Adults may need media literacy even more than students

The debate over how to fight disinformation in the digital age has divided leading experts and raised thorny questions about free speech and truth on the web.

Should Facebook ban political ads, as Twitter has done, or at least stop exempting politicians from its rules barring misinformation? Should social media platforms ban the "microtargeting" that allows politicians to hand pick narrow audiences while evading public scrutiny? Google recently took steps to limit microtargeting, but political players say that will just cut off small donors and hurt challengers.

Such dilemmas point...