Scientific studies of meditation and other forms of contemplative experience
have only recently become a subject of scientific interest within the
last half century. In 1931 Kovoor Behanan, an Indian graduate student
in psychology at Yale, was awarded a Sterling Fellowship to undertake
what has since been recognized as the first empirical study of yoga
and meditation. Supported in this research by Walter Miles, an eminent
professor of psychology, Behanan wrote a book about yoga that described
quantitative studies of his own yogic breathing. During 72 days of experiments
at Yale, he found that one breathing exercise, or pranayama,
increased his oxygen consumption by 24.5%, a second by 18.5%, and a
third by 12% (Behanan,
1937, Miles,
1964). This study helped stimulate interest in meditation research
by showing that the physiological effects of yoga could be examined
in the laboratory (Behanan,
1937). Unlike many tales by travelers to the East, Behanan's straightforward,
well-observed account of his laboratory research was free of exaggeration
and mystification.
Behanan also studied Indian yogis. He was guided in this work by Swami
Kuvalayananda, who promoted yoga research at a center for meditation
practice he founded in the 1920s at Lonavla, a hill station near Bombay.
Kuvalayananda developed a system of physical culture that included asanas
and pranayamas, and he established a yogic therapy for many afflictions.
His work was supported by several Indian states, two provincial governments
of British India, Indian health agencies, and American foundations.
For many years, the results of his laboratory research were published
in a quarterly journal, Yoga Mimamsa, which also provided instruction
on postures, breathing exercises, and other disciplines. Many people
interested in yoga research visited Lonavla, among them psychologists
Basu Bagchi of the University of Michigan Medical Center and M. A. Wenger
of UCLA, who gave new impetus to meditation studies in the 1950s. From
the 1920s into the 1960s, Swami Kuvalayananda did much to promote the
scientific study of yoga.
In 1935 a French cardiologist, Therese Brosse, took an electrocardiograph
to India and studied yogis who said they could stop their heart. According
to Brosse's published report, readings produced by a single EKG lead
and pulse recordings indicated that the heart potentials and pulse of
one of her subjects decreased almost to zero, where they stayed for
several seconds (Brosse, 1946). Her finding was criticized, though,
by Wenger, Bagchi, and B. K. Anand in their later, more thorough studies
of yogic adepts (see below). Brosse also studied a yogi who was buried
for ten hours, and described other examples of self-control she had
witnessed. Like Behanan and Swami Kuvalayananda, she helped promote
the idea that yogic feats could be studied with scientific instruments.
The instrumented study of yogic functioning was expanded by Bagchi,
Wenger, and Anand. Anand was then chairman of the Department of Physiology
at the All-India Institute of Medical Sciences in Delhi. Their landmark
studies during the late 1950s were reported in American scientific journals.
Along with studies of Zen masters by Akira Kasamatsu and Tomio Hirai in Japan (see below) the Indian studies gave new
momentum to meditation research. For five months in 1957, Bagchi and
Wenger traveled through India with an eight-channel electro-encephalograph
and accessory instruments to record respiration, skin temperature, skin
conductance, and finger blood-volume changes. During their trip they
established experiments in Calcutta, Madras, Lonavla, and New Delhi,
and conducted further tests in homes and a mountain retreat (Bagchi
and Wenger, 1957;
Wenger and Bagchi, 1961;
Wenger et al., 1961;
Bagchi, 1969).
Among the subjects they examined, one could perspire from his forehead
upon command in his freezing Himalayan retreat; a second could regurgitate
at will to cleanse himself (Wenger & Bagchi, 1961). Three others
altered their heartbeats so that they could not be heard with a stethoscope,
though EKG and plethysmographic records showed that their hearts were
active and their pulses had not disappeared. [28]
In tests to compare relaxation in a supine position with seated meditation,
Bagchi and Wenger found that four yoga students had faster heart rates,
lower finger temperatures, greater palmar sweating, and higher blood
pressure during meditation, though their respiration rates were reduced.
Five yogis given similar tests exhibited even faster heart rates, lower
finger temperatures, greater palmar conductance, and higher blood pressures
during meditation than the students, though their breathing was slower.
