"Untraining" The Brain: Meditation and Executive Function

In a fascinating review of the cognitive neuroscience of attention, authors Raz and Buhle note that most research on attention focuses on defining situations in which it is no longer required to perform a task - in other words, the automatization of thought and behavior. Yet relatively few studies focus on whether thought and behavior can be de-automatized - or, as I might call it if I were asking for trouble, deprogrammed.

What would count as deprogramming? For example, consider the Stroop task, where subjects must name the ink color of each word in a list of color words (e.g., "red" might be written in blue ink, and the task is to say "blue" while suppressing the urge to automatically read the word "red"). Reaction time is reliably increased when subjects name the ink color of incongruent words ("red" written in blue ink) relative to congruent words ("red" written in red ink), presumably because the subjects need to inhibit their prepotent tendency to read the words. But is it possible to regain control over our automatized processes - in this case, reading - and hence name the ink color of incongruent words as quickly as we would name the ink color of congruent or even non-words?

The Role of Meditation in "Deprogramming"

Some meditative practices purport to reverse automatization of thought and behavior, such as transcendental or mindfulness meditation, and indeed there is some evidence that these techniques can reduce interference on the Stroop task.

For example, in a study by Alexander, Langer, Newman, Chandler, and Davies from the Journal of Personality and Social psychology, 73 elderly participants were randomly assigned to either no treatment, a transcendental meditation program, mindfulness training, or relaxation training. Note that transcendental and mindfulness techniques are frequently described as inducing a state of "pure consciousness" during which the mind is "silent," and yet not empty: in this state, meditators claim to be intensely aware only of awareness itself. Less cryptically, this state is also referred to as "restful alertness." Subjective reports aside, this state is also accompanied by increased interhemispheric phase coherence in frontal alpha EEG (Alexander, 1982, cited by Alexander et al, 1989), the amount of which is highly correlated with subsequent measures of fluid intelligence (Dillbeck & Vesley, 1986, cited by Alexander et al, 1989).

Those subjects who underwent training met with instructors for 30 minutes each week, and were instructed to train 20 minutes twice daily for 2 months. Transcendental meditation (TM) required the use of a mantra, and other specific techniques, as described in Maharaishi (1969, cited by Alexander et al., 1989). Mindfulness training (MF) involved a structured word generation exercise, in which subjects must think of a word, then think of another word beginning with the last letter of the previous word, and then repeat this process throughout training without ever repeating a word. Subsequently subjects were afterwards simply asked to generate words belonging to specific categories, and then undergo a fairly generic "creative thinking" exercise (think of novel uses for various objects, but don't daydream). Mental relaxation simply involved focusing on a pleasant or relaxing thought.

Various statistical procedures were also used to equate instructor effectiveness, subjects' expectancy of benefits, or regularity of practice; the study was double-blind, in that the instructors and the subjects were unaware of the hypotheses being tested. After training, subjects were tested on a variety of cognitive and personality tests, including associate learning, word fluency, depression, anxiety, locus of control, and of course Stroop. Results showed that the TM and MF groups together scored significantly higher on associate learning and word fluency than the no-training and relaxation-training groups. Perhaps most surprisingly, over a 36 month period, the survival rate for the TM and MF groups was significantly higher than for the relaxation and no-training groups (p<.00025). But more to the point, both TM and MF scored higher than MR and no-training on the Stroop task (p<.1; one-tailed test).

The Role of Hypnotism in "Deprogramming"

According to Raz & Buhle, the studies showing effects of hypnotism on reducing automaticity in the Stroop task are even more compelling than those that use meditation. Several of these studies are written by Raz himself, such as a fascinating article by Raz, Fan & Posner from a 2005 issue of the prestigious Proceedings of the National Academy of Sciences.

In this study, the authors used fMRI and scalp EEG to record the neural correlates of Stroop performance. Eight (4 male, 4 female) of the sixteen participants were assigned to the experimental group, and had been previously selected from a pool of 95 potential participants for being "highly hypnotizable" (as determined through administration of the Harvard Group Scale and the Stanford Hypnotic Susceptibility Scale), whereas the control subjects all scored very low on these tests.

After a "standard hypnotic induction" (described in full on page 6, here), subjects were told the following:

''Very soon you will be playing the computer game. Every time you will hear my voice talking to you over the intercom system, you will immediately realize that meaningless symbols are going to appear in the middle of the screen. They will feel like characters of a foreign language that you do not know, and you will not attempt to attribute any meaning to them. This gibberish will be printed in
one of four ink colors: red, blue, green, or yellow. Although you will only be able to attend to the symbols' ink color, you will look straight at the scrambled signs and crisply see all of them. Your job is to quickly and accurately depress the key that corresponds to the ink color shown. You will find that you can play this game easily and effortlessly. As soon as the scanning noise stops, you will relax back to your regular reading self.''

Incredibly, behavioral data showed that the standard stroop effect (again, a cost in reaction time when reading incongruent words relative to congruent words) was completely eliminated in terms of both reaction time and accuracy for both the experimental and control groups. [ERP analyses revealed decreased visual activity under suggestions , including suppression of early visual effects commonly known as the P100 and N100, while fMRI showed reductions in a variety of regions including anterior cingulate]. The bottom line, then, is that even strong suggestion is enough to accomplish some amount of deprogramming, as measured through the Stroop task.

Originally posted on 7/18/2006.