The formation and maintenance of friendship closeness is an important developmental task in adolescence. To obtain insight in real-time processes that may underly the development of friendship closeness in middle adolescence, this preregistered experience sampling study [ESM] investigated the effects of social media use on friendship closeness. The study was conducted among 387 adolescents (54% girls; Mage = 14.11 years; 96% Dutch) from different educational tracks (44% lower prevocational secondary education, 31% intermediate general secondary education, 26% academic preparatory education). Adolescents reported six times per day for 3 weeks on their Instagram, WhatsApp, and Snapchat use in the previous hour and their momentary experiences of friendship closeness (126 assessments; 34,930 observations). Multilevel analyses revealed positive between-person associations of friendship closeness with general WhatsApp use and Instagram use with close friends. In contrast, at the within-person level, we found small negative overall associations of general WhatsApp use and Instagram use (with and without close friends) with friendship closeness. However, there was large heterogeneity in the person-specific effect sizes of the within-person associations of social media use with friendship closeness. For example, person-specific effect sizes of the association of Instagram use with close friends with friendship closeness ranged from β = -.745 to β = .697. These results underline the importance of acknowledging person-specific effects in developmental and media effect theories. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

中文翻译：

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青少年日常生活中的社交媒体使用和友谊亲密：一项经验抽样研究。

友谊亲密关系的形成和维持是青春期一项重要的发展任务。为了深入了解可能是青春期中期友谊亲密度发展的基础的实时过程，这项预先注册的经验抽样研究 [ESM] 调查了社交媒体使用对友谊亲密度的影响。该研究在来自不同教育领域（44% 的初级职业中等教育、31% 的普通中等教育、26% 的学术预备教育）的 387 名青少年（54% 女孩；法师 = 14.11 岁；96% 荷兰人）中进行。青少年报告了前一小时在 Instagram、WhatsApp 和 Snapchat 上的使用情况，每天六次，持续 3 周，以及他们对友谊亲密的瞬间体验（126 次评估；34,930 次观察）。多层次分析显示，一般使用 WhatsApp 和使用 Instagram 与亲密朋友之间的友谊亲近度之间存在积极的关联。相比之下，在个人层面，我们发现一般 WhatsApp 使用和 Instagram 使用（有和没有密友）与友谊亲密程度之间存在小的负面整体关联。然而，社交媒体使用与友谊亲密的个人内部关联的特定于个人的效应大小存在很大的异质性。例如，Instagram 使用与亲密朋友之间的关联的特定于个人的效果大小范围从 β = -.745 到 β = .697。这些结果强调了在发展和媒体效应理论中承认个体效应的重要性。（PsycInfo 数据库记录 (c) 2021 APA，保留所有权利）。