Such differences suggested that for these yogis meditation was an active
rather than a passive process (Wenger and Bagchi, 1961).
Bagchi and Wenger also studied the effects of breathing exercises and
found that some of their subjects, especially experienced ones, could
produce bidirectional changes in every autonomic variable that the experimenters
measured. Though the two psychologists found that their subjects exhibited
some dramatic physiological changes, they were cautious in drawing conclusions
about yogic claims in general. "Direct voluntary control of autonomic
functions is probably rare among yogis," they wrote. "When
such control is claimed, intervening voluntary mechanisms are usually
employed." They made this qualification, however: "We have
met many dedicated yogis who described experiences to us that few Western
scientists have heard of and none has investigated. It is possible that
the mere presence of a foreigner precludes optimum results"(Wenger
and Bagchi, 1961).
Other researchers have confirmed the discovery by Bagchi and Wenger
that some subjects exhibit more than one pattern of physiological activity
during their yogic practices. N. N. Das and H. Gastaut studied seven
Indian yogis, who registered no muscular electrical activity during
periods of complete immobility though their heart rates accelerated
in almost perfect parallel with accelerations of their brain waves during
moments of ecstasy. The most accomplished among these seven subjects,
moreover, exhibited "progressive and very spectacular modifications" in their EEG records during their deepest meditations, including
recurrent beta rhythms of 18-20 cycles per second in the Rolandic area of the
brain, a generalized fast activity of small amplitude as high as 40-45
cycles per second with occasional amplitudes reaching 30 to 50 microvolts,
and the reappearance of slower alpha waves after samadhi, or
ecstasy, ended. In summarizing their study, Das and Gastaut concluded
that:
The modifications [we] recorded during very deep meditation are much
more dramatic than those known up till now, which leads us to suppose
that western subjects are far from being able to attain the yogi state
of mental concentration.
It is probable that this supreme concentration of attention . . .
is responsible for the perfect insensibility of the yogi during samadhi;
this insensibility, accompanied by immobility and pallor often led
people to describe this state as sleep, lethargy, anesthesia, or coma.
The electroencephalographic evidence here described contradicts such
opinions and suggests that a state of intense generalized cortical
stimulation is sufficient to explain such states without having to
invoke associated processes of diffuse or local inhibition (Das and
Gastaut, 1955)
Das and Gastaut's conclusion does not contradict the widespread findings
of subsequent meditation studies that many or most meditators experience
the trophotropic or relaxation response described by E. Gellhorn, W.
Kiely, Herbert Benson, and other researchers (Gellhorn
and Kiely, 1972; and Benson,
1975). Most subjects in meditation studies do not experience yogic
ecstasy and so do not exhibit the cortical excitement that Das and Gastaut
observed. Furthermore, different kinds of religious practice produce
different types of experience accompanied by different types of physiological
change. Kasamatsu and Hirai's Zen masters, for example, exhibited high-amplitude
alpha and theta waves, not beta waves, during their deepest meditations
(see below).
Further evidence that contemplative practice produces different physiological
profiles was provided by B. K. Anand, G. S. Chhina, and Baldev Singh,
who found that four yogis exhibited persistent alpha activity with increased
amplitude during trance. These four yogis exhibited no alpha-wave blocking
when they were bombarded with loud banging, strong lights, and other
sensory stimuli, and two of them showed persistent alpha activity while
holding their hands in ice-cold water for forty-five to fifty-five minutes
(Anand, Chhina, and
Singh, 1961a). The yogis in this experiment exhibited physiological
differences during meditation from at least two other groups of accomplished
meditators. They did not exhibit alpha blocking in response to strong
stimuli, in contrast to the Zen masters studied by Kasamatsu and Hirai
(see below). Nor did they exhibit the beta waves
that appeared on the EEGs of Das and Gastaut's subjects. The difference
from the Zen masters probably resulted from a basic difference in focus
between the two groups, the yogis having withdrawn their attention from
external stimuli, whereas the Zen masters remained aware of their external
environment. Their difference from Das and Gastaut's yogis, on the other
hand, might have been due to differences between their styles of meditation,
the conditions of the experiments, or the qualities of their experience.
