How we change what others think, feel, believe and do
The need for: Beauty
Beauty is a curious need, especially viewed in evolutionary terms. Physical attractiveness is understandable as a standard by which mates may be chosen, but the value of art or music for the survival of the species is not that clear.
No matter why it works, but beauty works directly on the emotions. If we like a person, a house, a painting or a pop song, we do not logically decompose it--we just like it. Aesthetics connects directly with our emotions, which makes it a subtle factors in the domain of persuasion.
The engineering discipline of Value Analysis recognizes two types of need when designing or improving something. Functional needs are to do with what the device does and how well it does it. For example, a car has functions of transporting people, displaying speed, and so on. Aesthetic needs are about how appealing the car is, from overall shape to the color of the speedometer needle.
Engineers will thus reduce aesthetics to very precise terms, discovering the angles, colors, textures and so on that are most appealing to their customers. This can be a long process, but the rewards can be significant. People will pay a significant premium for something which is attractive rather than plainly functional.
Beauty is in the eye of the beholder, and although there are some fairly common view of what a beautiful person looks like, there are also some very individual perceptions, as you can easily see by looking at the couples walking down any street.
Beauty also changes across cultures. In some countries, especially where food is scarce, a fat person is considered particularly attractive.
When a woman covers up a part of her body, men will find it very attractive. For example in Victorian England, women covered up their ankles, and the sight of a bare lower leg was enough to make a man break out in a sweat (in fact they even put skirts on their chairs to cover up the chair legs to save some embarrassing moments). These days, the sight of a t-shirt-wearing Western woman in some Eastern countries will similarly heat up the local male populace.
Not only does the scarcity principle make me want something, it will also make it more aesthetically attractive. Fleeting glimpses can seem wonderfully beautiful, where a long-hard stare might cool anyone's ardor.
Beauty sells. Use the common standards of aesthetics and beauty to make things unthinkingly attractive.
You can also find those things for which the other person has particular mores. Find their fetish and unusual aesthetic appreciations, and play to these.