Toward a Definition of Visual Complexity as an Implicit Measure of Cognitive Load

The visual complexity of Web pages is much talked about; "complex Web pages are difficult to use," but often regarded as a subjective decision by the user. This subjective decision is of limited use if we wish to understand the importance of visual complexity, what it means, and how it can be used. We theorize that by understanding a user's visual perception of Web page complexity, we can understand the cognitive effort required for interaction with that page. This is important because by using an easily identifiable measure, such as visual complexity, as an implicit marker of cognitive load, we can design Web pages which are easier to interact with. We have devised an initial empirical experiment, using card sorting and triadic elicitation, to test our theories and assumptions, and have built an initial baseline sequence of 20 Web pages along with a library of qualitative and anecdotal feedback. Using this library, we define visual complexity, ergo perceived interaction complexity, and by taking these pages as "prototypes" and ranking them into a sequence of complexity, we are able to group them into: simple, neutral, and complex. This means we can now work toward a definition of visual complexity as an implicit measure of cognitive load.