This is the fourth in a series of six articles about how research by psychologists, neuroscientists, robot engineers, and other scientists could help geography educators design better lessons. This article will focus on teaching about regions as narrowly defined: a region is a group of places that have something in common and are close to each other. Making region maps and then comparing them to identify spatial associations are powerful tools for geographic inquiry. As an added bonus, knowledge acquired with these tools can be cumulative.