Behavioral Proxies of Early Brain Development: Memory, Executive Function, and Language Outcomes in a Nationally Representative Taiwanese Cohort

Background: Early memory and executive function (EF) in young children are widely regarded as behavioral proxies of hippocampal and prefrontal maturation, which in turn scaffold the emergence of language networks. We test whether early cognitive proxies predict later language outcomes in a nationally representative cohort. Methods: Data were drawn from the Kids in Taiwan (KIT) longitudinal database (n = 6,652 at 36 months). Hierarchical regression models examined whether 12-month memory and EF predicted 24-month language comprehension and expression, and whether 24-month cognition predicted 36-month outcomes, controlling for parental education, involvement, responsiveness, child gender, and child temperament. Results: At 12 months, both memory and executive function (EF) significantly predicted language comprehension and expression at 24 months, with incremental ΔR² of approximately .06 for comprehension and .04 for expression. For comprehension, memory (β ≈ 0.26, p < .001) and EF (β ≈ 0.04, p = .006) were significant predictors. For expression, memory (β ≈ 0.21, p < 0.001) and EF (β ≈ 0.06, p < 0.001) were also significant predictors. In contrast, cognitive predictors at 24 months showed negligible associations with 36-month outcomes. For both comprehension and expression, adding memory and EF at Step 3 resulted in minimal increases in explained variance (ΔR² ≈ .001; ns), and coefficients did not reach significance. Conclusions: Memory and EF serve as behavioral indicators of early neu-rocognitive development, demonstrating predictive power for subsequent language outcomes. Although predictive links from 24 to 36 months were weaker, measures of memory and EF at 12 months showed robust associations with 24-month language comprehension and expression. These findings underscore the value of identifying cognitive markers of early brain development for informing early screening and intervention.