We've just updated our site to include Facebook integration.
Please reload your browser if you can see this message!

Double Trouble

Test type: Reasoning

What colour is your fridge?

What do cows drink? If you said 'milk', then you need to try this test to find out why.

View video instructions

Read full test instructions

About this test

Getting distracted?

The Double Trouble task is our take on a widely-discussed phenomenon in the cognitive psychology literature known as the Stroop effect (Stroop, 1935). This effect refers to the increased difficulty one has in naming the print colour of a word, when the text of that word refers to an 'incongruent' colour. For example, people are slower to name the colour of red ink when the word that is written in red ink is the word 'green'. This difficulty in colour naming vanishes when the semantic meaning of the word is the same as the text colour (e.g. the word ' red ' written in red ink) or is a nonsense syllable (e.g. ' kyshqw ' written in red ink) and is diminished for semantically unrelated words (e.g. the word ' window ' written in red ink) (Scheibe et al, 1967). This effect is thought to be the result of interference caused by automatic word recognition; it seems that we access the meaning of these words without consciously trying to do so. To perform this task successfully you must selectively focus your attention in order to inhibit the automatic access of distracting word information.


In the last ten years, we have conducted many studies looking at how the brain is able to focus attention in order to perform tasks like this. By using fMRI to scan people's brains while they were performing really boring tasks (e.g. the Sustained Attentional to Response Task or 'SART'), we found that the right frontal areas of the brain help us to sustain attention (Manly et al., 2003). Damage to this area is thought to be responsible for poor concentration abilities in people who have suffered a traumatic brain injury (Robertson, 2003). We have made the Double Trouble task even harder than the classic Stroop task; in our version, you do not merely have to say the colour word, but you also have to distinguish between one of two possibilities. This requires an extra cognitive step because you have to remap information from one representation to another, making it altogether more cognitively demanding and engaging for your brain.

-Manly, T., Owen, A.M., McAvinue, L., Datta, A., Lewis, G.H., Scott, S.K., Rorden, C., Pickard, J., Robertson, I.H. (2003). Enhancing the sensitivity of a sustained attention task to frontal damage: convergent clinical and functional imaging evidence. Neurocase, 9(4), 340-349.Read Abstract
-Scheibe, K. E., Shaver, P.R. and Carrier, S.C.(1967). Colour association values and response interference on variants of the Stroop test. Acta Psychologica,26: 286-95.
Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18: 643-62.

Stats and scores
Please log in or register to view your scores.
The highest score is 32767.

View tests by


IQ Challenge

Test your planning, reasoning, working memory and attentional abilities to the limit.

Tests by type

Our suite of cognitive tests is divided into 4 key areas, designed to test different types of cognitive ability.