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WAFV: thirty minutes of nearly nothing

A grey square appears, and occasionally it is darker than usual. That is the whole test, for half an hour. It is the most honest test on the day and the one people prepare for least.

gold Stage 2 7 min read

Vigilance — watching for a rare, low-salience signal over a long, uneventful period — is the part of driving that no simulator ride can teach and no enthusiasm can fake. Everyone can do it for two minutes. The test runs for thirty because the interesting information is in the last ten.

Length
Around thirty minutes, continuous
Task
Respond when the stimulus changes; ignore everything else
Scoring
Hits, misses, false alarms, and response times across the run
The real measure
How all of those change between minute five and minute twenty-eight

The decline curve

Vigilance decrement is a well-documented effect: detection gets worse over a long watch, in everybody, including people who are good at it. The operator is not looking for someone immune to it. They are looking at the shape of your curve — how steep the fall is, whether your response times scatter, and whether you start pressing at nothing when boredom sets in.

That last one deserves emphasis. False alarms count. A candidate who responds to every flicker keeps their hit rate up and produces a profile that is worse, not better, than one with a few honest misses. On the railway that is a driver who brakes for shadows, and it is not a safe behaviour just because it is a cautious one.

How to hold attention for half an hour

  1. Set up before you start. Feet flat, back supported, screen at arm's length, responding hand resting rather than hovering. You cannot fix your posture at minute twenty without losing your place, and a hovering hand is an aching hand by minute ten.
  2. Soft focus, not staring. Look at the stimulus area rather than drilling into its centre. Hard staring fatigues you quickly, dries your eyes and makes small changes harder to see, which is the opposite of what it feels like it is doing.
  3. Blink deliberately. People under-blink when concentrating. Dry eyes at minute twenty are a real and avoidable cause of missed signals.
  4. Anchor on your breathing, not on thoughts. You need something to occupy the part of your mind that will otherwise start planning your evening, and it has to be something that does not compete for vision. Slow, regular breathing is ideal. Daydreaming, mental arithmetic and song lyrics are not.
  5. Do not predict. The interval between signals is irregular by design. The moment you start thinking "one is due", you are generating false alarms.
  6. Reset at the dips. You will feel attention go — usually somewhere between minutes twelve and eighteen. Roll your shoulders once, blink twice, return. Three seconds. That is an intentional recovery rather than a slow slide.
  7. Respond as soon as you are sure, not after you have confirmed. A second look to be certain is a slow response on a signal you already saw.
Drill it: WAFV

The exam version runs the full thirty minutes and is the only length that sets your best — because ten minutes stops before the decline the test exists to find. There is a five-minute version too, but only as a check that your screen and finger are working.

Open the drill

Sit it in full, once

This is the strongest single recommendation on this site. Almost nobody does thirty unbroken minutes at home, and it is not the same experience as three ten-minute runs. You learn three things you cannot learn any other way: where your personal dip falls, what it feels like just before a miss, and that the last five minutes are survivable.

Do it at the same time of day as your assessment, after eating what you would normally eat. If your slot is at two in the afternoon, a nine in the morning practice tells you very little.

Where people lose it

How to practise it