Fiske observed that “Market pricing is so pervasive in Western society and so important in the Western cultural conceptions of human nature and society that many theorists have postulated that all human social behavior is based on more or less rational calculations of cost-benefit ratios in self-interested exchange.” (Fiske, Reference Fiske1992, p. 706). It seems that Thomas’ article falls into this exact trap, with one difference: she replaces the market metaphor with a computer metaphor of the mind (Brette, Reference Brette2019; Searle, Reference Searle1984). In essence, following Fiske, we argue that her approach illustrates how computer modelling has become one of the mainstream Western cultural conceptions of human nature and society, leading to postulates that all human social behaviour is based on more or less computational calculations. Consistently, relationships are represented as the by-product of two “basic computations”: one that categorises the connection by model and one that computes the strength of the social connection. In other words, babies are portrayed as information-processing machines, equipped with the capacity to perform continuous computations of their relational environment. Indeed, Thomas’s approach to infants is predicated on the premise that infants possess the ability to organise vast amounts of information in their environment and to direct their attention to that which is relevant. Since she sees this faculty as underpinned by “core knowledge,” something either innate or developed very early in life, she thus conceives of infants as natural-born computers.

Ironically, although Thomas rejects Market Pricing as a distinct relational model, using the computer metaphor leads her to place market logic at the heart of all relational models. A striking illustration of this is her “untested hypothesis” about the strength of relationships, which essentially states that the stronger the relationship, the less “replaceable” the relationship and the person concerned. This expresses the economic concept of “elasticity of substitution,” a ratio measuring how easy it is to substitute one input for another (Dixon, Reference Dixon, Blaug and Lloyd2010). Unsurprisingly, this line of reasoning ultimately leads Thomas to illustrate her argument explicitly in market terms, namely the parental investment of resources put into raising children. This approach echoes the economic metaphor that children are “durable consumer goods” in which parents invest (Becker, Reference Becker1976, p. 169), and is closely linked to the notion of “human capital” lifted straight from economics (Becker, Reference Becker1993). Consistently, through the market metaphor that pervades some parts of Thomas’ argument, people are goods that can be “swapped” or “replaced,” whether it is a colleague for another colleague, a worker for the owner of a factory, or a friend.

We appreciate Thomas’ explicit acknowledgement that generalisations based on the economic notion of “utility” can be challenged. Nevertheless, although she may shy away from asserting market logic as underlying every aspect of social relations, it is noteworthy that the economic reasoning associated with Market Pricing can lie at the heart of every other relational model in her argument. Her proposed characterisation of the “computations” that infants supposedly employ to infer the category and strength of Communal Sharing relationships is one of “naïve utility calculus,” whereby costs and rewards are computed to infer the value an individual places on something. This corresponds to a standard utility-based model of economic reasoning and market behaviour (Becker, Reference Becker1993). Likewise, Thomas’ approach to Equality Matching does not rule out infants using “naïve utility calculus” to “track ‘value’,” while Authority Ranking (or asymmetrical relationships) is understood through computations in terms of the “benefits” that people can provide. Crucially, such framing is antithetical to assertions of Fiske and colleagues that there is no common logic through which different relational models can be compared, meaning that conflicting priorities will result in confusion and negative affect (Fiske & Tetlock, Reference Fiske and Tetlock1997; Gallus et al., Reference Gallus, Reiff, Kamenica and Fiske2022). By contrast, Thomas’ approach implies that all apparent conflicts can ultimately be resolved through utility calculations.

We believe that Thomas’ market-based framing of all relational models has to do with her use of the “mind as computer” metaphor (Basso & Herrmann-Pillath, Reference Basso, Herrmann-Pillath, Basso and Herrmann-Pillath2024a). This, however, could be circumvented by the use of other metaphors. Thomas’ argument could lend itself to an embodied approach to infant cognition, similar to her analogy of reasoning between the domains of physics and psychology. The embodied cognition literature, including Piaget’s (Reference Piaget1952) description of how infants’ physical experience of the world provides the background for their psychological understanding of the world, obviates the assumption that infants are computers (Marshall, Reference Marshall2016) and promotes instead an embodied metaphor approach (Lakoff & Johnson, Reference Lakoff and Johnson1980, Reference Lakoff and Johnson1999). That way, Fiske’s (Reference Fiske1992) relational models can be understood as the social expression of physical experience through kinaesthetic image schemas (Johnson, Reference Johnson1987, Reference Johnson2017; Lakoff, Reference Lakoff1987). Of course, other schemas and additional embodied mechanisms may be at play, but a close reading of Fiske’s relational models shows that Communal Sharing can be seen as emerging from the experience of the body as a container through consubstantial assimilation (IN/OUT); Authority Ranking from the body being in space, giving rise to the vertical metaphor (UP/DOWN); and Equality Matching as structured around the BALANCE metaphor, related to the experience of proprioception (Basso & Herrmann-Pillath, Reference Basso, Herrmann-Pillath, Basso and Herrmann-Pillath2024b). Moreover, despite the assertion that Market Pricing is “not embodied” (Fiske, Thomsen, & Thein, Reference Fiske, Thomsen and Thein2009), we propose that it can indeed be viewed as derived from the embodied RESOURCE metaphor, in which everything, including people, is understood as a means to an end (Basso & Herrmann-Pillath, Reference Basso, Herrmann-Pillath, Basso and Herrmann-Pillath2024b; Lakoff & Johnson, Reference Lakoff and Johnson1999).

By taking an embodiment approach, Thomas would not only move beyond the computer metaphor but also account for how different kinds of relationships are embedded within different types of social structures, promoting different metaphorical understandings of the relationship model. For example, an infant potentially comes to understand familial relations as being fundamentally different from friendships because the family is socially structured around containers (“in/out” family), whereas friendships are structured around balance (obligations must balance). This might resolve Thomas’ question as to why infants initially seem to confuse these two relationship types and yet later hold them to be quite different.