Why shareholders are pushing Apple to study smartphone effects on kids

Smartphones have changed the way kids live and interact, prompting growing concerns about the consequences. In January, two of Apple's big shareholders called on the iPhone maker to come up with ways for parents to restrict their kids' phone use and study the effect that heavy usage has on mental health. John Yang talks to Charles Penner of Jana Partners LLC and Jean Twenge, author of "IGen."

(Source: PBS NewsHour, https://www.youtube.com/watch?v=aOy3H57XvEM)