Stroop test
Read the colour, not the word.
A word flashes up in coloured ink, and the word and the ink often disagree. Tap the button for the ink colour. You have thirty seconds, and at the end you see exactly how much the clash slowed you down.
Press start. Right answer +1, wrong answer −1. Keys 1 to 4 or R G B Y also work.
This is a game based on a classic psychology task. It is not a diagnostic test of attention or anything else, and the colours depend on your screen.
Free tool from Focus and Screen Time
What the Stroop test shows
Reading is so automatic that you cannot easily switch it off. When the word BLUE is printed in red ink, your brain reads the word before you have decided to, and the answer you want, "red", has to push past the one it just produced, "blue". That small fight costs time. Psychologist John Ridley Stroop described the effect in a paper published in 1935, and it has been a standard tool in attention research ever since.
Why it is hard to beat
- You cannot stop reading. Even people who know the trick still read the word.
- Speed fights accuracy. Rushing raises mistakes, and each mistake costs a point.
- Look through the word. Many people do better by focusing on the colour of one letter or by blurring their gaze.
A note on what it means
Researchers use Stroop-type tasks to study how people control attention and ignore distractions. A single thirty second game on your own screen is a bit of fun and a way to compare yourself with your last run, not a measurement of anything about you. Tired, hurried or distracted, almost everyone scores lower.
Make it harder or easier
Take your time at first and get every one right. Then speed up until mistakes appear. The best runs sit just below that point. If you want to train the same skill more broadly, the Focus Test in the app below mixes in other drills.
Questions people ask
What is the Stroop effect?
It is the delay in naming a colour when the colour word printed in it names a different colour. Reading the word is automatic, so it interferes with naming the ink.
What is a good Stroop test score?
Scores depend on the version. Here, one point per correct answer in 30 seconds, minus one for each mistake. Compare with your own earlier runs, or with a friend on the same device.
Is the Stroop test a test for ADHD?
No. This page is a game. Stroop-type tasks are used in research and clinics, but a quick online run is not a diagnosis of anything.
Why am I slower when the word and the colour do not match?
Your brain reads the word automatically, then has to override that reading to give the colour of the ink. The extra step takes a fraction of a second.
Curious how the rest of your attention holds up?
Attention Age: Focus Test is an iPhone app built around a five-minute test with five category scores. Its listing says the three core practice drills, weekly results and a 10- or 25-minute timer are free.
Get Attention Age on the App StoreOptional auto-renewing Pro adds drills, circuits and longer timers. Scores describe performance in its own games; it is not a medical or diagnostic test. iOS 18 or later.
Honest Little Apps publishes both Attention Age and this page. This is a separate browser tool and does not sync with the app. App details checked November 10, 2026.
On a computer? Open it on your iPhone
