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. The updating methods reflect fundamentally different mechanisms. Theoretical and educational implications are discussed.