Echo chamber? What echo chamber? Reviewing the evidence

The success of political movements that appear to be immune to any factual evidence that contradicts their claims – from the Brexiteers to the 'alt‐right', neo‐fascist groups supporting Donald Trump – has reinvigorated claims that social media spaces constitute so‐called 'filter bubbles' or 'echo chambers'. But while such claims may appear intuitively true to politicians and journalists – who have themselves been accused of living in filter bubbles (Bradshaw 2016) –, the evidence that ordinary users experience their everyday social media environments as echo chambers is far more limited. For instance, a 2016 Pew Center study has shown that only 23% of U.S. users on Facebook and 17% on Twitter now say with confidence that most of their contacts' views are similar to their own. 20% have changed their minds about a political or social issue because of interactions on social media (Duggan and Smith 2016). Similarly, large‐scale studies of follower and interaction networks on Twitter (e.g. Bruns et al., 2014) show that national Twitterspheres are often thoroughly interconnected and facilitate the flow of information across boundaries of personal ideology and interest, except for a few especially hardcore partisan communities. Building on new, comprehensive data from a project that maps and tracks interactions between 4 million accounts in the Australian Twittersphere, this paper explores in detail the evidence for the existence of echo chambers in that country. It thereby moves the present debate beyond a merely anecdotal footing, and offers a more reliable assessment of the 'echo chamber' threat