In the target article, Tomasello argues that children initially view obligations as holding among collaborative partners, then they extend this knowledge to collaborative and cultural groups during the preschool years. Overall, this is a convincing argument that makes sense given the extensive literature on when and how children develop an understanding of norms.

Yet, the argument that children's sense of obligation is dependent on their developing concept of “we” implies that it is children's own direct experience in social groups that drives all of their moral understanding. Clearly, children's firsthand experiences with the social groups in their environment influence a range of social category-based processes, including obligation. Yet, this argument overlooks the possibility that at least some of children's beliefs about groups exist as part of a more abstract framework of how social groups function, beyond children's own experiences. For example, Tomasello reviews a great deal of work showing that preschool-aged children show preferential treatment for in-group over out-group members across a range of experimental paradigms (Fehr et al. Reference Fehr, Bernhard and Rockenbach2008; Misch et al. Reference Misch, Over and Carpenter2014; Over Reference Over2018; Over et al. Reference Over, Vaish and Tomasello2016). These findings are not trivial and provide strong support for the suggestion that children's beliefs about obligation are embedded within their understanding of social groups. But they do not disentangle children's own affective biases toward the groups they have encountered in the world from their broader understanding of how social groups function in general.

Across development, children build intuitive theories – abstract, domain-specific, causal-explanatory frameworks – of how the world works (Wellman & Gelman Reference Wellman and Gelman1992). In the social world, children's intuitive theories involve both (a) what social group members are like, and (b) how social group members act toward one another (Rhodes Reference Rhodes2013). Importantly, these theories are normative in nature – they involve not just descriptions of how group members act, but also prescriptions of how group members are supposed to act (Haward et al. Reference Haward, Wagner, Carey and Prasada2018; Prasada & Dillingham Reference Prasada and Dillingham2009). In other words, children's intuitive theories establish the obligations by which group members are believed to be bound. To that end, by the preschool years, children view moral obligation as shaped by group membership: They think that people are more likely to harm out-group members than in-group members (Chalik & Rhodes Reference Chalik and Rhodes2014; Reference Chalik and Rhodes2018; Chalik et al. Reference Chalik, Rivera and Rhodes2014; Rhodes Reference Rhodes2012), and that people will protect in-group members over out-group members from harm (Chalik & Rhodes Reference Chalik and Rhodes2018). Furthermore, as soon as children receive input to suggest that a given behavior is morally relevant, they spontaneously expect that behavior to play out according to group boundaries, even if they have had no experience with the particular behavior or groups in question (Chalik & Dunham Reference Chalik and Dunham2020). Importantly, in contrast to most of the in-group preferences documented in the target article, these findings have all come from tests of children's third-person reasoning. In these third-party paradigms, children's judgments cannot be based on any personal biases that they hold in favor of their own social groups, since children are not members of the groups they are reasoning about. Thus, these findings do not seem to rely on a sense of “we” – rather, they depend on a sense of “they.” This sense is abstract in nature, involving children's beliefs about how groups are supposed to function in the world, rather than whatever children have actually experienced with the specific groups in their environment.

This possibility need not be in direct opposition to the one presented by Tomasello. It is certainly possible that children could build their understanding of obligation from both their experiences in collaborative partnerships and their intuitive theories of how social groups function. Yet, if both of these proposals are true, then an open question remains: When and how do children incorporate their specific experiences into their more abstract expectations of the world? The relation between children's personal biases, as documented in first-person work, and their abstract expectations of the world, as documented in third-person work, remains largely unexplored, and will be an important area for future research.

An additional issue raised by the intuitive theories account regards the time-course of children's developing understanding of obligation. Tomasello reviews a great deal of work suggesting that it is only after age 3 that children have a true sense of “we.” Yet, the strong conclusion that children do not incorporate social groups into their beliefs about moral obligation until this age is premature. If children hold an intuitive theory by which social groups mark moral obligation, and notions of obligation are thus embedded in representations of social groups, then children may begin to develop these beliefs as soon as they start to recognize that social distinctions exist in the world. A great deal of work now shows that infants are sensitive to social groupings within the first year of life (Bar-Haim et al. Reference Bar-Haim, Ziv, Lamy and Hodes2006; Kinzler et al. Reference Kinzler, Dupoux and Spelke2007; Quinn et al. Reference Quinn, Yahr, Kuhn, Slater and Pascalis2002), and that toddlers can represent novel social groups, given the right input (Diesendruck & Deblinger-Tangi Reference Diesendruck and Deblinger-Tangi2014; Rhodes et al. Reference Rhodes, Leslie, Bianchi and Chalik2018). Furthermore, infants and toddlers do appear to have different expectations about how people will interact with one another, depending on group membership (Bian et al. Reference Bian, Sloane and Baillargeon2018; Jin & Baillargeon Reference Jin and Baillargeon2017; Ting et al. Reference Ting, He and Baillargeon2019). This evidence is somewhat limited, and there is undoubtedly much about children's understanding of obligation that continues to develop beyond age 3; still, to some extent, it seems likely that children begin to hold these concepts within the first three years of life.

Thus, the argument that children's beliefs about obligation arise from their experiences in collaborative partnerships and groups is a strong one. Yet, it is incomplete without also considering the intuitive theories of social groups that children hold regardless of their direct experiences, as well as the social group-based judgments made by infants and toddlers.