ABSTRACT-Prior research supports the inference that scientific disciplines can be ordered into a hierarchy ranging from the "hard" natural sciences to the "soft" social sciences.This ordering corresponds with such objective criteria as disciplinary consensus, knowledge obsolescence rate, anticipation frequency, theories-to-laws ratio, lecture disfluency, and age at recognition. It is then argued that this hierarchy can be extrapolated to encompass the humanities and arts and interpolated within specific domains to accommodate contrasts in subdomains (e.g., revolutionary versus normal science). This expanded and more finely differentiated hierarchy is then shown to have a partial psychological basis in terms of dispositional traits (e.g., psychopathology) and developmental experiences (e.g., family background). This demonstration then leads to three hypotheses about how a creator's domain-specific impact depends on his or her disposition and development: the domain-progressive, domain-typical, and domainregressive creator hypotheses. Studies published thus far lend the most support to the domainregressive creator hypothesis. In particular, major contributors to a domain are more likely to have dispositional traits and developmental experiences most similar to those that prevail in a domain lower in the disciplinary hierarchy. However, some complications to this generalization suggest the need for more research on the proposed hierarchical model.