Suzuki Kunitake, Shikishima Chizuru, Ando Juko
Keio Advanced Research Centers, Tokyo, Japan.
Twin Res Hum Genet. 2011 Oct;14(5):437-43. doi: 10.1375/twin.14.5.437.
Sex differences in mental rotation ability have been observed in many countries. A previous study of Finnish participants reported that genetic and environmental influences on mental rotation ability differ between sexes. In this study, we assessed genetic and environmental influences on variance in mental rotation ability in 649 Japanese twins using a mental rotation test. To explain the influence of sex on variance in mental rotation ability, we applied genetic analysis using the sex limitation model. The following two factors explained variance in mental rotation ability: (1) the additive genetic factor, which reflects the accumulated small influence of many genes, and (2) the unique environmental factor, which is a type of environmental factor that differs between co-twins. The shared environmental factor, a type of environmental factor common for co-twins, could not explain the variance in mental rotation ability. Furthermore, the additive genetic factor was the same between sexes (i.e., not qualitative sex differences for the additive genetic factor), indicating that the same genes affect mental rotation ability in both sexes. Despite this observation, the additive genetic influence was greater in males than in females. In contrast, the unique environmental influence was not different between sexes. Considering the current results and those of a previous study, the quantitative sex difference for the additive genetic influences in mental rotation ability may be universal, while the unique environmental differences may depend on the characteristics of specific populations.
许多国家都观察到了心理旋转能力的性别差异。此前一项针对芬兰参与者的研究报告称，基因和环境对心理旋转能力的影响在性别上存在差异。在本研究中，我们使用心理旋转测试评估了649对日本双胞胎心理旋转能力差异中的基因和环境影响。为了解释性别对心理旋转能力差异的影响，我们应用了性别限制模型进行基因分析。以下两个因素解释了心理旋转能力的差异：（1）加性遗传因素，它反映了许多基因累积的微小影响；（2）独特环境因素，这是一种在双胞胎之间存在差异的环境因素类型。共同环境因素，即双胞胎共有的一种环境因素类型，无法解释心理旋转能力的差异。此外，加性遗传因素在性别之间是相同的（即加性遗传因素不存在质性性别差异），这表明相同的基因对两性的心理旋转能力都有影响。尽管有此观察结果，但加性遗传影响在男性中比在女性中更大。相比之下，独特环境影响在性别之间没有差异。综合当前结果和先前一项研究的结果来看，心理旋转能力中加性遗传影响的定量性别差异可能是普遍存在的，而独特环境差异可能取决于特定人群的特征。
