Fun with Stroop

April 30, 2008

The Stroop Effect is often used to demonstrate the nature of automatic processing versus conscious visual control. It also illustrates our ability to quickly recognize word shapes based on familiarity, even more quickly than color.

This effect was first described by J. Ridley Stroop in 1935, and was demonstrated by giving participants lists of words printed in various colors of ink. The participants were instructed to name the color of the ink for each word as quickly as they could.

Control condition
In Stroop’s original study, the control condition consisted of neutral, non-color related words (for example, the word “dog” appeared in green ink and “chair” in blue ink).

Compatible condition
Next, the compatible condition consisted of a list of colors – the words red, green, blue, etc. – printed in their corresponding ink colors (“red” was printed in red ink, “blue” in blue ink, and so on).

Incompatible condition
The final list consisted of the names of colors written in different colored ink (for example, the word “red” appeared in green ink).

Stroop found that people could name the color of the ink faster in the compatible condition (“red” in red ink) than the control condition (“dog” in green ink). However in the incompatible condition, people took longer to name the color of the ink (“red” in green ink) than in the control condition (dog” in green ink). One explanation is that naming the color of the ink is an unfamiliar task to most people and requires conscious effort, while reading is so well practiced that it becomes automatic. So, in the third condition people experience interference – as they try to name the color of the ink, they have already read the word (for example, “red”) and need to consciously adjust their answer.

Try Stroop’s experiment for yourself and see if it takes longer to complete list number 3. Remember, for each group you’re trying to say the color of the words.