Psychomotor Vigilance Task (PVT)

History of the PVT

The Psychomotor Vigilance Task (PVT) is a widely used test to assess sustained attention and vigilance. Sleep researchers have known for decades that a loss of sleep reduces vigilance. What is now widely known as the Psychomotor Vigilance Test is based on the work by Wilkinson and Houghton (1982). David Dinges elaborated this task and called it first simply Visual Reaction Time in a much cited paper (Dinges & Powell, 1985).

Task Description

In this task, you see a red box. Every so often, a yellow running counter is presented within this box. You need to respond as quickly as possible to the running counter. When responded, the running counter disappears and you wait for the next counter.

The PVT scores include multiple measures: mean and median response time (over all valid responses, including lapses), reciprocal RT (1/RT), mean of the fastest 10% of RTs, number of failures to respond within 500ms (lapses), and number of responses when there is no yellow counter (commissions/false starts).

Test Versions

Brief (PVT-B)

A 3-minute version for quick assessment. Uses random delays between 0-3 seconds before the counter appears. Ideal for rapid screening or when time is limited.

Standard (PVT)

A 40-trial version (~5 minutes) for comprehensive evaluation. Uses random delays between 2-10 seconds before the counter appears. Provides more data points and is a shortened version of the classic PVT format.

Timing of Trials

• An empty red box is shown and continuously visible
• Wait for a random delay before the counter appears (0-3s for Brief, 2-10s for Standard)
• A counter starts running and is updated every 50ms
• You have up to 30 seconds to respond (responses slower than 500ms are considered lapses)
• Feedback is shown for 1 second

Scoring

Sleep deprivation and fatigue can be measured in three ways: slower responses (longer mean/median RT), increased number of omissions (lapses), and increased number of commissions (responding when there is no counter).

You can calculate an overall performance score: Overall Performance Score = 1 - (Number of False starts + Number of lapses) / (All trials)

References

• Dinges, D. F., & Powell, J. W. (1985). Microcomputer analyses of performance on a portable, simple visual RT task during sustained operations. Behavior Research Methods, Instruments, & Computers, 17(6), 652-655. 10.3758/BF03200977
• Basner, M., Mollicone, D., Dinges, D.F. (2011). Validity and Sensitivity of a Brief Psychomotor Vigilance Test (PVT-B) to Total and Partial Sleep Deprivation. Acta Astronautica, 69, 949-959.
• Lim, J., & Dinges, D. F. (2008). Sleep deprivation and vigilant attention.
• Wilkinson, R. T., & Houghton, D. (1982). Field test of arousal: A portable reaction time test with day- variability of individual alertness.