Infant-parent attachment has been theoretically proposed to serve a key regulatory function for chil-dren's emotion, cognition, and behavior, with secure attachment leading to more favorable outcomes, but much of the research supporting this claim has been conducted solely on infant-mother dyads. While research on infant-father attachment has gained traction, studies including fathers often examine their contributions as independent from mothers, which may overlook the interacting influence of multiple at-tachment relationships on child development. Here, we use a new approach in which we consider infant attachment to both mothers and fathers as a configuration. This study examined whether infant attach-ment configurations to both mothers and fathers predicted effortful control, compliance, and defiance during toddlerhood. Using data from a longitudinal study on socio-emotional development, 117 infants participated in the Strange Situation, first with their mothers at 12 months, and then again with their fathers at 14 months to assess attachment. When toddlers were 20 months of age, mothers completed a questionnaire assessing toddlers' effortful control, and toddlers were video recorded with their mothers and fathers in a gratification delay and clean-up task during a laboratory visit. Toddlers' compliance and defiance towards parents were coded. Using linear mixed models, attachment configuration in infancy significantly distinguished effortful control, compliance, and defiance in toddlerhood. Infants with a se-cure attachment only to fathers had significantly lower effortful control and higher defiance at 20 months than the other 3 attachment configurations. In contrast, infants with a secure attachment to mothers were significantly more compliant than infants without a secure attachment to mothers. Our findings provide evidence that when analyzed from a family systems perspective, attachment security (and insecurity) to mothers and fathers may be functionally distinct for children's developing socio-emotional competence. (c) 2021 Elsevier Inc. All rights reserved.
