Background

The Stroop Test originated as part of a series of scientific experiments into the the "Stroop Effect"; interference in the reaction time of a task. Demonstrated by (and named after) John Ridley Stroop, who first published the effect in 1935; before the start of World War II. Whilst it dates back to 1929, 1935 is the first English publication on the subject. Over the years, the Stroop Effect has become one of the most famous psychology papers in existance, with over 700 replications in various formats. From this paper of three tests, the Stroop Test is most famous and most recognizable in modern society.

Overview of the three tests

The family of "Stroop Effects" consists of three variations on the same basic idea. These variations were called "Stimulus". The first, was a list of names of colours in black ink. Second, names of the colours were wriitten in inks distinctly different to their respective written word. The third stimulus was a list of squares in several colours.

Evidence Gathered and Results

Stroop found a significant increase in the time needed for people to complete Stimulus 2, compared to Stimulus 3 (naming of the squares). However, no such delay occurred in Stimulus 1. After several re-tries, John Ridley Stroop concluded that the time delay (or "interference") was due to:

"The natural process of reading, where the mind automatically determines the meaning of the word, and then must override this first impression with the identification of the color of the word, a process which is not automatized."

Try it out for yourself

Below is a standard layout of Stimulus 2. Time yourself (using a wristwatch probably, or though if you want to go scientific you can use a stopwatch) reading each of the colours of the words, not the words themselves. Once all words have been finished, see how you did. Compare with the below image of Stimulus 1. You should find a significant difference in the timings.

• Stimulus 2

• Stimulus 1

How did you do? Did you see a difference? As always we want to hear your voice over in the forum.