Donald T. Campbell argued that the organization of university departments shaped the boundaries among specialties. This article extends his argument in two ways. First, specialties are also shaped by other institutions, such as sponsors and learned societies. Second, the intersection among specialties is shaped by the complexity of the problems that research addresses. Specialization of research is a way to deal with the complexity of nature. One way of doing this is to erect specialties that focus on different aspects of (...) nature, and which do not overlap in subject matter. This view is the basis of Campbell’s “fish-scale” model of relations among specialties, and assumes that nature is descriptively complex in the sense of William C. Wimsatt . But specialties often overlap and are thus interactively complex as well. Here I argue that a kind of interactive complexity—collaborative complexity—arises when research on a problem must take the not-yet-established contents of multiple specialties into account. Such compound problems are exemplified by attempts to explain historical particulars, such as particular adaptations in single species, e.g., masculinization in Spotted Hyenas. (shrink)