Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Human Factors Psychology


Pak, Richard

Committee Member

Greenstein , Joel

Committee Member

Gugerty , Leo

Committee Member

Pagano , Christopher


A consistent interface is thought to be beneficial because it allows users to draw on previous training and experience when operating a new interface. Design guidelines like the eight golden rules of interface design argue that a highly consistent interface improves system usability (Shneiderman, 1987). However, interface consistency is not monolithic; instead it is a complex, multidimensional construct. I refer to the two dimensions of interface consistency as perceptual consistency (the appearance) and conceptual consistency (the functionality) of an interface. Perceptual consistency considers aspects like interface layout and orientation; conceptual consistency considers how the system operates or responds. I sought to understand how combinations of these dimensions might affect performance and user perceptions of a system. For example, what if a system looks the same but operates differently? Results indicate that both an inconsistent appearance and an inconsistent functionality can hurt performance. Forcing consistency, however, may not be beneficial either. When there was a mismatch between dimensions (i.e., one was consistent and the other inconsistent) performance was worse than that of an entirely inconsistent version. Specifically, participants in the conceptual inconsistency and perceptual consistency condition (operates differently but looks the same) performed worse and reported higher workloads. Designers should encourage interface consistency by making systems that function similarly also share a similar appearance; however, when the systems are functionally disparate (i.e., they do different things) designers should take care to avoid implying similarities where they do not exist.

Included in

Psychology Commons



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