Stroop Color and Word Test


To assess the ability to inhibit cognitive interference of an individual using the Stroop test.


The Stroop Color and Word Test (SCWT) is a neuropsychological test extensively used for both experimental and clinical purposes. It assesses the ability to inhibit cognitive interference, which occurs when the processing of a stimulus feature affects the simultaneous processing of another attribute of the same stimulus (Stroop, 1935). In the most common version of the SCWT, which was originally proposed by Stroop in the 1935, subjects are required to read three different tables as fast as possible. Two of them represent the “congruous condition” in which participants are required to read names of colors (henceforth referred to as color-words) printed in black ink (W) and name different color patches (C). Conversely, in the third table, named color-word (CW) condition, color-words are printed in an inconsistent color ink (for instance the word “red” is printed in green ink). Thus, in this incongruent condition, participants are required to name the color of the ink instead of reading the word. In other words, the participants are required to perform a less automated task (i.e., naming ink color) while inhibiting the interference arising from a more automated task (i.e., reading the word; MacLeod and Dunbar, 1988; Ivnik et al., 1996). This difficulty in inhibiting the more automated process is called the Stroop effect (Stroop, 1935). While the SCWT is widely used to measure the ability to inhibit cognitive interference; previous literature also reports its application to measure other cognitive functions such as attention, processing speed, cognitive flexibility (Jensen and Rohwer, 1966), and working memory (Kane and Engle, 2003). Thus, it may be possible to use the SCWT to measure multiple cognitive functions.

The Stroop effect (Stroop, 1935) is a long-studied, yet still intriguing, a phenomenon in cognitive psychology. In its most general form, the Stroop effect occurs when two competing processes are relevant to the task at hand, but only one of these processes should govern the participants’ response. The standard Stroop task requires naming the ink color of a word that, in some cases, spells a color (e.g., the word red printed in blue ink). The robust result is that performance varies as a function of the congruency between the ink color and the word. When the word spells a color that conflicts with the ink color, latencies and error rates increase relative to nonword and non-color-word controls, an effect known as Stroop interference. Conversely, Stroop facilitation occurs when the word spells a color that matches the ink color, with latencies and error rates decreasing relative to controls. The most important aspect of the Stroop phenomena is that these effects disappear under word-reading instructions.

The Stroop test and its variations

The Stroop test is performed so that 3 different phases are included, which are as follows:

  • Names of colors written in black ink.
  • Color stimulations.
  • Names of colors, written in ink other than the color indicated by the word.

What is expected is that in the third phase, the person takes much longer to complete the task than in the other two phases.

This occurs when there is an interference between reading and color recognition. Attention must be divided to overcome the test with satisfaction.

Theories about the Stroop effect

There are several theories that explain the Stroop effect. Theories are based on the idea that both relevant and irrelevant information is processed in parallel. That is, information reaches our brain and is stored at the same time to give an answer, but only one of the two stimuli must be fully processed for the body to perform the expected behavior.

Below are the theories that can explain this curious effect, we could say that they are not mutually exclusive and that all are of equal importance to explain the effect.

  1. The processing speed

This theory suggests that there is a delay in the ability of our brain to recognize what color the word is painted, because for our brain reading is faster than the recognition of colors.

This means that text is processed faster than color. In order to understand it better, let us say that the written word comes before the stage where we must make a decision about the answer we must give, and when the word is processed faster than the color, it causes a conflict when it comes to giving the answer immediately.

  • Selective attention

If we are based on selective attention theory, where we must discriminate which stimulus is important, we see that the brain really needs more time and focus more attention to recognize a color, compared to writing a word .

At this point, it should be added that in order for the brain to have a correct answer in a task in which the subject must select which information is relevant, the inhibitory function of the brain comes into play, since the response to be given quickly is Of reading the word, so that is the answer that the mind must inhibit in the presence of letters and color.

There are several brain areas that are dedicated to inhibiting those responses that should not be given, related to the decision making And the execution of a particular response.

The area of ​​the brain responsible for this inhibitory function is found in the Prefrontal area , i.e just the front of our brain, although in fact inhibition is possible to many more structures.

Specialized structures in this function are:

  • The dorsolateral prefrontal cortex (CPFDL)
  • The ventrolateral prefrontal cortex (CPFVL)
  • The dorsal cingulate cortex (DACC)
  • And the parietal cortex (PC).

I leave you a drawing where the structures that I have told you are indicated.

  • Automaticity

It is the most common theory to explain the Stroop effect. This theory is based on the fact that reading is a process that is automated, and color recognition is not. This means that when we are adults, the brain, when seeing a written word, automatically understands its meaning, since reading is a habitual activity.

