The Stroop Effect: A Key Finding in Psychological Research
The Stroop effect is a simple phenomenon that has profound implications for how our brains process information. First discovered by John Ridley Stroop in the 1930s, it is a key finding that continues to play an important role in psychological research and clinical psychology.
Understanding Stroop Tests and Cognitive Processing
Stroop tests involve presenting a stimulus with two dimensions that either mandate the same (congruent trials) or conflicting (incongruent trials) response. This causes a delay in cognitive processing of the stimulus by the brain. It is this delay that allows the more automatic, easy process to access selective attention and be processed by the brain, while a more difficult, less automatic process remains unprocessed.
Automatized Behaviors and Revealing Brain Processes
Automatized behaviors are a common feature of our daily lives, whether it's typing, reading, writing, driving, or even playing piano! Putting observers in situations where an automatized response is in conflict with a more conscious, desired one can help to reveal the behind-the-scenes working of the brain and reduce biases that can arise during experimental testing.
The Variants of Stroop Test and the Resulting Delay
Several variants of the Stroop test exist, including those that manipulate the stimulus or the duration of the task. These tests vary in their sensitivity to incongruence, but all share the same result: a delayed response time that can be attributed to interference between the automatic and controlled processes of cognitive processing.
Stroop Effect in Different Populations and Factors Contributing to Incongruence
This delay is found in people who have frontal lobe damage or other problems with selective attention and in older individuals who have trouble remembering words (Demakis, 2004). However, it also occurs in normal children, adolescents, and adults.
Incongruence in a word's meaning and color are the most common factors that cause this effect to occur, but it can also be caused by incongruence between numerical size or even the way a number is presented. Numerical size incongruence is particularly strong and increases the delay, but it also interferes with the ability to report numbers in a sequence.
The Brain's Processing Speed and Prioritizing Relevant Information
The delay that results from this incongruence may be a result of the brain's processing speed, but it could also be a consequence of the way our brains are designed to prioritize the most relevant information among the constant flow of stimuli we encounter on a daily basis.
Demonstrating the Stroop Effect with Students
You can use this demonstration with your students to show them how a stimulus can be incongruent between its meaning and its color and still cause a delayed response by the brain. For example, you can demonstrate this with a simple experiment where participants read a list of color words, but the words are written in a different color than their meaning.
The Stroop Effect: Attending to Automatic and Easy Processes
When comparing the data of the incongruent and congruent trials, you will notice that the incongruence between the word's meaning and the color of the ink makes it harder to name the color than when the word's meaning is the same as the color of the ink.
This difference is called the Stroop effect and is a fascinating and useful demonstration of how the brain can choose to attend to more automatic and easy processes and ignore those that require more conscious effort.
