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Vigilance

Sustained Attention (AX-CPT)

Letters flash one by one. Press Space when you see the specific sequence: A followed by X. Most trials are decoys — your job is to stay focused for the full 5 minutes.

What makes this one different

We measure the time-on-task drift — your accuracy in the first minute vs. the last minute. The difference is your vigilance decay — a sensitive marker of attention sustainability.

Time 5:00
Score 0
Hits 0
Miss 0
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Press Space when you see A → X

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Time-on-task drift

Your accuracy across the 5-minute session. A downward slope = vigilance decay.

History

No sessions yet.

What problem does it solve?

Sustained attention (vigilance) is the ability to maintain focus over time on a monotonous task. It's a key executive function — and it measurably declines within a single session for most people.

Who is this for

How to interpret your results

Drift of 5–10 percentage points across 5 minutes is normal. Above 20% means significant vigilance decay.

Hits above 80% is good for AX-CPT.

Limitations

  • 5 minutes is short by lab standards; longer sessions (15–30 min) would show larger drift.
  • The AX-CPT requires holding the "A" in mind until the next letter. Working memory load adds to vigilance load.

FAQ

Why is the session 5 minutes long?

Long enough to show vigilance decay in most adults, short enough to fit in a break. If you want more challenge, run multiple sessions back-to-back.

What if I drift a lot?

That's normal — it's the whole point of the task. Practice reduces drift, but it never goes to zero.

How do I use Sustained Attention (AX-CPT) step by step without mistakes?Follow the order given in the usage section: Watch for a specific cue-then-target sequence (AX-CPT). Tracks time-on-task drift to reveal vigilance decay. The step-by-step part matters less than the unit check that sits inside it. Confirm every unit matches the thing you are actually trying to measure before you press calculate - that single check catches more wrong answers than any other habit, and it costs about ten seconds.
What are the common mistakes when using Sustained Attention (AX-CPT)?Most common mistakes come down to four habits: entering 20 when the field expects 0.2 because the field is a percentage; leaving a field blank and accepting the default without checking what it stands for; changing one input and reading a result that was calculated before the change; and quoting the output as an exact figure when the page describes it as a reference estimate. Press calculate again after any edit, and treat the number as a reference point rather than a final answer.
How do I read the result from Sustained Attention (AX-CPT)?Read the final figure first, then come back to this section for the conditions behind it: Drift of 5–10 percentage points across 5 minutes is normal. Above 20% means significant vigilance decay. Hits above 80% is good for AX-CPT. Keep two things apart: the number itself, which comes from the values you typed, and the assumptions it depends on, which decide whether that number is meaningful. The page sets out what a higher or lower result means for your case, so check that direction as well as the magnitude.
Can I act on the Sustained Attention (AX-CPT) result directly?Treat it as one reference sheet before you decide, rather than as the answer itself: 5 minutes is short by lab standards; longer sessions (15–30 min) would show larger drift. The AX-CPT requires holding the "A" in mind until the next letter. Working memory load adds to vigilance load. The output describes a magnitude under the conditions you entered. It does not include what it actually costs to act, what might change while you act, or how the other side behaves. Before you commit, compare the result against reality and note which assumptions do not hold where you are.
What inputs does Sustained Attention (AX-CPT) need?The inputs for this tool sit in the form area of the page - fill them in one at a time as prompted. Before you start, check that each one uses the unit you actually measured: mismatched units are the most common source of a wrong answer here.