Speed and Economy.

By 1910 three innovations in the way Americans did their shopping were already familiar to many people: the department store, the mail-order house, and the chain store. A radical departure from centuries of small local merchants, these mechanisms for mass distribution of mass-produced goods often lowered prices and improved quality. These enterprises bypassed wholesalers and aggressively marketed directly to the consumer. Each store had its own advertising department, and when it purchased name-brand goods from manufacturers, the price included a fee for "cooperative advertising." For the first time, prices were set in advance; there was no bargaining at the sales counter, which made it possible for employers to hire inexperienced and lower-paid workers. Moreover, prices were set low enough so that the profits that were reaped resulted from turning over large inventories.

Service.

By 1915 department stores had redesigned...