The strong stimuli Anand gave his subjects, for example, may well have
prevented the more ecstatic absorptions experienced by Das and Gastaut's
yogis. The published reports of the Das-Gastaut and Anand-Chhina-Singh
experiments do not provide enough detail to fully explain their different
results, but they remind us that there are different kinds of contemplative
experience. Roland Fischer, Julian Davidson, and other researchers have
proposed some ways in which internal states might be correlated with
different physiological profiles (Fischer,
1971; and Davidson,
1976).
In a study published in 1958, the Indian researchers G. G. Satyanarayanamurthi
and B. P. Shastry described a yogi whose heart kept beating for thirty
seconds even though his radial pulse could not be felt and his heart
could not be heard with a stethoscope. This yogi's EKG showed no abnormalities,
moreover, and finger plethysmography showed that his pulse was present
though greatly reduced. The two researchers claimed that fluoroscopy
conducted while the yogi was lying down showed that for several 30-second
periods the beating of his heart was just a "flicker along the
left border below the pulmonary conus and in the apical segment of the
left ventrical." They concluded that he achieved this control through
the Valsalva maneuver. [29]
Elmer and Alyce Green, with their colleagues at the Menninger Foundation
in Topeka, Kansas, also observed exhibitions of yogic heart control.
Their subject, Swami Rama, while sitting perfectly still, produced an
atrial flutter of 306 beats per minute that lasted for sixteen seconds.
During a fibrillation of this kind, a section of the heart oscillates
rapidly while its chambers do not fill and its valves do not work properly,
but Swami Rama gave no sign that the maneuver caused him any pain or
heart damage. The swami also produced an IIF difference between the
left and right sides of his right palm. While he did this, the left
side of his palm turned pink and the right side gray (Green and Green,
1977).
Yogis frequently use abdominal contractions to slow their heart rate
rather than intervening more directly through the central nervous system.
Curiously, though, an earlier study had examined a man with no yogic
training at all who could stop his heart without such maneuvers, simply
by relaxing and "allowing everything to stop." By this procedure,
he could induce a gradual slowing of his pulse until he started to faint,
at which point he would take a deep breath. When EKG tests showed that
his heartbeat did indeed disappear, the doctor who examined him concluded
that the man's cardiac arrest was induced through some mechanism which,
although under voluntary control, is not known to the patient himself.
Careful observation did not reveal any breath-holding or Valsalva maneuver.
Apparently the patient simply abolished all sympathetic tone by complete
mental and physical relaxation (McClure, 1959).
Like heart stopping, the live burial of yogis has excited the interest
of several researchers. A physician, Rustom Jal Vakil, published an
account in the British journal Lancet of such a confinement that
was witnessed by some 10,000 people near Bombay in February 1950. According
to Vakil, an emaciated sadhu named Ramdasji sat cross-legged in a subterranean
216-cubic-foot cubicle and remained there for sixty-two hours. His pulse
remained steady at eighty beats per minute; his blood pressure was 112/78;
and his respiratory rate fluctuated from eight to ten breaths per minute.
Though he had some scratches and cuts, Vakil wrote, Ramdasji appeared "none the worse for his grueling experience.'' (Vakil, 1950).
In June 1956, a more closely observed study of yogic confinement was
conducted under the auspices of the All-India Institute of Mental Health
in Bangalore with a Hatha yogi, Krishna Iyengar. Hoenig, a psychiatrist
from the University of Manchester, witnessed the experiment and described
it in a review of yoga research published in 1968 (Hoenig, 1968).
