The Sandy Hook gunman, Adam Lanza, reportedly spent hours playing a game called "Call of Duty" every day.
Those who have not played "first-person shooter" games like this may not understand how realistic they have become in recent years. Because this topic has now become part of the national debate on how to reduce or stop gun massacres, we will walk through an example of these games.
Importantly, we have no idea what short-circuited in Lanza's head that made him decide to use real guns to kill real people in Newtown last week. But as you will see, the experience of walking around shooting people would not have been unfamiliar to him.