According to the article “Spatial Metaphor and Real Estate,” several studies suggest that Chicago’s North Side–South Side divide may come in part from an unconscious bias generated by the customary position of north at the top of maps. “In a number of cities, there is this perception that the northern areas are more affluent,” says Arlen Moller, a social and health psychologist in Northwestern University’s Department of Preventive Medicine and one of four authors of the article. “In Chicago, the song that relates is ‘Bad, Bad Leroy Brown’ [where ‘the South Side of Chicago is the baddest part of town’]. It’s irrational, but it persists.” The research team is now using home-sales data to determine just how much the tendency influences real-estate values.