How does the Stroop effect work ?

 Although it turns out to be of impressive power, our brain is not immune to certain deceptive phenomena. The Stroop effect, named after the psychologist who discovered it in the 1930s, is one of those biases that sometimes prevent our brain from performing as well as usual.

What is the Stroop effect ?

This psychological phenomenon, discovered by psychologist John Ridley Stroop, highlights the interference that occurs in the reaction to a given task when conflicting information disrupts the brain's ability to react quickly and precisely.

The most typical example is that of colors. If you need to identify the color of a word, and it doesn't match what is written (the word "red" written in green), your brain will take extra time to identify the color of the ink used.

Indeed, when the brain detects the word “red”, it associates the corresponding color with it. If the ink is green in color, it produces a mismatch in the thinking process that the brain has to divert. It must then overcome its initial impulse to say “red” in order to correctly identify the green ink. It is not uncommon for people to perform this test to make mistakes.

Why does the brain have trouble processing conflicting information ?

Our brain has great capacities, in particular because it can perform effective cognitive shortcuts that save us time. This is also what limits it in the event of conflicting information. According to a 2000 study by McLeod and McDonald, the part of the brain dedicated to word recognition is faster than the part dedicated to color processing. The brain will therefore instinctively first pay attention to the word that is written before processing the color information. For this reason, it will take longer to determine the true perceived color if it does not match the written word.

The use of the Stroop effect today

Beyond the fun tests carried out to test the Stroop effect, this phenomenon is also used in the context of psychological evaluation and in the field of neuroscience. It is used to judge selective attention and cognitive processing, for example in people with attention disorders or eating disorders. It further reveals the ability or lack of impulse control in individuals prone to impulsive behavior problems.