While many Costco customers join the warehouse club for its low prices, others appreciate its treasure-hunt business model. That's the ever-changing selection of merchandise designed to delight customers and encourage them to visit the store looking for ground beef, paper towels, and coffee, but leave with a kayak or a new winter coat. "The treasure-hunt concept is built on the behavioral principle that people are motivated by variability. Humans respond strongly to unpredictable rewards — a phenomenon s ...