We interact with our environment in different ways. Visual processing is just one of the many ways that we use to understand the world around us. When we see an object, we don’t just see its physical characteristics, we understand it’s uses and purpose in our lives. For example, we recognize that legs are needed on a chair because the seat needs to be elevated, and without even being aware, we have automatically processed and understood this information.

When psychologist John Ridley Stroop asked people to read words on a sheet of paper, he hypothesized that their automatic processing would produce conflicting mental commands. Stroop wanted to discover which command would dominate the thought process in each person and if that dominate process would be the norm for the majority of people. He knew that with further and more detailed testing he could provide the medical community with a breakthrough discovery into brain function. His research technique is one of the most famous and renowned examples of a psychological test and is now widely used in clinical practices all over the world. The Stroop Test has been instrumental in helping to diagnose different neurological and psychiatric disorders. In recent years, variations have been used to help people increase their mental strength and improve their attention skills.

The Stroop Effect was named after John Ridley Stroop, who published an article in the journal of experimental psychology, in 1935, entitled “Studies of interference in serial verbal reactions”. He was not the first to publish this occurrence as Eric Rudolf Jaensch published his article in Germany in 1929. The Stroop Effect can be found documented as far back to works in the nineteenth century by James McKeen  Cattell and Wilhelm Maximilian Wundt.

To conduct his experiments, Stroop gave participants variations of the same test: The first variation was to read color words written in the same color ink as the word (congruent), the second variation asked the participant to name the ink color a word is written independently of the written word (incongruent) and a third neutral test in which participants stated the name of colored squares.

Stroop observed that participants took significantly longer to complete the color reading in the second variation of the test than they had taken to name the colors of the squares in the third variation. This delay had not appeared in the first variation. Such interference was explained by the automation of reading, where the mind automatically determines the meaning of the word (it reads the word “red” and thinks of the color “red”), and then must intentionally check itself and identify instead the color of the word (the ink is a color other than red), a process that is not automated.