Fulker D W, DeFries J C, Plomin R
Institute for Behavioural Genetics, University of Colorado, Boulder 80309-0447.
Nature. 1988;336(6201):767-9. doi: 10.1038/336767a0.
Adoption studies can provide direct evidence for the independent effects of family environment and heredity that are always confounded in intact nuclear families. When children are separated from their biological mothers shortly after birth and placed nonselectively in adoptive homes, adoptive-parent/adopted-child resemblance can be ascribed to cultural transmission, whereas biological-parent/adopted-child similarities are due to heritable factors. Furthermore, a longitudinal adoption study facilitates examination of changes in these two main sources of variation during development. The Colorado Adoption Project is the first large-scale longitudinal adoption study of behavioural development and was initiated in 1975. Data were collected from biological parents of 245 adopted children, the adoptive parents and parents of 245 matched nonadopted children. The children have subsequently been tested at 1, 2, 3 and 4 years of age, and at the end of their first year in primary school (average age, 7.4 years). The number of subjects tested is now adequate for analysis of data over 7 years. The results provide conclusive evidence for increasing heritable variation of general mental ability, ranging from 9% at 1 year of age to 36% at 7 years.
收养研究能够为家庭环境和遗传的独立影响提供直接证据，而在完整的核心家庭中，这两者的影响总是相互混淆的。当孩子在出生后不久就与其亲生母亲分离，并被随机安置在收养家庭中时，养父母与养子女之间的相似性可归因于文化传承，而亲生父母与养子女之间的相似性则归因于遗传因素。此外，一项纵向收养研究有助于考察这两种主要变异来源在发育过程中的变化。科罗拉多收养项目是第一项关于行为发展的大规模纵向收养研究，始于1975年。数据收集自245名被收养儿童的亲生父母、收养父母以及245名匹配的非收养儿童的父母。这些孩子随后在1岁、2岁、3岁、4岁时接受了测试，并在小学一年级结束时（平均年龄7.4岁）再次接受测试。目前，接受测试的受试者数量足以对7年的数据进行分析。结果为一般智力能力的遗传变异增加提供了确凿证据，其遗传变异从1岁时的9%增至7岁时的36%。
