Human-computer interaction (HCI) design generally involves collaboration from professionals in different disciplines. Trained in different design education systems, these professionals can have different conceptual understandings about design. Recognizing and identifying these differences are key issues for establishing shared design practices within the educational community. Contributing to this understanding, we examined whether and how two different populations of students have different knowledge structures with respect to HCI design. We adopted the romantic, conservative and pragmatic dimensions, previously investigated in the related research, to elucidate those differences. This paper compares one specific type of design artefact--conceptual frameworks--created by groups of students with different educational backgrounds: Arts and Engineering. It was based on a set of 22 criteria divided by two main domains: scheme (addressing form) and realm (focusing on contents). The obtained results show that students with background in Engineering (1) focus more on the product of design; (2) rely less on conceptual frameworks to guide the design process; and (3) produce artefacts that are more constrained in terms of signal-to-noise ratio, definition of a symbolic system, and information organization and shaping. We suggest that conceptual frameworks serve to communicate and understand design practice. We note that Engineering students seem to be more susceptible to fixation than Arts students and suggest that an emphasis of reflection-in-action could help compensating this problem.