This is hidden brain.
I'm Shankar Vedantam.
In 2011, Richard Freeman was studying scientists, specifically how scientists work together.
Richard, who's a Harvard economics professor, noticed something surprising.
Scientists in the United States stick to their own kind.
You'd see chinese folk concentrated in one lab, indian folk concentrated in another lab, Europeans of different groups associating more with their compatriots.
This was not surprising.
You see this kind of clustering in lots of workplaces.
But Rischer thought science ought to be different.
In general, people who are more alike are likely to think more alike.
And one of the things that gives a kick to science and scientific productivity is that you get people with somewhat different views, different perspectives coming together.
Some people agree with Richard's contention that a mix of perspectives will produce better ideas, but others say no.
A group that has lots of different views will end up in gridlock.
So which is it?
Richard decided to figure out whether scientists who collaborate with others from the same group produce better or worse research than scientists who have a wide network of collaborators.
He looked at one of the most important signals of scientific success, research publications.
He found that in a large share of these scientific publications, co authors shared a common ethnicity.
No surprise.
But then he went further.
He looked at citations in general.