McLuhan's four laws of mediaMarshall McLuhan, a Canadian professor of Sociology, was best known for popularising views on the effect of the new communication technologies of television and radio on a society's culture. He saw culture as a derivative of technological change rather than an independent factor. He introduced the public to such terms as the 'global village' and the 'message is the medium'.McLuhan saw media as an extension of self, that is, as technology that extends natural human abilities. Technologies are not simple additions to human existence. These technologies change how humans think, feel and act, even the individual's perception and information processing. New technologies have had psychological, physical and social effects. "We shape our tools and our tools shape us". McLuhan abstracted four laws of media from his research.The four laws help describe the properties of each medium or technology:1. EXTENDAn individual's or organisation's use of technology in a new way extends the reach of body and mind: the car can be seen as an extension of the feet; a microscope as an extension of the eye; an engine an extension of our feet and arms, a library an extension of the mind. 'What does the artifact enhance or intensify or make possible or accelerate?'.2. REVERSEEvery innovation has within itself the seeds of its reversal. When a technology is pushed to its limit, it risks reversing the target audience's enthusiasm for its original benefits into complementary or even opposite emotions, e.g. an over-extended automobile culture that is stressed by traffic jams and smog, longs for a pedestrian lifestyle.3. RETRIEVEHumans have a limited set of senses and motor skills. The current media stimulate and reinforce only some of them. For example, the internet enhanced the visual senses over the aural. A successful new medium will "retrieve" and enhance a sense or skill that the current media do not stimulate. Since the number of senses and skills is limited, an older, outdated medium had probably addressed this sense or skill. 'What recurrence or retrieval of earlier actions and services is brought into play simultaneously by the new form?'4. OBSOLESCEThe new media subsumes older forms of media. 'What is pushed aside or obsolesced by the new 'organ'. New technologies keep expanding the limited number of senses and motor skills. The content of the old technology becomes incorporated into the new, further reaching technology. Writing made speech "obsolete", just as printing made writing "obsolete". The old technology is not eliminated, but loses its initial reputation and effectiveness.McLuhan observed that communication media went full circle in the 1960's, from oral (folk stories) to a written (books), then back to an oral culture. This time, tv and radio reached larger audiences at greater distances. He predicted that these new connections would lead to a 'global village' that shared a common, oral culture.McLuhan's model can be used as a thinking tool to assess successful product or organisational change adoptions where human interaction is essential. Noel Rosa Noel Rosa pode nao ter sido o melhor compositor da chamada Epoca de Ouro da musica popular brasileira (1930-1945), mas foi,