Tracking the flow of information.

By using words transmitted and words attended to as common denominators, novel indexes were constructed of growth trends in 17 major communications media from 1960 to 1977. There have been extraordinary rates of growth in the transmission of electronic communications, but much lower rates of growth in the material that people actually consume, representing the phenomenon often labeled information overload. Growth in print media has sharply decelerated, and a close relationship is found between the cheapness of a medium and its rate of growth.