A TTENTIONAL fluctuations during televison viewing are common.Some programs demand only loose monitoring, and others arequite compelling. Measuring attentional changes and relating them to the content and structure of messages has, however, proved a difficult task. The present study is one of a series that uses reaction times to intermittent cues during viewing as an index of attentional commitment. A method called the secondary task procedure is used to determine how audio and video complexity are related to viewer attention to subunits of messages.