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.

Thomas explicitly negates the Market Pricing relational model. However, her use of the computer metaphor of the mind implicitly renders Market Pricing as the universal framework through which all other relational models can be understood. Alternative metaphors could overcome this self-contradiction, allowing her to develop an embodiment approach to the developmental origins of the cognitive representations of social relations.

Thomas’s account suggests that infants are limited to reasoning about interpersonal relationships. We argue that this account fails to do justice to infants’ sociomoral reasoning. We describe an alternative account that grants infants expectations of harm avoidance, ingroup support, authority, fairness, and reciprocity. We highlight differences between the two accounts and suggest research directions for moving beyond these differences.

Social relationships are crucial in human development, but we criticize Thomas’s approach in terms of epistemology, methodology, genetics, neural development, and evolutionary theory. We critique the evidence Thomas cites to support claims of innate knowledge and instead propose that understanding relationships develops gradually through infants’ interaction within developmental systems elicited by their embodiment, not from innate knowledge.

In this paper, I use findings from infant psychology to propose that humans have core knowledge of social relationships. I propose that these representations allow even infants to categorize relationships into a model (following relational models theory, i.e., communal sharing, authority ranking, or equality matching) and compute their strength (based on factors like expectation of future interaction, obligations, and commitment). Throughout the paper, I review evidence in support of this proposal and consider alternative explanations.

In response to commentaries, we refine our Merit-Appreciation (M-A) love model and extend it. The model’s revised formulation highlights its flexibility over personal and life circumstances in that (1) the emphasis on partner’s Merit versus Appreciation may differ across life phases and individuals’ own sense of Merit, (2) the Novelty of a given love relationship enhances the significance partners derive from it; their shared experiences in novel domains may revitalize it, however (3) the weight of an instance of romantic love as a significance source may depend on the availability of other sources of significance (e.g., work/career and alternative relationships), The latter may differ across cultures, of which some (e.g., the traditional ones) may view alternative pairwise arrangements (e.g., arranged marriages) as sources of significance. Even though its prevalence may vary, however, there is evidence that romantic love constitutes a universal experience manifest across societies and cultures. We view the M-A love model as compatible with broader conceptualizations such as evolutionary or goal theories, yet as occupying a unique niche and level of analysis, allowing insights into love as a lived experience with its many vicissitudes. The understandings it affords suggest ways of addressing love’s “trials and tribulations” to reduce the suffering it might entail and enhance its potential to promote happiness and well-being.

Kruglanski’s “significance quest” model of romantic love purports to be functionalist. But it only explains one positive emotion (falling in love) as a way to feel another positive emotion (feeling significant), without explaining why the second should be considered more fundamental or important than the first. Evolutionarily, the model does not make sense, and even descriptively, it seems incoherent.

Kruglanski et al.’s model redefines love as a pathway to personal significance, offering a compelling new lens through which to understand romantic relationships. This commentary explores the model’s implications for areas of the literature, including mate value, attachment styles, self-esteem, and narcissism. It also outlines promising directions for future research, emphasizing love’s role in fulfilling the need to feel significant.

We extend the model developed by Kruglanski et al. by proposing that the relevance of merit and appreciation for love varies by gender, age, and relationship duration: (1) appreciation is more decisive for falling in love among men; (2) merit matters more for younger adults and appreciation for older adults; and (3) appreciation becomes increasingly important as relationships evolve.

The model by Kruglanski et al. accounts for a phenomenon that is idiosyncratic and unique to societies high in relational mobility. As such, partner’s merit and appreciation, and actor’s significance quest are neither necessary nor sufficient conditions for romantic love in other societies. To illustrate this, we present the construal of relationships in Chinese society as a case study.

We extend Kruglanski et al.’s model by embedding it within a Goal-Directed Predictive Processing framework. This perspective conceptualizes romantic love as arising from self-referential inferences tied to personal goals and reveals that love may include merit, appreciation, and significance, but is not defined or limited by them. It also explains love experiences that exceed the scope of the authors’ model.

Kruglanski et al.’s “love as a quest” model casts romantic love as a path to personal significance. We argue this framing misrepresents love’s core nature, overlooking relational, emotional, and cultural dimensions. Love is not merely a reflection of individual validation but is dynamic and co-constructed. We advocate for a more relationally grounded and culturally inclusive framework on love.

The tri-factorial model of love attempts to explain the motivational underpinnings of romantic love. Given how the components are defined, the model has limited falsifiability and generalizability. We argue that a broader variety of interpersonal phenomena can be better explained with a framework that considers others’ instrumentality to various goals that dynamically shift in importance.

Love emerges through interpersonal exchanges that evolve over time. A comprehensive account of love should reflect this dynamic nature and encompass its temporal and interpersonal aspects. As such, we propose integrating these dynamics into the target article’s framework to better align with relationship science and more accurately capture how romantic relationships develop, persist, and change across time and interaction.

I offer a commentary on the “love as quest” model presented by Kruglanski and colleagues, highlighting its novel additions to our understanding of love, its potential and limitations as an empirically testable theory, and its clinical value.

We critically evaluate the robustness of the “quest for significance” as a foundational driver of love. Drawing on attachment and belongingness theories, we argue that love stems from fundamental evolutionary needs for human connection. Furthermore, we propose that there should be a distinction on how the model is applied to explain love across different types and stages of relationships.