President Trump held a roundtable at the White House Thursday to discuss violent video games and how they relate to school shootings. NPR's Ari Shapiro speaks with Douglas Gentile, psychology professor at Iowa State University, about what research tells us about video games and violence in children.

One of the vital roles of sleep is to help us solidify and consolidate memories. As we go about our day, our brains take in an incredible amount of information. Rather than being directly logged and recorded, however, these facts and experiences first need to be processed and stored; and many of these steps happen while we sleep,