How the WAFV vigilance test works
WAFV is part of Schuhfried’s Vienna Test System. Stimuli appear over and over, and now and then one is slightly less intense than the rest; your task is to respond to those rare cases. On the vigilance forms they make up about 5% of the stimuli, and the test runs for 15 to 30 minutes depending on the form.
In the train driver assessment, candidate guides describe a grey square flashing on screen for around 30 minutes, and a button to press when it changes shade. RSSB’s standard uses WAFV for vigilance and, together with ATAVT, for reaction time.
Results cover your reaction times and the kinds of error you make, such as missing a change or pressing when nothing changed, compared with Schuhfried’s norms.
How to stay alert for half an hour
The test is long and quiet on purpose. These habits help:
- Get comfortable before it starts, with your finger resting beside the button rather than on it.
- Keep your eyes on the square but relaxed, and blink normally. Staring hard tires your eyes long before the end.
- Expect long gaps. Changes are rare, so a quiet spell does not mean you missed one.
- Press only for a change you actually saw. If you are unsure, do not press.
- When your mind drifts, bring it back without dwelling on the lapse. The next change could come at any moment.
Tips for the real WAFV
- Eat, drink and use the toilet before you start. It is a long stretch of concentration.
- Ignore sounds around you. Your only cue is the square.
- Build up to it: practise one dull task for half an hour with no phone in reach.
- Listen to the instructions and do the example. Once the test starts you cannot ask questions.
- Wear your glasses or lenses if you need them for screens.
Practise WAFV on CogniPrep
Our WAFV runs for a full 30 minutes: a grey square flashes about once a second and now and then darkens half a second after it appears. Press Space, or tap the large button on a touch screen, only then. There is no clock or progress bar and the run cannot be paused; leave the page for more than two seconds and it stops. Your score out of 100 is three parts detection, minus a cost for false presses, and one part speed, and the feedback compares your first ten minutes with your last. Browsers add a little timing noise, so treat reaction times as a guide.