Gaze-Contingent Displays for Interactive Text Enhancement

Eye trackers are used for measuring a person’s eye movements, for example, while reading text on a screen. This information can be used by scientists to study the human visual system during object recognition or text comprehension. Moreover, engineers can build gaze-controlled interfaces that trigger a variety of actions when the user looks at pre-specified icons on a screen. In my research, I studied how gaze-contingent displays can be used to enhance the information that is provided by texts. First, I implemented a simple scripting language that allows even users without programming experience to set up gaze-contingent text displays. The language allows to display any text on the screen and define keywords that trigger actions when the user looks at them. These actions can either be a specific sound file being played or a specific bitmap image being displayed at a given position on the screen. Second, using this scripting language, I conducted an experiment on 15 users. They saw displays of 20 written words, which they had to memorize. In a control condition, the display would be static. In another condition, whenever they looked at a word, that word would be spoken, in a third condition, an image associated with the word would be shown, and in a fourth condition, both effects would occur at the same time. Surprisingly, memory performance was reduced by all gaze-contingent effects, whereas subjects believed that especially the image condition was helpful for memorization. The results suggest that gaze-contingent text enhancement is appreciated by its users but, instead of presenting identical information in different forms, should provide additional information related to the attended words