Three tests, one raw capacity: how fast you can perceive, compare and act on detail before the clock runs out. Perceptual Speed puts two strings side by side — a number, a code, a name — and asks a single speeded judgement per pair: identical, or different somewhere? Processing Speed keeps a symbol-to-digit key on screen throughout and streams symbols at you one at a time, each needing its matching digit entered immediately — the classic digit-symbol coding format. Visual Scanning scatters numbered points across a cluttered board and asks you to connect them in order, board after board, until time runs out.
Why airlines test it
Perceptual and processing speed are measured separately from reasoning because they capture something reasoning tests miss entirely: how fast you can execute simple, well-learned perceptual work, over and over, without the pace degrading your accuracy. That throughput under time pressure is unusually sensitive to fatigue and workload, which is precisely why selectors care about it. A candidate who reasons brilliantly but processes routine detail slowly will bottleneck the moment the cockpit gets busy; these tests find that bottleneck before a training captain has to.
In the cockpit
This is the speed underneath the instrument scan — not the judgement of what the numbers mean, but the raw rate at which you can look, read, compare and move on. It is the same capacity that lets you find the correct line on a chart or approach plate quickly under time pressure, and the one that catches a lookalike error in a frequency, callsign or squawk before it becomes a readback mistake.
For example: cleared to contact the next sector on 121.05, you dial it in, glance back at the clearance to confirm, and the two strings — what's written and what you set — have to be checked for an exact match in under a second, because 121.05 and 121.50 differ by nothing more than digit order, and a transposition puts you on the wrong frequency at the worst possible moment. That instant same-or-different check, done correctly every time under pressure, is perceptual speed doing its job.
How to practise
On Perceptual Speed, don't read every character in sequence — let your eyes jump between the two strings at the points most likely to differ (the last few digits, a letter that is easy to swap); genuine speed gains come from a smarter search pattern, not faster reading. On Processing Speed, stop treating the key as a lookup table you consult every time — the symbol-digit pairs are few enough to memorise within the first minute, and once they are in memory your score stops being limited by recognition and starts being limited by pure motor speed. On Visual Scanning, work in a consistent sweep pattern across the board instead of hunting randomly; a systematic search cuts the time spent re-scanning the same empty patch of clutter, which is where most of the wasted seconds go.
The Air France cadet selection's PSY1 morning runs a counting test that is really a test of finding edges, recreated as ENAC Mosaic Count: a four-by-four mosaic drawn with no grid lines and no frame, so neighbouring tiles fuse into one black shape, and a number to give for each of ten tile shapes, zeros included. The ten counts must add to sixteen, which is the one check you get for free. The Air France course sets it in its day.