Читать книгу Eye Tracking the User Experience - Aga Bojko - Страница 13

Your eyes jump from place to place a few times per second (three to four times, on average). These rapid movements, called saccades, are the fastest movements produced by an external part of the human body. To prevent blurring, your vision is mostly suppressed during saccades. Visual information is only extracted during fixations, which is when the eyes are relatively motionless and are focusing on something (see Figure 1.7). Fixations tend to last between one-tenth and one-half of a second, after which the eye moves (via a saccade) to the next part of the visual field. Although there are a few other types of eye movements, saccadic eye movements, consisting of saccades and fixations, are most common and of the greatest interest to UX research.

FIGURE 1.7 Gaze plot representing eye movements of a person looking up a train schedule in a timetable. Fixations are represented as dots and saccades are shown as lines connecting the dots. The size of the dot is proportional to the fixation duration.