Increased stress tolerance in combat pilot selection test

 Zur deutschen Version    

 À la version Française

Research on Transcendental Meditation at the Swedish Air force

Sensitive test for selection of COMBAT pilots indicateD
profound effects on mental health

By Jaan Suurküla M.D.


Swedish Air force pilots were taught Transcendental Meditation (TM) and the effect was checked with a sensitive test used for selecting combat pilots. This test has been found to be a very reliable indicator of suitability for pilot duty, because it indicates the presence of defence mechanisms that makes a pilot unable to realistically grasp the situation, and therefore he can make fatal mistakes. Presence of defence mechanisms indicates anxiety-proneness (trait anxiety) and low stress tolerance.

Through TM-practice the pilots underwent improvements in one year that the best available psychotherapies can achieve only after about 20 years or more according to Thomas Neuman, the psychologist who designed the test.

The result indicates that TM can improve performance significantly under psychologically highly demanding conditions. Also, it indicates that TM can improve stress tolerance.

Differently from common stress treatment and prevention methods that are geared at changing stress-generating habits and behavior, TM affects the fundamental causes of stress sensitivity.


DMT-Neuman was developed by the military psychologist Thomas Neuman, Ph.D. from a test called the Defence Mechanism Test, developed by prof. Ulf Kragh. Neuman made fundamental changes and important improvements of the test, especially regarding the assessment of test results. Therefore, to distinguish it, we call it DMT-Neuman.

This test is an unusally sensitive and reliable method for detecting deeply rooted disturbances in the psychology, greatly superior to MMPI and other common tests for detecting trait anxiety. The most important reason is that, differently from such tests, it does not depend on verbal responses to questions. Actually DMT-Neuman was developed because MMPI and similar paper-pencil tests were not able to detect trait anxiety reliably.

Instead, DMT-Neuman detects disturbances in the perception of threatening pictures presented in a fraction of a second. Persons with with trait anxiety react with reality-distorting defence mechanims in such situations, and this is what the test detects. For an explanation of defence mechanisms, see Appendix.

Experience from the use of DMT in Sweden and other airforces has confirmed that this test is very effective in detecting persons with trait anxiety. For more, see “The Defence Mechanism Test”

research on subjects practising Transcendental Meditation

1. Pilot study on grounded pilots

Pilots who were found to have pathologically high DMT-Neuman points (risk category 4) were grounded. The Air force wanted to recover these pilots but they had been informed that the disturbances that DMT-Neuman indicated were such that it would take too many years with the best psychotherapy methods to cure them. An Air force officer, involved in the DMT-Neuman project, contacted the undersigned, who then was the medical advisor of the TM movement. The officer asked if I had some experience about the effects of TM on such disturbances and wondered if TM might promote a more rapid cure. I told him that, against my experience of considerable improvement in a number of cases with serious anxiety problems, I was certain that one year would be enough to produce a significant improvement in the grounded pilots. Five of these, who were eager to regain flight duty, were encouraged by the Air force officer in charge of the project to start TM.

After one year, the pilots were retested by Thomas Neuman. In all five he found pronounced improvement, from the highest risk group (IV) to the lowest risk group (I). Neuman commented that the result was sensational considering that the serious and profound disturbances the test revealed in these five cases takes decades of psychotherapy to improve.

2. Prospective study

Although the test was designed to reveal stable deep-seated disturbances, the question arose if there was a flaw in the test considering the dramatic improvement after one year of TM. So the Air Force set out a program to investigate whether DMT-Neuman might sometimes give errors, measuring more superficial and temporary disturbances.

Part of this program was to make a one year controlled study with TM (2). A group of 15 persons who had failed at Air Force pilot selection due to high DMT-Neuman scores was used. Eight of them were instructed in TM and seven were controls. The average DMT-Neuman score was similar in both groups (slightly higher among controls).

At retesting after one year, the DMT-Neuman scores of the control group were unchanged. The scores of the TM group had improved at an average with about ten points. The statistical significance of the change was p < .005. See the diagram above.


The results indicate that TM considerably improves deep-seated anxiety-causing personality disturbances (trait anxiety) of importance for combat pilot performance.

Additional info

Additional retesting studies were made, further confirming that DMT-Neuman detected a stable trait unless the persons did TM.

Thomas Neuman concluded that TM would be of great value for enabling “crashproof” and resilient performance in combat pilots. The introduction of TM as part of the standard training of Air Force pilots was therefore recommended by the Four Star Colonel Hedberg, responsible for national military flight security. But for reasons other than scientific, the High Commander of the Air Force did not decide to integrate TM in the training.


