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hypnotic phenomena, spiritualist mediums, classical notions, state of consciousness

What is hypnotic trance? Does it provide unusual physical or mental capacities?

Author: Todd I. Stark

From the FAQ regarding the scientific study of hypnosis by Todd I. Stark

© 1993.

2.1 'Trance;' descriptive or misleading?

Most of the classical notions of hypnosis have long held that
hypnosis was special in some way from other types of interpersonal
communication and that an induction (preparatory
process considered by some to be neccessary in the production
of hypnotic phenomena) would lead to a state in which the subject's
awareness and behavioral responding was some how altered from the

The name historically most commonly associated with this altered
state of functioning is 'trance,' a term shared by the description
of the activities of certain spiritualist mediums and other phenomena
that some psychologists might refer to as 'dissociative,' because
something about the individual's personality appears split off
from the usual response patterns to the environment.

Trance, for reasons we shall examine here, can be a very misleading
term for what is going on in hypnosis, since it is not neccessarily
a sleep or stupor as some of traditional connotations of the term
trance imply.

But 'trance' is so ubiquitous in literature that it might serve
us to be familiar with its uses and the issues underlying it,
and to use it as a starting point.

There were a great many experimental and clinical studies done
to try to determine what might be unique about hypnosis, as opposed
to other kinds of situations (e.g. people simply being motivated
to comply with the hypnotist; i.e. hypnotic simulators). Outward
behavioral signs and virtually every physiological measurement
reported in hypnosis differ seemingly not at all from the usual
waking state of consciousness, as the non-state theorists contend.

Years of careful analysis by a number of researchers were mostly
fruitless in turning up any reliable physiological correlates
of hypnosis that were not (1) related to the relaxation associated
with the induction (most inductions, but not all, involve physical
relaxation); or (2) an obvious result of a suggestion rather than
the mechanism responsible for the observed suggestibility
assumed to some degree unique to hypnotic trance.

At least one theory of hypnosis considers it equivalent to a form
of relaxation. Comparison of various relaxation methods with regard
to both objective measurements and subjective reports indicate
deep relaxation accompanying some hypnosis but not all hypnosis.
Hypnotic suggestibility is apparently not limited to relaxed states.

In Morse, Martin, Furst, & Dubin, "A physiological and
subjective evaluation of meditation, hypnosis, and relaxation,"
from Journal Psychosomatic Medicine. 39(5):304-24, 1977 Sep-Oct,
a representative study of relaxation was done.

Subjects were monitored for respiratory rate, pulse rate, blood
pressure, skin resistance, EEG activity, and muscle activity.
They were monitored during the alert state, meditation (TM or
simple word type), hypnosis (relaxation and task types), and relaxation.
Ss gave a verbal comparative evaluation of each state. The results
showed significantly better relaxation responses for the relaxation
states (relaxation, relaxation- hypnosis, meditation) than for
the alert state. There were no significant differences between
the relaxation states except for the measure "muscle activity"
in which meditation was significantly better than the other relaxation
states. Overall, there were significant differences between task-hypnosis
and relaxation-hypnosis. No significant differences were found
between TM and simple word meditation. For the subjective measures,
relaxation-hypnosis and meditation were significantly better than
relaxation, but no significant differences were found between
meditation and relaxation-hypnosis.

There are a few more recent attempts to find physiological correlates
of hypnotic suggestibility. One of these was EEG research by David
Spiegel of Stanford, published in the Journal of Abnormal Psychology,
94:249-255, by Spiegel, Cutcomb, Ren, and Pribram, (1985) "Hypnotic
Hallucination Alters Evoked Potentials." Spiegel seemed to
find an evoked response pattern that appeared during hypnotically
suggested hallucination yet not during simulation of hypnotic
hallucination. Nicholas Spanos and others have argued that this
EEG data has been misinterpreted given the nature of the control
subjects used. (Author's response to commentary by Spiegel, of
Spanos, N. (1986) "Hypnotic Behavior: A Social-Psychological
Interpretation of Amnesia, Analgesia, and 'Trance Logic'."
Behavioral and Brain Sciences 9:449-502).

In another similar attempt, from 1976, but measuring certain frequencies
of EEG activity rather than evoked potentials, a Russian journal
reports some tentative success at finding a physiological correlate
to hypnotic induction. See Aladzhalova, Rozhnov, & Kamenetskii,
"Human hypnosis and super-slow electrical activity of the
brain." [RUSSIAN] Zhurnal Nevropatologii I Psikhiatrii Imeni
S - S - Korsakova. 76(5):704- 9, 1976.

