The objective of this study was to examine the genetic and environmental contributions to shyness throughout the school-age period. Participants were 553 twin pairs from the ongoing prospective longitudinal Quebec Newborn Twin Study. Teacher-rated measures of shyness were collected at five time-points from age 6-12 years. On average, shyness was moderately stable over time (r = 0.23-0.33) and this stability was almost entirely accounted for by genetic factors. Genetic factors at age 6 accounted for 44% of individual differences and these early genetic factors also explained individual differences at all subsequent ages (6-22%). Non-shared environmental factors explained most of individual differences at single time-points (51-63%), and did not account for stability in shyness. Contributions of shared environment were not significant. Our results suggest that the stability in shyness is mostly accounted for by early and persistent genetic contributions.

中文翻译：

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童年期害羞的遗传和环境病因。

这项研究的目的是研究在整个学龄期间遗传和环境对害羞的影响。正在进行的前瞻性纵向魁北克新生儿双胞胎研究的参与者为553对双胞胎。从6至12岁的五个时间点收集教师评估的害羞程度。平均而言，害羞度随着时间的推移适度稳定（r = 0.23-0.33），并且这种稳定性几乎完全由遗传因素引起。6岁时的遗传因素占个体差异的44％，而这些早期遗传因素也解释了所有随后年龄（6-22％）的个体差异。非共享环境因素解释了单个时间点的大多数个体差异（51-63％），并且没有说明害羞的稳定性。共享环境的贡献不大。