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The Science Behind The Stroop Effect


The Stroop Effect is a famous paradigm and phenomenon used in both experimental and clinical psychology. It shows the delay in reaction time between incongruent and congruent stimuli. Congruence is when the meaning and the color of the word are identical. For example, the word “green” is written in the color green. Incongruence is when the meaning of the word and the color are different. For example, the word “green” may be written in the color red. The Stroop test can measure someone’s selective attention capacity abilities, processing speed, and with other tests, it can show overall executive processing skills.

Although it was discovered in 1935 by John Ridley Stroop, it has since been modified in a way that helps psychologists and psychopathologists understand brain mechanisms. Their studies using the Stroop Effect have helped aid brain damage research. In the Stroop test, individuals look at a list of words that are printed in a different color than the meaning of the word. They are told to name the color of the word instead of the word itself as fast as they can. Reading is something that our brains are more used to and are trained to do. It takes precedence over color naming, which needs higher cognitive demands. That’s why naming the color of a word takes longer than reading the word itself.

There are several reasons why there’s a difference in the reaction times of the Stroop test, including the processing speed theory, the selective attention theory, the automaticity theory, and the distributed processing theory. The processing speed theory says that people can read words faster than they can name the color of the word. Looking at the incongruent stimuli, our brain reads the word first as it is trained to do so. That makes it more difficult to name the color after as the word that was read differs from the color. As a result, a delay happens when we try to name the color of the word instead of the word itself because doing that wasn’t our brain’s first instinct.

The theory of selective attention says that recognizing colors requires more attention than reading actual words. The brain has to use more attention when attempting to name a color, which results in this process taking longer. The automaticity theory states that recognizing colors isn’t an automatic process, rather processes in the brain that are relatively fast and don’t require many cognitive resources. This kind of information processing usually occurs outside of conscious awareness. It’s regular when undertaking familiar tasks that have been done several times in the past. The brain can automatically understand the meaning of a word because of habitual reading, though.

Researchers who support this theory say that automatic reading doesn’t require controlled attention, but still uses enough of the brain’s attentional resources to shorten the amount left for color processing. This parallels the brain’s dueling modes of thinking – that of System 1 and System 2. While System 1 is more automatic and instinctive, something that you have a habit of doing, System 2 is slower and more controlled, like something you have to think about doing. This relates to the Stroop Effect – we see an automatic process trying to dominate over a more managed one. The interference happens when we try to use System 2 to override System 1, which creates a delay in reaction time.

The last but not least theory says that when the brain completes unalike tasks, unique pathways are created. Some pathways, like reading words, are stronger than others, like naming colors. That shows that the interference isn’t because of processing speed, attention, or automaticity, but instead a conflict between the stronger (System 1) and weaker (System 2) neural pathways.

The Stroop Effect was a test that showed the relationship between color and word processing. With further research, it has become a popular test that investigates processing interferences. It contributes a lot to psychopathology, psychology, and brain damage. It shows a lot about the human brain and how it operates! Even though several factors that affect results have been identified, psychologists are still researching the Stroop Effect to find the true cause of it. There are some variations in the severity of the Stroop effect found in females and males. John Ridley Stroop himself saw that women experience shorter interruptions than men. Studies have also found that older people show longer delays than younger people. The Stroop Effect is a very interesting phenomenon that challenges our brains!

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