Automatic processes are those that we learn and which with practice become automatic, such as driving, cycling or reading. When the process becomes automatic, fewer resources are spent at the brain level to complete the task. So, being automatic we put less attention and we spend less energy.

So, according to what I just explained, you may now understand why the automaticity can explain the Stroop effect, since the automatic reading does not need controlled attention, and yet the recognition of the color if, having an interference at the time of giving A response, since the first behavior to be executed will be to read the word automatically.

  • Distributed Processing in Parallel

In this case, the theory refers to how the brain is analyzing the information.

In the brain there are two types of processing or analysis of information:

  • Sequential processing : When we talk about a sequential brain processing, we refer that if there are two tasks, we will first process one and then the other. This kind of processing is slow, and if one of the tasks takes a little longer to process, by going one after the other, the whole process will take longer.
  • Parallel processing : In this case, reference is made to several processes that occur at the same time. It is a more complex processing in reference to sequential processing. Each process will be related to a stimulus, so it is difficult to divide the word processing and color in order to allocate the resources that the brain has to carry out the task.

So this theory suggests that as the brain is analyzing the information, having two types of stimuli that discriminate processing will be done in parallel.

Let’s say that once the information has arrived at the visual system, at the central level, each stimulus will enter a different pathway to the brain to become processed. The conflict arises because there are more powerful ways to process, and in the case of the Stroop effect, the path chosen by the reading has a greater strength compared to the one chosen by the color. So when being processed at the same time, the brain must compete to give relevance to the weaker path.

History :

Since the very beginning of experimental psychology, it has been clear that words are faster to read than objects or their properties are to name. In his dissertation in 1886, Cattell even went so far as to suggest that word reading is automatic due to extensive practice, introducing the concept of automaticity to cognitive science. Automatic processes can be thought of as unintentional, uncontrolled, unconscious, and fast. Under the automaticity account, people cannot comply with an instruction not to read because reading cannot be “turned off”; hence it is guaranteed that incompatible words will cause interference when attempting to name their print colors. From early on, the other prevalent explanation of Stroop interference was the relative speed of processing account, which in its simplest form argued that faster processes can affect slower processes but not vice versa . Thus, because words are read faster than colors can be named, interference results when the task is to name the colors and ignore the words. This also fits nicely with Stroop’s other finding – that there was no “reverse Stroop” interference when the task was to read the words and ignore the colors: Reading performance for incongruently colored words was equivalent to that for words printed in standard black ink. Stroop’s results are highly replicable, as MacLeod showed over a half-century later. Since Stroop’s landmark study, many hundreds of studies have sought to understand this superficially simple phenomenon, and many more have used his method to explore key aspects of attention, learning, memory, reading, language, and other cognitive skills . More recently, the Stroop task has also been extended to investigate neural mechanisms and clinical disorders, among other issues. Interest in Stroop’s method shows no signs of abating; indeed, it is one of the rare phenomena/tasks where interest seems to be growing rather than diminishing with the passage of time.

The Stroop test is considered by some to be an effective measure of executive functioning—the ability to plan, apply knowledge and make decisions. Executive functioning, along with short term memory impairment, is often one of the symptoms of early-stage Alzheimer’s disease. Impaired executive functioning may also be an early symptom of other kinds of dementia, such as frontotemporal dementia, even when memory is intact.

What Does the Stroop Test Contain?

The Stroop Test consists of colors that are written in words but in the wrong color ink. The test-taker has to be able to state the color that the word is written in and be able to ignore whatever the actual word is. For example, if you see the word “red” but it’s written in blue ink, the correct answer would be “blue”.

Stroop Test Results

Older adults who do not have any cognitive impairment have, on average, a slower response time than younger and middle-aged adults, but they typically answer the questions correctly.

People with mild cognitive impairment, Alzheimer’s, or another dementia, on the other hand, will be slower in answering but also will have a significantly higher rate of incorrect answers because of their decline in processing information and the inability to ignore one stimulus (the word) while focusing on the other one (the color).

The test has been administered across several languages and consistently been shown to be effective in identifying executive functioning impairments. However, results have been shown to be influenced by age, education levels, and sex.

What Does the Stroop Test Identify?

The Stroop Test has been associated with impairment specifically in the prefrontal cortices of the brain, especially in earlier stages of Alzheimer’s. As Alzheimer’s progresses into the middle and late stages, the Stroop effect is not a valid indicator of the location or extent of impairment in the brain.



Pencil, Stroop Color-Word Test, and stop watch.


