It's not really surprising that meditation might aid in executive control, since the act of meditation is basically an exercise in executive control. Take mindfulness, for example, I would say that the fundamental aspects of mindfulness practice is present moment awareness and emotional acceptance; practices that easily could be described as the executive functions inhibition and emotional regulation.
What they researchers did
What Teper and Ingzlict wanted to look as was more why meditation is effective in enhancing executive control, and not so much if it’s effective. They did so by recruiting from Craigslist and from local meditations centers; in total they included 20 meditators and 18 non-meditators in their analyses. Their experiment entailed recording EEG-activity during the Stroop-task. EEG stands for electroencephalography and it’s a method to measure neural activity by placing a bunch of electrodes on the scalp of the test subject. Specifically they wanted to look at the neural correlates of performance monitoring by looking at something called error-related negativity (ERN). ERN is a physiological response (as measured by EEG) that occurs within 100 ms after you perform an error. There are some different theories in the scientific community of what the ERN reflects, but many agree that ERN represent some kind of conflict monitoring, Teper and Ingzlict write that: “According to this theory, negative-going waves like the ERN occur not only upon the commission of an error, but also upon correct responses that are high in conflict, such as incongruent trails on the Stroop task”. And they continue with adding that more recent research suggests that the ERN may also represent a distress response to performing worse than expected. In their study they also measured something called error positivity (Pe), which occurs after the ERN and it’s presumed to represent whether and error was consciously detected.
As expected the meditators performed better on the Stroop task, and the researchers' analysis confirmed that meditators indeed exhibited higher neurophysiological responses to errors (i.e. ERN). In addition meditators did not show significant higher Pes than non-meditators, indicating that meditators are quick to let go of their errors, even though they are good at noticing them (as indicated by an elevated ERN). They also ruled out that meditators showed higher ERNs simply due to performing better on the Stroop task, i.e. the effect being an epiphenomenon of cognitive performance. Meditators also exhibited significantly higher emotional acceptance, but interestingly there were no significant differences on the “present moment-awareness”-subscale.
What this study tells us is that meditation might aid executive functioning by enhanced performance monitoring in combination with increased acceptance of emotions. This reminds me of Acceptance and Commitment Therapy-studies done on sports performance (see Gardner & Moore, 2004), where it has been shown that emotional acceptance can increase performance. The theory is that athletes can “choose” to lose as an act of emotional avoidance, and that enhanced acceptance can aid in engaging in more value oriented actions, i.e. to fight through the pain or shame of being on the loosing end of a game. The same mechanism could be at work in the study by Teper and Ingzlict. I have done the Stroop-task myself on several occasions and it can be really frustrating getting stuck on the incongruent items. So I can really see that mindfulness and acceptance skills could truly help subjects in letting go of unhelpful thoughts, and keep them focused on the present task one item at a time. Additionally, acceptance skills might also aid you by helping you progress even though you feel panic about being about the fail miserably on the task. I think mindfulness-naive people might be more at risk of getting demoralized and basically half-ass their way through the rest of the test, if they feel that their performance is worse than expected.
Quality of the evidence
My main issue with Teper & Ingzlict’s study is drawing a casual inference between meditation training and improved executive control, i.e. the risk of committing the ex-post-facto fallacy. Since the study is a case-control study we can’t really know if meditation training caused the increased executive control or if individuals with better-than-average executive control are just more likely to enjoy meditation practices due to an innate prowess. I would image that you’d be more likely to give up meditation training if you have very low executive inhibition. However, other studies have shown that brief mindfulness training for meditation-naive subjects can improve executive control. So in it’s research context the results of this study is very interesting, even though I’d prefer to see more high constraint study designs.
R, & Inzlicht M (2012). Meditation, mindfulness, and executive control:
The importance of emotional acceptance and brain-based performance
monitoring. Social cognitive and
affective neuroscience PMID: 22507824
Garner, F., & Moore, Z. (2004). A mindfulness-acceptance-commitment-based approach to athletic performance enhancement: Theoretical considerations Behavior Therapy, 35 (4), 707-723 DOI: 10.1016/S0005-7894(04)80016-9