Video games don't create killers, new book says

"If you have, for example, a girl who plays 15 hours a week of exclusively violent video games, I'd be very concerned because it's very unusual," Kutner said.

"But for boys (the danger sign) is not playing video games at all, because it looks like for this generation, video games are a measure of social competence for boys."

Many video game fans have embraced the pair as champions of the industry, a label that makes them uncomfortable.

"We're not comfortable doing pro and con. We've been asked to do the pro-game side in debates, and I don't consider myself a pro-game person. Video games are a medium," Olson said.

(Reporting by Scott Hillis; editing by Patricia Reaney)