Attention tasks

Take a Stroop test and see your interference in milliseconds

Name the ink colour while ignoring the word. Compare your speed and accuracy when they clash.

48 trials
1 min
Free, no sign-up

For the fairest comparison, retake on the same device.

Results on screen · no email

About this test

Name the ink colour of words shown in matching or conflicting colours. Results show accuracy and median response time for each condition, plus their difference in milliseconds. For reference, in one published online study (Crump and colleagues, 2013) adults took 859 ms on average when the word and its ink matched and 1,152 ms when they clashed, a Stroop effect of 293 ms. They typed the colour's name, so their times are not directly comparable with taps here; the size of your own gap is the figure to track.

How the task works

A colour word appears in coloured ink; choose the ink colour with the buttons or keys 1 to 4.
Half the words match their ink and half clash.
Answer as quickly as you can while staying accurate; below 80% correct in either condition the interference figure is not printed, because it is a difference between two medians taken over correct trials.
Forty-eight trials; each waits up to three seconds, and the run takes about a minute.

Task accessibility

Time: 1 minute
Length: 48 trials
Result: your times and counts

Your answers stay in this browser tab. If you sign in, you can save your result (not your answers). When session replay is on, it can include visible questions, choices and results. Privacy details.

For context

The Stroop effect in a published online study

Published research figures for adults, not targets and not a ranking. Each study used its own equipment and method, so set your own figure beside your earlier runs first.

From Crump, McDonnell and Gureckis (2013): 40 online participants who typed each ink colour's name; times run to the first key pressed.
Condition	Mean time	Errors
Word and ink match	859 ms	4.5%
Word and ink clash	1,152 ms	5.9%
Difference (the Stroop effect)	293 ms	1.4 points

This page asks for a tap or a key rather than a typed name, so its times are not the same measure; what carries over is the gap between the two conditions. In a three-week test and retest study (Hedge and colleagues, 2018), that gap ranked people fairly consistently, so it is worth tracking across your own runs.

Where these figures come from

Use the result

What this test adds

Results show accuracy and median response time for matching and conflicting trials. The interference figure appears only when accuracy is at least 80% in each condition.

A small next step

Repeat once after a short break and see whether the interference shrinks; practice at ignoring the word is exactly what the task exercises.

Telling the ink colours apart is part of this task. If some colours are hard for you to tell apart, the colour vision check shows red-green and blue-yellow dot plates and says what a screen can and cannot tell you.

Questions people ask

What is the Stroop effect, and what is this measuring?

Reading a word is so practised that it happens whether you want it to or not, so when the word says one colour and the ink is another, answering the ink takes longer. The difference between your clashing and matching trials is that cost, measured on your own device.

Is a phone a fair device for this?

Yes, as long as you compare a phone run with your other phone runs: tapping a button is slower than pressing a key, and that lands on both conditions, so the difference between them survives better than either median alone.

What should I do with the interference number, and why was mine not printed?

Treat it as a baseline and run it again after a short break, because practice at ignoring the word is exactly what this task exercises and a second figure tells you more than the first did. If no figure appeared at all, accuracy fell below 80% in one condition, where a difference between two medians over correct trials would be noise.

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