Advertising
Advertising is an audio or visual form of marketing communication that employs an openly sponsored, non-personal message to promote or sell a product, service or idea. Sponsors of advertising are typically businesses wishing to promote their products or services. Advertising is differentiated from public relations in that an advertiser pays for and has control over the message. It differs from personal selling in that the message is non-personal, i.e., not directed to a particular individual. Advertising is communicated through various mass media, including traditional media such as newspapers, magazines, television, radio, outdoor advertising or direct mail; and new media such as search results, blogs, social media, websites or text messages. The actual presentation of the message in a medium is referred to as an advertisement or "ad" for short.
Psychology
Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as feeling and thought. It is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest. As a social science it aims to understand individuals and groups by establishing general principles and researching specific cases.
Advertising
There are a lot of great technicians in advertising. And unfortunately they talk the best game. They know all the rules. They can tell you that people in an ad will get you greater readership. They can tell you that a sentence should be this short or that long. They can tell you that body copy should be broken up for easier reading. They can give you fact after fact after fact. They are the scientists of advertising. But there's one little rub. Advertising is fundamentally persuasion and persuasion happens to be not a science, but an art.
William Bernbach, Letter (5/15/47) as quoted in Shaun Usher, Letters of Note: Volume 2: An Eclectic Collection of Correspondence Deserving of a Wider Audience (2016), p.190
Psychology
The great shift … is the movement away from the value-laden languages of … the “humanities,” and toward the ostensibly value-neutral languages of the “sciences.” This attempt to escape from, or to deny, valuation is … especially important in psychology … and the so-called social sciences. Indeed, one could go so far as to say that the specialized languages of these disciplines serve virtually no other purpose than to conceal valuation behind an ostensibly scientific and therefore nonvaluational semantic screen.
Thomas Szasz, Anti-Freud (1990), p. 44