Journalist Andrew Marantz spent three years embedded in the world of internet trolls and social media propagandists, seeking out the people who are propelling fringe talking points into the heart of conversation online and trying to understand how they're making their ideas spread. Go down the rabbit hole of online propaganda and misinformation -- and learn how we can start to make the internet less toxic. After the talk, our host Shoshana shares some scientific insights on how social media interacts with your brain’s wiring. We love making TED Health, and we want to make it better. So if you have a few minutes, share your thoughts at surveynerds.com/ted