Cognitive Mobility: Labor Market Responses to Supply Shocks in the Space of Ideas
George J. Borjas, Kirk B. Doran
NBER Working Paper No. 18614
Issued in December 2012 NBER Program(s): LS
Knowledge producers who are conducting research on a particular set of questions may respond to supply and demand shocks by shifting their resources to a different set of questions. Cognitive mobility measures the transition from one location in idea space to another location in that space. This paper examines the cognitive mobility flows unleashed by the influx of a large number of Soviet mathematicians into the United States after the collapse of the Soviet Union. Our analysis exploits the fact that the influx of Soviet mathematicians into the American mathematics community was larger in some fields than in others. The data reveal substantial cognitive mobility in response to the influx, with American mathematicians moving away from, rather than moving to, fields that likely received large numbers of Soviet émigrés. It appears that diminishing returns in specific research areas, rather than beneficial human capital spillovers, dominated the cognitive mobility decisions of pre-existing knowledge producers.
I would be interested in thinking more about whether this is a labor market move or an ideas market move. By that I mean that if there was a strong interchange of ideas between Soviet and U.S. mathematicians already (there probably wasn't, of course), you wouldn't expect to see this unless the differentiation had labor market benefits (i.e. - the department only wants to hire one person in a specific field). That's different from thinking to yourself that there are a lot of people working on the same problem, so you can make a bigger contribution to the stock of knowledge by working on something else.
The two phenomena are not unrelated, of course - but one is about the knowledge production function and the other is about the structure of academic labor markets.