Reynolds C A, Baker L A, Pedersen N L
Institute for Behavioral Genetics, University of Colorado at Boulder 80309-0447, USA.
Behav Genet. 1996 Mar;26(2):73-88. doi: 10.1007/BF02359886.
Genetic influences have consistently been reported to be the principal explanation for resemblance among relatives for intelligence, with shared environmental effects playing a much smaller role. However, crucial to understanding the nature of environmental influences are the mechanisms of assortative mating. Phenotypic assortment, albeit widely assumed or modeled in biometrical analyses, may be less important than other assortment processes, such as social homogamy. Consequently, effects of shared environment may play a greater role than prior studies have suggested. The goal of this study was to resolve environmental and genetic influences on fluid ability based on alternative models of assortment by examining the similarity of monozygotic (MZ) and dizygotic (DZ) twins and their spouses. Raven's Progressive Matrices scores were available from a population-based Swedish sample of 138 twin kinships. The effects of both social homogamy and phenotypic assortment were tested simultaneously in each of two alternate assortment models. A factor/delta path model represented social homogamy as a common factor and phenotypic assortment as a delta path, while a delta/delta path model represented both social homogamy and phenotypic assortment as delta paths. Overall, the factor/delta path model was found to be superior. Results suggested that social homogamy completely explained spouse similarity; phenotypic assortment was not significant. The results of these analyses suggest the presence of shared environmental effects among twins and their spouses, which would have been underestimated if only phenotypic modeled phenotypic assortment may have underestimated the effects of environment.
一直以来，遗传影响都被认为是亲属间智力相似性的主要解释，而共享环境影响所起的作用则小得多。然而，理解环境影响本质的关键在于选型交配机制。表型选型交配尽管在生物统计学分析中被广泛假设或建模，但可能不如其他选型交配过程重要，比如社会同质性。因此，共享环境的影响可能比先前研究所表明的更大。本研究的目的是通过检验同卵（MZ）和异卵（DZ）双胞胎及其配偶的相似性，基于替代的选型交配模型来解析环境和遗传对流体能力的影响。瑞文标准推理测验分数来自瑞典一个基于人群的包含138对双胞胎亲属关系的样本。在两个替代选型交配模型中的每一个中，同时检验了社会同质性和表型选型交配的影响。一个因素/增量路径模型将社会同质性表示为一个共同因素，将表型选型交配表示为一条增量路径，而一个增量/增量路径模型将社会同质性和表型选型交配都表示为增量路径。总体而言，发现因素/增量路径模型更优。结果表明社会同质性完全解释了配偶间的相似性；表型选型交配不显著。这些分析结果表明双胞胎及其配偶之间存在共享环境影响，如果仅对表型进行建模，表型选型交配可能低估了环境的影响。
