If you've ever had a creeping suspicion that city dwellers seem a little more frenetic on foot than their small-town counterparts, it turns out there's ample research to back it up.
According to Jaffe, "Most work on urban walking speed dates back to 1976, when psychologists Marc and Helen Bornstein published a provocative paper linking "pace of life" with population size. The Bornsteins found that people in Brooklyn (pop. 2.6 million) walked more than twice as fast as people in Itea, Greece (pop. 2,200), and posited that hurrying one's gait was a natural response to overcrowding, to reduce "social interference."
In 1989 and again in 1999, however, other researchers set out to support an alternative explanation: that population is merely a surrogate for the true determinant of walking speed, economic success. Both studies found that "pace of life" indicators were significantly higher in cities located in countries with high GDP and purchasing power parity.
Jaffe offers the following summary of their explanation: "When a city grows larger, wage rate and cost of living increase, and with that the value of a resident's time."
In addition to economic considerations, Robert Levine's 1999 study found individualism to be a strong "social predictor of walking speed."