Reeves et al in Nature:
There has never been more anxiety about the effects of our love of screens — which now bombard us with social-media updates, news (real and fake), advertising and blue-spectrum light that could disrupt our sleep. Concerns are growing about impacts on mental and physical health, education, relationships, even on politics and democracy. Just last year, the World Health Organization issued new guidelines about limiting children’s screen time; the US Congress investigated the influence of social media on political bias and voting; and California introduced a law (Assembly Bill 272) that allows schools to restrict pupils’ use of smartphones.
All the concerns expressed and actions taken, including by scientists, legislators, medical and public-health professionals and advocacy groups, are based on the assumption that digital media — in particular, social media — have powerful and invariably negative effects on human behaviour. Yet so far, it has been a challenge for researchers to demonstrate empirically what seems obvious experientially. Conversely, it has also been hard for them to demonstrate that such concerns are misplaced.
…According to a 2019 systematic review and meta-analysis3, over the past 12 years, 226 studies have examined how media use is related to psychological well-being. These studies consider mental-health problems such as anxiety, depression and thoughts of suicide, as well as degrees of loneliness, life satisfaction and social integration. The meta-analysis found almost no systematic relationship between people’s levels of exposure to digital media and their well-being. But almost all of these 226 studies used responses to interviews or questionnaires about how long people had spent on social media, say, the previous day.