Figure 21. International Autism Publication Collaboration Networks in 1990, 1995, 2000, 2005, and 2010.

Five circular network graphs, one each from 1990, 1995, 2000, 2005, and 2010. All countries that published autism research in any year from 1990 to 2010 are represented by the smaller network of circles, or nodes, around the five larger circles. Lines between country nodes indicate a publication with authors from both countries within that time period.  The total number of lines and the thickness of lines between country nodes provide a measure of collaboration activity across the five years. Only a few connecting lines are evident in 1990, and both the number and thickness of lines increases with time, culminating in the year 2010 with the largest number of international collaborations.