The Stroop Effect

The Stroop effect is one of the best known phenomena in all of cognitive science and indeed in psychology more broadly. It is also one of the most long standing, having been reported by John Ridley Stroop in the published version of his dissertation in 1935 [1]. In its basic form, the task is to name the color in which a word is printed, ignoring the word itself. When the word is a color word printed in a mismatched ink color, this is very difficult to do and results in slow, error-prone responding. To illustrate, consider GREEN: To say “red” to the ink color is difficult relative to a variety of comparison or control conditions such as naming the color of XXXXX or the word TABLE or even the word RED. The performance cost in the mismatch condition – usually referred to as the incongruent condition – relative to the controls is called the Stroop effect or Stroop interference. Figure 1 provides an illustration of the phenomenon.