Political communication is the transmitting of politically relevant information from one part of the political system to another, and between the social and political systems. Political communication, like communication generally, is inevitably affected by a variety of factors physical, technological, economic, socio-cultural and political. Karl Deutsch in his classic study The Nerves of Government places communication at the very heart of an understanding of politics. Harold Lasswell's formula is simple and straightforward; it identifies four of the five elements to be found in any communication model: the source of a message, the message itself, the channel by which the message is transmitted, and the receiver of the message. John Fiske divides media into three categories: presentational, representational and mechanical. Maletzke's model incorporates the personal and social characteristics of both the communicator and the receiver of the message, taking account of self-image and personality on the one hand, for instance, and the social and organisational environment on the other.