có thể được áp dụng để kiểm tra hay không và bằng cách nào các phương tiện truyền thông ảnh hưởng đến nhận thức có liên quan, thái độ, hoặc những hành vi (xem, ví dụ, Comstock, năm 1991; Comstock et al, 1978; Strasburger & Wilson, 2002). Vì vậy, nhận thức của công chúng | 508 Adolescents and Media can be applied to examine whether and how media influence relevant cognitive attitudinal or behavioral outcomes see for example Comstock 1991 Comstock et al. 1978 Strasburger Wilson 2002 . Thus public perceptions and empirical evidence of increases in youth violence sexual activity substance use and so on often raise questions about the media s role in such behavior stimulating systematic examination of media content and of how such content affects beliefs and behavior. Hence many more studies have examined potentially harmful or antisocial behaviors than helpful or prosocial behaviors. For the most part research on adolescents and media falls under one of three general headings content analyses media use studies and effects studies. A large number of content analyses are relevant to adolescents and most media. One exception is a dearth of systematic information about content available on the World Wide Web. The most relevant content analyses document the quantity and nature of media messages that are particularly germane to adolescent audiences that is studies emphasizing perceived or real social problems. Such research has documented how much media portray various problem issues and related behaviors and how such portrayals are framed identifying the prevalence of numerous message-related variables that have been documented to influence learning and acceptance of any kind of message. In addition to content analyses a large and consistent research literature indicates that adolescents spend a substantial part of their time exposed to media messages. Surveys focus on the relationship between various demographic and social variables and media consumption documenting important age-related and individual differences in the amount type and content of media adolescents consume. Two recent trends are important to the understanding of the potential consequences of adolescent media use. First the preponderance of adolescent media use occurs in .
