noting the people's well being is mixed and social media is not good or bad for people. promising to address the problems. >> mark zuckerberg there saying instagram can have a positive mental impact. what know it has a negative impact. i want to bring in georgia wells, who co-wrote the piece for the washington journal and dr. melissa hunt, clinical psychologist and associate director of clinical training at the university of pennsylvania. she has been studying this for years. doctor, i want to start with you. for people who aren't exactly familiar with how instagram works, explain how the platform is built and why it's so dangerous. >> particularly dangerous for young people, because the very nature of the platform is it's a photo-sharing platform. and it allows for editing and