WHEN politicians in the rich world speak of job losses and stagnant incomes brought about by immigration and foreign competition, they usually have blue-collar work in mind—car manufacturing, steelmaking and the like. But even the cognitive 1% can be adversely affected by foreign competition.

In a forthcoming paper in the Journal of Human Resources, George Borjas of Harvard University, and Kirk Doran and Ying Shen of the University of Notre Dame, study the effects of globalisation on a select group of particularly brainy Westerners: professors of mathematics. Distinguishing between cause and effect is always hard in the social sciences. One approach researchers use is to search for a “natural experiment”, and that is exactly what Drs Borjas, Doran and Shen found when they examined what happened to the productivity of American mathematicians after China’s liberalisation in 1978.

Mao Zedong, in power from 1949 to 1976, was not keen on foreign ideas. For most of his rule, Chinese academics had little contact with the West; emigration was largely banned. Between 1949 and 1965, only around 200 Chinese students left for Western universities, with the majority studying foreign languages. Just 21 studied natural sciences.

Chinese education policy changed dramatically after Mao’s death, however. His successor Deng Xiaoping sought to modernise China, and encouraged bright, young Chinese to leave for Western universities. By the late 1980s China had become the largest source of foreign students in America. In mathematics, their sudden influx had considerable effects on the productivity of the professors they collaborated with.

Culture seems to matter, even in the most detached of academic fields. Newly graduated Chinese arrivals were far more likely than American graduate students to work with professors of Chinese descent. In response Chinese-American professors’ productivity, as measured by their publication rates, increased relative to that of their peers (see chart). And because reputable academic journals can accept only so many articles per issue (or, at least, could in the days when they were paper only), the relative productivity of non-Chinese American academics fell, as weaker papers were crowded out. Allowing for the lags caused by admissions offices, the lengths of PhD programmes and the process of peer review, the full effects on American academia of China’s liberalisation were not felt until the late 1980s. By the early 1990s, though, Chinese-American maths professors were producing 0.3 more papers a year than they had been prior to the influx of immigrants—a gap that had doubled by 2003.

Red revolution

A similar shock to the American mathematics market happened in 1991, with the abrupt collapse of the Soviet Union. As with Maoist China, emigration from the Soviet Union had been minimal. Soviet scholars had had little contact with their Western peers. When the Iron Curtain fell, over 1,000 Soviet mathematicians left, with a large share settling in America. In an earlier paper, Dr Borjas and Dr Doran note that, because most of these new entrants were established professors rather than graduate students, the effects of this supply shock were felt more immediately.

In the academic year 1991-92, 13% of new hires to American maths departments came from east Europe and the disintegrating USSR. Unemployment, a concept previously alien to newly minted American maths graduates, shot up that year to an unprecedented 12%. Whether you wear a tweed jacket or safety goggles, then, globalisation creates losers as well as winners.