How is the rise of social media changing news consumption? This is one of the most pressing questions concerning the media today. The growth of social media may be slowing down in some countries, but the influence of platforms – in particular Facebook and Google – has never been greater, as people worry about misinformation, polarisation, filter bubbles, echo chambers, and the erosion of the shared news agenda, to name just a few concerns.

In this section we shed some light on these issues by focusing on incidental exposure to news – situations where people end up consuming something while intending to do something else. Our data show that people recognise that social media, search engines, and aggregators offer incidental exposure to news, and that this has real consequences for the diversity of their news consumption. We also examine in more detail how people actually use social media for news, including the extent to which people curate their news consumption and fine-tune the experience.

Many twentieth-century mass media environments were in part characterised by incidental exposure to news. People often read newspapers for their non-news content (e.g. reviews, recipes, and puzzles), and people carried on watching television news bulletins after their favourite entertainment programme had finished. This meant that people with low interest in the news still ended up being exposed to news content. But in high-choice media environments – like the web – where people also enjoy greater control over what they consume, the potential for incidental exposure to news feels much lower. Some worry that this will produce a situation where people most interested in news will be much better informed, but those with low interest will be left behind.

It is perhaps easy to forget that algorithmically driven services like search engines, aggregators, and social media have the potential to reintroduce incidental exposure to news, for the simple reason that they assume some responsibility for what we see online. We decided to see whether our respondents experience and recognise this. It appears that many do.

For users of both social media and news aggregators, more people agree that they often see news from sources they wouldn’t normally use (36% and 35%) than disagree (27%). As a possible consequence of this, but also because these services have the potential to incidentally expose users to different topics as well as different news sources, more agree (40% and 37%) that they often see news stories that do not interest them than disagree (27%).

Another way of thinking about this is to compare users and non-users of these services in terms of how many online news brands they use. If people are incidentally exposed to news, we would expect them to end up using more news brands. And indeed when we count the number of brands, we find that on average social media users access more brands (4.34 per week) than non-users (3.10 per week). Likewise, those who use search engines for news, or news aggregators, use more online news brands than those who don’t.

Of course, some people use these for news intentionally, so we can’t say this is entirely down to incidental exposure. So, we asked users of Facebook, YouTube, and Twitter a series of follow-up questions that aimed to better understand how they use them. Of all respondents across all markets, 19% say they see Facebook as a useful source of news, 26% say they see news when using it for other reasons, and 23% say they use Facebook but don’t generally come across news when using it. One in ten say they see YouTube as a useful source of news, but the majority of YouTube users don’t see any news there. Just 6% say they intentionally use Twitter for news, and it is striking that the total Twitter user base (20% of respondents) is about the same size as the number of people who use Facebook as a news source (19%). This question is a repeat of one we asked in four countries (UK, USA, Italy and Australia) in 2015. In each case the numbers have changed little in the last two years.

We can think of those who say each is a useful source of news as ‘news users’ because they say they intentionally use each as a source of news. Those who use them primarily for other reasons have the potential to be incidentally exposed to news, but those who don’t use them at all (non-users) do not. If we compare the average number of online news brands used by each of these groups, we can see that the incidentally exposed on each network use more online news brands on average than non-users. The incidentally exposed on Facebook consume news from around 20% more brands (compared to non-users), whereas the equivalent figure for YouTube and Twitter is around 50%. In other words, users of Facebook, YouTube, and Twitter see news from brands they would not otherwise use, regardless of whether they were intending to do so.

We shouldn’t underestimate the consequences of self-selection. Even on social media, self-selection is an important consideration; one that is often absent from discussions. A significant number of people across all 36 markets say that they curate their social feeds based on the news content they want to see. Over a third (36%) have added a user for news, and around one in five have blocked someone because of news they posted. A similar number have also fine-tuned their feeds in order to see more or less news from a particular account.

We see some national variation in the extent to which people curate their social feeds based on news. The figures for adding/deleting and fine-tuning are higher in the USA than everywhere outside of Turkey and Latin America. This may explain why some studies find evidence of partisan consumption patterns when they look at data from social media. But it is important to understand that this may be because people have chosen to do this, and not because the platforms have forced it upon them without them knowing, as the filter bubble argument implies.