Stroop Color and Word Test

The Stroop Color and Word Test developed from the observation by early experimental psychologists that the naming of color hues is always slower than the reading of color names in literate adults. The earliest published report of this phenomenon was offered by Cattell in 1886. J. Ridley Stroop suggested in 1935 that the difference in color naming and word reading was due to colors' being associated with a variety of behavioral responses while words were associated with only one behavioral response: reading. In order to further study the relationship between color naming and word reading, Stroop devised the test that has come to be called the Stroop Color and Word Test.

The earliest version of the Stroop consisted of the words red, green, brown, blue, and purple printed on a page consisting of ten rows and ten columns. Each word was printed in colored ink, but never in the color it represented by the word (e.g., red could be printed in blue ink but never in red ink). Another page of the test consisted of colored ink printed as small rectangles. The final page consisted of the color words listed above, this time printed in black ink.

Since Stroop's original studies, several hundred studies have been published on the Stroop test. The Stroop has attracted such attention because of its high reliability in identifying individual differences and because of its somewhat paradoxical nature. The research has examined the use of the Stroop in cognitive and personality research, in experimental psychopathology, and in the diagnosis and understanding of organic brain dysfunction.

Neuropsychological studies have suggested that Stroop interference occurs not at the response stage or in the confusion of the participant but as a result of interference in verbal processing. The Stroop stimuli appear to activate an automatic verbal processing response that interferes with the consciously instructed color naming. The participant completes the task either by completing both responses sequentially (reading the word, followed by naming the color) or by suppressing the automatic, word-reading response through volitional control.

Current versions of the Stroop test consist of three pages and generally use only three colors. Page 1 consists only of color word names (e.g., red, green, and blue) while page 2 uses XXXX's printed in red, green, and blue ink. The third page (interference) consists of the color words on page 1 printed in nonmatching ink (e.g., the word red printed in blue ink). The participant must name the color of the ink rather than the word. The Stroop may be scored as the total number of items finished in a set time (usually between 30 and 60 seconds) or the time to complete an entire page. The former version has the advantage of limiting the time the test takes without apparently limiting the information that is gathered. It is used widely as a neuropsychological instrument, primarily as a measure of possible reading disorders (when there is no interference effect) and as a measure of complex executive functions (when the interference effect is unusually large).

...