Since the 1980s, labour demand has shifted toward more educated workers in the US. The most common explanation is that the productivity of skilled workers has risen relative to the unskilled, but it is not easy to explain why aggregate labour productivity was stagnant during the 1980s. This paper suggests an alternative story: introducing new goods involves a xed labour input, which is biased toward white-collar workers. Hence the transition from Ford-style mass production towards more diversied one has shifted labour demand toward white-collar workers.