Stroop Test FAQ

The Stroop test is the task built around the Stroop effect. You are shown colour words printed in various inks and must respond with the ink colour, not the word. This browser version flashes one word at a time for a timed run and records how fast and how accurately you answer, plus your Stroop interference score.

Yes. strooptest.app is completely free and runs entirely in your browser. There is nothing to buy, download, or install, and there is no sign-up. Open the page and the start screen is ready.

Pick a run length (30 seconds, 60 seconds, or two minutes), wait out the 3·2·1 countdown, then answer each word by tapping the colour button that matches the ink or pressing its number key 1–6. Keep going until the timer reaches zero, then read your results.

The page needs a connection to load the first time. After that some browsers keep the tab playable without a network, but there is no dedicated offline app or installer.

The Stroop effect is the delay and extra errors that happen when you try to name the ink colour of a word whose meaning is a different colour — for example the word "RED" printed in blue. Reading is so automatic for fluent readers that the brain processes the word even when the task is to ignore it, and overriding that takes measurable extra time. It was first described in detail by John Ridley Stroop in 1935.

A congruent trial is one where the word and its ink match — "GREEN" in green ink — so reading and colour naming agree and you answer quickly. An incongruent trial is one where they disagree — "GREEN" in orange ink — so you have to suppress the word to name the ink, which is slower. About 70% of trials in a run are incongruent.

John Ridley Stroop (1897–1973) was an American psychologist. His 1935 paper "Studies of interference in serial verbal reactions", drawn from his doctoral work at George Peabody College, showed that naming the ink colour of mismatched colour words takes far longer than reading the words or naming colours of neutral shapes. The task has carried his name ever since.

The leading explanation is automaticity: for a fluent reader, recognising a word is fast and involuntary, while naming a colour is slower and effortful. When the two responses conflict, the automatic reading response interferes with the deliberate colour-naming response, and your executive control system needs extra time to suppress it. Brain imaging links this to the anterior cingulate and prefrontal cortex.

Practice makes you faster overall and can shrink your interference somewhat, but the effect does not disappear in healthy adults — reading stays automatic. Non-native readers of the language, and young children who cannot yet read fluently, tend to show a smaller effect because the word interferes less.

Interference is your mean reaction time on incongruent trials minus your mean reaction time on congruent trials, in milliseconds, counting only correct answers. It isolates the cost of the conflicting word from your general speed. A lower interference number means you are better at filtering out the distracting word. Typical values fall somewhere between about 50 ms and 250 ms.

Each correct answer is worth a base of 20 points plus a speed bonus of up to about 120 that shrinks as your reaction time grows, all multiplied by a streak bonus that increases 25% for every five correct answers in a row. Wrong answers and trials you did not answer before time ran out score zero and reset the streak.

On the 60-second run, most people land around 85–95% accuracy with a mean reaction time between 700 ms and 1100 ms and interference of 80–200 ms. Faster reaction times, accuracy near 100%, and a smaller interference number are all better, but the useful comparison is against your own past runs on the same length.

Score rewards speed and streaks, not just correctness. If you answer accurately but slowly, the speed bonus is small; if you break your streak often, you lose the multiplier. To raise your score, tighten your reaction time while staying near 100% correct and try to string long runs of correct answers together.

If the timer runs out while a word is on screen, that trial is simply not counted — it does not lower your accuracy. Only trials you actually answered go into your score, accuracy, reaction time, and interference.

Your best score, best accuracy, fastest mean reaction time, longest streak, lowest interference, and your last twelve runs are saved locally in your browser. Nothing is sent to a server and there is no account. A run in progress is not saved if you close the tab, and clearing site data erases the history.

Yes. The word card and all six colour buttons fit on one portrait screen with no scrolling, and buttons are sized for a thumb. Starting a new run is instant with no page reload.

No. strooptest.app is for education, self-measurement, and curiosity only. The Stroop effect is a normal feature of every healthy brain, and an online score is affected by your device, sleep, caffeine, and mood. It cannot diagnose ADHD, dementia, or any other condition. For clinical concerns, see a qualified professional.

Any current browser with JavaScript: Chrome, Edge, Firefox, and Safari on desktop, plus their mobile versions. If the buttons do not respond, update the browser, allow scripts for this site, and reload.

Open the stats panel from the HUD and use Reset history, then confirm with the second tap. That clears every best and the last twelve runs on this browser. It cannot be undone.