Stroop Test
Name the ink, ignore the word. 20 scored trials, and your time on the mismatched ones.
Name the colour, not the word.
Your score is the median time on the mismatched trials - lower is better.
- A colour word appears in the middle.
- Its ink, not the word - BLUE -> key 1.
- Answer within 1.5 seconds, using one of the four keys.
If you cannot tell the four blocks below apart, this result will not hold for you.
On a desktop keyboard, 1 / 2 / 3 / 4 work too.How to read your score
| Score | What it means |
|---|---|
| Under 750 ms on mismatched trials | A median under 750 milliseconds on the mismatched Stroop trials - the incongruent ones, where the word and the ink disagree - is fast for a four-key colour-word task, where each answer needs a colour named and a word suppressed. No reference sample stands behind this band, so it does not say how many people you outscored. Check your accuracy alongside it: with four keys, answers that outrun the decision show up as errors rather than as a faster time. |
| 750 to 950 ms on mismatched trials | A median of 750 to 950 milliseconds on the mismatched Stroop trials is a brisk result for this four-choice version, and lower is better. No reference sample stands behind this band either, so it describes the round rather than your rank. Compare it with your own matched baseline on the same screen: the gap between the two is what the interference actually cost you on this round. |
| 950 to 1,150 ms on mismatched trials | A median of 950 to 1,150 milliseconds on the mismatched Stroop trials falls in the middle band of the five this site defines for its four-key version, which is slower than the two-key and spoken versions used in laboratories. No reference sample has been collected yet, so the band describes this round on this device and says nothing about how common the result is. |
| 1,150 to 1,400 ms on mismatched trials | A median of 1,150 to 1,400 milliseconds on the mismatched Stroop trials. No reference sample stands behind this band, so it says nothing about how many people land here; read it against your own matched baseline on the same screen. If that baseline is close behind it, the time is going into finding the right key and the mapping is the thing to practise; if the gap is wide, the word is. |
| 1,400 ms or more on mismatched trials | A median of 1,400 milliseconds or more on the mismatched Stroop trials is near the 1.5-second cut-off this test uses, so some trials may also have run out of time. No reference sample stands behind this band, and a slow first round says nothing about you beyond this round. If this was your first round on this key layout, the number still has learning the keys inside it: run a second round once the mapping is familiar and read the two against each other. |
These five bands describe how long the mismatched trials - the incongruent ones - took you on this site's own four-key version, and faster is better; they are not norms, not pass marks, and they do not say how many people you outscored. They are not comparable with published Stroop timings either, which mostly come from spoken or two-key versions. Read them next to your own matched baseline and across several of your own rounds, keeping the device, the input method and the language the same.
How to play
- Learn the four colour keys: Four colour blocks sit along the bottom, always in the same order: red, blue, green, purple, numbered 1 to 4. They never move, within a round or between rounds, so the mapping you learn in practice is the mapping you use all the way through.
- Answer the four practice trials: Four unscored practice trials come first, two with matching words and two with mismatched ones. They give you a tick or a cross on the key you pressed, and nothing they produce reaches your records.
- Press the key for the ink, not the word: A colour word appears in the middle of the screen, printed in one of the four inks. Press the key for the colour it is printed in and ignore what it says. On a desktop keyboard the number keys 1 to 4 do the same thing.
- Answer between 0.2 and 1.5 seconds: A press before the word appears, or within 200 milliseconds of it, is recorded as a false start rather than an answer. No answer within 1.5 seconds ends that trial. Either way the trial is used up and is not run again.
- Read your time on the mismatched trials: The score is your median time on the mismatched trials you answered correctly, so lower is better. Beside it are your accuracy and your own baseline: the same median taken over the matched trials, where the word and the ink agree.
What this measures
This is a non-standardised adaptation, and the result cannot be exchanged with a clinical or standardised scale. A colour word is shown in a colour, and your job is to report the colour of the ink and ignore the word itself. Twelve of the 20 scored trials are mismatched - the word BLUE printed in red - and eight are matched, where the word and the ink are the same colour. Where you see the task written up elsewhere, the mismatched trials are called incongruent and the matched ones congruent; this page uses the plainer words for the same two things.
Reading is quicker and more automatic than naming a colour, so on a mismatched trial the word arrives at the answer before the ink does and you have to hold it back. That extra fraction of a second is the interference this task measures, and it is the reason the score is taken from the mismatched trials only.
The four colour keys keep the same order for every trial of every round: red, blue, green, purple, numbered 1 to 4. The keys carry no colour names, because a word on the key would be a second colour-word conflict on top of the one being measured. The four practice trials exist so the mapping is learned before anything counts.
Two mistakes account for most of a first round. One is pressing the key for the colour you just read instead of the colour you are looking at - that is the task working as intended, and it costs you accuracy rather than time. The other is knowing the answer and then hunting along the bottom for the key, which costs you time rather than accuracy. Your errors and your time are reported separately, so you can see which of the two is happening to you: errors point at the word, a slow time on an accurate round points at the keys.
A trial runs like this: a small cross marks where the word will appear, for somewhere between 350 and 550 milliseconds, then the word replaces it in the same spot. That wait is a different length every trial, so there is no beat to count along with - watch the cross and wait for the word. The word stays until you answer or until 1.5 seconds have passed.
