TEST: Follow-Solve-Listen™

The Follow-Solve-Listen Test (FSLT) is a test battery of short, continuous tasks that may be used to assess physiological aspects of individual performance during multi-tasking. FSLT was originally created by Dr. Sandra Marshall through her research on cognitive workload and pupil dilation.

Download the Follow-Solve-Listen Test


Ground Breaking Functions

The FSLT consists of three tasks, presented consecutively to an individual. Each task takes about 45 seconds to complete.

  • Task 1 is a variation of a classical smooth pursuit task in which an individual is asked to focus on a visual target and follow the target as it moves randomly about a screen. In the FSLT, several equally-sized dots are presented on the screen. One is designated as the target. All the dots then move in approximately random patterns around the display. The individual is asked to focus on the target, follow it with his or her eyes as it moves around the screen, and then identify the target at the conclusion of the task.
  • Task 2 retains all of the elements of the first task and adds a second component, mental arithmetic. Numbers are presented one at a time on the right side of the screen while the dots are moving on the left side. The individual is asked to follow the target dot as before and at the same time to solve the arithmetic problem as it is presented. At the conclusion of the task, the individual must indicate the target dot and provide the correct arithmetic solution.
  • Task 3 retains all the elements of the first two tasks and adds a third component, an auditory vigilance task. A small spinning dial is shown continuously in the middle of the display. The dial spins either clockwise or counterclockwise, changing direction at random intervals. Every 10 seconds during the task, a tone sounds and the individual is asked whether the dial was moving clockwise or counterclockwise when the tone sounded. While monitoring the dial, the individual again must follow the target dot and solve the arithmetic problem.


follow solve listen test overview
  • The FSLT was developed in 2010 by Dr. Sandra Marshall (CEO, EyeTracking, Inc. and Professor Emeritus, San Diego State University) to provide a standard test that could be easily used across a wide range of eye tracking systems.
  • The physiological metric tested with each eye tracker was the Index of Cognitive Activity, a proprietary measure of cognitive workload based on pupil dilation.
  • To date, more than 10 eye trackers have been evaluated with the FSLT, with the majority of them able to detect—similarly and reliably— the predetermined difficulty levels of the FSLT tasks using only the ICA.
  • A list of eye trackers for which the FSLT is appropriate may be found in the matrix on this page



FSLT and contents of the download are Copyright © 2010, EyeTracking, Inc.

This FSLT implementation is free to use for all commercial and non-commercial users so long as all terms of this license are met.

The source of the test should be cited in any use. Any and all presentations and/or publications that utilize any aspect of the FSLT must include at least one of the following citations:

  • Marshall, S. (2012). Follow-Solve-Listen Test [Measurement instrument]. Retrieved from
  • Bartels, M., & Marshall, S. (2012). Measuring Cognitive Workload Across Different Eye Trackers. In Proceedings of 2012 Eye Tracking Research and Applications (ETRA) Symposium (pp. 161-164). New York: ACM.
  • Marshall, S. (2013). Interaction Science and the Aging User: Techniques to Assist in Design and Evaluation. In Stephanidis, C., & Antona, M. (Eds.), Universal Access in Human-Computer Interaction, Proceedings of the 7th International UAHCI, Part II, pp. 133-141. Springer Lecture Notes in Computer Science.

All files provided in the FSLT package may only be used in accordance with the FSLT Instructions file and in no other manner.

No FSLT files may be distributed by you or your organization. The latest copies may be downloaded directly from at the sole discretion of EyeTracking, Inc.