Twin studies are important for research on genetic and environmental influences on child development, but it is imperative to test whether findings can be generalised from twins to singletons. Since the first months of life are defined by the emergence of important sleep behaviours, we compared 451 (54.8% females) twins and 77 singletons (48.1% females) on a range of sleep, settle and crying behaviours at 5 months of age. No significant differences were found regarding duration of crying or time until settled. However, singletons were reported to wake up more frequently during nighttime than twins (F(1, 509) = 35.10, p < 0.001, ηp2 = 0.065), suggesting that, when reported in twin studies, this measure might be slightly underestimated at a mean level in relation to singletons. In conclusion, despite the unique challenges and additional caregiver load of infant twins, there seem to be few differences between twins and singletons regarding parent‐reported settle and crying behaviours in early infancy.

中文翻译：

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双胞胎和单胞胎在 5 个月大时的睡眠和安定行为比较


双胞胎研究对于遗传和环境对儿童发育影响的研究很重要，但必须检验研究结果是否可以从双胞胎推广到单胎。由于生命的最初几个月是由重要睡眠行为的出现定义的，因此我们比较了 451 名（54.8% 女性）双胞胎和 77 名单胞胎（48.1% 女性）在 5 个月大时的睡眠、安定和哭泣行为。在哭泣持续时间或稳定时间方面未发现显著差异。然而，据报道，单胎在夜间醒来的频率高于双胞胎 （F（1， 509） = 35.10，p < 0.001，ηp2 = 0.065），这表明，当在双胞胎研究中报告时，相对于单胎的平均水平，该指标可能被略微低估。总之，尽管婴儿双胞胎面临独特的挑战和额外的照顾者负担，但双胞胎和单胞胎之间在父母报告的婴儿早期安定和哭泣行为方面似乎几乎没有差异。