Monday, December 14, 2009

Transcendental Meditation: The Alpha Coherence Lie

In keeping with some of the questions raised in the previous post on TM teachers, and the misinformation they routinely disseminate, I'd like to talk a bit about the prevalent TM claim that TM, and esp. the TM - Sidhi programme, that these meditation techniques:

1.  Produce alpha coherence in a range that is significant, important, helpful and/or indicates a "unique" or "higher state of consciousness".


2. That there is an actual increase in Alpha power during Transcendental Meditation.

As early as the 1980's independent scientists were exploring the significance of EEG claims made by Transcendental Meditation researchers. In 1983 what researchers found was that EEG alpha waves (often simply "alpha") changed during meditation, when compared to baseline. What they weren't sure of was this change significant when utilizing appropriate controls? A study was performed on long term TM meditators and novice TM meditators and then compared to appropriate controls.

What the researchers found was that when appropriate controls were used, instead of alpha increasing during TM, it actually decreased: leaving the student at a lower level of alpha after their meditation session:

So what's the big deal about "alpha"? Is their a big deal about alpha?

The pioneer of EEG interpretation Barbara Brown was very clear when it comes to drawing any conclusions on alpha waves:

"Concluding anything about alpha is perilous."
...yet numerous TM studies try to do just this: associate alpha coherence with "higher states of consciousness". And just like Brown's warning, this is a perilous claim indeed, as it turns out: there's really nothing remarkable about alpha or alpha coherence in the range found in Transcendental Meditation meditators.

It might help to explain a little bit about the now obsolete measurement known as "EEG coherence" and what it actually is. Coherence, when referring to EEG waves, is when EEG waves at different sites in the cerebral cortex are "in synch". This is also known as "spectral covariance". "Coherence is the frequency correlation coefficient, and represents the degree to which the frequency profiles of two distant areas of the head, as reflected in the electrical signals detected by scalp electrodes, are similar." The reason this is no longer a helpful form of measurement is that coherence is a measure that does not separate the effects of amplitude and phase in the interrelations between two signals (1999, Jean-Philippe Lachaux, Eugenio Rodriguez, Jacques Martinerie, and Francisco J. Varela ).  

EEG coherence, particularly in regard to slow brain wave (like alpha), it turns out is a common phenomenon. In order for the nervous system to do what it commonly does, neurons in the brain need to work together routinely, just as part of normal human functioning. As recent researchers commented: "It is important to keep in mind that such measures reflect extremely blurred and crude estimates of the synchronous processes of the ~10^11 neurons in a human brain."

It should therefore come as no surprise, when leading neuroscientists were writing a synopsis for the state of the art in meditation research in textbook form, they would comment on the unusual claims of Transcendental Meditation researchers. They pointed out that:

The dominant frequency in the scalp EEG of human adults is the alpha rhythm. It is manifest by a ‘peak’ in spectral analysis around 10 Hz and reflects rhythmic ‘alpha waves’ (Klimesch, 1999; Nunez et al., 2001). Alpha oscillations are found primarily over occipital-parietal channels particularly when the eyes are closed, yet alpha activity can be recorded from nearly the entire upper cortical surface. During wakefulness, it is a basic EEG phenomenon that the alpha peak reflects a tonic large-scale synchronization of a very large population of neurons.

...alpha frequencies frequently produce spontaneously moderate to large coherence (0.3-0.8 over large inter-electrode distance (Nunez et al., 1997)). The alpha coherence values reported in TM studies, as a trait in the baseline or during meditation, belong to this same range. Thus a global increase of alpha power and alpha coherence might not reflect a more “ordered” or “integrated” experience, as frequently claimed in TM literature...
 It's also common for TM advocates to claim that this common EEG coherence is "unique" to TM. It turns out this has not only been long known to be untrue, but TM advocates, TM teachers and TM researchers still state this as if it were true:

Other relaxation techniques have led to the same EEG profile and studies that employed counterbalanced control relaxation conditions consistently found a lack of alpha power increases or even decreases comparing relaxation or hypnosis to TM meditation (Morse et al., 1977; Tebecis, 1975; Warrenburg, Pagano, Woods, & Hlastala, 1980).

But what of claims that this magic alpha coherence is representative of a "higher state of consciousness" different or beyond waking, dreaming and sleeping? The researchers nipped this myth in the bud as well:

Similarly, the initial claim that TM produces a unique state of consciousness different than sleep has been refuted by several EEG meditation studies which reported sleep-like stages during this technique with increased alpha and then theta power (Pagano, Rose, Stivers, & Warrenburg, 1976; Younger, Adriance, & Berger, 1975).

 So not only does Transcendental Meditation not produce a unique and/or "higher" state of consciousness, it actually is within the waking-sleeping-dreaming cycle that healthy humans normally experience.

This observation jives with recent television reports of supposedly advanced TM meditators in Maharishi Vedic City which shows these "experts" often nodding off or asleep. Anecdotal reports of Golden Domes in Fairfield, IA indicate the many people sleeping and snoring has actually become a widespread problem. Certainly not what most people would consider a "higher" type of consciousness.

This global alpha increase is similar to other relaxation techniques. The passive absorption during the recitation of the mantra, as practiced in this technique, produces a brain pattern that suggests a decrease of processing of sensory or motor information and of mental activity in general. Because alpha rhythms are ubiquitous and functionally non-specific, the claim that alpha oscillations and alpha coherence are desirable or are linked to an original and higher state of consciousness seem quite premature.

It appears this "relaxation response" is common to numerous other relaxation techniques (meditation expert and former TM researcher Dr. Herbert Benson lists 8 common techniques which produce this same type of relaxation effect) but it does not (after 50 years of Transcendental Meditation practice) produce any "higher state of consciousness". Thus even wilder metaphysical claims such as "enlightenment" seem rather preposterous, in light of actual, independent research.

No higher states of consciousness here, please keep moving!

While there are forms of EEG coherence that do correspond to the states of consciousness seen in advanced yogis and meditators, these types of changes have not been found in Transcendental Meditation meditators.

More on these fascinating findings in a later post.


  1. Great explanation of alpha and TM's misapplication of the term in TM study designs!
    Thank you!
    g :)

  2. Great explanation of alpha and TM's misapplication of the term in TM study designs!
    Thank you!

    Thanks Gina. Glad to do it.