FIGURE 15.1 TV PARENTAL GUIDELINES The TV industry continues to study its self-imposed rating categories, promising to fine-tune them to ensure that the government keeps its distance. These standards are one example of a policy that was shaped in part by media research. Since the 1960s, research has attempted to demonstrate links between violent TV images and increased levels of aggression among children and adolescents. Data from: TV Parental Guidelines Monitoring Board, accessed November 24, 2014, www.tvguidelines.org.