DOCTORS and policymakers in the rich world are increasingly worried about loneliness. Researchers define loneliness as perceived social isolation, a feeling of not having the social contacts one would like. To find out how many people feel this way, The Economist and the Kaiser Family Foundation (KFF), an American non-profit group focused on health, surveyed nationally representative samples of people in three rich countries. The study found that over 9% of adults in Japan, 22% in America and 23% in Britain always or often feel lonely, or lack companionship, or else feel left out or isolated.

One villain in the contemporary debate is technology. Smartphones and social media are blamed for a rise in loneliness in young people. This is plausible. Data from the OECD club of mostly rich countries suggest that in nearly every member country the share of 15-year-olds saying that they feel lonely at school rose between 2003 and 2015.

The smartphone makes an easy scapegoat. A sharp drop in how often American teenagers go out without their parents began in 2009, around when mobile phones became ubiquitous. Rather than meet up as often in person, so the story goes, young people are connecting online.

But this need not make them lonelier. Snapchat and Instagram may help them feel more connected with friends. Of those who said they felt lonely in the KFF/Economist survey, roughly as many found social media helpful as thought it made them feel worse. Yet some psychologists say that scrolling through others’ carefully curated photos can make people feel they are missing out, and lonely.

It is not clear whether it is heavy social-media use leading to loneliness, or vice versa. The most rigorous recent study of British adolescents’ social-media use, published by Andrew Przybylski and Netta Weinstein in 2017, found no link between “moderate” use and measures of well-being. They found evidence to support their “digital Goldilocks hypothesis”: neither too little nor too much screen time is probably best.

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