More than correlates: Longitudinal evidence of bidirectional effects between associative learning and fluid intelligence in elementary school children

Associative learning enables children to flexibly acquire, organize, and retrieve structured knowledge, while fluid intelligence equips them with the ability to reason, adapt, and apply strategies in unfamiliar situations. Although these abilities have been extensively studied, the developmental relationship between associative learning and fluid intelligence remains underexplored. This three-year longitudinal study examined the bidirectional relationship between associative learning and fluid intelligence in elementary school children. Using a sample of 160 fourth-grade elementary school students assessed at three time points, we employed random intercept cross-lagged panel modeling to disentangle within-person from between-person effects in their relationship, while controlling for working memory and processing speed. Results revealed a significant positive correlation between associative learning and fluid intelligence at the between-person level. At the within-person level, analyses demonstrated reciprocal predictive effects: higher-than-expected associative learning predicted subsequent improvements in fluid intelligence, and vice versa. These bidirectional effects remained significant after controlling for working memory and processing speed. These results provide evidence that associative learning and reasoning ability are reciprocally linked during late childhood, suggesting that supporting both domains may promote broader cognitive development over time.