Ninety-six percent of American homes have at least one television set which is turned on for an average of six hours each day. During the last three decades television has become a major agent of socialization, often competing with parents, siblings (兄弟姐妹), peers, and teachers. Kenneth Keniston, chairman of the Carnegie Council on Children, has referred to television as the 'flickering blue parent occupying more of the waking hours of American children than any other single influence -- including both parents and schools'. Singer and Singer have characterized it as 'a member of the family'. How much television and what kinds of programs do children watch? The answer depends on many factors, including children's age and season of the year. According to Winick and Winick, school-age children watch television between seventeen and thirty hours a week. For preschool children it is often as high as fifty four hours a week. Nancy 'Larrick, a reading specialist and children' s author, has pointed out that 'by the time the child goes to kindergarten, he or she will have devoted more hours to watching television than a college student spends in tour years of classes... And by the time the youngster graduates from high school, he or she will have spent roughly 11,000 hours in school compared to more than 22,000 hours in front of television.' Children are not just watching so-called children' s programs. On the contrary, according to figures re- leased by the A.C. Nielsen Company, only 13 percent of television viewing among six-to-eleven-year-old children occurs on Saturday between eight A.M. and one P.M.. The largest portion of their viewing, 33 percent, takes place between eight and eleven P.M. Monday through Saturday and between seven and eleven P.M. on Sunday. Who selects the programs that children watch? According to Bower, when mothers and children watch together, the mother makes selections in 37 percent of the cases joint decisions occur 27 percent of the time 33 percent of the time children decide by themselves. In a study by Lyle and Hoffman, over 60 of mothers of first-graders reported that they placed no restrictions on the amount of time they permitted their children to watch television. Teachers, schools, and parent associations have become increasingly concerned about the effects of television on school performance. Based on their class-room experiences, many teachers have reported mounting incidences of fatigue, tension, and aggressive behavior, as well as lessened spontaneity and imagination. The author uses the 'flickering blue parent' in Para. 2 to imply that_____.