But what does it all mean? Understanding eye-tracking results (Part 2)
Part II: What can you learn from eye-tracking data?
People often ask me what exactly they can learn from eye tracking. I have a short version answer which is:
We track:
• Where people look
• Where people click
• What people ignore
• And we discover why they decide to click ...or not click.
Why does it work?
• Your eyes are hardwired into your brain and the eyes cannot lie.
• Eyes can’t be "put down" like a mouse between clicks.
• Eyes + clicks + subjective questions give a comprehensive view into the user experience.
This explanation is pretty common, but in reality, you can gain much more insight into the user experience from these kinds of studies. Some advantages of eye tracking studies include:
• Biometric measurements are more accurate than user feedback. User feedback is invaluable, but notoriously unreliable. Feedback regarding feelings, opinions, etc. must be acquired through survey methods. However, measuring natural behavior gives a much more accurate picture of a user’s immediate experience than asking them after the task is complete.
• Eye-tracking data can be used to accurately predict user feedback. This is true for questions regarding ease of use, ease of navigation, etc. All of these items also affect user confidence in the site and company.
• Site navigation patterns can be mapped. For instance, we can map out common navigation paths from a homepage to an interior page, and can begin to understand why some are being used more than others.
• Results are representative of a “natural work environment”. In other words, eye tracking does not require that a moderator be in the room with the user. Obviously the studies are done in a controlled environment, but not having other people in the room makes the experience very comfortable for users.
• Viewing order of pages and page elements can be established. We begin to understand what information is most likely to be seen/missed by users, and in what order. For example, are users viewing a “Free Trial” offer 1st or 15th when seeing the page? Now you can know.
• DHTML elements can be tracked separately. The visual effectiveness and frequency of use of DHTML elements can be studied.
• Short iterative testing can also be implemented. Because we can test prototypes (yes, even jpeg mock-ups), short eye tracking tests can be used to modify designs quickly. This kind of testing is not a standard use of eye-tracking, but is proving to be very effective.
• Page element placement, copy, etc effects can be ranked. Should I change my header text? Move a menu to the right rail? Change the icon size or background? Certain layout changes can be ranked as to how much effect they will have on viewing patterns.
One point to keep in mind is that eye-tracking, like all other usability tests, is not going to provide all of the answers by itself. Eye-tracking is a valuable and powerful tool when implemented alone. But if you want the best over all picture, use it in conjunction with other usability tests, and as a part of an iterative process.
Does eye tracking measure visual attention?
Yes, eye tracking can estimate the areas of an interface which receive visual attention. The “bouncing around” of the eye trace shown in the video is created by a series of fast eye movements called saccades. When your brain is planning an eye movement, it shifts covert attention to the eye’s destination [ 1]. The attentional shift and saccade movement have been shown to be inseparable [ 2 ]. And, of course, once you fixate something, your visual system starts processing the image.
Does this mean that we remember 100% of everything we fixated on a screen? Definitely not. Our brains can suppress images, or use the visual signal to inform any number of low level cognitive functions. Does it mean that what we fixated has had an opportunity to directly affect our experience with an interface? Absolutely.
Gaze trace information helps us to understand the areas of a page which most helped to form a user's visual experience with the site or email.
References:
Here's an EXELLENT introduction to eye tracking and usability:
Matteo Penzo's Introduction to Eyetracking: Seeing Through Your Users’ Eyes
[1] Shipp S. (2004) The brain circuitry of attention. Trends Cogn Sci. 8, 223-30.
[2] Peterson MS, Kramer AF, Irwin DE. (2004) Covert shifts of attention precede involuntary eye movements. Percept Psychophys. 66, 398-405.
[ref] Liversedge SP, Findlay JM. (2000) Saccadic eye movements and cognition. Trends Cogn Sci. 4, 6-14.
Article by Teresa Hernandez - Eyetools, Inc.
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