The role of mental workload in determining the relation between website complexity and usability: an eye-tracking study

Digital technology is now crucial for carrying out many activities and the drive for innovation in digitization has involved not only private organizations but also public administrations. However, despite a growing awareness of the importance of digitization of public services, usability issues have been addressed only recently. Terms like “Usability”, “User Experience”, and “Human-Centred Design” are surely becoming part of the vocabulary, but often they are used as empty keywords by policymakers, while there is a lack of specific research in this domain. One notable example is the lack of studies on cognitive load imposed by information abundant websites and its influence on both users’ performance and perceptions of usability. The main objective of the present study is to evaluate the mental workload of users navigating websites with different levels of complexity in their information architecture. Eye movements of twenty users were recorded during the execution of search tasks carried out on websites of three public agencies previously selected for their complexity level. Mental workload assessment was obtained by analysing subjects’ ocular behaviour. Results showed that low complexity websites were associated with better performance, lower mental workload and higher usability rates compared to high complexity websites.