Two different tests, one shared demand: hold two rule sets active at once and pick the right one under pressure. Attention Switching scatters numbers and letters across a board and has you connect them in strict alternation — 1, A, 2, B, 3, C — hunting for each target in clutter with nothing highlighted to help you. Stroop prints a colour word in a mismatched ink — the word BLUE rendered in red — and gives you a couple of seconds to name the ink colour, not read the word, trial after trial, with the automatic response and the correct one pulling in opposite directions the whole time.
Why airlines test it
These are the two classic faces of executive control, and they fail differently. Attention Switching isolates the cost of set-shifting: the giveaway error is perseveration, staying in the set you were just in (reaching for 4 right after 3 instead of switching to C), which shows up as a rising error rate the moment the rule changes rather than a uniform slowdown. Stroop isolates inhibition: the interference effect — how much slower and less accurate you are on mismatched trials than matched ones — measures your ability to suppress a stronger, automatic response in favour of a weaker, correct one. Airlines test both because they predict a specific, costly failure mode: the right action executed a beat too late, or the wrong action executed with total confidence.
In the cockpit
A flight deck runs on constant task-switching — from hand-flying to monitoring to talking to ATC to running a checklist and back — and each switch carries a moment of vulnerability where the mental set from the last task bleeds into the next one. Clean switching means dropping the previous frame completely and picking up the new one with no carry-over error. Inhibition is the other half: the trained, correct response has to override a felt, instinctive one that is wrong, and under stress the felt response is faster to fire.
For example: on a dark-night go-around, the aircraft's forward acceleration triggers the somatogravic illusion — a strong, physical sensation that the nose has pitched up too far, when in fact the aircraft is climbing normally. The instinctive response is to push forward on the controls to correct the felt pitch-up. The trained response is to trust the attitude indicator and hold the climb. That override, executed in the two or three seconds it matters, is inhibitory control under load — exactly the capacity a Stroop trial measures at low stakes so it can be trusted at high ones.
How to practise
On Attention Switching, don't chase speed first — chase the rule. The perseverative slip happens when your eyes find a number before your brain has confirmed it is actually the letter's turn; say the next target to yourself ('next is C') before you scan, so the alternation stays in front of your eye movements instead of behind them. On the Stroop Test, resist the urge to slow right down on mismatched trials to 'get it right' — that is avoidance, not inhibition. Keep your pace steady across matched and mismatched trials and let the accuracy show where the interference bites; that is the pattern that actually improves with practice.
The ENAC EPL concours tests this family through two counting tests: a board of near-identical symbols to count one of, and lines of x where a slash counts every x negative until a plus restores it. Both are in ENAC Symbol Counting. The ENAC Test Preparation course covers the whole battery. The Air France cadet pre-selection opens on a switching test of its own, ENAC Odd and Even: click every numbered circle on the board in one chain, alternating odd and even, always taking the smallest number you have not used of the parity you owe. Nothing on the board tells you what to look for next, and the odds and the evens climb as two separate ladders — so the circle you want is repeatedly smaller than the one you just clicked, and on some boards the numbers sit only one or two apart, like 239, 241 and 243. A wrong click sends you back to START with the clock still running. The Air France course sets it in its stage.