The Stroop Test

This week’s brainteaser is about a psychometric test that you might have seen before as it was used in the Nintendo ‘Brain Training’ game a few years ago! You might not recognise the name though, but it is actually called the Stroop test.

In this test, participants are told that they must “say aloud the colour of the word shown, not what the word actually says”. It is named after John Stroop, who discovered the effect in 1935. In his original experiments, he compared the time it took for participants to read words printed in incongruent colours (e.g. the word black written in red ink) with the time it took them to name the colours of the words. He found it took participants 74% longer to name the colours than read the words.

The Stoop Effect shown by participants is as follows: they are quicker to read words shown in the congruent (same) colour to what the word says, and are slower when the word is printed in a different colour to what it says – this is known as the incongruent condition.


This test therefore shows that are brains are slower at responding when shown conflicting information than when stimuli are easily recognised. There are a few hypotheses for why this effect occurs. One hypothesis is that we are naturally faster at recognising words than colours, so we are able to read the word faster than identifying the colour. Another hypothesis is that reading is ‘automatic’ and doesn’t require conscious effort, unlike naming colours which requires our attention.

Since the Stroop test has been developed, it has been used to assess several psychometric functions. A common use is to measure inhibition – as the test requires you to inhibit your natural response to read the word. For example, in developmental psychology, this is part of several tests used to test executive functions (cognitive abilities including switching between tasks, working memory, planning, and inhibiting responses) in children with ADHD.

Different variations of the Stroop test have been developed, underlying the same principle that participants will identify congruent words faster than incongruent ones. One of these variations is the Emotional Stroop test, where instead of being colour words, emotionally-charged and neutral words are presented in different colours, and participants have to name the colour. The Stroop effect is that participants are slower to name the colour of the emotionally-charged words. An Emotional Stroop test was used by Bentall & Kaney (1989) to test patients with delusions (to read more about the background of delusions see here) and compare their responses to healthy controls. Participants were presented with neutral words, words with negative meaning, and words related to paranoia. They found that compared to control participants, participants with delusions look longer to name the colour of the words related to paranoia, suggesting they are more easily distracted by emotional stimuli.

So, how do you think you’d perform on the stroop test? Have a go here and find out!


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