There exists a relatively new subdiscipline within the study of psychology called "media psychology."  With the explosion in information technologies over the past 30 years, especially the introduction of personal computers and the internet into most American homes, there has been a growing interest in the effects of mass media on how people process information and on how they respond to external stimuli.  The influence of mass media on the public, particularly on how consumers arrive at decisions on what products they purchase, has long been a topic of investigation by marketers and psychologists alike.  Now that advertisements are in front of us almost every waking hour of the day -- for example, this educator can't begin to answer a question such as this one without first having to maneuver around advertisements featuring live-action characters that move around on the screen -- the effects of this near-constant exposure to marketers and those seeking to influence our thought processes is potentially enormous.

The whole point of advertising in the first place is to manipulate the public into purchasing one particular company's product rather than those of its competitors.  The late Vance Packard, in 1957, published The Hidden Persuaders, a study of how advertisers use subliminal suggestion to influence consumer decisions.  While the use of such marketing devices would run afoul of Federal Trade Commission regulations today, it is still employed precisely because it remains successful.

Through repetition of images and annoying but difficult to forget jingles, advertisers routinely attempt to influence how the public thinks.  That is why businesses, from the largest to the smallest, use advertising.  McDonald's is a classic example of how superior marketing helped that fast-food company rise to the top of its industry.  Similarly, Apple's early use of innovative advertising techniques helped it breakthrough the market dominance previously enjoyed by companies like IBM and Osborne.  

It is not only consumer goods companies that employ these types of tactics to influence consumer decisions.  Politicians and special interest groups also use advertising to develop name recognition and to influence how people view issues and policies.  As with providers of consumer goods, politicians and special interest groups advertise on television, the radio, in newspapers, and on the internet.  The advertising companies and marketers hired by these groups and indivduals hope to influence how people will vote and how they approach issues like environmental degradation through the repetition of images and messages.