Equality matching describes a mode in which reciprocal relationships are maintained. While Thomas argues for core representations that can support equality matching, we argue that two forms of reciprocity must be considered and may require distinct representations: positive and negative direct reciprocity. We review both evolutionary and developmental evidence in support of this proposal.

Core social knowledge is not limited to humans; it has evolved in other species. A comparative, evolutionary perspective prompts one to ask: what, exactly, has been favored by natural selection? A rigid, intuitive theory that matches each species’ society, or a more general tendency to search for social patterns, leaving the details and theory to emerge during development?

Integrating Relational Models Theory with Carey’s core cognition theorizing is possible, promises to be productive, but requires clarifications. We sketch how such an integration can strengthen social psychological theorizing in three areas.

In addition to core knowledge, the prenatal environment, parental care, and early life experience play substantial roles in the establishment of social cognition. Given the evolutionary importance of early life care in humans and mammals in general, there are innate reward and stress based neuroendocrine mechanisms that are critical to maternal infant bonding as well as later social behavior.

Thomas proposes that infants use relational models to reason about interactions between relationship partners. However, many basic social interactions do not contain enough information to differentiate between models. We propose that both basic interaction reasoning and the formation of diverse, culturally relevant relationship categories are better accounted for by positing relationship features that can be flexibly combined.

Thomas’ paper provides a compelling account of the nature and development of mental representations of social relationships. Understandably, it focuses on dyadic and triadic relationships. We emphasize the need to elucidate the development of another key component of humans’ understanding of social relationships: “stitching together” knowledge of social ties into representations of social networks that shape one’s thoughts and actions.

Thomas proposes the existence of core knowledge that supports an innate, or early developing, intuitive theory, where social relationships are understood in reference to three models: communal sharing, authority ranking, and equality matching. We consider possible precursor-representations that could support infants’ discovery of relationships in the social world and how these representations relate to the basic models discussed by Thomas.

The target article notes ways infants can use direct interactions between individuals to recognize relationships. We ask whether infants might also recognize relationships between individuals indirectly, by observing how they interact with other people. We suggest that indirect information might be used to distinguish between communal sharing and equality matching relationships and discuss how it might support inferences of relationship strength.

This commentary proposes a dynamic approach to the construction of relationship representations and mentalization. We argue that these processes result from early caregiver–infant interactions, particularly through mechanisms of synchrony, parental sensitivity, and attachment. This extends the author’s model beyond cognitive and innate perspectives by emphasizing the role of early interactions in constructing representations that are embodied, affective, and dynamic.

Infants and young children appear to have core knowledge structures related to social dynamics. However, I think intuitions about group categories are too easily dismissed or ignored in the target article. More substantively, I argue for a theoretical distinction between intuitive sociology and intuitive social psychology.

Ashley Thomas’s account does not detail mechanisms for processing structural regularities, organizing sets of social relationships. I argue that combinatoriality and relational reasoning are essential for processing social structures. These abilities, foundational to processing social relationships, enable early, abstract, and flexible understanding of social hierarchies and networks, supporting adaptive social inference across species and development.

Thomas compellingly argues that infants are especially attuned to relationships. We agree but suggest her claims can reach further in her discussion of infants’ reactions to distributional events. Thomas overlooks an interpretation of this literature in which unequal allocations might reflect relational inferences, challenging some of her claims regarding equality matching relationships and whether infants possess an “innate moral core.”

The tripartite relationship model is unlikely to reflect how relationships are represented in the mind, given considerable difficulty in wresting clear conceptual distinctions from it. Instead, it offers a descriptive framework for organizing findings. Here, we present examples of conceptual difficulties of the model and elaborate on the functional importance of third-party inference based on our agent-based modeling work.

This commentary highlights the importance of articulating Ashley Thomas’s perspective on representations of social relationships with a reflection on the rules that constitute or sustain them. This approach may also help bridge the gap between developmental studies on intuitive sociology and both theoretical and empirical research in scholarly sociology.

Thomas theorizes that infants have cognitive representations of social relationships. However, this theory does not explain all the findings on infant morality. We highlight these discrepancies and propose that infants make moral decisions based on the perception of bodily responses (interoception), such as Damasio’s somatic marker. This opens up new directions for research into infant morals.

Thomas (in press) proposes that infants possess core systems for reasoning about social relationships. Using Tinbergen’s four questions – phylogeny, ontogeny, mechanism, and function – I critically evaluate this claim, focusing on infants’ sensitivity to saliva-sharing cues. I argue that integrating evolutionary, developmental, neural, and adaptive perspectives, particularly those linked to cooperative breeding, provides a fuller account of relational reasoning’s origins.

We present three challenges to Thomas’ theory leveraging our expertise in social and cognitive development. First, Thomas’ theory fails to capture defining relationship characteristics, necessitating consideration of relationship science. Second, we argue that declaring innate knowledge of relationships is premature. Third, we propose that in the core domain of social cognition, relationship and sociomoral representations exist simultaneously without need for replacement.

Children do not need socialization by adults, and in fully traditional societies, adults do not inculcate norms for children to internalize. From infancy, children actively seek to externalize the relational models they know. To function in the community in which they find themselves, children need to discover when and with whom to coordinate using which relational model in what ways.

We concur with the author’s hypothesis regarding innate knowledge of social relationships, but we suggest that (a) cultural learning and the social context are determining factors, as evidenced by cross-cultural variations in the perception of authority and reciprocity, and (b) infants’ expectations may also reflect learning processes based on early statistical associations.

Relational primitives can facilitate rapid inductive generalization beyond individual mental-state reasoning. Computational models of social cognition should incorporate social relationships as core primitives, enabling richer explanations for how minimal social observations lead to flexible, efficient, and culturally adaptive social predictions.