Video: Dan Ariely- How we decide how much we are willing to pay for things
Excerpt (Via Predictably Irrational Blog)
The interesting thing about black pearls is that when they were first introduced to the market there was essentially no way to gauge how much they were worth: were they worth more or less than white pearls? Most people instinctually believed that white pearls were still more desirable. Then these discoverers had the insight: take these familiar black pearls to a famous jeweler and have them displayed next to the more precious gems: rubies, sapphires, etc.. The result still lives with us today: black pearls are now worth more.