What is a flanker test?
A flanker test shows you a row of arrows and asks which way the middle one points, while the arrows around it either agree or point the other way; the extra time you need on the mixed rows is your interference cost. That one number is the heart of the test.
This guide walks through it the way you'll see it: screen by screen, with the demo above so you can feel the effect yourself. We make Attention Age, an iPhone app whose Interference task is a flanker test. Updated November 2026.
Flanker test questions beginners ask
What does a flanker test measure?
How well you respond to one target while ignoring the things right next to it. Researchers usually look at the gap between rows where the neighbours agree with the middle arrow and rows where they point the other way. The NIH Toolbox describes its version as an assessment of inhibitory control and attention.
Where does the name come from?
The distracting items sit on the flanks of the target. The classic version comes from Eriksen and Eriksen in Perception & Psychophysics (1974), who used letters rather than arrows and found that nearby, response-conflicting letters slowed people down.
Is a slower time on mixed rows a bad sign?
No. Nearly everyone is slower when the neighbours point the other way; that slowdown is the effect the test is built to show. What people compare is the size of the gap, ideally with their own earlier results.
How long does a flanker test take?
Usually a few minutes. The NIH Toolbox lists about 3 minutes for its version. In Attention Age the Interference task is one of three tasks in a five-minute session.
Can a flanker test diagnose ADHD?
Not on its own, and a phone version certainly can't. Attention Age is an entertainment and self-practice app, not a medical, clinical or diagnostic test.
Is there a free flanker test on iPhone?
Attention Age includes one as the Interference task. The five-minute test, weekly re-test and Interference practice are free; seven extra drills and longer focus sessions are part of an optional Pro subscription.
Should I use my thumb or index finger?
Either, but use the same one each time. Reaction times shift with grip, so a fair comparison keeps the hand, phone and posture the same.
The flanker test, step by step
Four moments in every trial. Read down the thread.
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1. A cross holds your eyes in the middle
A small fixation point appears where the target will be. Its job is to stop you scanning the row from the left like a sentence. Keep your eyes there.
2. The row appears: same direction
On a congruent row every arrow agrees. Your answer is easy because the whole row is shouting the same thing. These rows give your baseline speed.
3. Or a mixed row: the neighbours disagree
On an incongruent row the flankers point the other way. Most people are a little slower here and make the occasional wrong tap, because the neighbours pull the response toward the wrong side. Eriksen and Eriksen in Perception & Psychophysics (1974) found the pull is stronger when the distractors sit close to the target.
mixedsame
4. The score: the gap, not the speed
Your average time on mixed rows minus your average on same-direction rows is the interference cost. A fast person and a slower person can have the same gap. That is why the gap, not raw speed, is what most versions focus on.
Speed tells you how quick your thumb is; the gap tells you how much the neighbours got to you.
What your demo result means
The demo at the top mixes six same-direction and six mixed rows in random order, times each tap from the moment the row appears, and reports both averages and the gap. Here's how to read it, and what the app does with the same idea.
Reading a flanker result
| What you see | What it means |
|---|
| Mixed rows slower than same rows | The normal flanker effect. Expected. |
| A gap near zero | The neighbours barely slowed you this time, or you slowed down on every row. |
| Errors only on mixed rows | You answered for the flankers. Slow down by a hair. |
| Times under about 150 ms | Probably guessing before looking. Attention Age flags that in a real session. |
In Attention Age, Interference feeds two of the five category scores. Distractor Handling (25% of the Attention Index) looks at how much conflicting arrows slowed you or caused errors compared with calm trials. Consistency (30%) uses the variation in your reaction times across Interference and Signal Watch. Both are explained on our methodology page, including the fact that the scale uses fixed reference points chosen during design rather than population norms.
A browser demo on your screen, with your mouse or thumb, is not comparable to the app or to a lab. Use it to understand the idea, not to score yourself.
Comparison strip: flanker vs go/no-go vs Stroop
Flanker
Answer for the middle item, ignore its neighbours.
In Attention Age: Interference
Go/no-go
Tap for the target, hold back for the decoy.
In Attention Age: Signal Watch
Stroop
Name the ink color, not the color word you read.
Not in Attention Age
All three measure some version of "do the right thing while something else pulls you the wrong way". They are not interchangeable, so if a study asked you to do a flanker task, a Stroop app won't feel the same.
Honest limits
- Attention Age's Index reflects your performance on these specific tasks on this device. It is not an age, a percentile or a ranking, and it is not compared with any population.
- Scores usually rise with practice. On a flanker task that mostly means you got better at flanker rows.
- Phones differ in screen response and size, so compare a result only with your own earlier results on the same phone.
- The test, weekly re-tests and Interference practice are free. Seven extra drills and 45 and 90-minute focus sessions need the optional Pro subscription.
This is general information, not medical advice. Talk to your clinician.
How it works in 3 steps
- Start the five-minute test. Three timed tasks: Signal Watch, Interference (the flanker) and Tracking. Not ready? Try the 20-second practice challenge.
- Read the five scores. Distractor Handling is the one that comes straight from the arrows; each score is explained in plain language.
- Practice, then re-test weekly. Interference is free to practice. The weekly re-test uses the same tasks and scoring, and calls changes under 5 points "about the same".
A design decision: decoys in the app are always shape-coded (diamonds and stars), never told apart by color alone, and a colorblind mode adds extra markers. A limitation: there's no Android version. If you need a validated research instrument, ask the team running your study which one they use instead.
Start on your iPhone
Felt the pull of the neighbours in the demo? The full version takes five minutes and keeps your history. Start on your iPhone with the free test.
A beginner's guide to the arrow test
