Customer search and market power: some laboratory evidence

Abstract

Posted offer markets with costly buyer search are investigated in 18 laboratory sessions. Each period sellers simultaneously post prices. Then each buyer costlessly observes one or two of the posted prices and either accepts an observed price, drops out, or pays a cost to search again that period. The sessions vary the number of observed prices (one or two), the search cost, and the number and kind of buyers. When there are more buyers (especially robot buyers), observed transaction prices conform remarkably closely to theory (competitive Bertrand prices when buyers observe two prices and monopoly Diamond prices when buyers observe only one price). With human subject buyers we observe less extreme prices, but outcomes are closer to theory than outcomes in previous laboratory experiments with similar environments.