According to Hoenig's report, a pit some two by three by four feet was
dug on the institute's grounds and covered with wire meshing, a rubber
sheet, and cotton carpet. An electrode junction box connected to an
EEG and an EKG was placed in the pit along with instruments to measure
temperature and concentration of gas. The yogi was confined for nine
hours. When he was released he immediately walked about the grounds,
according to Hoenig's firsthand account, and demonstrated athletic feats
including a headstand with his legs in the lotus position. The percentage
of carbon dioxide in the air in his enclosure, which was 1.34% at the
beginning of the experiment, was only 3.8% at the end, lower than would
normally be expected. Iyengar's heart rate gradually slowed from 100
to 40 beats a minute in recurring twenty- to twenty-five-minute cycles,
but his EKG record did not register any other abnormality and the cycles
did not coincide with his breathing or brain-wave patterns. The yogi's
EEG showed a normal waking record for the full nine hours, characterized
by a stable alpha rhythm of 50 microvolts with no evidence of sleep
or interference caused by physical movement. From these records, the
experimenters concluded that their subject lay motionless and wide awake,
without the active cognition that would have reduced or eliminated his
alpha rhythm. Iyengar said he had maintained the shavasana, or
corpse pose, using ujjaya breathing while remembering the names
of God. He was surprised that his heart had speeded and slowed, and
could not explain why it had done so. It beat normally, however, after
the experiment.
Because the earthen pits used in most yogic confinements leak oxygen
and carbon dioxide, Anand, Chhina, and Singh tested a yogi named Ramanand
in an airtight glass and metal box, once for eight hours and again for
ten hours. The yogi's average oxygen use during the first experiment
decreased from the basal rate of 19.5 liters per hour to 12.2, and during
the second experiment to 13.3 liters per hour. His carbon dioxide output
went down during both experiments. Ramanand, moreover, did not exhibit
any rapid breathing or speeded heart rate as the oxygen in his box diminished
and carbon dioxide increased. "Sri Ramanand Yogi could reduce his
oxygen intake and carbon dioxide output to levels significantly lower
than his requirements under basal conditions," Anand and his colleagues
wrote. "It appears from this study that [he] could voluntarily
reduce his basal metabolic rate on both occasions he went into the box." [30]
During a remarkable experiment reported by L. K. Kothari and associates,
a yogi was buried for eight days in an earthen pit and connected by
leads to an EKG in a nearby laboratory. After the pit was boarded up,
the subject's heart rate sometimes went as high as fifty beats per minute,
until a straight line appeared on the EKG tracing when the yogi had
been in the pit for twenty-nine hours. There had been no slowing of
his heart immediately before the straight line appeared, nor any sign
of electrical disturbance, but the experimenters proceeded with certainty
that their subject had not died. Suspecting that their EKG leads had
been deliberately or accidentally disconnected, they checked their machine
and continued to monitor its tracings. To their astonishment, it started
to register electrical activity some seven days later, about a half
hour before the yogi's scheduled disinterment. "After some initial
disturbance," they wrote, "a normal configuration appeared.
The [speeded heart rate] was again there but there was no other abnormality." When the pit was opened, the yogi was found sitting
in the same posture he had started in, but in a stuporous condition. In accounting for his
remarkable EKG record, the experimenters argued that a disconnection
of the EKG lead would have produced obvious markings on the tracings
in their laboratory, as they found when they tried to simulate ways
in which the yogi might have tinkered with it.
Furthermore, the yogi was ignorant about such machines, and the pit
was completely dark. If the machine had malfunctioned in some way they
could not ascertain, it seemed an extraordinary coincidence that it
started again just a half hour before their subject's scheduled release.
Apparently, the yogi was operating with some kind of internal clock
that did not depend upon the daily cycles of light and darkness, for
the most likely cause of the straight line on his EKG tracing was a
dramatic decrease in the activity of his heart. Kothari and his colleagues
finally could not account for this remarkable cardiac record (Kothari
et al., 1973).
In a study that attracted much attention among meditation and biofeedback
researchers during the 1960s, Akira Kasamatsu and Tomio Hirai, physicians
at the University of Tokyo, studied the EEG changes exhibited during
meditation by Zen teachers and their disciples (forty-eight in all)
from Soto and Rinzai centers in Japan. For experimental control, they
studied the EEGs of twenty-two subjects with no experience at meditation.
They made EEG recordings; recorded their subjects' pulse rates, respiration,
and galvanic skin response; and tested their responses to sensory stimuli
during meditation. The recordings on the Zen monks were made during
a weeklong retreat, or sesshin, at a Zendo, except for a few
tests at the experimenters' laboratory. The Zen teachers and their most
experienced students exhibited a typical progression of brain-wave activity
during meditation, which Kasamatsu and Hirai divided into four stages:
- Stage 1: Characterized by the appearance of alpha waves in spite
of opened eyes.
