As a start, a commentator "doris" says the following
philosophers are often significantly better experiment designers than psychologists.
I doubt this is true, at least if "often" is taken to mean something stronger than "occasionally." It would be more than a bit of a surprise if graduate training in psychology offered little advantage over graduate training in philosophy regards experimental design. ...
I (perhaps with considerable good company) was guilty of the very sort of inference I'm now complaining about back in the early days of Xphi: supposing that because I'd read a bunch of psychology, and sometimes had reasonable things to say about it, that I'd be able to rather easily design (and publish) worthwhile studies.
Not a bad idea, for autodidactic philosophical experimentalists to proceed with a bit of humility. Could be it's harder than it looks -- which would help explain the existence of graduate programs in psychology."
This seems just right to me, as far as it goes. But it seems to me that there is far more to professional expertise than graduate training, or even learning of skills that are usually thought to fall under such headings as "experimental design". I'll illustrate with a different sort of collaboration, one that I'm far more familiar with in my work: mathematics.
Here, there is no doubt that many philosophers have lots of background. Some of us have degrees, graduate coursework, in some cases even PhDs. Typically mathematicians know more, and are more adept at highly complicated techniques and proof procedures, but this is a difference of degree and not the one I find most interesting. Rather, I am most interested by the difference in culture between mathematical philosophers and philosophical mathematicians. When we intersect - say on issues of impredicativity in the foundations of mathematics, to pick an issue that I've muddled around in for the last 5 years - there is considerable overlap, but subtly important difference. I have one numerous occasions been taken up short by the reaction of mathematician colleagues to a paper that I took to be clearly important. In some cases it strikes them as nearly trivial - not in the sense that the proof was easy, or that the result was known, but in the sense that it just isn't important, isn't getting at any of the most pressing issues.
Upon painstaking, careful discussion, it starts to emerge that while we took ourselves to be motivated by the same problems, our understanding of them was shaped by a very different intellectual culture. What I think of as core epistemological issues are peripheral to the mathematician. What he takes to be the paradigm instances of a phenomenon strike me as peripheral. Ultimately, this is just to echo widely discussed points in philosophy of science - that work takes place within a complex institutional/practical/environmental culture, one that gives working scientists a sense of what is important, what counts as an explanation, what anomalies matter, what theoretical paths are natural, elegant, ad hoc, etc.
These cultures differ across disciplines, and they are internalized only by fairly long-term engagement with the discipline. The culturally inculcated sense of what is an important line to pursue is not something one learns from a few math grad courses. It comes from pursuing cutting edge problems, from sharing one's tentative solutions with colleagues, from attending meetings to see what others are pursuing, etc.
It is good that there are multiple independent cultures overlapping on specific topics. It is good because these "trading zones" - to take up another poplular theme in philosophy/sociology of science - are often where the most exciting action is to be found. I have certainly come to the opinion that ideas emerge through collaboration between mathematically literate philosophers and philosophically literate mathematicians that would never emerge in either discipline on its own, because the cultural forms that are generally useful for the discipline aren't conducive to so much as looking in the direction of the relevant ideas. I don't know how to prove that, but I don't think it is an implausible suggestion and I think it is one that will resonate with anyone who has worked closely with expert colleagues in other fields.
Since I suspect the same phenomena play out in other collaborations - indeed, if anything I would expect the differences to be more significant in empirical science than in math - it seems to me that the case for collaboration goes well beyond any argument to the effect that there are topics they know more about than we do. Humility in our judgments about what we understand about other disciplines is, indeed, a good strategy.