Ordinarily, scholars who propose a new approach to the field try to illustrate its value by first describing a viewpoint lacking this perspective to its detriment, and then describing a viewpoint incorporating this perspective to its benefit. This paper almost exclusively focuses on the first. The primary reason is the authors’ overuse of what Margaret Mead called the “anthropological veto” – any universal claim is negated by one exceptional case – so they quickly make short work of major perspectives in developmental science by concluding that their claims are not universal. But what do they have left? Their only gesture in the direction of a constructive, generalizable alternative is a small modification to the concept of joint attention, which they redub “joint engagement” or “triadic connectedness,” and an effort to demonstrate its applicability to several human and primate samples (Bard et al., 2021). But they acknowledged that the samples of infants and primates on which they relied were small, there were no developmental data, and no definitive conclusions could be drawn about species similarities or differences. Moreover, future researchers might themselves levy the anthropological veto on joint engagement. We are left, where we began, with the conclusion that diversity exists. But diversity is not a theory.

The problem is with sterile arguments about behavioral universality that go nowhere and fail to address the important questions about how each culture, and species, confronts common adaptive challenges. Instead of rejecting every claim for which exceptions can be found in a new social ecology or primate living experience, it is more productive to recognize that each primate group must ensure that the young survive to reproductive maturity, and that their offspring do so also. How, then, do they accomplish this universal function within their ecological niche? Life history is one of several theories proposing that there are alternative means of accomplishing adaptive goals, with trade-offs between competing demands in the physical and social ecology. Cultural diversity should be explored not as an end, but as an avenue by which different populations have created alternative strategies toward shared adaptive goals, with significant consequences for behavior and development. This functionalist approach is a much more constructive and generalizable avenue than what the authors propose.

The authors cannot advance on this or any tack, however, without first abandoning their caricatures of the theories they critique. With respect to attachment theory, the authors cite me as an early and continuing critic of attachment theory, and several years ago, I wrote a chapter at the invitation of the first two authors entitled “Twenty-first Century Attachment Theory” that identified how attachment theory has changed over the past half century (Thompson, Reference Thompson, Keller and Bard2017). The evidence of the chapter has been almost entirely ignored here. It is, in fact, astonishing that a theory of early human relationships is portrayed as resisting human interdependence, and most of their recommendations for applying the “five steps to inclusivity” to attachment theory have already been achieved. Specifically, attachment researchers have (a) adapted attachment measures to local cultures using cultural informants and in situ observations (e.g., Hewlett et al., Reference Hewlett, Lamb, Leyendecker and Scholmerich2000; True, Pisani, & Oumar, Reference True, Pisani and Oumar2001) (b) recognized cultural variations in sensitive caregiving and measured them with culturally-informed tools in situ using local informants (see Mesman, Reference Mesman2021, and other contributors to the special issue of Attachment & Human Development, 23, 2021), (c) studied multiple family relationships, attachment in child care and on kibbutzim, and other kinds of attachment networks, underscoring their awareness that multiple early attachments including nonparents are normative (e.g., Dagan & Sagi-Schwartz, Reference Bard, Keller, Ross, Hewett, Butler, Boysen and Matsuzawa2021; Lewis & Takahashi, Reference Lewis and Takahashi2007), (d) recognized diverse functions of attachments and of attachment relationships in early development (e.g., Pasco Fearon & Schuengel, Reference Pascal Fearon, Schuengel, Thompson, Simpson and Berlin2021; Zeanah & Gleason, Reference Zeanah and Gleason2015), and even recognized group-based sensitivity in collective care (Ahnert, Pinquart, & Lamb, Reference Ahnert, Pinquart and Lamb2006) and infant–sibling attachment (Mooya, Sichimba, & Bakermans-Kranenburg, Reference Mooya, Sichimba and Bakermans-Kranenburg2016).

The penchant for caricaturizing the theories they critique extends to the authors’ representations of central concepts. The operationalization of joint attention in the research reported here (from Bard et al., 2021) includes: that it is infant-initiated, the female partner has a positive emotional tone, and they share an object focus. None of these, by my reading, is core to the joint attention construct, which can include situations in which the infant is responding to the adult’s initiative, emotion may or may not be positive, the adult can be male or female, and there can be a nonobject reference, as long as there are “two people experiencing the same thing at the same time and knowing that they are doing this” (see, e.g., Tomasello & Carpenter, Reference Tomasello and Carpenter2007; italics in original). But their constrained definition of joint attention is, unsurprisingly, less generalizable, likewise with the operationalization of sensitivity in the attachment literature. Several years ago, Mesman et al. (Reference Mesman, Minter, Angnged, Cissé, Salali and Migliano2018) profiled the original definition of sensitive responsiveness by Ainsworth from her Ugandan studies that, Mesman noted, did not include references to positive emotion, verbal responses, or face-to-face interaction, and then proceeded to demonstrate its cultural inclusiveness from observations of infants in Mali, the Republic of Congo, and the Philippines. The lead authors of this paper were not mollified, however, and along with their colleagues, insisted that warmth, face-to-face interaction, and verbal and vocal exchanges are, indeed, essential aspects of the sensitivity construct regardless of Ainsworth’s measure (Keller et al., Reference Keller, Bard, Morelli, Chaudhary, Vicedo, Rosabal-Coto, Scheidecker, Murray and Gottlieb2018). These authors appear committed to impressing on unfavored theories a stereotypically WEIRD portrayal of adult–infant interaction, even when it is a misleading portrayal of those theoretical views.

In the end, there is considerable value in advancing theoretical views in developmental science that incorporate the broad human experience. Scholarly fields move forward by a convincing vision and compelling examples, but this paper offers neither. Theoretical critiques lose relevance if the theories are portrayed in outdated ways and central concepts are misrepresented. Developmental science is better served by constructive critiques that lead to a compelling view, in this case, of how behavioral diversity advances species’ adaptive functions.