Exploring how Attachment and Caregiving Discourse relate to Caregivers’ Physiological Regulation of Arousal in both Adoptive and Biological Parent-Child Relationships

Abstract: Systematic Literature Review Attachment theory increasingly recognises the role of physiological processes in shaping parent-child relationships. This systematic review robustly synthesised empirical studies examining how parental physiology relates to attachment in parent-child dyads, excluding studies based on self-report. A comprehensive literature search of 2,552 papers was conducted across Scopus, PubMed, and PsycArticles, identifying 11 eligible studies published between 1990 and 2025. All studies were quantitative: five experimental, six observational, one pre-test-post-test, and one longitudinal with experimental components. Studies were generally of good quality, assessed using Joanna Briggs Institute (JBI) critical appraisal tools. The review followed narrative synthesis guidance by Popay et al. (2006) and PRISMA guidelines. Findings suggested secure parental attachment is broadly associated with greater physiological flexibility and regulation, while insecure attachment reflects distinct patterns of dysregulation. Avoidant attachment was most frequently studied, with anxious and disorganised patterns underrepresented. Most studies focused on autonomic nervous system (ANS) indices, particularly respiratory sinus arrhythmia (RSA), with fewer examining hormonal, neural, or alternative physiological indices. Emerging evidence suggested parental physiological regulation may influence caregiving behaviours and contribute to intergenerational transmission of attachment patterns. These findings support theoretical models positioning attachment as an embodied, neurobiological process. However, significant heterogeneity in methodology limited comparability across studies. Sample sizes were often small, with fathers or diverse populations rarely included. Despite these limitations, the review highlights the value of integrating physiological and attachment constructs into assessments. Future research should standardise physiological protocols, broaden the range of systems studied beyond the ANS, and incorporate qualitative approaches to deepen understanding of underlying processes. Greater inclusion of underrepresented attachment styles, diverse populations and caregiving contexts is needed. The review highlights the potential of physiological insights to inform clinical interventions, particularly for dyads affected by trauma or co-regulation difficulties. Abstract: Empirical Study Embodied models of attachment suggest physiological processes play a key role in shaping caregiving relationships, yet few studies have explored how these systems interact, particularly in adoptive contexts. This qualitative multiple case study examined whether and how caregivers’ attachment narratives align with their physiological regulation during attachment interviews, across both adoptive and biological parent-child relationships. Eight caregivers took part in video-recorded interviews, which were coded using the Meaning of the Child (MotC) to assess attachment discourse and the Sensory Attachment Intervention (SAI) to identify subtle behavioural indicators of physiological regulation. Cross-case and within-case analyses were conducted using McLeod’s (2010) theory-building framework. Most cases demonstrated strong coherence between narrative and physiological regulation, providing support for embodied models of caregiving. However, several nuanced patterns emerged, including mismatches between discourse and physiology, different patterns for biological and adoptive caregivers, low-arousal sensitivity, effortful regulation, and physiological collapse under strain. These findings suggest caregiver regulation is dynamic and context-sensitive, rather than fixed. Adoptive caregivers generally showed more pronounced attachment or physiology patterns, potentially reflecting the complex relational and psychological demands of adoptive parenting. Notably, some sensitive caregiving emerged from low-arousal states, indicating that sensitivity can arise through top-down regulation, reflective capacity, and relational support, even from less “ideal” physiological baselines. These findings extend embodied theories of attachment by showing narrative-physiology coherence is shaped by history, context, and relational scaffolding. Clinical implications include supporting caregiver regulation through body-based attachment interventions, particularly relevant for adoptive caregivers or those facing trauma or heightened relational stress. Future research could triangulate behavioural and biometric data, adopt longitudinal designs, and explore generalisability to diverse caregiving contexts such as foster families or neurodiverse populations.