A talk with Levi Boxell about his research showing that older Americans, who use social media less than younger Americans, have become more antagonistic towards the opposite political party than younger people. We also discuss his research studying how political polarization has changed over time in other countries. We discuss what factors may contribute to polarization, and whether it's still possible that social media could be a major factor. He also discusses his research on news outlet bias being present in the types of politician images are chosen.