The following fact was recently told to me: apparently, the leading physics journals no longer accept social network analysis, even though these articles are now among the most cited in these journals. I found this odd. From a “pure” perspective, it makes sense: why should a journal dedicated to stuff like quantum mechanics accept articles on the Internet just because a physicist wrote it? On the other hand, it seems like disciplinary suicide. Why ditch the folks who’ve done such great work?
In contrast, the economics profession seems to strongly support boundary crossing, long as you stick to some variant of the neo-classical framework. It’s hard to find a topic in the social sciences where economists – often highly regarded ones – haven’t treaded... Sure, there’s a core to the economics profession, but there are lots of well supported outposts.
So we have an interesting puzzle: two highly regarded fields with an abundance of clever people. Yet, one has very tight internal control, while the other is quite pleased with imperialism. The flippant answer is that, well, economists are self-interested. By requiring people to use a neo-classical framework, you maintain the brand. By allowing imperialism, you increase the value of the brand. But why don’t physicists do the same? Why don’t they say (like economists do), “we’ll just come in and clean up?” As a field with some serious internal problems (small market/running out of easy problems), conquering other disciplines would seem like a good solution.
It's a very good question. It could be that economists understand branding and value better. After all, they are two of the many things we do study. For the record, the folks out at the Santa Fe Institute are encouraging a lot of cross-disciplinary work from physicists. I didn't realize they had such a hard time getting things published.
On my part, the "imperialist" nature of economics is a large part of what drew me into the profession. (Particularly after reading some of Gary Becker's popular work.) In my time here at GMU, I have learned how to apply economics to study areas as diverse as politics, religion, law, marriage, economic development, entrepreneurship, innovation, and much, much more. Once you begin to learn economics, you quite literally see it everywhere. It would truly be a shame to have this kind of perspective, to have your profession discourage it, and no outlet to share it from.