While eye tracking is a very accurate indicator of what research participants are looking at and the order they view objects in, eye tracking can’t tell us why a participant is looking where they are looking. It is extremely important to keep the difference between visual behavior and cognitive or physical processes in mind when conducting an eye tracking study.
In order to make certain that your eye tracking study is valid, it is important to considering using eye tracking in conjunction with more qualitative methods, such as Think Aloud, to help avoid the misinterpretation of the studies data. If these qualitative methods are not used, researchers must attempt to make sweeping (and quite possibly wrong) assumptions about why user’s eyes behaved the way that they did.
For example, in our article Eye Tracking Package Design: Do Smokers Ignore Health Warnings?, we detail an eye tracking study of health warnings on cigarette packs. While the results of the eye tracking indicate that non-smokers and light smokers looked more at the warning label than the branding on some of the packs in the study, the researchers failed to use qualitative methods to back up their findings. As a result, in the conclusion of the study researchers make the “assumption” that simply because light and non-smokers looked more at the health warnings than the branding portion of the cigarette package, they were “probably” less likely to purchase them. Researchers also assumed that because heavy smokers viewed both parts of the pack an equal number of times, that the warning labels would not have an impact on their purchasing habit.
If the researchers had added qualitative measurements, such as Think Aloud or a survey after the eye tracking, they could have come up with a stronger scientific conclusion about the correlation between cigarette package design, health warning labels, and purchasing behavior.