| Abstract: | We used structural equation modeling in the Early Childhood Longitudinal Study—Kindergarten Cohort (N = 17,020) to explore the influence of having an older sibling on kindergarten‐age focal children's cognitive self‐regulation. In model 1, we tested how having a sibling who is generally older than the focal child contributes to the focal child's working memory (WM) and cognitive flexibility (CF) upon entering kindergarten. In model 2, we assessed the contribution to the focal child's kindergarten WM and CF of having an older sibling in a non‐proximal age range (age 12–18) or not having siblings relative to having an older sibling in a proximal age range to the focal child (up to age 11). In model 3, we considered the contribution of having an older sister, an older brother, or both an older sister and an older brother of any age. Having an older sibling in general was associated with increased kindergarten WM, whereas having an older sister was related to increased WM and CF. Compared to having a proximal older sibling, having no siblings and having a non‐proximal older sibling were related to decreased WM and CF. Findings have implications for involving siblings in family interventions in early childhood. |
