The effect media violence has on families and the general public is an ongoing debate. Some scientists insist that violence in the media directly influences and shapes children's personality. Michael Suman, the Coordinator of the Center of Communications Policy at the University of California at Los Angeles, did a study on the effects of violence in media and drew a few conclusions.
His conclusions were that violence on television increases violent behavior in people, desensitizes people from violence, and increases fear, and that children are more vulnerable to all these negative effects.
However, many scientists would argue with Suman's claims and say that he could be confusing correlation and causation. It is possible that viewing violent television may cause people to have more violent behaviors, but it is also true that people with more violent personalities are more likely to watch violent television.
Some of the claims are also hard to falsify. For instance, the claim that violent television increases fear in people would be extremely hard to falsify, because there are so many different things that could contribute to a person being fearful.
Suman's exact claims can be found here: