Because most people’s automatic response is to read a word, the Stroop Test is a classic test of response inhibition. This skill involves responding quickly while avoiding incorrect impulses that may interfere with accomplishing goal-driven tasks. Response inhibition is associated with the brain’s executive function, and brain imaging studies have found that performing the Stroop Test activates brain areas involved in executive function, such as the dorsolateral prefrontal cortex.
In fact, individuals with ADHD and depression, whose poor executive function makes them struggle to pay attention and control reactions, often have a harder time performing the Stroop Test.
The Stroop Test also challenges selective attention, or the ability to choose which stimuli to focus on and which to ignore. The mental flexibility required to switch between multiple stimuli is essential: without good selective attention, it can also be easy to make errors.