Stroop Task in Mindfulness Research

The Stroop task is a commonly used assessment tool in cognitive science. It presents stimuli that contain two conflicting informational aspects and requires participants to respond to just one of the aspects. To achieve this requires participants to ignore the distracting aspect. Traditionally, participants are asked to respond to the color of a stimuli and ignore the color meaning of the word (e.g., “red” printed in green ink). Reaction times to these incongruent stimuli are usually slower, and response accuracy is often lower. This “Stroop interference” is usually considered as a relative measure of cognitive control, while Stroop performance is generally considered as a measure of sustained attention. These cognitive functions enable participants to ignore distracting information and focus on task-relevant information. Since these cognitive functions are thought to be modulated by mindfulness practice, the Stroop task has been used to assess the effects of mindfulness on cognition. Often, the task has been used to assess whether changes in cognition from mindfulness practice are the mechanism of action mediating the effects of mindfulness practice on mental health. This research has often shown mindfulness improves Stroop task performance, and the changes in Stroop performance are associated with changes in mental health. However, the specific Stroop task measure affected by mindfulness has varied (sometimes affecting accuracy, sometimes reaction time), and a sizable proportion of studies did not find that mindfulness was associated with improved Stroop performance. Additionally, the exact cognitive functions that the Stroop task measures are still being debated, and the construct validity and reliability of measures obtained from the Stroop task are generally modest. While the Stroop task may be useful for assessing the effects of mindfulness on cognition, careful study design and interpretation are required. This chapter provides a comprehensive overview of the Stroop task and its relevance in mindfulness research, and reflects on reliability and validity of this assessment method.