Longitudinal Links between Sibling Relationship Quality and Adolescent Academic Functioning in Black Families

Background. Evidence suggests that Black youth exhibit steeper declines in academic functioning across adolescence (Benner et al., 2018), but their family experiences, including their sibling relationships, may be protective (McHale et al., 2012). Grounded in family systems theory, which highlights connections between family subsystems (Minuchin, 1985), this study extends understandings of family factors in Black youth’s academic outcomes by examining whether sibling relationships protect against declines in adolescent academic functioning. We investigated whether sibling warmth— displayed to and/or experienced by a sibling—had implications for academic functioning and tested the impact of siblings shared personal characteristics— shared ethnic identity and gender — on the associations between sibling warmth and academic functioning.

Methods. Our sample included 191 sibling pairs from a three-year longitudinal study of two-parent Black families. The sample was almost equally divided by sibling gender constellation. At Time 1, firstborns averaged 13.80 (SD = 1.74) and secondborns averaged 10.36 (SD = 1.09) years of age. Median family income was $77,000 (SD: $57,312; range: $3,000 to $525,000). In annual home interviews, siblings reported on their warmth toward their sibling and their academic interest and self-esteem; grades were taken from the most recent report card. Siblings also rated their ethnic identity, and a difference score was calculated to determine the similarity (sharedness) between siblings’ ratings.

Using over-time actor-partner interdependence modeling (APIM) via multilevel modeling, Model 1 tested baseline models estimating associations between both actor (displayed) and partner (experienced) sibling warmth and each index of academic functioning at the within­– and between-person levels. We added shared ethnic identity and siblings’ gender constellation as moderators in Model 2. Control variables included younger siblings’ age (the time indicator), parent education, and parental warmth as reported by youth.

Results. Baseline models revealed that, on occasions when youth displayed (actor effect) more sibling warmth than usual (i.e., compared to their own cross-time mean level), both siblings reported greater academic interest (γ = .02, SE = .01, p < .01) and academic self-esteem (γ = .01, SE = .00, p < .01). Model 2 showed significant moderating effects for shared ethnic identity and gender constellation on academic interest and self-esteem. When siblings experienced more warmth (partner effect) and siblings’ ratings of ethnic identity were more similar (i.e., difference scores were small), youth reported stronger academic interest (γ = .05, SE = .01, p <.01). When siblings experienced more warmth, however, boys in brother-brother pairs reported less academic self-esteem (γ = -.02, SE = .01, p<.01). At the between person level, more displayed warmth (actor effect) was positively associated with both academic interest (γ = .04, SE = .01, p < .01) and self-esteem (γ = .01, SE = .00, p < .01) for both siblings.

Conclusion. Findings highlight that, net of parental warmth, sibling warmth may support positive academic functioning. Findings for brother pairs, however, were consistent with research suggestive of some risks in these close relationships (Patterson et al., 1984). Our findings also highlight the potential role of culture in these links—a topic for further study.