Statistically Controlling for Processing Fluency Reduces the Aesthetic-Usability Effect

Abstract

The aesthetic-usability effect asserts that user interfaces that appear aesthetic also appear easier to use. Most explanations for the effect see aesthetics in a causal role. In contrast, we propose that processing fluency as a third variable causes both judgements of aesthetics and usability. Processing fluency refers to the subjective ease of information processing and has been shown to influence, among others, judgements of aesthetics and usability. We tested our proposition in an experiment in which users rated screenshots of city websites. The aesthetic-usability effect was replicated by our data: aesthetics and usability correlated .79. When controlling for fluency, however, the aesthetic-usability effect was considerably diminished; the correlation decreased to .34. Future research will address the limitations of this study by investigating a wider range of website designs and adding interactivity to the interfaces.