Siblings' similarities and dissimilarities: A review of theoretical perspectives and empirical insights

Abstract

Although siblings may differ considerably, the similarities between them are often an important source of emotional support in one's life and influence one's life course trajectories. In this review on the topic of sibling relationship and cross-sibling effect interactions, we aim to encourage research interest and facilitate knowledge building. We begin our review by highlighting how the parental home may induce differentiation between siblings. Next, we illustrate the theories explaining sibling similarities and differences and discuss the factors that stimulate these. Throughout the review, we do not only highlight the complex mechanisms by which siblings imitate yet differentiate themselves, but also mutually relate to their life courses and education. New understandings of how similarities between siblings can simultaneously act as powerful influences and negative examples are provided.

Transitions and transformations in sibling relationships: Characteristics of Turkish and US young adults’ sibling-related turning-point memories

“…This developmental dissimilarity decreases siblings’ shared experiences. Focusing on siblings with a smaller age gap is also advantageous to discovery of comparison, modeling, or deidentification between the siblings (Her et al, 2021).…”

“…They may develop similar qualities as a function of observational learning or modeling. Conversely, they may establish a unique self by adopting different attitudes and engaging in different activities as a function of sibling deidentification (Her et al, 2021; Whiteman et al, 2011).…”

Sibling effects on problem and prosocial behavior in childhood: Patterns of intrafamilial “contagion” by birth order

“…With respect to the latter, for example, if siblings' age range is wide, then children would be at widely different points in development and therefore sibling effects may arguably vary substantially in both direction and magnitude. Sibship size, on the other hand, may moderate sibling effects not only because it is related to the dilution of parental recourses, as discussed (Her et al, 2021), but also because, it approximates, by definition, the number of sources of sibling input (Tippett & Wolke, 2015). In many twochild families, for example, the younger sibling grows up with the same source of sibling influence during key developmental periods (Prime et al, 2017).…”

Weighing psychosocial factors in relatives for the risk of depressive and anxious psychopathology: A sibling-pair comparison study

“…the feeling of 'being the black sheep' in the family) [23][24][25]. This may even extend to sociodemographic risk factors such as higher age and female gender: for instance, rumination seems to be 'contagious' especially among older and same-sex female sibling pairs potentially due to the stronger emotional bonds and social learning/sharing [26][27][28][29]. Co-rumination, in turn, has been found to be associated with affective psychopathology [30,31].…”