He Stroop test Is a test that is used in the field of psychology and shows the interference that can occur in a task that requires selective attention to be performed.
The selective attention is the one that allows us to be able to attend to two different stimuli at the same time to carry out an action and to discriminate between them to react to what 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 that the behavior will come into play the brain inhibitory function, which will give information to your mind to consider one of the two non-relevant stimuli.
For example, Imagine that you are in a disco, and the music is very loud, one of your friends wants to tell you something in your ear. The fact that you pay more attention to your friend's words than to the music that sounds, is the result of a selective attention task.
According to the stimuli that appear, your brain will be easier to discriminate and give importance to what it considers relevant. This will be influenced by the intensity of presentation, and even by the channel that the information reaches us, that is, if both stimuli come to us in a visual, auditory, tactile way?? etc
If the stimuli to discriminate are presented in the same way, the brain will have it more difficult for your response to be in function of the important stimulus.
To evaluate the ability of our mind to perform a task involving selective attention, professionals related to the world of psychology use a test called Stroop Test.
The stroop test demonstrates how the reaction time to a task is increased by the interference between two stimuli in a selective cutting task.
The reaction time, for you to 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, whether the answer given is correct or not.
During the stroop test, the subject is presented with colored names, whose letters are colored in a color other than the one they name. For example, the word RED Appears painted in green. The subject must say out loud what color the word is painted on. In the previous example the correct answer would be green.
This test was elaborated from the contribution of Ridley Stroop, who published in 1935 the effect provoked by the presentation of these stimuli. That is, from the discovery of the effect, is when the test is created, which is widely used in clinical practice and research.
To make known to the world the effect, Ridley makes an article called"Studies of interference in serial verbal reactions", or what is the same in Spanish?? studies of interference in the verbal reactions of series???.
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.
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 , Ie 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.
Using the Stroop Test
The Stroop effect has been widely used in psychology, both for testing people and for validating the theories I have discussed in the previous section.
With the Stroop test you can measure a person's ability to use selective attention and processing speed. The Stroop test is also used in combination with other neuropsychological assessments, as it examines an individual's executive processing power.
In studies conducted, it was found that the test was sensitive in discriminating those who suffered brain damage, and was even able to discriminate the location of the damage in reference to the affected brain area.
How to do the Stroop test?
Usually 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 you can get giving answers, here below I leave you two links where you can Perform the test
Do not worry if it's hard for you to do it at first, hit it or go faster, remember the number of processes involved in the task, and the theories I explained earlier.
Our mind is wonderful, but keep in mind sometimes it does all it can.
You can try the test in The following website .
If you prefer to do it in English This is another link Which will take you to the test in that language.