Only children's uniqueness has intrigued researchers for decades, but many gaps in knowledge remain as to whether only children differ from children who have siblings. We use data from four British birth cohorts (born in 1946, 1958, 1970, 2000–2002) to investigate cross-cohort differences in the composition of only child families and whether the association between being an only child and cognitive ability in childhood has changed over time. Only children show similar scores to children from two child families and higher scores than children with two or more siblings across each of the cohorts analyzed. However, the results also show that—consistent with the finding that, across cohorts, the composition of the only child group has become more associated with social disadvantage—the “only child advantage” has weakened when comparing the most recent birth cohort to the older ones. Adjustment by family sociodemographic characteristics attenuates within and cross-cohort differences. Moreover, the results show that the cognitive advantages associated with being an only child vary considerably by whether the cohort member has been exposed to parental separation or is growing up in a family with lower socioeconomic status. The results highlight diversity in being an only child whose characteristics are conditional on changes throughout time and society.

中文翻译：

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独生子女与童年认知能力：英国 50 年来的跨队列分析

几十年来，独生子女的独特性一直吸引着研究人员的兴趣，但对于独生子女是否与有兄弟姐妹的孩子是否不同，仍然存在许多知识空白。我们使用来自四个英国出生队列（1946年、1958年、1970年、2000-2002年出生）的数据来调查独生子女家庭构成的跨队列差异，以及独生子女与童年认知能力之间的关联是否发生了变化。随着时间的推移。在每个分析的队列中，独生子女的得分与来自两个孩子家庭的孩子相似，并且比有两个或更多兄弟姐妹的孩子得分更高。然而，结果还表明，与不同队列中的发现一致，独生子女群体的构成与社会劣势的关系越来越密切——当将最近出生的队列与较年长的队列进行比较时，“独生子女优势”已经减弱。通过家庭社会人口统计特征进行的调整会减弱队列内和队列间的差异。此外，结果表明，与独生子女相关的认知优势因队列成员是否经历过父母分居或在社会经济地位较低的家庭中长大而有很大差异。结果突显了独生子女的多样性，其特征取决于时间和社会的变化。结果表明，作为独生子女的认知优势因该群体成员是否经历过父母分居或在社会经济地位较低的家庭中长大而有很大差异。结果突显了独生子女的多样性，其特征取决于时间和社会的变化。结果表明，作为独生子女的认知优势因该群体成员是否经历过父母分居或在社会经济地位较低的家庭中长大而有很大差异。结果突显了独生子女的多样性，其特征取决于时间和社会的变化。