Altogether 13 persons were tested with DMT-Neuman by the Air force. They all underwent, without a single exception, improvements in one year that the best available psychotherapies can achieve only after about 20 times longer time or more – and only so in the best case. According to Thomas Neumann, this result is unprecedented in the history of psychology as such rapid improvement has not been achieved for this kind of deeply engrained disturbances.

The result indicates that TM improves performance under psychologically highly demanding conditions to a signifcant extent. Also, it indicates that TM can considerably improve stress tolerance in stress-prone people. Differently from common stress treatment and prevention methods, TM apparently affects the fundamental causes of stress sensitivity.

The result  concurs with other results on TM

The healing of profound psychological disturbances indicated by the DMT-Neuman study concurs well with other results indicating profound and rapid positive effects of TM on the psychology in cases where conventional methods have been ineffective. This includes considerable improvement of Chronic Post-Traumatic Stress Disorder in war veterans (4) and considerably reduced recidivism and reduced violence in severe criminals (5, 6). Increased stress tolerance has also been reported in a neural imaging study, finding 50% reduction in stress-related brain activity at the exposition to an intense stressor (14), for more, see Footnote 1.

Neurophysiological integration

The reason for its remarkable effectiveness seems to be that TM transforms the neurophysiological basis for psychological disturbances. A neurophysiological transformation towards higher integration of brain functioning is indicated by improvement of brain wave coherence (7, 8, 9, 10, 11) and alteration of Sensory Evoked Potentials (12).

The mechanism seems to be simple. By repeatedly experiencing increased integration of the brain activity at each meditation, the synaptic connections in the neural circuits and centers responsible for it become facilitated (more enabled to uphold those connections), bringing about an increasing ability to sustain more and more integrated brain activity. This is indicated by increasing brain wave coherence during activity.

Simply put, by repeated exposure to the orderly, integrated functioning that is present during TM, the brain learns to work in this way all the time. This apparently erases trauma-related brain connectivity and brings about the calm and stable mental functioning characteristic of high stress tolerance.

Additions Sept 2013:

  • Norwich military University in the US has, in order to increase “resilience”, that is tolerance to combat stress, introduced TM as part of the training of all officers.
  • In the last year two more studies confirm the Vietanm veteran study reporting a pronounced improvement in PostTraumaticStressDisorder. Presently a major study is being conducted on the effects on TM in PTSD, sponsored by Pentagon.

As the TM technique differs in important respects from meditation techniques and common stress reduction methods, there is no scientific basis for assuming that these results are applicable for other methods. An upcoming article on the brain physiology of different common techniques, confirms that TM is fundamentally different (13)


The test reveals deep-seated disturbances

The proneness to use psychological defence mechanisms in threatening situations caused by the presence of deeply seated, often early acquired memories of anxiety-provoking and otherwise traumatic or insecurity-causing experiences. These memories uphold an increased level of conscious or often subconscious anxiety.

When a situation somehow appears threatening to such a person, this anxiety tends to break through. As this is very uncomfortable, people tend unconsciously to develop habits to cope with anxiety provoking impressions. For this end they use defence mechanisms that transform the perception of them in such a was that it is no more anxiety-provoking (by distorting, belittling, ignoring etc). These habits may develop already in early childhood.

So, differently from secure and harmonious people who perceive the threat realistically and handle it adequately, the traumatized person is unable to do so because the defence mechanisms subconsciously distort the perception. This was found to be the major cause of flight accidents in the Swedish Air Force before DMT was introduced for pilot selection. The validity and sensitivity of this test is indicated by the fact that after its introduction, virtually no aircraft crashes have been caused by inadequate pilot action, while before that, about 20-30 crashes occurred annually.

Defence mechanims are remarkably common

Experience from DMT-Neuman studies has objectively verified the experience of psychologists that most people with these disturbances usually behave normally except for in threatening situations. The DMT-Neuman experience likewise confirms that common psychological tests for detecting such disturbances are far too insensitive. Barring reliable detection methods, their presence in the population has been greatly underestimated.

Experience from the use of DMT-Neumann indicates that few people are free from such disturbances (see Footnote 2). This concurs with experiences from developmental psychology that indicates that only a small proportion, a few percent at most, of the population has strong inner security, which is associated with absent trait anxiety and no defence mechanisms.

Experience from psychotherapy, which has been used since a hundred years, shows that it takes often 20-25 years or more to access and cure these deeply seated subconscious anxiety-provoking disturbances with psychotherapy.

Published Dec 2000.

