Psychology Department, Queen's University, Kingston, Canada.
Dev Sci. 2012 Mar;15(2):272-80. doi: 10.1111/j.1467-7687.2011.01124.x. Epub 2011 Dec 3.
Individual differences in preschoolers' understanding that human action is caused by internal mental states, or representational theory of mind (RTM), are heritable, as are developmental disorders such as autism in which RTM is particularly impaired. We investigated whether polymorphisms of genes affecting dopamine (DA) utilization and metabolism constitute part of the molecular basis of this heritability. Seventy-three 42- to 54-month-olds were given a battery of RTM tasks along with other task batteries that measured executive functioning and representational understanding more generally. Polymorphisms of the dopamine D4 receptor gene (DRD4) were associated with RTM performance such that preschoolers with shorter alleles outperformed those with one or more longer alleles. However, polymorphisms of the catechol-O-methyl transferase gene (COMT) and the dopamine transporter gene (DAT1) genes were not associated with children's RTM performance. Further tests showed that the association between DRD4 allele length and RTM performance was not attributable to a common association with executive functioning or representational understanding more generally. We conclude that DRD4 receptors, likely via their effects on frontal lobe development and functioning, may represent a neuromaturational constraint governing the stereotypical and universal trajectory of RTM development.
个体在幼儿时期对人类行为由内部心理状态引起的理解差异，或代表理论思维（RTM）是可遗传的，而自闭症等发育障碍中 RTM 特别受损也是可遗传的。我们调查了影响多巴胺（DA）利用和代谢的基因多态性是否构成这种遗传性的分子基础的一部分。73 名 42 至 54 个月大的儿童接受了一系列 RTM 任务以及其他任务，这些任务更广泛地测量了执行功能和代表性理解。多巴胺 D4 受体基因（DRD4）的多态性与 RTM 表现相关，即短等位基因的幼儿表现优于具有一个或多个长等位基因的幼儿。然而，儿茶酚-O-甲基转移酶基因（COMT）和多巴胺转运蛋白基因（DAT1）的多态性与儿童的 RTM 表现无关。进一步的测试表明，DRD4 等位基因长度与 RTM 表现之间的关联并非归因于与执行功能或更广泛的代表性理解的共同关联。我们的结论是，DRD4 受体可能通过其对额叶发育和功能的影响，代表了一种神经成熟约束，控制着 RTM 发展的典型和普遍轨迹。
