The relationship between family background and children’s language development and education

Doing well in education equips individuals with the skills and knowledge to succeed in life, yet significant gaps in school performance exist, particularly for disadvantaged children. Across three studies, this thesis explores the relative contribution family background measures – encompassing family socioeconomic status (SES) and children’s genetic propensities (polygenic scores) – and their early verbal abilities have on later school performance. And the confounding role family background plays in the relationship between early verbal abilities and school performance. First, a meta-analysis pooling data of polygenic predictions of education achievement, derived from a GWAS for years spent in education (Kestimates=19, Kstudies=12, Ntotal=83,788), found that polygenic predictions explained up to 25.0% of the variance in school grades after accounting for age of assessment and outcome measure (ρ=.50). Second, a meta-analysis snythesising 28 years of research since 1995, examined the association between family SES and children’s preschool language ability (Kestimates=46, Nstudies=15, Ntotal=115,514), and found that family SES accounted for up to 5.3% of variance in preschool language ability (ρ=.23). Third, an empirical study used structural equation modelling to estimate the relative contribution of children’s early verbal ability to later school performance. Using data from the Twins Early Development study (TEDS), early verbal ability at age 4.5 years accounted for up to 11.0% of the variance in school performance between ages 7 and 16. However, when family background measures were included in the models, up to 70.2% of the association between verbal ability and school performance was attributed to family background, indicating substantial confounding. Taken together, this thesis provides insights into family background inequality, highlighting the critical roles of both genetic and socioeconomic factors in shaping children’s language and educational outcomes, demonstrating how these influences even confound the association between early verbal ability and later school performance.