Neil Postman, in his book Technopoly: The Surrender of Culture to Technology, tells the story of how advertisers in the late 1800's began to realize marketing products isn't about extolling the benefits of the products themselves. Rather, effective advertising is, as Postman remarks, about using the persuasive power of language and photographs:
Advertising is most effective when it is irrational. By irrational, I do not, of course, mean crazy. I mean that products [can] best be sold by exploiting the magical and even poetical powers of language and pictures.
Postman uses the word "irrational" to reveal how advertisers previously employed logic and reason to sell products. However, they soon realized that compelling language and photographs were more powerful in consumers' minds than logic and reason; hence the irrationality of advertising:
By the turn of the century, advertisers no longer assumed that reason was the best instrument for the communication of commercial products and ideas. Advertising became one part depth psychology, one part aesthetic theory. In the process, a fundamental principle of capitalist ideology was rejected: namely, that the producer and consumer were engaged in a rational enterprise in which consumers made choices on the basis of a careful consideration of the quality of a product and their own self-interest.
This rejection of rationality in consumer enterprise led to the type of advertising we have today, where commercials and ads aren't about the products being sold but rather the character of the consumers viewing the ad:
Today, the television commercial, for example, is rarely about the character of the products. It is about the character of the consumers of products. Images of movie stars and famous athletes, of serene lakes and macho fishing trips, of elegant dinners and romantic interludes, of happy families packing their station wagons for a picnic in the country — these tell nothing about the products being sold. But they tell everything about the fears, fancies, and dreams of those who might buy them. What the advertiser needs to know is not what is right about the product but what is wrong about the buyer. And so the balance of business expenditures shifts from product research to market research, which means orienting business away from making products of value and toward making consumers feel valuable. The business of business becomes pseudo-therapy; the consumer, a patient reassured by psychodramas. (emphasis added)