Newman,ME . "Coauthorship networks and patterns of scientific collaboration." Proceedings of the National Academy of Sciences of the United States of America [0027-8424] 101 Suppl 1 (2004). 5200-5.

 

There is a very high rate of co-authorship in biology, a high rate in physics, and a somewhat lower rate in mathematics, though the rate in mathematics has been increasing along with the other fields. However, there is a lot of variation in the collaboration patterns among the sciences.  Also, collaborating leads to more collaboration.