The experiments were conducted at the University of Pretoria. We used a Tobii T120 desktop
eye tracker to record users’ eye movements while they completed the same task on each of the
three websites. The eye tracker was calibrated for each participant’s eyes to ensure accurate data
recording. In this study a five-point calibration was used. Once calibration was completed the
instructions were displayed to the participants, followed by the task they were required to
complete. They performed a task known as “mobile data top-up” or “purchasing of a data
bundle” after the following scenario was explained to them: “You just bought a new mobile SIM
card. After arriving home you insert the SIM card into your phone and realise that you are not
able to browse the Internet because you do not have any data available. On your computer, you
open the TelecomX website to top-up your SIM card with mobile data”. When they started the
task we had already logged into the website so that they did not need to go through the login
process. The task ended when they indicated that they have located the top-up function.