WHAT IS THE STROOP TEST? - ARTE

The stroop test is a test that is used in the field of psychology and that shows the interference that can occur in a task that requires selective attention to perform.

Selective attention is what allows us to attend to two different stimuli at the same time to carry out an action and discriminate between them to react to the one we consider important.

That is, in a task where we are exposed to more than one stimulus. To carry out our purpose, we only have to take into account one of them, so the brain's inhibitory function will come into play in the behavior, which will give information to your mind to consider one of the two stimuli not relevant.

For example, imagine that you are in a disco, and the music is very loud, one of your friends wants to whisper something to you. The fact that you pay more attention to the words of your friend than to the music that is playing is the result of a selective attention task.

Depending on the stimuli that are presented, it will be easier for your brain to discriminate them and give importance to the one it considers relevant. This will be influenced by the intensity of the presentation, and even by the channel that the information reaches us, that is, if both stimuli reach us in a visual, auditory, tactile way, etc.

If the stimuli to be discriminated are presented in the same way, the brain will have a harder time for your response to be given according to the important stimulus.

To assess the ability of our mind to perform a task that involves selective attention, professionals related to the world of psychology use a test called the Stroop Test.

The stroop test shows how the reaction time to a task is increased by the interference between two stimuli in a selective cutting task.

The reaction time, so that you know the term, in psychology is considered the amount of time that elapses between the presentation of a stimulus and the response given by the person. Sometimes it is also evaluated together with the reaction time, if the answer that has been given is correct or not.

During the stroop test, the subject is presented with names of colors, whose letters are colored a different color from the one they name. For example, the word RED is painted green. The subject must say out loud what color the word is painted. In the example above the correct answer would be green.

This test was developed from the contribution of Ridley Stroop, who published in 1935 the effect caused by the presentation of these stimuli. That is, from the discovery of the effect, it is when the test is created, which is widely used in clinical practice and research.

The stroop test and its variations

The Stroop test is performed in a way that includes 3 different phases, which are as follows:

Color names written in black ink.
color stimuli.
Names of colors, written in ink different from 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 pass the test successfully.

Theories about the Stroop effect

There are several theories that serve to explain the Stroop effect. The theories are based on the idea that both relevant and irrelevant information are processed in parallel.

That is, the information reaches our brain and is stored at the same time to give a response, but only one of the two stimuli must be fully processed for the body to carry out the expected behavior.

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

Processing speed

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

This means that text is processed faster than color. For you to understand it better, let's say that the written word reaches the stage earlier in which we must make a decision regarding the answer to be given, and by processing the word faster than the color, it causes a conflict when giving the answer immediately.

Selective attention

If we are based on the theory of selective attention, in which we must discriminate which stimulus is the important one, we see that the brain really needs more time and focus even more attention to recognize a color, if we compare it with the writing of a word.

At this point it should be added that in order for the brain to give a correct response in a task in which the subject must select what information is relevant, the inhibitory function of the brain comes into play, since the response that will be given quickly is the to read the word, so that is the response that the mind must inhibit before the joint presentation of letters and color.

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

The area of the brain responsible for this inhibitory function is located in the prefrontal area, that is, just the front part of our brain, although in reality inhibition is possible to many more structures.

Structures specialized in this function are:

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 mentioned are indicated.

Automaticity

It is the most common theory to explain the Stroop effect. This theory is based on the fact that reading is an automated process, and color recognition is not. This means that when we are adults, when the brain sees a written word, it 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 carry out the task. Therefore, being automatic, we pay less attention and spend less energy.

So, according to what I just explained to you, you may now understand why automaticity can explain the Stroop effect, since automatic reading does not need controlled attention, and yet color recognition does, there being an interference when giving an answer, since the first behavior to be executed will be to read the word automatically.

Parallel distributed processing

In this case, the theory refers to the way the brain analyzes the information.

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

Sequential processing: when we talk about brain sequential processing, we mean that if there are two tasks, one will be processed first and then the other. This type of processing is slow, and if one of the tasks takes a little longer to process, going one after the other, the entire process will take longer.
Parallel processing: In this case, it refers 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 dividing the word processing and color in parallel is difficult when having to distribute the resources that the brain has to carry out the task.

Therefore, this theory suggests that as the brain analyzes the information, having two types of stimuli to discriminate, the processing will be carried out in parallel.

Let's say that once the information has reached the visual system, at a central level, each stimulus will enter the brain through a different pathway to be processed.

The conflict occurs because there are more powerful ways to process, and in the case of the Stroop effect, the way that the reading chooses has a greater strength compared to that that chooses the color. Therefore, when processed at the same time, the brain must compete to give relevance to the weakest pathway.

Using the Stroop test

The Stroop effect has been widely used in psychology, both for testing people and for validating the theories that I have discussed in the previous section.

With the Stroop test, the ability of a person to use selective attention and processing speed can be measured. The Stroop test is also used in combination with other types of neuropsychological evaluations, since it examines the executive processing capacity that a person has.

In studies carried out, it was discovered that the test was sensitive when it came to discriminating those people who suffered brain damage, being able to even discriminate the location of the damage in reference to the affected brain area.

How to do the Stroop test?

Normally this test is applied in a clinical mental health context, but if you are curious to experience the effect and see your ability to discriminate stimuli and the speed that you can have by giving answers, here are two links where you can perform the test.

Do not worry if it is difficult for you to do it at the beginning, get it right or go faster, remember the number of processes involved in the task, and the theories that I explained previously.

Our mind is wonderful, but keep in mind that sometimes it does its best.

References

https://www.rit.edu/cla/gssp400/sbackground.html.
http://ci-training.com/test-efecto-stroop.asp.
https://faculty.washington.edu/chudler/words.html.
http://www.ncbi.nlm.nih.gov/pubmed/16553630.

WHAT IS THE STROOP TEST? - ARTE - 2025