Stroop effect

[1] A basic task that demonstrates this effect occurs when there is an incongruent mismatch between the word for a color (e.g., blue, green, or red) and the font color it is printed in (e.g., the word red printed in a blue font).

[2] However, the effect was first published in 1929 in Germany by Erich Rudolf Jaensch,[3] and its roots can be followed back to works of James McKeen Cattell and Wilhelm Maximilian Wundt in the nineteenth century.

[7] The second finding, semantic facilitation, explains the finding that naming the ink of congruent stimuli is faster (e.g. when the ink color and the word match) than when neutral stimuli are present (e.g. stimulus 3; when only a colored square is shown).

The third finding is that both semantic interference and facilitation disappear when the task consists of reading the word instead of naming the ink color.

It has been sometimes called Stroop asynchrony, and has been explained by a reduced automatization when naming colors compared to reading words.

[7] In the study of interference theory, the most commonly used procedure has been similar to Stroop's second experiment, in which subjects were tested on naming colors of incompatible words and of control patches.

The first experiment in Stroop's study (reading words in black versus incongruent colors) has been discussed less.

In both cases, the interference score is expressed as the difference between the times needed to read each of the two types of cards.

[12] The posterior dorsolateral prefrontal cortex creates the appropriate rules for the brain to accomplish the current goal.

[13] It counteracts biases and irrelevant information, for instance, the fact that the semantic perception of the word is more striking than the color in which it is printed.

[11] Moreover, the posterior dorsal anterior cingulate cortex is responsible for what decision is made (i.e. whether someone will say the written word or the ink color).

This is based on the underlying notion that both relevant and irrelevant information are processed in parallel, but that they "race" to enter the single central processor during response selection.

Moreover, this research strongly suggests that changes in these processes with age are very closely associated with development in working memory and various aspects of thought.

Among the most important uses is the creation of validated psychological tests based on the Stroop effect permit to measure a person's selective attention capacity and skills, as well as their processing speed ability.

[25] It is also used in conjunction with other neuropsychological assessments to examine a person's executive processing abilities,[18] and can help in the diagnosis and characterization of different psychiatric and neurological disorders.

[26] The Stroop effect has been used to investigate a person's psychological capacities; since its discovery during the twentieth century, it has become a popular neuropsychological test.

[27] The number of stimuli varies between fewer than twenty items to more than 150, being closely related to the scoring system used.

[27] This test is considered to measure selective attention, cognitive flexibility and processing speed, and it is used as a tool in the evaluation of executive functions.

[27][29][30] Ergonomists could even show a relationship between the ergonomic characteristics of the educational furniture and the number of cognitive errors based on Stroop test.

[37] The idea here is the way the words are printed slows down both the brain's reaction and processing time, making it harder to complete the task.

[39] A notable study of this is Project Implicit from Harvard University which administered a test associating negative or positive emotions with pictures of race and measured the reaction time to determine racial preference.

[41] In one version of the spatial Stroop task, an up or down-pointing arrow appears randomly above or below a central point.

[44] MythBusters used the Stroop effect test to see if males and females are cognitively impaired by having an attractive person of the opposite sex in the room.

[45] A Nova episode used the Stroop Effect to illustrate the subtle changes of the mental flexibility of Mount Everest climbers in relation to altitude.

[46] 2024 horror video game The Outlast Trials features a "Stroop Test" minigame in which players compete against one another.