Behavioral and Physiological Metrics - Measuring the User Experience: Collecting, Analyzing, and Presenting Usability Metrics - page 169

Figure 7.6 shows the series or sequence of fixations that an individual partici-
pantmadeontheAmazonVideowebsite,alsoknownasascanpath.Thisisper-
haps the most common way to visually represent the eye movements for a single
participant. A fixation is defined by a pause in the eye's movement within a well-
defined area. Normally these pauses last at least 100 msec (1/10th of a second)
or longer. Fixations are usually numbered to indicate their sequence. The size of
each circle is proportional to the length or duration of the fixation. The saccades,
or movements between fixations, are shown by the lines. In Figure 7.6 it is easy
to note that the participant was focused primarily on the faces, as well as the
first “learn more” box (on the far left). Scan paths are an excellent way to show
how a participant looked at the page and what elements they saw in what order.
Figure 7.6 Example of one individual's scan path of eye movements on the Amazon Video website.
DID YOU KNOW?
During the saccades, when we're moving our eyes from one point to another, we're
essentially blind. This is true whether we're scanning a webpage or reading a topic like
this one. Of course, we don't perceive it that way. Our brains are constantly integrating
the information from the various fixations to give us the perception of a continuous
visual stream of information.