The target article proposes that to form and maintain weak social ties, some primate species developed two specific social cognitive mechanisms, namely self-control and mentalizing, the latter of which primarily facilitates social bonding by allowing individuals to read others’ intentions from their intentional (or even communicative) behavior. At the end of the article, the author rightly points out that humans have taken an extra big social cognitive step that catalyzes large-scale social bonding. Humans bond through conversation (Aron et al., Reference Aron, Melinat, Aron, Vallone and Bator1997; Bosson et al., Reference Bosson, Johnson, Niederhoffer and Swann2006), music and dance (Cirelli et al., Reference Cirelli, Wan, Spinelli and Trainor2017; Hove & Risen, Reference Hove and Risen2009; Pearce et al., Reference Pearce, Launay and Dunbar2015; Weinstein et al., Reference Weinstein, Launay, Pearce, Dunbar and Stewart2016), games (Artinger et al., Reference Artinger, Clapham, Hunt, Meigs, Milord, Sampson and Forrester2006; Dabbish, Reference Dabbish2008; Depping & Mandryk, Reference Depping and Mandryk2017; Zheng et al., Reference Zheng, Veinott, Bos, Olson and Olson2002), rituals (Charles et al., Reference Charles, van Mulukom, Brown, Watts, Dunbar and Farias2021; Singh et al., Reference Singh, Tewari, Kesberg, Karl, Bulbulia and Fischer2020), and even by simply watching something together with others (Wolf et al., Reference Wolf, Launay and Dunbar2015; Wolf & Tomasello, Reference Wolf and Tomasello2020b). In other words, humans seem to have a unique social cognitive capacity to bond through social activities centered around shared experiences (Wolf & Tomasello, Reference Wolf and Tomasello2023).

There is no doubt that humans are unique in how much time and energy they invest in creating such experiences. Yet the psychological differences between humans and other primates in this regard are smaller than one might expect. In recent research (Wolf & Tomasello, Reference Wolf and Tomasello2019), Chimpanzees and Bonobos watched a video of a playing juvenile conspecific while an experimenter either watched with them or not. The apes sought out subsequent interaction faster with the experimenter who watched with them than with the experimenter who did not. Similarly, pairs of Chimpanzees who watched a video on the same screen subsequently spent more time together than pairs of Chimpanzees who watched the video on separate screens (i.e., not being able to see their partners’ screen).

This increase in social behavior would be hard to explain from the currently proposed social cognitive framework. During these procedures, apes were not in any way interdependent, nor explicitly communicating or signaling. More generally, if the apes used mentalizing to infer their partner’s intentions, it seems unlikely that, in these specific study contexts, the act of (not) looking at the same screen taught them something about their partner’s intentions that bore relevance to their social interaction or was otherwise relationally meaningful.

Instead, what these results seem to suggest is that the apes were not only making inferences about the intentions of others toward them, but that they were also, at some level, comparing others’ mental states about the world to their own. As such, where social bonding in non-human primates has generally been assumed to be dyadic (i.e., behavior or communication is directly aimed at the individual), it seems like great apes also possess some triadic social bonding capabilities, by bonding with those who are reacting to the world in the same way they do.

As the target article points out, humans do seem to be uniquely creative when it comes to finding ways to trigger their triadic social bonding systems. However, rather than this being a direct consequence of the acquisition of language or symbolic communication, there is a deeper underlying cognitive explanation: Humans’ effective social bonding in these activities seems to be undergirded by a capacity to create more complex representations of the relationship between their minds and those of others (Shteynberg et al., Reference Shteynberg, Hirsh, Wolf, Bargh, Boothby, Colman, Echterhoff and Rossignac-Milon2023; Wolf & Tomasello, Reference Wolf and Tomasello2023). Specifically, humans are capable (and motivated) to create shared metacognitive representations: During social interactions, they infer mutual awareness about having mental states similar to others, which converge on the same part of reality. These inferences can be created through language, but also through triadic touch (i.e., touch in response to things happening in the world) or by engaging in communicative eye contact (Siposova et al., Reference Siposova, Tomasello and Carpenter2018): In a comparative study (Wolf & Tomasello, Reference Wolf and Tomasello2020a), children and apes were watching a video while an experimenter in front of them did so as well. However, in one condition, the experimenter turned around and made communicative eye contact in response to the video starting, whereas in the other condition, the experimenter simply turned to the video and started watching (eye contact was made later in the procedure, to keep this factor constant across conditions). Results showed that human children who made eye contact with the experimenter in response to what occurred on the screen (i.e., inferred mutual awareness of their experience being shared) sought out a subsequent interaction with the experimenter faster than children who were merely observing the experimenter going through a similar experience. The apes, however, did not seem to react to this attempt to create mutual awareness at all.

These results have two implications for the social cognitive dimension of forming and maintaining weaker social ties in primates. First, the final step that bridges the bonding gap toward human-like social bonding activities seems indeed related to a capacity to represent (multiple) mental states (perhaps recursively). However, its core psychological underpinnings seem more specific than a general capacity for high-level multilayered recursive mindreading or language, namely a specific capacity to create shared metacognitive representations or mutual awareness about the relationship between one’s own mental states and those of others. This capacity not only forms the foundation for human language and other forms of symbolic communication, cultural norms, and social institutions that allow large scale social bonding (Clark & Brennan, Reference Clark, Brennan, Resnick, Levine and Teasley1991; Grice, Reference Grice1957; Searle, Reference Searle1992; Shteynberg et al., Reference Shteynberg, Hirsh, Wolf, Bargh, Boothby, Colman, Echterhoff and Rossignac-Milon2023; Tomasello, Reference Tomasello2019) but, importantly, in itself also directly elicits social closeness.

Second, it seems that at least some non-human primates (i.e., great apes) are more similar to humans than many scholars have long thought. Chimpanzees and Bonobos behave more socially and seek out interactions more often with those with whom they undergo similar (vs different) experiences. This suggests that they, at some level, bond triadically by making inferences about the relationship between their others’ mental states and their own, at least in a rudimentary way. How far this capacity extends within the primate phylogenetic tree remains, however, unknown and is thus a crucial endeavor for future research.