Examining self-regulation as a heterogeneous construct: A nuanced approach to understanding its relational antecedents.

Secure attachment to parents is known to promote children's self-regulation (SR), but the mechanisms explaining its associations with different aspects of SR, particularly in high-risk families, remain underexplored. We investigated maternal and child responsiveness as parallel mediators linking early attachment security to later SR, assessed within and outside mother-child relationships, with 186 low-income mother-child dyads. Attachment security was assessed using the Attachment Q-Set at 2.5 years, maternal and child responsiveness were observed during mother-child interactions at 3.5 years, and SR was measured at 7 years as mother-related (internalized compliance) and decontextualized (set-shifting tasks). Results demonstrated that both maternal and child responsiveness mediated the relations between attachment security and mother-related SR. Indirect relations were non-significant or weaker for decontextualized SR. Findings highlight the importance of mutually responsive interactions, with a particular focus on children's active contributions, in accounting for links between early parent-child relationships and later relational regulatory capacities.