The development of geographic categories and biases.

Children and university students (N=58) estimated the locations of major cities in North America. At age 9, a distinct home region was apparent, but no differentiation between northern US and Canadian cities. At 11, four developments were observed: Children divided North America into regions that were not based solely on national boundaries but were the same as university students' regions; psychological border zones between regions exaggerated distances between them; children used new location information to update their estimates for all cities in a seeded region and in adjacent and nonadjacent regions; children preserved the ordinal structure of their initial location estimates for cities in their home region but relied on regional prototype locations to adjust estimates in less familiar regions.