Department of Psychology, The Hebrew University of Jerusalem.
Faculty of Psychology and Educational Sciences, School Psychology and Child and Adolescent Development, KU Leuven.
Dev Psychol. 2017 Nov;53(11):2092-2102. doi: 10.1037/dev0000318.
Identity formation is a key developmental task in adolescence. Although many adolescents in modern societies face issues of identity, there are substantial individual differences in identity exploration and commitment. Little is known about the origins of these individual differences. The current study investigated the genetic and environmental contributions to identity formation. In total, 571 11-year-old twins (85 monozygotic complete pairs and 176 dizygotic complete pairs) reported on their identity formation, using the Dimensions of Identity Development Scale (DIDS; Luyckx, Schwartz, Berzonsky, et al., 2008), as part of the Longitudinal Israeli Study of Twins (LIST; Avinun & Knafo, 2013). Multidimensional scaling analysis and confirmatory factor analysis supported the presence of all 5 dimensions at this young age: commitment making, exploration in-breadth, ruminative exploration, identification with commitment, and exploration in-depth. However, a model where exploration in-depth was divided into two subscales had a better fit to the data. Monozygotic twins were more similar to each other than dizygotic twins on all dimensions, except for one of the exploration in-depth subscales, supporting the idea that individual differences in various dimensions of identity formation are at least partially influenced by genetics (18-45%). For these dimensions, the rest of the variance was explained by nonshared environment effects (55-82%). Only one of the exploration in-depth subscales, that is, the tendency to explore commitments through discussion with others, showed evidence for the influence of the environment shared by twins (21%) but no genetic effect. Implications of the findings regarding the role of genetics and environment to identity formation are discussed. (PsycINFO Database Record
身份形成是青春期的一个关键发展任务。尽管现代社会中的许多青少年都面临着身份认同问题，但在身份探索和承诺方面存在着很大的个体差异。对于这些个体差异的起源知之甚少。本研究调查了身份形成的遗传和环境贡献。共有 571 对 11 岁的双胞胎（85 对同卵完全对和 176 对异卵完全对）参与了身份形成的研究，使用了身份发展维度量表（DIDS；Luyckx、Schwartz、Berzonsky 等人，2008），作为纵向以色列双胞胎研究（LIST；Avinun 和 Knafo，2013）的一部分。多维标度分析和验证性因素分析支持在这个年轻的年龄存在所有 5 个维度：承诺制定、广泛探索、沉思探索、承诺认同和深入探索。然而，将深入探索分为两个子量表的模型更符合数据。除了深入探索的一个子量表外，同卵双胞胎彼此之间比异卵双胞胎更相似，这支持了这样一种观点，即各种身份形成维度的个体差异至少部分受到遗传的影响（18-45%）。对于这些维度，其余的差异由非共享环境效应（55-82%）解释。只有深入探索的一个子量表，即通过与他人讨论来探索承诺的倾向，显示出双胞胎之间共享环境的影响（21%），但没有遗传效应。关于遗传和环境对身份形成的作用的发现的意义将在讨论中讨论。
