I n Chapter 2 (Introduction to the Origins, Nature, and Uses of Theories) the processes by which new theories are developed and tested were explained. As noted, there are two major sources from which specific mass communication theories have been put together in initial
form. As was also explained in Chapter 2, most of the theories presented in the present text and that are now available to scholars trying to understand mass communication today have been derived from empirical data obtained from research projects that make use of scientific methods (see pp. 25-26). For those who use this approach, such theories offer both descriptions and explanations of the process, causes, and effects of mass communications. They also serve as guides for further research.