MATLAB Examples

# Take the Stroop Test

## Reference

The test along with its experimental results is described in:

Stroop, John Ridley (1935). "Studies of interference in serial verbal reactions". Journal of Experimental Psychology 18 (6): 643–662.

## Documentation

```help StroopTest ```
``` Produce a figure to take the Stroop test. Description A figure is produced which contains words in #prob_size# rows which are known color names, and are shown in a colored font. To take the Stroop test, quickly identify the color of each of these words (don’t read them). Say the colors out loud. Try to be as accurate as you can, and finish the test as quickly as you can. This task, called the Stroop Test, is much more challenging than it first appears. It’s much harder to identify a color when it is different from the word (#SHUFFLE#=1) than it is to identify when the two match (#SHUFFLE#=0). This challenging test relies on two key cognitive skills, response inhibition and selective attention. Doing the test for #SHUFFLE#=1 results in considerably more time than it would take for #SHUFFLE#=0. Required input arguments #words# (column vector) contains the color names as strings, one string per row. all of the vertically concatenated strings must have the same length. #colors# ([size(#words#,1) x 3]) contains the color denoted by each string in #words# in rgb representation. Look for ColorSpec (Color Specification) in the MATLAB documentation #SHUFFLE# (binary) determined if the colors in the figure are to be shuffled, so that the Stroop Test can begin. If #SHUFFLE#=0 no shuffling occurs and in the figure produced the various color names appear with the respective color. #prob_size# (integer) is the size of the problem, i.e. the number of the rows of words in the final figure. #FigID# (integer) is the number of the label of the figure to be produced. Output parameters none __________________________________________________________________________ Copyright (c) 13-May-2014 George Papazafeiropoulos First Lieutenant, Infrastructure Engineer, Hellenic Air Force Civil Engineer, M.Sc., Ph.D. candidate, NTUA Email: gpapazafeiropoulos@yahoo.gr Website: http://users.ntua.gr/gpapazaf/ ```

## Brief history of the Stroop Test

In 1935, a farmer’s son named John Ridley Stroop became the first to publish in English on the current version of this cognitive task. Developed as part of his dissertation at George Peabody College, his task became the basis for the Stroop Test, which remains a widely used neuropsychological assessment to this day.

## How your brain processes the Stroop Test

Because most people’s automatic response is to read a word, the Stroop Test is a classic test of response inhibition. This skill involves responding quickly while avoiding incorrect impulses that may interfere with accomplishing goal-driven tasks. Response inhibition is associated with the brain’s executive function, and brain imaging studies have found that performing the Stroop Test activates brain areas involved in executive function, such as the dorsolateral prefrontal cortex. In fact, individuals with ADHD and depression, whose poor executive function makes them struggle to pay attention and control reactions, often have a harder time performing the Stroop Test. The Stroop Test also challenges selective attention, or the ability to choose which stimuli to focus on and which to ignore. The mental flexibility required to switch between multiple stimuli is essential: without good selective attention, it can also be easy to make errors.

## Initial definitions

In the subsequent code the following initial definitions are made (in the order presented below):

1. Set the column vector containing the color names
2. Set the column vector containing the color denoted by each string in the previous vector in rgb representation
3. Set SHUFFLE parameter so that colors are not shuffled
4. Set SHUFFLE parameter so that colors are shuffled
5. Set the problem size for a small problem (5 rows)
6. Set the problem size for a large problem (15 rows)
```words=['YELLOW ';'MAGENTA';'CYAN ';'RED ';'GREEN ';'BLUE ';'BLACK ']; %1 colors=[1 1 0;1 0 1;0 1 1;1 0 0;0 1 0;0 0 1;0 0 0]; %2 SHUFFLE1=0; %3 SHUFFLE2=1; %4 prob_size1=5; %5 prob_size2=15; %6 ```

## Applications

1. Produce Figure 1 (small problem with matching colors)
2. Produce Figure 2 (large problem with matching colors)
3. Produce Figure 3 (small problem with non-matching colors)
4. Produce Figure 4 (large problem with non-matching colors)
```StroopTest(words,colors,SHUFFLE1,prob_size1,1) StroopTest(words,colors,SHUFFLE1,prob_size2,2) StroopTest(words,colors,SHUFFLE2,prob_size1,3) StroopTest(words,colors,SHUFFLE2,prob_size2,4) ```