Eye Tracking and Composition, Part 2

Below is a scanpath image of the artwork that we saw in yesterday’s post. The chart represents the behavior of an individual who, with no prompting, looked at the artwork for a sixteen second period on a computer screen.

The computer recorded a series of circles, indicating where the eye paused momentarily, connected by a thin blue line.

The scanpath reveals that the eye darts unpredictably in straight jagged leaps known as saccades. Saccades occur between three and five times per second, alternating with brief periods of rest called fixations.

The white glow around each circle represents the subject’s peripheral vision. (The heavier blue shows a running average of the center of attention and the orange line is an attempt by the computer to detect reading behavior. Those lines are not important for the study of artwork.)

The numbered black boxes are time markers, indicating the position of the eye at each passing second. The session begins at the green dot and ends at the red dot, the last point of rest before the image disappeared. By following the blue line second by second, you can precisely reconstruct the viewer’s experience.

The test subject’s eye enters the composition at the top center and zigzags down to the figures at left center. This happens within the first second. In the next three seconds it swoops to the right, leaps upward to glance at the upper right corner, and then moves across the center of the picture in large strokes, pausing briefly to look at the near and far buildings.

For the remaining ten seconds the subject’s gaze slides back and forth in smaller saccades, examining the people in the scene.

According to Greg Edwards, President and CEO of Eyetools, “During the first 3 1/2 seconds, this particular person was getting the lay of the land. How long people take to get this initial overview will depend on each picture. They’re trying to understand the basic structure or the context of the picture.”

After that, they usually settle into finer eye movements. “If they make a big movement,” he said, “they’re typically searching for context. If they make a smaller movement, they’re looking for detail.”

The second person’s scanpath (above) both resembles and differs from the first one. The eye also makes large orienting moves initially, taking in the far vista and the full array of people below. But this scanpath shifts between large and small movements throughout the session and spends more of the time looking at the distant vista and the surrounding architecture.


It might be hard to make out these diagrams in small Web illustrations. For the sake of clarity, this video roughly reconstructs the sequence of saccades over the same approximate overall duration——though it doesn’t accurately represent the relative duration of each fixation.

Tomorrow we’ll see what we can learn from crunching together data from a lot of different observers, and I'll suggest some preliminary conclusions.
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Thanks, Greg! Link to Greg Edwards's Eyetools blog. and Eyetools website.

Related posts on GurneyJourney:
Eyetracking and Composition, part 1
Eyetracking and Composition, part 2
Eyetracking and Composition part 3
Introduction to eyetracking, link.
How perception of faces is coded differently, link.