The Victoria Stroop Test (VST) is a test of cognitive flexibility and inhibition, both executive functions.
The test can be accessed through texts such as Strauss, Sherman, & Spreen (2006). This means that users need not purchase the test and may make their own stimuli, using the description below (Strauss, Sherman, & Spreen, 2006).
The test can be made out of three cards, sized 21.5 X 14 cm. Each card contains six rows of four items (using Helvitica font, size 28 points). The rows are spaced 1 cm apart. All the cards must have four rows on six items, making up 24 items.
In the first card (Dots (also know as Part D)), the card must have four rows of six dots. The colour of the dots must be either blue, green, red or yellow. Each of the four colours must be used six times and the four colours must be arranged in a pseudorandom order within the array, each colour appearing at least once in each row.
The second card (Words (Also known as Part W)), is similar to Part D (above), except that the dots are replaced by common words (e.g. “when”, “hard”, “over” and “and”). The words must be printed in lower case letters. Each word must be printed in one of the four colours.
The third card (Colours/Colors (also known as Part C)), is similar to Parts D and W above, but here the coloured stimuli are the colour names (“blue”, “green”, “red” and “yellow”), printed in lower case, in a way that the print name never corresponds to the print colour (e.g. red can be printed in blue, green or yellow ink, but not in red ink).
The administration for the test is described below.
The three cards are always presented in the same sequence: Dots, Words, then Colours. The examiner starts the timer immediately after providing instructions. The instructions are as follows:
First Part – Part D (Dots): Say, “Name the colours of the dots as quickly as you can. Begin here” (point to the examinee’s top left corner dot), “and go across from left to right.” Direct the examinee’s eyes across the rows from left to right.
Second Part – Part W (Words): Say, “This time, name the colours of the words as quickly as you can. Begin here,” (point to the examinee’s top left corner), “and go across the rows from left to right”. If necessary to clarify, say, “Name the colours in which the words are printed”.
Third Part – Part C (Colours): Say, “Again, name the colours in which the words are printed as quickly as you can.” If necessary, clarify by saying, “Don’t read the word, tell me the colour in which the word is printed.”
The examiner is required to interrupt the examinee as soon as an error is made, after which the examinee must correct the error and continue with the next item. Mistakes spontaneously corrected by the individual before being interrupted by the examiner are not counted as errors. The examiner records the amount of time required to complete each task (to the nearest full second) and the number of errors that are not spontaneously corrected (Strauss, Sherman, & Spreen, 2006) (Troyer, Leach, & Strauss, 2006).
Scoring: The score is the time taken to finish each of the three tasks. An interference effect can be calculated by subtracting the score of the Colour task (naming the colours in the interference task) from the score of the Dot task (naming the colours in the control task), to determine the additional time required to do the interference task.
Strauss, E. S., Sherman, E. M., & Spreen, O. (2006). A Compendium of Neuropsychological Tests: Administration, Norms, and Commentary. Oxford: Oxford University Press.
Truter, S., & Shuttleworth-Edwards, A. B. (2018a). Eleven neuropsychological tests in the public domain: Normative data for disadvantaged adults. In P. S. (PsySSA) (Ed.), Mamela Psychology, 2018 Congress Programme (p. 29). Johannesburg: PsySSA.