Studies on mass communication confirm that the media have significant effects on society, although there is hardly a consensus on the nature and extent of such effects. The problem of the degree of influence of the media on individuals and society has had different responses. Most authors confirm that the development of the media achieved the installation of a public agenda in society, that is to say, it is they who have the power to inform or not to society. It is also clear that the information is usually found concentrated in few media and therefore it is these that directly influence the public opinion.
