No field of study can advance significantly unless outsiders bring their knowledge and experience to that field of study.
As the evolution of human's knowledge and the universalness of the information technology this time. Peoples can very easily to get various of material in different subject. In addition, every individual field developed to current level , they must require other domain's knowledge to get further study.
Take the computer science for an example, at original, computer just used to handle the compute task. In that age, it is no problem to research it as a single subject. But with it's evolution, it can does more things than mathematical calculation. It has a display, so it could be used for graphical operation that could show animation on the display. As the further step,it can play computer games. This development produce a new branch called Computer Graphics. This field requires the knowledge of mathematic and geomagnetic to help computer to handle graphic compute more efficiently. If not have the support of these associative knowledge , we might not seen the amazing games in current computers.
Let us touch another example, again to computer science. Today, we all enjoy the benefit of the internet. We could easily to contact our family or friends through email or IM software like MSN; we also could find every information we want by the search engine like Google. But the born of at the Internet not strictly by computer science own. The found of the medium of network connection is requires physics knowledge. The algorithm of net working route is also a mathematic problem. So the formation of the internet is the combination of these fields, not the single one of them.
As we can see,today's every great achievement is not a single field can reach, but the cooperation of some related fields. So no field could achieve significant improvement without the support of other field study