Much of advertising strategy is based on understanding consumer psychology and stimulating demand for a product by psychological manipulation.
If customers were perfectly rational, there would be no need for advertising campaigns. A company could simply list product specifications and customers would buy products by rationally choosing those which best fit their needs or which gave the best functionality for the price.
There are many factors which influence buying decisions which are inherently emotional rather than rational. In the cases where products are essentially identical (cleaning products, paper, USB drives, sheets and towels) or have to do with self-image and social aspiration (fashion, jewelry, home decor, etc.), the advertiser needs to stimulate emotional attachment to create brand loyalty and recognition.
The term stimulation value is used to refer to evoking the emotional responses in advertisements. Perhaps the most common technique is use of what rhetoricians refer to as "ethos", or persuasion through character. One way to do this is to exploit tribalism, or group loyalty, whether by hiring celebrities, identifying closely with a specific peer group (e.g. portraying users of the product as having similar lifestyles to the target market), or appealing to regional loyalty. Another technique is to evoke positive emotions, such as pictures of happy families, active retirees, or young lovers (sometimes embedded in mini-narratives) to engage the reader's or viewer's emotions.