Despite the reliability of intelligence measures in predicting important life outcomes such as educational achievement and mortality, the exact configuration and neural correlates of cognitive abilities remain poorly understood, especially in childhood and adolescence. Therefore, we sought to elucidate the factorial structure and neural substrates of child and adolescent intelligence using two cross-sectional, developmental samples (CALM: N = 551 (N = 165 imaging), age range: 5–18 years, NKI-Rockland: N = 337 (N = 65 imaging), age range: 6–18 years). In a preregistered analysis, we used structural equation modelling (SEM) to examine the neurocognitive architecture of individual differences in childhood and adolescent cognitive ability. In both samples, we found that cognitive ability in lower and typical-ability cohorts is best understood as two separable constructs, crystallized and fluid intelligence, which became more distinct across development, in line with the age differentiation hypothesis. Further analyses revealed that white matter microstructure, most prominently the superior longitudinal fasciculus, was strongly associated with crystallized (gc) and fluid (gf) abilities. Finally, we used SEM trees to demonstrate evidence for developmental reorganization of gc and gf and their white matter substrates such that the relationships among these factors dropped between 7–8 years before increasing around age 10. Together, our results suggest that shortly before puberty marks a pivotal phase of change in the neurocognitive architecture of intelligence.

尽管智力测量在预测教育成就和死亡率等重要生活结果方面具有可靠性，但认知能力的确切结构和神经相关性仍然知之甚少，尤其是在儿童和青少年时期。因此，我们试图使用两个横截面发育样本来阐明儿童和青少年智力的因子结构和神经基础（CALM：N = 551（N = 165 成像），年龄范围：5-18 岁，NKI-Rockland： N = 337（N = 65 成像），年龄范围：6-18 岁）。在预先注册的分析中，我们使用结构方程模型（SEM）来检查儿童和青少年认知能力个体差异的神经认知结构。在这两个样本中，我们发现较低能力和典型能力群体的认知能力最好理解为两个可分离的结构：结晶智力和流体智力，它们在发展过程中变得更加明显，与年龄分化假说一致。进一步的分析表明，白质微观结构，尤其是上纵束，与结晶（gc）和流体（gf）能力密切相关。最后，我们使用 SEM 树来证明 gc 和 gf 及其白质基质的发育重组的证据，使得这些因素之间的关系在 7-8 岁之间下降，然后在 10 岁左右增加。总之，我们的结果表明，在青春期标志之前不久，智力神经认知结构变化的关键阶段。