- Stage 2: Characterized by an increase in amplitude of persistent
alpha waves.
- Stage 3: Characterized by a decrease in alpha frequency.
- Stage 4: Characterized by the appearance of rhythmical theta trains
(Kasamatsu and Hirai, 1966).
Not all four stages were evident in every Zen practitioner, nor in
any of the controls, but a strong correlation existed between the number
of stages a given student exhibited and that student's length of time
in Zen training. This correlation was supported by a Zen teacher's evaluation
of each student's proficiency. The teacher ranked the students in three
levels, without seeing their EEG records, and his rankings correlated
well with Kasamatsu and Hirai's assessment of their EEGs.
The Kasamatsu-Hirai study also revealed significant differences between
four Zen masters and four control subjects in their response to repetitive
click stimuli. Like the Zen masters, the controls exhibited a blocking
of alpha when a click sound first occurred, but they gradually became
habituated to such stimuli so that their brain-wave activity no longer
responded when a click was made. The Zen masters, however, did not become
habituated, but continued to exhibit blocking as long as the stimuli
continued. This finding indicates that Zen practice promotes a serene,
alert awareness that is consistently responsive to both external and
internal stimuli (Kasamatsu
et al., 1957; Hirai,
1960; and Kasamatsu
and Hirai, 1963).
Though people testified under oath before the Congregation of Rites
that they had seen Saint Teresa of Avila or Saint Joseph of Cupertino
defy gravity, no scientific studies have recorded instances of levitation.
There are at least three possible reasons for this lack of evidence.
First, of course, it might be that levitation has never happened. Second,
the contemplative traditions might have lost their power to evoke the
phenomenon. Third, levitation might only occur during rare and spontaneous
ecstasies that cannot be programmed to meet the requirements of a scientific
experiment. Superordinary lifting from the ground, if it in fact occurs,
would require an improbable set of circumstances which a scientist would
be lucky to witness. Levitation, like other holy powers, would have
to be caught "in the wild." In a laboratory, with wires attached
to his head and a thermometer up his rectum, a yogi or lama is unlikely
to exhibit a capacity that is rare in any case. In studies of extraordinary
functioning there is a trade-off between robust results and scientific
precision. Uninhibited by recording machines and safety rules, for example,
the Maharaja Runjeet Singh could bury Haridas for forty days. More recent
studies of yogic confinement, however, have been constrained by procedural
controls and humane considerations.
Furthermore, there is often a disjunction between a scientist's attitude
toward exceptional powers and an adept's ideas about them. Elmer Green,
for example, described differences he had with the healer Jack Schwartz
in interpreting Schwartz's intuitive diagnosis of illness. According
to Schwartz, the question was:
Are the auras one sees always radiatory patterns of energy from the
human body . . . or are they automatic mental projections of one kind
or another that are used psychologically to interpret a "knowing"?
Sometimes when we "know" something in this way we tend to
"see" it in the same way that we see a memory (Green and
Green, 1977, p. 240).
Green was sympathetic to Schwartz, however, realizing that a scientist's
constant doubt can inhibit or destroy a psychic's intuitions. This fundamental
difference between scientists and psychics, Green wrote:
Need not cause problems if each takes time to understand the framework
in which the other necessarily operates. If the psychic tries to pull
apart every perception in order to find out if it is incorrect, so
as to better determine the "truth," what is most likely
to be pulled apart is the faculty of "seeing." The talent
for perceiving might well fade away. On the other hand, if scientists
stopped trying to find alternate explanations for the facts, they
might get lost in a maze of [incoherent] ideas. For both scientists
and mystics, however, the area of facts rather than interpretations
is common ground. Excluding the opinions of fanatics, most of the
arguments that we are aware of between the two camps have revolved
around interpretations. Because psychics almost always have idiosyncratic
factors in their frames of reference, scientists often do not understand
them. And psychics do not understand what seems to them to be a destructive
attitude on the part of scientists (Green and Green, 1977, p. 242).
