Harold Dwight Lasswell was born 13 February 1902 in the United States. He was interested in the practice, technique and effects of propaganda. He emerged from the knowledge gained by studying US military propaganda. in the First World War. Based on these findings, he wrote in 1927 his first monograph Techniques military in World War propaganda (Propaganda Technique in the World War). This work became the core conceptual system and the impetus for the development of interdisciplinary science media.
His communication model based on the thesis that media content can directly affect public opinion in a behavioral sense (meaning that it is immediately reflected in the social behavior of the population). This definition includes media determinism. At the same time is based on a so-called ideas. Synoptic orientation - the creation of individual ideas about the world of incomplete sources complemented with valuable ideas.
Lasswell model named after his term infusion needle, because the media constantly pulsing and continuous unidirectional linear effect has a cause-effect and thereby influence public opinion. In this case, the media can generate in society and such changes and processes with which mass addressee disagree, but sociativně is a must, whether directly or displaced, accept. This principle Lasswell summed up in one sentence: “The mass communication is important who speaks what he says … … whom it says … how mediation … and with what effect.”