Robert B. Cialdini, Influence: The Psychology Of Persuasion Quotes
A well-known principle of human behavior says that when we ask someone to do us a favor we will be more successful if we provide a reason. People simply like to have reasons for what they do.
The customers, mostly well-to-do vacationers with little knowledge of turquoise, were using a standard principle—a stereotype—to guide their buying: “expensive = good.