Psychomotor
Vigilance Task
The PVT is the standard laboratory measure of behavioural alertness. It is deliberately the simplest task in this collection: nothing to learn, nothing to remember, no strategy that helps. That is what makes it work — with aptitude and practice taken out of the picture, what moves your numbers between sessions is state, not skill. What it detects is not slowness but wake-state instability: brief attentional failures intruding into otherwise normal responding.
The task
Do not press before the counter appears. Early presses are recorded as false starts and restart the wait with a fresh random interval, so pressing to a rhythm gets you nothing but a worse score. On a phone, tap anywhere instead of SPACE.
What comes out
Two numbers carry the session, and neither is your average reaction time.
Mean RT is reported too, and pointedly not scored: an average over a distribution with a long lapse tail moves mostly with that tail, so it is noisiest exactly where the signal lives — and it cannot tell uniformly mediocre responding apart from fast responding punctuated by failures. Those are different states.
These are fixed, not preferences. The parameterisation is the instrument — change the interval range or the threshold and the numbers stop being comparable with anyone else's, or with your own.
Ten minutes is a lot to ask of yourself repeatedly. The 3-minute PVT-B is validated against this test and loses about 23% of its sensitivity — worth taking if the alternative is skipping the measurement.
Go to PVT-B — 3 min, lapse ≥ 355 ms →They are scored as separate instruments and keep separate histories. Runs on one are not comparable with runs on the other, so pick a version you can stick with rather than alternating.
This is a research-style measurement instrument and an educational demonstration — not a medical or diagnostic device. A browser adds display and input latency that a laboratory PVT device does not, so absolute values here are not comparable with published norms; what is usable is the change in your own numbers across sessions on the same hardware. Nothing here can confirm or rule out a condition, diagnose sleep disorders, or tell you whether you are fit to drive.
Psychomotor Vigilance Task
What this test measures
The Psychomotor Vigilance Task (Dinges & Powell, 1985) is the reference measure of behavioural alertness, used in sleep research from hospital wards to the International Space Station. An empty box sits on screen; after a random wait a millisecond counter starts running, and you stop it as fast as you can — for ten minutes.
The task is trivial on purpose. With nothing to learn and no strategy, performance is nearly immune to practice, so what it measures is state: how sleep pressure and fatigue destabilise attention. Sleep loss does not slow you uniformly — it makes brief attentional failures intrude into otherwise normal responding. That is why the PVT is scored on lapses (responses of 500 ms or more) and mean response speed (1/RT), the metrics most sensitive to sleep loss, rather than average reaction time.
How to use it
Take it under consistent conditions and the trend tracks your alertness — after poor sleep, across the workday, or around caffeine. Ten minutes is long by design: sustaining vigilance is part of what is measured, and time-on-task decline is reported too. If you will not reliably sit through ten minutes, use the validated 3-minute PVT-B instead — a shorter test you actually take beats a longer one you skip.
Sapiens Bench tasks are educational instruments for self-tracking, not medical or diagnostic devices.