Malicious online behaviour: what is happening, and what can we do about it? Jon Roozenbeek, University of Cambridge In this talk, Jon Roozenbeek examines the various problems associated with social behaviour online and takes us through the different types of solutions that are being proposed. Malicious online behaviour occurs in all sorts of contexts and can have both human (e.g. through trolling and bullying) and artificial (e.g. by way of bots) origins. In some cases, such behaviour takes the form of online campaigns, and may have an overt political or financial motivation, posing a risk to the democratic process. Various entities have proposed solutions to this growing problem by proposing algorithmic fixes, changing legislation, increasing our ability to fact-check misleading information, or by focusing on providing news consumers with appropriate defence mechanisms. Finally, Jon will talk about the interventions developed at the Cambridge Social Decision-Making Lab that function as psychological ‘vaccines’ against online misinformation.