One common shortcoming of mindfulness research is a reliance on self-report measures of mindfulness. Researchers can never be certain if participants are accurate in their self-ratings. In a recent study, two researchers at Liverpool John Moores University, Moore and Malinowski, made a useful contribution to the literature by including two measures of attention along with a self-report measure of mindfulness.
The researchers compared a group of 25 Buddhist meditators to a group of 25 non-meditators matched for age and gender. Participants were administered the Kentucky Inventory of Mindfulness Skills, a self-report measure of mindfulness, and two attentional tasks: the Stroop Task and the d2-concentration and endurance test.
The Stroop is an older and well-known pencil-and-paper test in which participants are presented a series of words written in colored ink and asked to identify the color of the word. This task becomes tricky when participants are asked to identify colors in words spelling out the names of other colors (e.g., the word “red” written in green ink). When there in an incongruity between ink color and color name, reaction time slows and participants must refrain from reading the name of the color instead of identifying the ink. Mistakes made in misidentifying a stimulus are known as commission errors.
I’m not familiar with the d2, but the authors describe it as a speeded test that requires participants to discriminate a particular target from other similar non-targets. Participants may make errors of commission by identifying a non-target as a target, or errors of omission by not identifying targets, mistaking them for a non-target.
In short, meditators performed significantly better than non-meditators on all aspects of the two attentional tasks. These tasks require both attention and cognitive flexibility in order to attend to the tasks through responding and inhibiting responses. Better performance was related to higher mindfulness. Analyses also suggested that cognitive flexibility was best predicted by two aspects of mindfulness: mindfully acting with awareness in everyday life and the ability to observe one’s immediate experience. Because the design was cross sectional, however, it is impossible to know for certain if meditation improves attention and cognitive flexibility, or if individuals attracted to meditation are higher in cognitive flexibility and attentional control.
You can find a link to the study at the second author's website.
Here’s the full citation:
Moore, A. & Malinowski, P. (2009). Meditation, mindfulness and cognitive flexibility. Consciousness & Cognition, 18(1), 176-186