Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, De Crespigny Park, London, UK.
Mol Psychiatry. 2010 Nov;15(11):1112-20. doi: 10.1038/mp.2009.55. Epub 2009 Jun 2.
Although common sense suggests that environmental influences increasingly account for individual differences in behavior as experiences accumulate during the course of life, this hypothesis has not previously been tested, in part because of the large sample sizes needed for an adequately powered analysis. Here we show for general cognitive ability that, to the contrary, genetic influence increases with age. The heritability of general cognitive ability increases significantly and linearly from 41% in childhood (9 years) to 55% in adolescence (12 years) and to 66% in young adulthood (17 years) in a sample of 11 000 pairs of twins from four countries, a larger sample than all previous studies combined. In addition to its far-reaching implications for neuroscience and molecular genetics, this finding suggests new ways of thinking about the interface between nature and nurture during the school years. Why, despite life's 'slings and arrows of outrageous fortune', do genetically driven differences increasingly account for differences in general cognitive ability? We suggest that the answer lies with genotype-environment correlation: as children grow up, they increasingly select, modify and even create their own experiences in part based on their genetic propensities.
尽管常识表明，随着生活过程中经验的积累，环境影响越来越能解释行为上的个体差异，但这一假设以前从未得到过验证，部分原因是需要足够大的样本量才能进行充分有效的分析。在这里，我们展示了一般认知能力的情况恰恰相反，遗传影响随着年龄的增长而增加。在来自四个国家的 11000 对双胞胎样本中，一般认知能力的遗传力从儿童期（9 岁）的 41%显著线性增加到青春期（12 岁）的 55%，再增加到成年早期（17 岁）的 66%，这一样本量比以往所有研究的总和还要大。除了对神经科学和分子遗传学具有深远的意义外，这一发现还为我们在学校教育期间思考自然与教养之间的相互作用提供了新的思路。为什么尽管生活中充满了“突如其来的不幸”，但遗传驱动的差异却越来越能解释一般认知能力的差异呢？我们认为，答案在于基因型-环境相关性：随着孩子的成长，他们越来越多地根据自己的遗传倾向选择、改变甚至创造自己的经验。
