Media have been recognized as powerful instruments to mould public opinion. Therefore, various interests have tried to control them. The clash of interests always leads to tremendous pressure on the media and the media men. Besides the possibility of government pressure on media, often there is a clash of interest between media owners and media practitioners, advertisers and public relations men. Interests of media consumers may also clash with the interest of media owners and practitioners. This has led to the establishment of some statutory bodies and formation of several associations and councils to regulate, study, record and pursue interests of professionals of various categories. Yet there has been an extensively documented history of bias in commercial media because of their ownership structure. The Mass Manipulative Model of the Media proposed by academics such as Stuart Hall cites "structured ideological biases" as significant influences on the selection and presentation of news by the media. At a practical level, there have been numerous studies showing osmosis and hegemony - passed down attitudes and practices within the culture of media organisations - exerting a major influence on media reporting. Increasingly in the past few decades, public relations has been cited as a major influence on modern mass media, but journalists reject such suggestions too and cling to an ideologically-based notion of independence and objectivity.
