Huguet Pascal, Carlier Michèle, Dolan Conor V, de Geus Eco J, Boomsma Dorret I
University Clermont Auvergne and CNRS,LAPSCO,Clermont-Ferrand,France.
Aix Marseille University,CNRS,LPC,Cognitive Psychology,Marseille,France.
Twin Res Hum Genet. 2017 Dec;20(6):550-557. doi: 10.1017/thg.2017.61. Epub 2017 Nov 10.
Twin research has offered evidence that monozygotic (MZ) twins are more socially close than dizygotic (DZ) twins, but has not paid much attention to the way twins compare themselves with their co-twin. The few studies in this area suggest that 'horizontal comparisons' (social comparison motivated by solidarity or communion with others) matter more for MZ twins than for DZ twins, at least when the co-twin is the social comparison standard. Consistent with this view, we predicted higher interest in MZ twins relative to DZ twins to select their co-twin rather than other people in general as the social comparison standard. The Social Comparison Orientation (SCO) scale, which measures the inclination to compare with others in a horizontal rather than vertical mode (comparing either upward or downward), was administered in 90 MZ pairs and 57 same-sex DZ pairs (63% female; average age 18.06 years) from the Netherlands Twin Register. MZ twin pairs showed significantly higher SCO scores than DZ twin pairs (with a large effect size) on the co-twin SCO, whereas the two groups did not differ from each other on the general SCO excluding the co-twin as social comparison standard. In MZ twin pairs, anxiety was associated with social comparison with others in general, not with their co-twin. For both scales, twin resemblance was explained by additive genetic variance. The present findings provide direct evidence that horizontal comparisons with the co-twin are of particular importance for MZ twins.
双胞胎研究提供了证据表明，同卵双胞胎比异卵双胞胎在社交上更为亲密，但却没有过多关注双胞胎将自己与同胞双胞胎进行比较的方式。该领域为数不多的研究表明，“横向比较”（因与他人的团结或亲密关系而产生的社会比较）对同卵双胞胎比对异卵双胞胎更为重要，至少当同胞双胞胎是社会比较标准时是这样。与这一观点一致，我们预测，相对于异卵双胞胎，同卵双胞胎会更倾向于选择他们的同胞双胞胎而非其他人作为社会比较标准。我们对来自荷兰双胞胎登记处的90对同卵双胞胎和57对同性异卵双胞胎（63%为女性；平均年龄18.06岁）施测了社会比较取向（SCO）量表，该量表测量的是在横向而非纵向模式下（向上或向下比较）与他人进行比较的倾向。在同胞双胞胎SCO方面，同卵双胞胎对的SCO得分显著高于异卵双胞胎对（效应量较大），而在将同胞双胞胎排除在社会比较标准之外的一般SCO方面，两组之间没有差异。在同卵双胞胎对中，焦虑与一般与他人的社会比较有关，而与他们的同胞双胞胎无关。对于这两个量表，双胞胎的相似性都可以由加性遗传方差来解释。目前的研究结果提供了直接证据，表明与同胞双胞胎的横向比较对同卵双胞胎尤为重要。
