Grossman targets video games in particular, which he says are increasingly sophisticated and often attempt to simulate military warfare. Combined with overwhelmingly violent television shows, the result is a desensitizing of viewers - particularly children.

Grossman makes further comparisons between exposure to media violence and cigarette smoking. As he puts it, "The television industry has gained its market share through an addictive and toxic ingredient."

Grossman says he looks forward to the day when media companies are subject to the same criticism as tobacco companies. He hopes that preventative measures will be put in place to ensure that incidents of youth violence, such as the recent one in Littleton, Colorado, do not occur.

As Grossman says, "We're not just teaching kids to kill. We're teaching them to like it."

Grossman has written two books examining the link between media violence and violence in real life - his first, On Killing: The Psychological Cost of Learning to Kill in War and Society, was a best-seller when released in 1995. His second book, Teaching Kids to Kill, will be published in the latter part of 1999.