Research on violent television programs and movies， as well as video games and music， suggests that media violence has serious negative effects on both children and adults.
In many television programs and movies， the characters that carry out violent acts on “bad guys” are perceived as“good guys”， whom both children and adults wish to copy. Although people can learn to distinguish right from wrong， television and movies convince people that violent actions can be justified（合理的）.
With people seeing more and more violence， they forget the negative impact of violence. They may become insensitive to people who have been victims of violence， regarding it as a common situation.
In conclusion， media violence does harm to people especially to children， because children can be easily misled when there is no proper supervision（监督）.
While negative effects of TV violence have been repeatedly annouced by conservative groups， there are still some positive effects of TV violence.
Violence in movies， television shows and games can satisfy the considerable（相当多的） need to experience and release（释放） strong emotions that people can not show in reality. It’s a way of letting off pressure or evil minds， which helps people to relax.
In another word， violence in movies can be compared with some sort of children’s literature， such as Little Red Riding Hood（《小红帽》） which has often featured acts of violence in order to scare children.
To sum up， any sort of violence， for better or worse， has been a part of human culture for thousands of years for the sake of entertainment.