Childhood personality and academic performance: A sibling fixed-effects study

Abstract

Objective: This study investigated the associations between personality traits at age 8 and academic performance between ages 10 and 14, controlling for family confounds. Background: Many studies have shown links between children’s personality traits and their school performance. However, we lack evidence on whether these associations remain after genetic and environmental confounders are accounted for. Method: Sibling data from the Norwegian Mother and Child Cohort Study (MoBa) were used (n = 9701). First, we estimated the overall associations be- tween Big Five personality traits and academic performance, including literacy, numeracy, and foreign language. Second, we added sibling fixed effects to remove unmeasured confounders shared by siblings as well as rating bias. Results: Openness to Experience (between-person β = 0.22 [95% CI: 0.21–0.24]) and Conscientiousness (between-person β = 0.18 [95% CI 0.16–0.20]) were most strongly related to educational performance. Agreeableness (between-per- son β = 0.06 [95% CI −0.08–0.04]) and Extraversion (between-person β = 0.02 [95% CI 0.00–0.04]) showed small associations with educational performance. Neuroticism had a moderate negative association (between-person β = −0.14 [95% CI −0.15–0.11]). All associations between personality and performance were ro- bust to confounding: the within-family estimates from sibling fixed-effects mod- els overlapped with the between-person effects. Finally, childhood personality was equally predictive of educational performance across ages and genders. Conclusions: Although family background is influential for academic achieve- ment, it does not confound associations with personality. Childhood personal- ity traits reflect unbiased and consistent individual differences in educational potential.