In Distributed Cognition: A Methdological Note, cognitive scientist David Kirsh describes six assumptions that "guides his own research":

"1. We act locally and are closely coupled to our local environment (two entities that reciprocally interact) 2. We externalize thought and intention to harness external sources of cognitive power 3. Economic metrics have a place in evaluating distributed systems, but they must be complemented with studies of computational complexity, descriptive complexity and new metrics yet to be defined. 4. The best metrics apply at many levels of analysis, from the system level where our concern is with the goodness of a system's design to the level of individual artifacts, where our concern is with the goodness of the design of the artifacts individuals interact with. 5. Coordination is the glue of distributed cognition and it occurs at all levels of analysis 6. History matters"

Why do I blog this? because the work of David Kirsh is very interesting to me, this assumptions are a kind of summary of his work. Each of them are well described in the paper and are supported by methodologies (or methodological tricks) that are useful for a researcher.