Department of Psychology, Centrefor Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Scotland, United Kingdom.
Psychol Aging. 2012 Sep;27(3):761-7. doi: 10.1037/a0026527. Epub 2011 Dec 19.
Investment traits--the tendency to seek out and engage in cognitive activity--might affect intellectual growth across the life span, specifically the development from fluid to crystallized intelligence. Here we explore how childhood IQ at age 11 years, IQ at age 79, and the investment trait Typical Intellectual Engagement (TIE) at age 81 affect the mean level and change in verbal fluency scores, used as an indicator of crystallized intelligence, across the ages 79, 83, and 87 in the Lothian Birth Cohort 1921 (maximum N = 569; Deary, Whiteman, Starr, Whalley, & Fox, 2004). A first latent growth model showed significant variance in the mean level of verbal fluency and significant decline in verbal fluency from age 79 to age 87. The rate of change was invariant across study participants in the Lothian Birth Cohort 1921. A second model found that IQ at age 11 significantly predicted IQ at age 79 (β = .66; p < .001), which in turn predicted verbal fluency and TIE in the ninth decade of life with standardized path parameters of .46 and .15 (p < .001), respectively. TIE had a significant association with verbal fluency (β = .14, p = .002); together, IQ at age 11 and 79 and TIE accounted for 25.5% of the variance in verbal fluency. A final model identified the TIE subfactor of intellectual curiosity as a significant mediator of the effect of IQ on verbal fluency; the TIE subfactors abstract thinking, reading, and problem solving showed no significant associations. In summary, TIE--in particular, intellectual curiosity--significantly mediated the effects of IQ on crystallized intelligence in old age. Because there was no significant between-subjects variance in verbal fluency trajectories in the current study, neither TIE nor IQ were associated with individual differences in cognitive decline.
投资特质——即寻求和参与认知活动的倾向——可能会影响整个生命周期的智力发展，特别是从流体智力到晶体智力的发展。在这里，我们探讨了 11 岁时的儿童智商、79 岁时的智商以及 81 岁时的投资特质典型智力参与（TIE）如何影响言语流畅性得分的平均水平和变化，言语流畅性得分作为晶体智力的指标，在洛锡安出生队列 1921 年的 79 岁、83 岁和 87 岁时使用（最大 N = 569；Deary、Whiteman、Starr、Whalley 和 Fox，2004）。第一个潜在增长模型显示言语流畅性的平均水平存在显著差异，并且言语流畅性从 79 岁到 87 岁呈下降趋势。洛锡安出生队列 1921 年的研究参与者的变化率是不变的。第二个模型发现，11 岁时的智商显著预测了 79 岁时的智商（β=0.66；p<0.001），而 79 岁时的智商又预测了 90 岁时的言语流畅性和 TIE，标准化路径参数分别为 0.46 和 0.15（p<0.001）。TIE 与言语流畅性显著相关（β=0.14，p=0.002）；11 岁和 79 岁时的智商和 TIE 共解释了言语流畅性的 25.5%。最后一个模型确定了 TIE 中智力好奇心的子因素是智商对言语流畅性影响的重要中介；TIE 的抽象思维、阅读和解决问题的子因素没有显示出显著的关联。总之，TIE——特别是智力好奇心——显著中介了智商对老年晶体智力的影响。由于在当前研究中，言语流畅性轨迹在被试间没有显著差异，因此 TIE 和 IQ 都与认知衰退的个体差异无关。
