Intelligence Quotient (IQ) is regularly used in both education and employment as a measure of cognitive ability. Although an individual's IQ is generally assumed to stay constant across the lifespan, a few studies have suggested that there may be substantial variation at the individual level. Motivated by previous reports that reading quality/quantity has a positive influence on vocabulary acquisition, we hypothesised that reading ability in the early teenage years might contribute to changes in verbal IQ (VIQ) over the next few years. We found that good readers were more likely to experience relative improvements in VIQ over time, with the reverse true for poor readers. These effects were largest when there was a discrepancy between Time 1 reading ability and Time 1 VIQ. In other words, VIQ increases tended to be greatest when reading ability was high relative to VIQ. Additional analyses supported these findings by showing that variance in VIQ change associated with Time 1 behaviour was also associated with independent measurements of brain structure. Our finding that reading in the early teenage years can predict a significant proportion of the variance in subsequent VIQ change has implications for targeted education in both home and school environments.

智商 (IQ) 在教育和就业中经常用作衡量认知能力的指标。尽管人们通常假设一个人的智商在整个生命周期中保持不变，但一些研究表明，个人水平可能存在重大差异。受之前报告阅读质量/数量对词汇习得有积极影响的启发，我们假设青少年早期的阅读能力可能会导致未来几年语言智商 (VIQ) 的变化。我们发现，随着时间的推移，优秀的读者更有可能体验到 VIQ 的相对改善，而差的读者则相反。当时间 1 阅读能力和时间 1 VIQ 之间存在差异时，这些影响最大。换句话说，当阅读能力相对于 VIQ 高时，VIQ 增加往往最大。其他分析通过显示与时间 1 行为相关的 VIQ 变化的差异也与大脑结构的独立测量相关，从而支持了这些发现。我们发现，青少年早期的阅读可以预测随后 VIQ 变化的很大一部分差异，这对家庭和学校环境中的有针对性的教育都有影响。