The media technology highly developed these days; therefore, nowadays, there are many cases how it influences on people.I believe it seriously affect on children who are much more innocent and have imperfect knowledge. The article on "Violence in the media" from American Psychological Association provides the fact how the media brings harmful effect on children and With 15 years of researches on the media violence, several psychologist could find facts: less sensitive to pain, more aggressive, more fearful. The research also says about 8,000 murderers in the U.S mostly watched TV for many hours in their childhood and it led them to be brutal and aggressive. Also, in this article, they said not only the TV media, but also Violent video games or musics harm children and adult.
While having searched about this topic, I also could find that watching TV or movies, playing computer games for a long time may affect on children in harmful way. David Martinez-Gomez in 2009 shows the study, it causes children high blood pressure. Also, I have heard that more than 360 children in Japan suffered "seizure-like symptoms," while watching the TV cartoon, "Pocket Monster." On the scene, when one of the character produced strong light and the scene got contrast between dark and bright light, children began vomiting of blood and were taken to hospital.