African Americans influenced technological developments as consumers and creators during and following America's industrialization (1870s–1930s). As automation and the factory system powered the rise of cities, millions of rural black southerners migrated to the urban South, North, and West, where they interfaced whites and foreign immigrants in the nation's labor pool. An estimated 5.1 million or 43 percent of blacks were city residents by 1930.
Blacks contributed inventions along the way. Lewis H. Latimer devised the blueprint for Bell's telephone and remade Edison's electric light bulb with a longer-burning filament. Garrett A. Morgan invented the gas mask and traffic light. A number of others made women's hair straighteners and skin lighteners, creating a profitable beauty industry in a “race market” of banks, insurance firms, newspapers, funeral homes, groceries, eateries, and more. Black workers (especially those in coal, steel, automobile, meat packing, textile, tobacco, and timber industries) increasingly used new products. Those included cast-iron stoves, which domestics for white employers cooked on and cleaned, and factory-made clothes. More and more blacks bought tractors, cars, electricity, radios, and telephones, all mirroring intrablack educational, income, and cultural differences.
World War II and the postwar period brought shifts in race relations and influences of technology. Even as car, tractor, and television-buying increased among middle-class blacks, tractors and mechanical cotton pickers displaced black sharecropper and tenant farmer families. An estimated 1.5 million of them migrated to the North and West between 1939 and 1950. The percentage of all African American urban dwellers rose from 50 percent in 1940 to 80 percent in 1970. Desegregation and civil rights reforms leveraged blacks’ progress in education, technical training, skilled occupations, and professions, including medicine, engineering, electronics, and computer science. But poor and unskilled blacks were left behind. Deindustrialization (severe in steel, auto, and other manufacturing plants by the late 1960s) brought massive layoffs and plant shutdowns. Plants also moved from industrial centers like Detroit, Michigan and reopened in Sun Belt states. Conspicuous among the jobless and unemployable were African Americans without skills as well as a growing black underclass, who, with their counterparts in Rural America, had become victims of America's service and information economy.