Enabling Innovative Human Computer Research
The labs are equipped with Tobii Eye tracker equipment. You can either request for the software to be used during an expert supported study or you can use the software during a self service session (if you have been trained how to use it). The equipment can be set up in any of the labs, although its default home is HCI 2.
Eye tracking equipment can determine where a user is gazing at any time and hence record eye movements. The eye tracking data gathered in usability, accessibility and developmental testing studies shows what users are really looking at on a web page. Eye tracking uses heatmaps and gazeplots to show what has attracted interest.
Infrared illuminators built into the screen or in the mobile eye tracker glasses, invisible to the human eye, create reflection patterns on the cornea of the eyes, which the image sensors use to register the image of the user’s eyes. The image processor finds the eyes, detects the exact position of the pupil and identifies the correct reflections from the illuminators and their positions. A mathematical model calculates the eye position in space and the point of gaze. At the start of an eye tracking session, the system calibrates the user’s eyes to ensure it is tracking them correctly (it copes with users wearing glasses or contact lenses). The system records what the user is looking at throughout the session. For screen-based eye tracking, the researcher observes the live gaze on a separate screen which shows eye movement, overlaid as a red blob with a trail, moving around the screen. In mobile studies, eye tracking glasses record the user gaze then the data is downloaded into the system for analysis.
Eye tracking analysis software uses heat-maps and gaze-plots to illustrate what has attracted attention. Data collected includes visualisations (a list of web pages and who has looked at them) and the gaze plot showing order of gaze, length of fixation and time elapsed. Different gaze plots for each web page can be compared in the analysis software and each recording played back in real time, showing the order of gaze with the audio recording. Heat-maps show where the eye has lingered the longest. Researchers also use an ‘area of interest’ tool which provides quantitative data to measure and compare different places on a screen. This analysis software allows data interpretation and recommendation of design and navigation improvements. Other optional analysis tools include Cluster, Bee Swarm, data exported to statistical or video analysis software, depending on the depth of analysis needed. The eye tracker can reveal problems with a website, software or learning materials very quickly and provide visual evidence to help a development team solve usability issues.
The mobile eye tracker provides data on studies involving physical objects or things displayed on large displays or projection screens, for example interactive TV, actual print media and physical product design and packaging.
The user works through the tasks or scenarios to try and find or do something on screen. On a separate screen the researcher watches the eye tracking spot which shows where the user is looking. A ‘retrospective protocol’ is used instead of the usability testing ‘think aloud protocol’. This involves asking questions after the user has finished each task, though the user can talk about what they are seeing during the task if they wish.
Eye tracking enables comparison of what users are looking at in a learning exercise, revealing differences in how beginner or more advanced learners are working with materials on screen. Users may have spent time looking at a particular place on the screen, perhaps because they are reading and comprehending, or trying to understand something. Alternatively they may have glanced over different parts of the screen. The researcher asks careful questions about what the user was thinking or trying to do when this happened, to discover the extent of their learning.
Using the Tobii Eye Tracker - Doug Clow’s liveblog of an IET Technology Coffee morning http://dougclow.wordpress.com/2009/12/16/seeing-how-people-really-use-online-technology-with-the-tobii-eye-tracker/
In addition Jonathan San Diego and Patrick McAndrew’s research using Eye Tracking can be found at the following links http://kn.open.ac.uk/public/document.cfm?documentid=10474 (link not found) and http://www.slideshare.net/JPSan_Diego/ter-workshop-j-p-san-diego?from=share_email
Please note: The Open University is not responsible for the content of the above external websites.
For a description of eye tracking being used for usability testing, please read the Eye Tracking Case Study.
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