Spreading Lies

The recent increase in partisan media has generated interest in what drives media outlets to become more partisan. I develop a model where a media outlet can report news with a partisan slant and the news then spread by word of mouth in a population of agents with heterogeneous preferences. The level of slant has an impact on whether the agents find the news credible and on their incentives to pass the news to others. The analysis elucidates how partisanship of media can be driven by political polarisation of the public and by the tendency of people to interact with people with similar political views. Extensions of the model shed light on the influences of social media and the fact that people with different political views tend to trust different media outlets