Acknowledgement: I want to thank Air Force Colonel Lieutenant Folke P Sandahl, who supervised the Air Force DMT development project, for checking and confirming the correctness of this manuscript and for valuable suggestions and advice.


    1. Neural imaging found considerable increase of stress tolerance.  After 5 months of TM practice the signs of stress activation of the brain at exposition to intense pain was reduced by almost 50%. See image below.

  1. A High proportion of the population seems to have trait anxietyThe Airforce submits about 700-800 air force pilot training applicants to testing every year. The proportion that has passed DMT without showing a dangerous propensity for using defence mechanisms has been about 1 on 30-40, that is about 2,5-3%.However, it must be pointed out that the applicants were not a random sample from the population. It consisted of persons interested in undergoing pilot training. To be eligible, they had to be approved for military service by the drafting organization, which dismisses a significant proportion every year, including pepople with behavioral disturbances, alcohol- or drug-addiction and other problems. Also people with pronounced psychosomatic and stress-related disorders are eliminated.Therefore, the applicants for pilot training are most probably, at an average, more healthy than the population in general. This may indicate that the real proportion not having trait anxiety and the associated propensity for defence mechanisms is even less than 2,5%.


1. Sandahl, F.P.: The Defence Mechanism Test DMT as a Selection Instrument when Testing Applicants for Training as Military Pilots. Stockholm: Kungl Krigsvetenskapsakademiens Handlingar och Tidskrift (Proceedings and Journal of the Swedish Military Academy) nr 4, p 132-154, 1988.

2. Sandahl, F.P.: Inverkan av tm-utövning på neurotiseringsgrad. Stockholm: Läkartidningen (Journal of the Swedish Medical Association), vol 77, nr 34, p 2808 ff, 1980. (Swedish)

3. Eppley, K.R., Abrams, A.I., and Shear, J. Differential effects of relaxation techniques on trait anxiety: A meta-analysis. Journal of Clinical Psychology, 45(6), 957-974, 1989.

4. Brooks JS, Scarano T; Transcendental Meditation in the treatment of Post-Vietnam Adjustment. Journal of Counselling and Development 65:212-215. 1985.

5. Bleick CR, Abrams AI; The Transcendental Meditation Program and Criminal Recidivism in California, Journal of Criminal Justice 15:211-230, 1987.

6. Abrams AJ, Siegel LM, The Transcendental Meditation Program and rehabilitation at Folsom state prison: A cross validation study; Criminal Justice and behaviour 5:3-20, 1978; ALEXANDER CN, Doktorsavh vid Harvard University: “Ego development, personality and behavioural change in inmates practicing the Transcendental Meditation Technique or participating in other programs: A crossectional and longitudinal study. Dissertation Abstracts International 43:539B, 1982

7. Levine, P. Proceedings of the San Diego Biomedical Symposium sid 15 ff, 1976.

8. Dillbeck MC, Bronson EC, International Journal of Neuroscience 14:147-151, 1981.

9. Orme-Johnson DW et al Scientific Research on the Transcendental Meditation Program, Collected Papers vol 3:215, Vlodrop, Holland, MVU Press, 1989.

10. Nidich R et al, Scientific Research on the Transcendental Meditation Program, Collected Papers vol 4, Vlodrop, Holland, MVU Press, 1989, 2273-2277.

11. Travis, F. T. Eyes open and TM EEG patterns after one and eight years of TM practice. Psychophysiology 28(3a): S58, (Abstract), 1991.

12. Lyubimov, N. N. Mobilization of the hidden reserves of the brain. Program Abstracts of the 2nd Russian-Swedish Symposium “New Research in Neurobiology,” Brain Research Institute, Russian Academy of Medical Sciences, Moscow, May 19-21, 1992.

13. Travis F, Shear F. “Focused Attention, Open Monitoring and Automatic Self-Transcending: Categories to Organize Meditations from Vedic, Buddhist and Chinese Traditions”. Consciousness and Cognition, 2010. In Press.

14. Orme-Johnson, D. W., Schneider, R. H., Son, Y. D., Nidich, S., Cho, Z-H. Neuroimaging of Meditation’s Effect on Brain Reactivity to Pain. NeuroReport, August 23, 2006.

14. Orme-Johnson, D. W., Schneider, R. H., Son, Y. D., Nidich, S., Cho, Z-H. Neuroimaging of Meditation’s Effect on Brain Reactivity to Pain. NeuroReport, August 23, 2006Brief summary. In Swedish: Hjärnforskare fann kraftigt minskad stressreaktion vid smärta hos TM-utvövare