The Psychomotor Vigilance Task (hereafter ‘PVT’) is a sustained-attention, reaction-timed task that measures the speed with which subjects respond to a visual stimulus. Quantitative dependent variables involve omission and commission errors, reflecting fluctuations in endogenous cognitive condition. Research indicates increased sleepiness correlates with deteriorated alertness, slower problem-solving, declined psycho-motor skills, and increased rate of false responding.

The PVT was championed by David F. Dinges

David F. Dinges

David F. Dinges is a major American sleep researcher and teacher.He is Professor of Psychology in Psychiatry, Chief of the Division of Sleep and Chronobiology in the Department of Psychiatry, and Associate Director of the Center for Sleep and Respiratory Neurobiology in the University of...

 and popularized by its ease of scoring, simple metrics, and convergent validity

Convergent validity

Convergent validity, is the degree to which an operation is similar to other operations that it theoretically should also be similar to. For instance, to show the convergent validity of a test of mathematics skills, the scores on the test can be correlated with scores on other tests that are also...

. It has a learning curve of only 1–3 trials and the 10-minute variant has become a standard laboratory tool for assessing sustained performance. However, it was shown that motivation can counteract the detrimental effects of sleep loss for up to 36 hours.

PVT Overview

The PVT is a simple task where the subject presses a button as soon as the light appears. The light will turn on randomly every few seconds for 5–10 minutes. The main measurement of this task is not to assess the reaction time, but to see how many times the button is not pressed when the light is on. The purpose of the PVT is to measure sustained attention, and give a numerical measure of sleepiness by counting the number of lapses in attention of the tested subject.