Cities and marketplaces are central to economic development, but we know little about why such agglomerations initially form. I argue that evolutionary forces select for agglomerations when individuals' desire to spatially coordinate exchange in complex environments. To test this idea, I perform...

"The agglomeration force behind the New Economic Geography literature initiated by Krugman is based on the notion that larger markets should have a lower variety adjusted price index. Despite his Nobel Prize, there have been no tests of this idea. This paper represents the first such test. Using...