From Rick Altman, "Television/Sound" in Studies in Entertainment: Critical Approaches to Mass Culture, ed. Tania Modleski, Bloomington: Indiana U. Press, 1986. 43

There must be the sense that anything really important will be cued by the sound track. This notion grows in part out of the continued identification of television programming with live presentation [such as elections or the Olympics].... If we can be assured of being called back for the important moment, then it remains worthwhile to keep the set on even when we cannot remain within viewing distance.43.