Sympathy between scientists and adepts was evident in Swami Kuvalayananda's
projects noted above, and in other experimenter-subject teams described
in the preceding pages. Even the stern mutual challenge between Haridas
and Maharaja Runjeet Singh exhibited an exemplary, if somewhat perverse,
cooperation. Productive study of extraordinary functioning requires
understanding between accomplished subjects and imaginative experimenters.
Meditation research increased dramatically during the 1970s and 1980s,
particularly in the United States. This burgeoning effort was stimulated
in part by the studies of yogis and Zen masters noted in the previous
section, and in part by the publication of landmark studies by Herbert
Benson and Keith Wallace in Science, the American Journal
of Physiology, and Scientific American between 1970 and 1972
(Wallace, 1970; Wallace et al., 1971b; Wallace and Benson, 1972). The
Transcendental Meditation Society supported much of this work, though
its enthusiastic claims and advertising efforts caused doubts among
some researchers about the highly favorable outcomes in studies it sponsored
(Shapiro, 1982). These doubts led to further research, which has either
contradicted, tempered, or confirmed the TM-sponsored claims. Since
the early 1970s, more than a thousand studies of meditation have been
reported in English-language journals, books, and graduate theses. The range of outcomes included in this research has grown considerably
since the studies of yogis and Zen masters by Bagchi, Wenger, Kasamatsu,
and Hirai. Cardiovascular, cortical, hormonal, and metabolic changes,
several behavioral effects, and alterations of consciousness resulting
from meditation have been explored in recent years. The medical instrumentation,
psychological tests, and methods of analysis used in such experiments
have been improved, and the range of subject populations has been enlarged
to include different kinds of subject groups. This growth in sophistication
of method is gradually improving our scientific understanding of meditation
in ways that complement the insights contained in the traditional contemplative
literature. However, the overall picture of results on the subject of
meditation produced by modern research remains uneven. Some effects
have appeared consistently, but others have not.
The apparent inconsistencies defining the effects of meditation can
be accounted for in various ways. Some physiological processes, perhaps,
are unaffected by meditation, no matter how proficient or experienced
the meditator might be; or perhaps they are affected to an insignificant
degree. For some changes, such as amino acid concentrations in the blood,
there has not been enough research to establish a consistent picture,
partly because there has not been as much interest in these variables
as in the effect of meditation on blood pressure, heart rate, and other
indices that have an obvious bearing on health. Taking blood samples
during meditation, moreover, is harder to accomplish than recording
blood pressure or skin responses.
Individual differences also present a special problem for understanding
the results of meditation studies, because subject populations have
included people of both sexes, all ages, various levels of education,
and different kinds of social background. Many subjects have been college
students with no previous experience at meditating; others have been
recent converts to religious groups; but only a few have been highly
skilled in spiritual practice. The incentives to concentrate during
experimental sessions have also varied. Some subjects have wanted success
for religious or other reasons, while others seem not to have been well
motivated. And differences between meditation styles also complicate
the results of such research. Though most studies have used some type
of quiet concentration, some have used active methods such as rapid
breathing. Julian Davidson, Roland Fischer, and others have distinguished
between two classes of meditation, those that relax and those that excite,
associating their effects with the trophotropic and ergotropic conditions
of the central nervous system modeled by Gellhorn and Kiely (Davidson,
1976; Fischer, 1971, 1976; Gellhorn and Kiely, 1972).
The results of scientific research on the subject of meditation are
accumulating now, forming a publicly accessible body of empirical data
that can serve generations to come. Unfortunately, however, these data
are derived mainly from beginning practitioners of meditation, and taken
as a whole do not reflect the richness of experience described in traditional
contemplative teachings. They are also limited by the conventional scientific
insistence that results be repeatable. Certain important experiences
occur only rarely in meditation, and a science that disregards them
loses important empirical results. For these reasons, contemporary research
does not illumine the full range of experience described in the contemplative
scriptures and the oral traditions from which they come. Modern studies
give us only a first picture of the foothills, with a few glimpses of
the peaks. Still, what they give us corresponds in several ways with
traditional accounts.
