Thomas begins with a clear truth that we depend on social relationships “from the moment we are born.” While we do not disagree with this stance, we levy two caveats. First, it is important to consider that social relationship formation is predicated upon influences that in fact precede birth, as the prenatal environment primes physiological mechanisms with direct implications for how we develop and react to social inputs. Second, while the theoretical framework explicated within the article is innovative, it is grounded in literature primarily conducted among children 6 months and older. Therefore, the developmental origins of social relationships, as outlined in Thomas, lack the critical nuances of the neonatal affective environment, including the development of the stress response, maternal mental health, and reciprocal parent–child affective processes.

In terms of prenatal exposures, maternal stress during gestation has been consistently linked with increased risk of self-regulatory and emotional deficits before the age of two (Korja, Nolvi, Grant, & McMahon, Reference Korja, Nolvi, Grant and McMahon2017), with particular implications for a child’s perceived strength of a given relationship, as outlined in Thomas’s framework. Much of this may be driven by neuroendocrine perturbations. The stress hormone cortisol is just one example, as a mother’s prenatal feelings of stress and anxiety specific to the pregnancy predict her infant’s cortisol reactivity throughout the first year of life (Tollenaar et al., Reference Tollenaar, Beijers, Jansen, Riksen-Walraven and de Weerth2011). Moreover, a mother’s own cortisol patterns have been similarly shown to prime stress reactivity in infancy (Irwin et al., Reference Irwin, Meyering, Peterson, Glynn, Sandman, Hicks and Davis2021). These physiological patterns may also be borne out in infant behavior, as one study found that infants exposed to higher levels of maternal cortisol cried and fussed more and displayed more negative facial expressions during the first five months of life (de Weerth, van Hees, & Buitelaar, Reference de Weerth, van Hees and Buitelaar2003). Alterations in hypothalamic-pituitary-adrenal axis responsivity and resultant cortisol profiles may have lifelong implications for social cognition and downstream relationship stability (Cheng & Kornienko, Reference Cheng, Kornienko, Granger and Taylor2020; Ji, Flouri, & Papachristou, Reference Ji, Flouri and Papachristou2021). This of course would affect social relationship formation and learning.

Another factor related to prenatal exposures is postpartum depression, which we here use as an example of the importance of maternal care and related learning in cognitive representations of social relationships. Looking upstream, much prior work links cortisol profiles to maternal depressive states (Seth, Lewis, & Galbally, Reference Seth, Lewis and Galbally2016). Similarly, our previous research has documented various prenatal stressors and other physiological factors – including DNA methylation of immunoregulatory genes, telomere length, and oxytocin levels in mothers – as related to postnatal mental health (Incollingo Rodriguez et al., Reference Incollingo Rodriguez, Polcari, Nephew, Harris, Zhang, Murgatroyd and Santos2022; Rodriguez et al., Reference Rodriguez, Smith, Harris, Nephew, Santos and Murgatroyd2022; Sluiter et al., Reference Sluiter, Incollingo Rodriguez, Nephew, Cali, Murgatroyd and Santos2020). Moreover, oxytocin is not only implicated in buffering against the consequences of maternal psychosocial stress, but it also serves as a key modulator of early parent–infant contact and interaction and, in turn, attachment development (Scatliffe, Casavant, Vittner, & Cong, Reference Scatliffe, Casavant, Vittner and Cong2019). Not surprisingly, then, a strong body of evidence points to maternal depressive symptoms as a risk factor for impaired maternal–infant bonding quality (Tichelman et al., Reference Tichelman, Westerneng, Witteveen, van Baar, van der Horst, de Jonge and Peters2019). Because maternal postnatal depression can develop shortly after birth, it is critical to examine very early life pathways in bonding and relationship formation that may create enduring models for how humans go on to perceive the social world and develop relationships.

The target article’s Intuitive Theory of Relationships also overlooks critical affective processes that are foundational to understanding parent–child dynamics, particularly during infancy and toddlerhood. While the theory incorporates behavioral and cognitive mechanisms, it neglects the roles of emotional reciprocity, maternal responsiveness, and dyadic regulation – factors that underpin socio-emotional development. This gap limits its explanatory power and practical utility in addressing early parent–child relational challenges.

The author can address this gap in various ways, but here are possible avenues to strengthen the theory with social and affective phenomena:

1. 1. Emotional Reciprocity and Validation: Affective processes such as mutual emotional attunement, validation, and positive affect exchange are central to secure parent–child relationships. For instance, Gottman and colleagues’ well-known work on marital interactions highlights how de-escalation of negative affect and ratios of positive versus negative affect predict relationship stability. Similarly, parent–child interactions thrive when caregivers respond sensitively to infants’ cues (e.g., soothing distress, mirroring joy), fostering trust and self-regulation (Brown et al., Reference Brown, Gao, Isenhour, Shakiba, Crowell, Raby and Conradt2025). The absence of these dynamics in the author’s model oversimplifies the emotional scaffolding required for healthy development.

2. 2. Dynamic Emotional Regulation: The theory does not account for the bidirectional nature of emotion regulation. Infants and toddlers rely on caregivers to co-regulate their emotions through responsive behaviors (e.g., calming touch, vocal modulation). Maternal overcontrol or intrusiveness, conversely, disrupts this process, leading to poorer reactive control and effortful control outcomes (Brown et al., Reference Brown, Gao, Isenhour, Shakiba, Crowell, Raby and Conradt2025). Affective processes like empathy and affection – linked to children’s later emotion regulation and social competence (Ornaghi, Conte, & Grazzani, Reference Ornaghi, Conte and Grazzani2020) – are critical yet missing from the author’s framework.

3. 3. Maternal Emotion Regulation Skills: To enhance emotional reciprocity and validation and dynamic emotion regulation, interventions could be designed to strengthen parental (especially maternal) emotion regulation skills. Some research indicates the promise of this approach, especially those that address psychosocial stressors. For example, Ribaudo and colleagues developed a home visit program that reduced PTSD symptoms in mothers and improved co-regulation capacities (Ribaudo et al., Reference Ribaudo, Lawler, Jester, Riggs, Erickson, Stacks and Rosenblum2022).

Affective processes are central to parent–child relationships. By foregrounding emotional reciprocity and dyadic regulation, Thomas’ framework could better predict and promote socio-emotional resilience from infancy onward.