identities. This neglect is particularly problematic for understanding violent extremism.

Groups have systems of norms – social rules or standards for behavior – that prescribe correct behavior for group members (Smith & Louis Reference Smith and Louis2009). When individuals fuse with groups, they appropriate not just perceived kinship to others in an abstract sense, but the normative content of the identities: what others do (the behavioral or descriptive norms) and what others think should be done (the moral or injunctive norms) (Cialdini et al. Reference Cialdini, Reno and Kallgren1990). Fused members of different groups need not act alike. Even if all are willing to sacrifice themselves for their groups, they will follow their different groups’ norms regarding how to sacrifice.

To take another lesson from Durkheim (Reference Durkheim1897), there is a division of labor, and that extends to suicide. Therefore, fusing with nation or religious groups will be more likely to lead to extreme actions such as self-starvation and suicide terrorism when the norms of the groups encourage such violence, but not when the norms encourage peaceful acts. For example, we would expect fused charity workers to be less violent in reacting to threats than fused soldiers. When group norms are peaceful, increasing fusion promotes pro-social actions, such as charitable giving (Buhrmester et al. Reference Buhrmester, Fraser, Lanman, Whitehouse and Swann2015; Swann et al. Reference Swann, Gómez, Huici, Morales and Hixon2010b). With peaceful groups, group identification inhibits violence (Jiménez-Moya et al. Reference Jiménez-Moya, Spears, Rodríguez-Bailón and Lemus2015). Therefore, collectively constructed normative systems are a missing moderator from the model: norms create facilitating but also inhibiting relationships of fusion with violent extremism (Louis Reference Louis2014; Domínguez et al. Reference Domínguez, van Nunspeet, Gupta, Eres, Louis, Decety and Molenberghs2017).

A related concern is that Whitehouse's model underspecifies the social interactions that shape extremism. Dysphoric rituals not only create fused identities, but establish norms for group behavior: we are people who go to extreme lengths (including harm) to express our commitment to the group. More generally, interacting groups provide the basis for people to negotiate their extremism and select options (Louis et al. Reference Louis, Amiot and Thomas2015; Thomas et al. Reference Thomas, McGarty and Louis2014). These small group processes are the crucibles of broader societal changes (Thomas et al. Reference Thomas, McGarty and Mavor2016) that enable the formation of social movements that are themselves based around norms (Smith et al. Reference Smith, Thomas and McGarty2015). Although Whitehouse clearly has in mind a social dynamic, the model shown in his Figure 1 is asocial and linear: the bystanders, target, and team of the violent extremists and the state actors all are absent; there are no feedback loops (e.g., from action to emotion or reflection); the model is static rather than dynamic.

We endorse Whitehouse's core premise that groups react to threats and that those fused with the group are more motivated to do so. We note, however, that the outcome is rarely violent extremism (McCauley & Moskalenko Reference McCauley and Moskalenko2017). Public support for violence increases when peaceful, nonviolent alternatives seem likely to fail (Thomas & Louis Reference Thomas and Louis2014). In the face of threat, different normative systems will lead fused members to engage in a range of behaviors, including prayer and fasting, political protest and civil disobedience, palliative support and emotion-focused coping, and also (but rarely) violent extremism (Thomas et al. Reference Thomas, Smith, McGarty and Postmes2010). The state will play an important role in supporting more democratic responses versus more violent ones, and the history of relations with the target also is important (Dugan & Chenoweth Reference Dugan and Chenoweth2012; Moghaddam Reference Moghaddam2013; Reference Moghaddam2018).

In addition, people belong to multiple groups, and these intersectionalities matter (Louis & Montiel Reference Louis and Montiel2018; Louis et al. Reference Louis, Amiot, Thomas and Blackwood2016a). Most of us feel a sense of psychological kinship, or oneness, with multiple social networks – from family to profession, from nation to faith. All groups are threatened at some point. Thus, Whitehouse's model overpredicts violent extremism and underpredicts other reactions.

A group-based model highlights that most groups actively teach members to see violence as immoral, costly, and nonbeneficial and develop norms of nonviolent conflict resolution (Christie & Louis Reference Christie, Louis and Tropp2012). As individuals internalize the norms against harm doing from different groups to which they belong, it becomes harder for any one group to develop pro-violence norms or for any group member to enact them (Amiot et al. Reference Amiot, Doucerain and Louis2017a; Reference Amiot, Louis, Bourdeau and Maalouf2017b). Doing harm as a member of one group becomes incompatible with the members’ other existing identities (Louis et al. Reference Louis, Amiot and Thomas2015).

Yet, when individuals identify with any group with norms supporting violence, this rupture in their commitment to nonviolence can reduce the need for them to compartmentalize their harm doing in other contexts and, thereby, increase the likelihood that they respond to threats with violence (Amiot et al. Reference Amiot, Louis, Bourdeau and Maalouf2017b; Louis et al. Reference Louis, Amiot, Thomas and Blackwood2016a). Correspondingly, fused group members who have internalized norms supporting peace from alternative identities may form anchors of resistance within violent groups, risking their lives to save others or to speak out against atrocities.

In short, we argue that normative violence can be fueled or inhibited by fusion. The strategic direction of self-sacrifice or intergroup behavior depends critically on the content of the group norms. Studies on fusion have so far examined the real and demonstrated association between fusion and violent extremism without grappling with the low base rate of violent actors; the intersectionalities of class, religion, ethnicity, or gender that moderate the fusion–violence link; or the key role of normative systems. Whitehouse's model could better explain violent extremism by assigning a more foundational role to normative systems (Louis et al. Reference Louis, La Macchia, Amiot, Thomas, Blackwood, Mavor, Saeri, Moghaddam and Harré2016b; Moghaddam Reference Moghaddam2013; Reference Moghaddam2018; van Zomeren & Louis Reference van Zomeren and Louis2017). It is our hope that this commentary creates a new norm that stimulates innovation in this theoretically rich and socially important area.