Social media is much more than a way to stay in touch with friends. According to today's guest, Tristan Harris, Facebook and platforms like it are actually manipulating billions of people's minds. Tristan joins Katie and Brian to explain how tech companies are creating addictions, steering elections and making many of us lonely. He would know: After selling a startup to Google in his twenties, Tristan worked there as an in-house design ethicist, where he studied how tech affects people's attention, well-being, and behavior. Now, as a founder of the Center for Humane Technology, Tristan is on a mission to reform the tech industry. Plus, he offers up some tips on how to track and curb your smartphone addiction.