As reporting on the ground in Syria becomes increasingly difficult, a disinformation war rages. We reveal a network of influential Twitter accounts, some with tens or hundreds of thousands of followers, which push conspiracy theories. Plus, against a backdrop of rising knife attacks in the UK, have social networks changed the nature of street violence? Understanding the way we think about our finances can help us to spend more carefully and save more efficiently, says economist Dan Ariely. Tim Harford talks to him about the psychology of money. Plus Dan has an idea for ending arguments over sharing a restaurant bill. Why in the USA are people who are least likely to be victims of gun violence the most likely to carry guns? Aasmah Mir talks to people getting their gun licence to try and untangle what lies behind their anxieties. Picture Caption: Profile picture of Sarah Abdallah, part of a network of pro-Syrian government accounts identified by the social media research company Graphika Picture Credit: Twitter/@sahouraxo