Practitioner Review: caregiver-infant relationship difficulties and intervention in infancy

The infant-caregiver relationship is foundational to early development. Early atypical development can lead to long-term developmental cascades that cause later-life behavioural, emotional, and cognitive difficulties. Here, we focus on co-regulation – i.e., dynamic processes of mutual adaptation that underpin the caregiver-child relationship - during the 0-3 years age range. We explore the practical relevance of understanding co-regulation for intervention by pinpointing key mechanisms of change that drive the effectiveness of interventions. We discuss how mutual adaptation can be both beneficial (as it helps children to achieve and maintain an optimal, ‘critical’ state and fosters bio-behavioural synchrony) and detrimental (as short-term stress cycles can be dynamically reinforced across the dyad, and atypical long-term rhythms in one partner can progressively influence the other partner over time). We review how these principles are applied in current interventions, such as Circle of Security Parenting (COS-P), Video Interaction Guidance (VIG), Child-Parent Psychotherapy (CPP), and Dyadic Developmental Psychotherapy (DDP). We discuss under-explored areas that could be targeted in future intervention research. We highlight that child-caregiver relationships have been extensively studied at short-interval timescales - from seconds to minutes - in both naturalistic and controlled settings, and that most interventions focus on this timescale. There remains, though, a lack of quantitative data on how short-term interactions influence longer-term relationship dynamics over days, weeks and months, and this area is relatively under-explored in intervention research.