“The behavioral differences that seem to be most commonly reported in studies of new or long-time meditators include
- an increase in the ability to focus one’s attention,
- an increase in the ability to regulate one’s emotions,
- a decrease in stress and pain, and
- cognitive changes that include an enhanced sense of empathy and “connectedness.”
What causes these effects? Researchers hypothesize a complex set of brain activities, in which the “mind” becomes more aware of thoughts and feelings yet at the same time is less affected by them. “We learn to bring a space between the emotion and the reaction,” says Britta Hölzel, a researcher at Massachussetts General Hospital and Harvard Medical School, and lead author of one of the first “clinical trial” type brain imaging studies of meditators.
The study, which appeared Jan. 30 in Psychiatry Research: Neuroimaging, examined a popular meditation technique known as Mindfulness-Based Stress Reduction (MBSR). Sixteen people with no prior experience of meditation took an eight-week MBSR course and—on average—showed significant increases in their “mindfulness” skills on three out of five tests. Magnetic resonance imaging (MRI) scans also showed a slightly larger volume in three brain regions: the hippocampus, the posterior cingulate cortex, and the temporo-parietal junction. By contrast, a control group of 17 people on the waiting list for the MBSR course showed no such changes.
“We don’t have a clear understanding neurologically what is really happening,” Hölzel says. But this study, as well as prior studies, hint that mindfulness meditation can boost brain regions involved in imaginatively “stepping back” and observing oneself. “The posterior cingulate cortex, the temporoparietal junction, and the hippocampus all form a network that gets involved when we imagine ourselves from different perspectives,” she adds. […]
Perhaps the greatest challenge facing the field has been that of defining a true “control group.” When testing pharmaceuticals, researchers can control for potentially confounding factors by randomly assigning people to two groups, then giving one the real treatment, and the other a lookalike sham treatment or “placebo”—so that the only difference in their experience is the ingredient being tested. But researchers have never achieved this level of control in meditation research.
For example, in the recent study by Hölzel and colleagues, the control group were non-meditators on the MBSR course waiting list. Their experience during the study would have differed from the course-takers’ in a number of ways, possibly including less physical exercise—and physical exercise is known to be able to stimulate neural stem cells in the hippocampus and boost its volume. “Any kind of intervention may have an impact on someone, and unless we have proper controls we can’t know what parts of the intervention account for that impact,” says Lutz.
Both Lutz and Hölzel say that they and their colleagues are now designing studies with “active control groups” whose experience will include the expectation of therapeutic benefits as well as every other part of the mindfulness meditation course—“only without the mindfulness ingredient,” says Lutz.”