Dan Ariely, best-selling author of Predictably Irrational and The Upside of Irrationality, joins us once again (to see his past discussion on how buying fake bags makes you lie more, click here). This time, he’s taking on the value of luxury goods. How do we decide how much something is worth? With certain goods, like diamonds or fur, scarcity can dictate how valuable it becomes. But what about when something entirely new, like black pearls, is introduced to the market?