In 1962 Canadian professor of English literature, literary critic, rhetorician, and communication theorist at the University of Toronto Marshall McLuhan published The Gutenberg Galaxy: The Making of Typographic Man in which he divided history in four epochs: oral tribe culture, manuscript culture, the Gutenberg galaxy and the electronic age.
McLuhan argued that a new communications medium was responsble for the break between each of the four time periods. Writing before computing was pervasive in society, he was concerned with the influence of radio, television and film on print culture, and on the impact of media, independent of content, upon thinking, and social organization:
"The main concept of McLuhan's argument (later elaborated upon in The Medium is the Massage) is that new technologies (like alphabets, printing presses, and even speech itself) exert a gravitational effect on cognition, which in turn affects social organization: print technology changes our perceptual habits ('visual homogenizing of experience'), which in turn impacts social interactions ('fosters a mentality that gradually resists all but a. . . specialist outlook'). According to McLuhan, the advent of print technology contributed to and made possible most of the salient trends in the Modern period in the Western world: individualism, democracy, Protestantism, capitalism, and nationalism. For McLuhan, these trends all reverberate with print technology's principle of 'segmentation of actions and functions and principle of visual quantification."