A press during the cross, or faster than 200 milliseconds after the word, is a false start: a four-way colour choice cannot be decided that fast, so such a press is a guess that was already on its way. It is recorded, the trial is used up, and it is not run again.
The main score is the median of your correct mismatched trials - the middle value once those times are sorted. A median rather than an average, because one slip should not move a result taken from at most a dozen trials. Times far outside the rest of yours are dropped before the median is taken, so a single stumble costs you that trial and not the round.
The matched trials are not a warm-up. Their median is your own baseline on this device, with this input, in this language, and the gap between the two is the only honest way to read the main number: a mismatched median of 1,024 ms on a 770 ms baseline is a different result from the same 1,024 ms on a 950 ms one.
The interference figure - the gap between the two medians - is shown but never scored. It is a difference between two medians taken from 12 and 8 trials, so it swings a great deal from round to round. Watch it across several rounds if at all, and read the main median for anything you actually want to conclude.
A round gives no score at all if fewer than 80% of your answers were right, or if too few of your correct mismatched trials survive - fewer than eight. With four keys, pressing at random is right about a quarter of the time, so the accuracy check is also what stops speed bought by guessing from producing a flattering median.
Stay on this page until the round ends. Moving to another tab or window, refreshing or stopping ends the round without saving anything, and there is no resume: half a round of reaction times is not a measurement that can be finished later.
The words are read in the language of the page, so an English round and a Chinese round are not the same measurement and are never compared with each other. Your own history is kept separately per language and per input method for the same reason.
If you cannot reliably tell the four colour blocks apart, this test does not measure anything about you, and the ready screen says so before you start. There is no colour-blind mode: changing the colours would change the task.
FAQ
What is the Stroop test?
It is a colour-word task in which a colour name is printed in a colour and you have to report the ink rather than read the word. Naming a colour is slower and less automatic than reading, so when the two disagree the word interferes and the answer takes longer. The effect was published by John Ridley Stroop in 1935; the paradigm is public, and this four-key adaptation, its timings and its band table are the site's own.
What is a good Stroop test score?
On this test, a median under about 950 milliseconds on the mismatched trials is a brisk result for a four-key version, and faster is better. What it cannot tell you is where you sit among other people, because there is no reference sample behind it. Read the five bands against your own matched baseline, then compare several of your own rounds on the same device.
How many milliseconds is a normal Stroop reaction time?
There is no single normal figure, and this test publishes no average because it has no reference sample to draw one from. For scale, laboratory versions with two keys or a spoken answer commonly report several hundred milliseconds of interference between matched and mismatched trials. This four-key version is slower across the board because every answer also has to find one of four keys, so its numbers should not be read against published ones.
What does the Stroop test measure?
It measures how much a practised, automatic response - reading - slows you down when it disagrees with the response the task asks for. That is one narrow thing, measured on one set of four colours, and on this site it is reported as your median time on the mismatched trials. It is not a general attention score and not a diagnostic instrument.
What causes the Stroop effect?
The usual explanation is that reading happens whether you want it to or not, so a colour word produces an answer of its own before you have finished naming the ink. That competing answer has to be held back, and holding it back takes time - which is the whole of the effect. When the word and the ink agree, the two answers point the same way and the word helps instead of hurting, which is why this test keeps the matched trials as your baseline rather than throwing them away.
What are congruent and incongruent trials in the Stroop test?
An incongruent trial shows a colour word printed in a different colour - BLUE in red ink - and a congruent trial shows the word printed in its own colour. This page calls them mismatched and matched, which are the same two things. A round here runs 12 incongruent and 8 congruent scored trials; your score is the median of the correct incongruent ones, and the congruent ones give you the baseline it is read against.
How long does the Stroop test take?
One round takes under a minute from the first trial to your score. A typical round is about 35 seconds of answering, the longest a round can run is under 52 seconds, and four unscored practice trials come before that on your first pass. The variation comes from you: every trial waits for your answer, up to a 1.5-second limit, so a slower round is a longer one.
How do you practise the Stroop test?
Learn the four keys first: most of the time lost in an early round goes into hunting for the right block, not into resisting the word. Look at the middle of the screen where the cross is, answer as soon as you have the colour, and let the wrong ones go. Keep the device, the input method and the language the same between rounds and read a run of rounds rather than one. Practice makes people faster at this task; read a falling time as a skill at this task rather than as a change in anything broader, because the evidence for that kind of transfer is weak (Simons et al., 2016).
Why did my Stroop round give no score?
A round is voided when one of two checks fails, and no number is reported. Either fewer than 80% of your answers were right - with four keys, guessing is right about a quarter of the time, so below that the round cannot be told apart from pressing at random - or fewer than eight of your correct mismatched trials survived after false starts, time-outs and outliers were removed, which leaves too few for a median to mean anything. In both cases the honest answer is no number, so the round is offered again instead.
What is the Stroop interference score?
It is the difference between your two medians: your time on the mismatched trials minus your time on the matched ones, in milliseconds. This test shows it but does not score it, and does not plot it. The figure is a gap between two medians taken from 12 and 8 trials, so it moves around a lot from round to round and a change in it usually says more about which trials landed where than about you. The main median is the stable number; treat the interference as context for it rather than as a result to chase.
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Last updated: 2026-09-28 · Scores stay on this device