Adam Lanza played violent video games for hours at a time. The Columbine killers loved Doom. And Anders Brevik told a court he played a Call of Duty game to practice his hand-eye coordination.
The fact of three young men playing video games would not be noteworthy in any other context. But when mass murderers are at issue, it raises the question of whether our entertainment can affect our behavior, and if so what we should do about it.