Keeping in mind the consideration that it would be difficult to find people who specifically might have ability to inhibit cognitive interference to suffice the nature of Stroop test criteria, the participant was picked as per convenience based on ease of access.


The participant was first given a brief description of the test. He was also informed that this test would be conducted entirely at his own discretion which implies that he could decline his participation in this experiment if it was not convenient.

She was then given a consent form and all the relevant details related to the form was explained before soliciting the signature.



This form seeks to take your consent to participate in a study. The following will provide you with information about the study that will help you in deciding whether or not you wish to participate. If you agree to participate, please be aware that you are free to withdraw at any point throughout the duration of the experiment.

All information you provide will remain confidential and will not be associated with your name. If for any reason during this study you do not feel comfortable, you may leave the laboratory and your information will be discarded.

When this study is complete you will be provided with the results of the experiment if you request them, and you will be free to ask any questions. Please indicate with your signature on the space below that you understand your rights and agree to participate in the experiment.

Your participation is solicited, yet strictly voluntary. All information will be kept confidential and your name will not be associated with any research findings.





To begin forming rapport and making the participant comfortable, the participant was told about the test, purpose of testing , and given assurance of confidentiality and informed consent. It was ensured that the study outline and all the other necessary details were discussed in the language that the participant was comfortable with, the participant was made aware of his freedom to participate voluntarily and dropout of the study of the at any point. All the concerns and queries of the participant were readily addressed including confidentiality and informed consent to gain complete trust from the participant. After taking the consent form, further proceedings with the study were made.


  • NAME: nik
  • AGE: 21
  • EDUCATION : BBA (3rd yr)


Following instructions were been provided to the subject :

  1. Instructions for the Word Page: “This is the test of how fast you can read the words on this Page. After I say begin, you have to read down the columns starting with the first one until you complete it and then continue without stopping down the remaining columns in order. If you finish all the columns before I say “Stop”, then return to the first column and begin again. Remember, do not stop reading until I tell you to “Stop” and read out loud as quickly as you can. If you made a mistake ,I will say “NO” to you. Correct your error and continue without stopping. You can ask questions, if you have”. Instructions may be repeated or paraphrased as often as necessary so that the subject understands what is to be done. As the subject says the first response , start timing. After 45 seconds, stop the subject and circle the item, on which the subject is. Turn to the next page.
  2. Instructions for the Color Page: “This is a test of how fast you can name the colors of the page”. “You will complete this page just as you did the previous page, starting with this first column. Remember to name the colors out loud as quickly as you can.” If the subject had any trouble followings instructions, they should be repeated in their entirely. As with the first page, the subject should be allowed 45seconds.
  3. Instructions for the Color-Word Page: “This Word page is like the page you just finished. I want you to name the color of the ink the words are printed in, ignoring the word that is printed for each item. You will do this page just like the others ,starting with the first column and then going on to as many columns as you can. Remember , if you make a mistake, just correct it and go on. When I will say “stop” circle the item you are on.


The subject was given a booklet of all three pages, but was allowed to view only one page at a time. The booklet was directly placed in front of the subject on a flat surface. The subject may be allowed to rotate the booklet up to 45 degrees to either the right or to the left, the subject is not allowed to rotate to a greater degree. The subject was provided with the instructions and the sheet was given to perform the test.


 Raw ScoreAGE/Ed. Predicted*ResidualT-Scores**
Word Score (W)92108-1639
Color Score (C)9081957
Color-Word Score (CW)3548-1337
CW–Predicted=  Interference-13 45.45 

Residual score = Raw score – predicted age

Interference score = Color word raw score – predicted age

T-score – 46


This test assesses the ability to inhibit cognitive interference, which occurs when the processing of a stimulus feature affects the simultaneous processing of another attribute of the same stimulus. The robust result is that performance varies as a function of the congruency between the ink color and the word. When the word spells a color that conflicts with the ink color, latencies and error rates increase relative to nonword and non-color-word controls, an effect known as Stroop interference. While performing the test, participant read out 92 words of word test, 90 words color test , and 35words of color-word test  respectively in 45seconds and since the overall T score is above than 40, it is considered to be as normal . These scores convert to the interference T score of 46. With the interference T score of 46 the participant’s scores indicate normal overall functioning , cognitive flexibility, resistance to interference from outside stimuli , creativity, and no indications of psychopathology.


The aim of this test is to assess the ability to inhibit the cognitive interference of the client. After calculating the results of the test, it can be said that the client has normal overall cognitive functions such as attention, processing speed, cognitive flexibility, and working memory.

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