Eye tracking in retrospective think-aloud usability testing: Is there added value?

Eye tracking is the process of recording users’ eye movements while they are looking at the location of an object. In usability testing, this technique is commonly used in combination with think-aloud protocols. This paper presents an experimental study involving 24 participants; with the aim of comparing two variants of retrospective think-aloud (RTA) methods, that is, video-cued RTA method and gaze-cued RTA method, to address the value of having an extra eye-cue in retrospective think-aloud usability testing. Results suggest that both RTA variants are effective in detecting major usability problems. Moreover, the combination of eye tracking techniques and think-aloud protocols can further help evaluators to detect more usability problems, especially minor navigational and comprehension problems. It also helps participants to remember their behavior details, such as what they were looking at on a web page, as mouse movement alone might not be representative of their actual thoughts. Nevertheless, we found that participants might become distracted while seeing their eye movement, which can affect their verbalization performance and, hence, they might experience longer silence periods.