Demonstration of Stroop Effect – "Name that color" test
(This is a demonstration only. It is not to be used as diagnosis or any other purpose.)
The easy practice test:
Read the colors aloud (not the meaning of the words).
To time your response, click "Start" when you are ready to begin; click "Finish" when you are done.
RED
YELLOW
BLUE
GREEN
BLACK
PINK
ORANGE
BROWN
GRAY
PURPLE
GREEN
RED
BLACK
BLUE
YELLOW
PURPLE
GRAY
PINK
ORANGE
BROWN
It is easy because the color and the word are congruent.
The real hard test: Read the colors aloud (not the meaning of the words).
Note that it is the same list of words but written in different color.
PAY ATTENTION: The color of the words are different from what the word says.
To time your response, click "Start" when you are ready to begin; click "Finish" when you are done.
RED
YELLOW
BLUE
GREEN
BLACK
PINK
ORANGE
BROWN
GRAY
PURPLE
GREEN
RED
BLACK
BLUE
YELLOW
PURPLE
GRAY
PINK
ORANGE
BROWN
Do you notice it takes twice the amount of the time to complete the second test?
The above demonstration does not even take into account the incorrect responses in naming the colors.
The reaction time will increase with fatigue and/or inattention to the task, so if you retake the test, it will show slightly different reaction times and error rates.
John Ridley Stroop first reported this effect in his Ph.D. thesis published in 1935, commonly known as "Stroop Effect":
When the meaning of a word and its color are congruent, such as the word "BLUE" written in blue color, it is easy to recognize the actual color of the word.
But when the meaning of the word is incongruent with the color, such as "BLUE" written in red color, it creates a conflict between the color and the word's meaning.
The "conflict" between two brain processes are word recognition and color recognition.
This conflict requires extra processing time for the brain to resolve.
It turns out that we are so fluent in our language that word recognition is slightly faster/stronger than color recognition.
Most people will recognize the meaning of the word before recognizing the color.
In order to name the color correctly, the two processes compete for the final decision-making process.
The brain has to inhibit the faster/stronger word recognition process in order to allow the color recognition to win in the final response.
This inhibition requires "selective attention" (attentional focus) to inhibit the competing conflicting process.
The reaction time is an indicator of the "attentional process" in the brain – it increases with attentional fatigue and/or inattentiveness.
Thus, Stroop Effect is widely used to indicate mental process of attentional fatigue and/or the decreased ability to inhibit ongoing competing conflicts often associated with ADHD.