StroopStroop test

The Stroop test is a task where the word “RED” is printed in blue and you must name the colour of the letters. It sounds easy, but the brain keeps offering the word it has just read, and the answer is delayed. That delay is called the Stroop effect.

It was described almost a hundred years ago and has since become one of the best-known experiments in psychology. The test shows how well a person holds back a habitual, automatic response and keeps attention on what matters right now.

In BB Gym the Stroop test is a trainer with three levels. “Colours” comes first, then “Word and colour”, and the higher levels add “Switching”. Each part starts with a warm-up, and the result shows a score and a skill profile.

Where the test comes from

Back in 1886 the psychologist James Cattell noticed that we read words faster than we name colours or objects. But the conflict between word and colour itself was described in 1935 by the American psychologist John Ridley Stroop in his doctoral thesis.

In one of his experiments people named the ink of 100 words printed in other colours, and on average it took them 74% longer than naming the colour of plain coloured squares. Reading the words while ignoring their colour, however, was almost as easy as ever.

Stroop himself soon left research for teaching. His paper is still cited today: a 1991 review counted more than 700 studies of the Stroop effect, and there have been many more since.

Why it is so hard

A fluent adult reader cannot “not read” a familiar word: reading has become automatic. So when the word and the colour disagree, the brain gets two ready answers, and it has to pick the right one and suppress the wrong one.

That suppression is where the extra time goes. Sometimes it fails and the person says the written word instead of the colour. Psychologists find such errors particularly telling, so our specialist report counts them separately as “wrong rule”.

Interestingly, young children who still sound words out show a weaker effect: the word does not yet jump at them. It grows noticeably once reading becomes automatic.

How the test is given

The classic paper version has three cards: words printed in black, colour patches or XXXX, and finally words printed in other colours. The person names them aloud as fast as possible, and the examiner records the time or the number of answers in 45 seconds.

In computer versions the words appear one at a time and the answer is given with a key. This makes it possible to measure each answer in milliseconds and compare words in their own and in other colours.

Some versions add one more rule: if the word is in a frame, read it instead of naming the colour. This condition tests not only suppression but also switching between two rules. In BB Gym it is the “Switching” part.

What the results show

The main measure is interference: how much slower a person answers words in another colour than XXXX. The ratio of these two times is also handy, because it does not depend on overall speed.

Everyone who reads fluently shows the Stroop effect, so what matters is not whether there is a delay but how big it is. It changes with age, tiredness, lack of sleep and even with how many words happen to match their colour.

The Stroop test is widely used in research on attention, executive functions, stress and ageing, and as part of neuropsychological assessment.

What the trainer trains

The trainer loads selective attention and inhibitory control: looking at the feature that matters and not giving in to the first impulse. The “Colours” part shows basic speed, and “Switching” adds cognitive flexibility.

Results improve quickly with practice because people get used to the task. But to be honest: there is still little evidence that such exercises improve attention in everyday life. A large 2016 review of brain-training research found that people mostly get better at exactly the tasks they practise.

So treat the Stroop test as a short warm-up for attention and self-control, and as a way to track how you are doing on different days.

How to play and what to watch for

Look at the colour, not “into” the word. Some people find it helps to soften their gaze slightly or to look at the bottom edge of the letters.

Do not chase speed at the cost of errors: the score combines speed and accuracy, and a mistake costs more than a few extra milliseconds.

In “Switching”, first check whether there is a frame and only then decide what to press. That way you are less likely to apply the wrong rule.

Screen and paper: about norms

The paper Stroop test has published norms, but a screen is different: keys instead of voice, a different word size, a different number of trials. So BB Gym results cannot be compared directly with paper norms. Compare them only with your own earlier attempts.

BB Gym results are not a medical diagnosis or a neuropsychological assessment. If you are worried about your attention, memory or speed of thinking, please see a specialist.

References

1. Stroop J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18(6), 643–662
2. MacLeod C. M. (1991). Half a century of research on the Stroop effect: an integrative review. Psychological Bulletin, 109(2), 163–203
3. Scarpina F., Tagini S. (2017). The Stroop Color and Word Test. Frontiers in Psychology, 8, 557
4. Simons D. J. et al. (2016). Do "brain-training" programs work? Psychological Science in the Public Interest, 17(3), 103–186
5. Stroop effect — Wikipedia