In the above article, the authors studied the transformation of
infraslow oscillations of brain potentials in 15 patients with
neuroses during 50 sessions of hypnosis. The results of such studies
permitted to distinguish some important traits in the changes
of infraslow oscillations of brain potentials in different stages
of hypnosis. It is concluded that a study of these changes during
hypnosis may establish some correlations between the physiological
state of the brain and the unconscious mental processes.

2.2. Are there potential clues in 'trance logic?'

One particular researcher, psychiatrist M.T. Orne of the University
of Pennsylvania, finally concluded that objective correlates were
not to be found in the available physiological measurements of
the time, and that they were apparently of no value in determining
whether a hypnotized subject was 'truly hypnotized' or 'simulating

Orne, who did recognize from both highly consistent verbal reports
of hypnotized subjects and from various clinical and empirical
studies that there was indeed something unique about hypnosis
in at least some subjects, concluded that that he would
have to use verbal reports of subjective experience rather than
rely on measurements. He carried out a series of clever experiments
which seemed to establish a reliable way of distinguishing simulators
from hypnotized subjects by their verbal reports. The resulting
alteration of mental function was found to be present in nearly
all deeply hypnotized subjects, and almost never found to the
same degree in people who were not hypnotized but were motivated
to simulate hypnotic phenomena.

The most obvious aspects of this alteration of function were dubbed
'trance logic,' and appeared to correlate well with the anecdotal
reports of the clinicians like Milton Erickson who had long considered
verbal reports of hypnotized subjects to be valuable in distinguishing
what was going on in hypnosis.

2.3. What is Trance Logic?

Trance logic refers to a set of characteristics of mental functioning
that are specifically found in 'deep trance' phenomena of hypnosis,
as opposed to 'light trance,' which has not even reliable subjective
correlates and cannot really be distinguished from simulation
experimentally. These characteristics involve particularly an
alteration in language processing. Words, in trance logic, are
interpreted much more literally, communication being conveyed
by focusing on words themselves rather than ideas. There is also
an associated decrease in critical judgement of language being
processed, and an increased tolerance for incongruity.

It is in some ways as if the subject were like a small child with
very limited experience to use in interpreting ideas conveyed
by the hypnotist. There also is a shift toward what psychoanalysts
call 'primary process' thinking, or thinking in terms of images
and symbols more than words; an increased availability of affect;
and other characteristics that simulators do not consistently

This consistent set of characteristics of deep trance has been
one of the influences leading to several kinds of theories of
what trance actually involves:

  1. Partly because language skills are 'child-like,' and meaningful
    long forgotten childhood memories can apparently sometimes be
    vividly re-experienced (see the later section on the reliability
    of recall in hypnosis) the theory that trance generally represents
    some kind of psychological regression to an earlier developmental
    stage has long been popular in some circles.
  2. Partly because the individual appears to become disconnected
    somehow with the usual context they use to evaluate ideas, a cognitive
    dissociation theory arose. (Also partly because of anomalies involving
    apparent multiple simultaneous 'intentions.')
  3. Partly because the cues prompting the subject's behavior become
    more internal and progressively more obscure to an outside observer,
    trance has been viewed as 'contact with the unconscious mind.'
  4. Largely because some of the characteristics of trance logic
    correlate well with some of those discovered to be specialized
    in many people in the non-dominant cerebral hemisphere, there
    is also a popular theory that deep trance involves a somehow selective
    use of one hemisphere of the brain, or in the most simplified
    version of this theory, a 'putting to sleep' somehow of the dominant
    (language specialized) hemisphere. Some brain scientists strongly
    disagree with this view, emphasizing the complex interdependence
    of the brain hemispheres even in typical hypnotic-type situations.

2.4. Critique of Trance Logic

The notion of trance logic, rooted as it is in subjective reports,
has been questioned by some of the non-state theorists, such as
Nicholas Spanos, who do not believe that trance logic represents
any sort of defining characteristic of hypnotic responding.

Examples of critiques of this concept can be found in Nicholas
Spanos, "Hypnotic behavior: A social-psychological interpretation
of amnesia, analgesia, and 'trance logic,'" Behavioral
and Brain Sciences
9(1986):449-502, and a paper cited by Spanos
in the above; Nicholas P. Spanos, H.P. de Groot, D.K. Tiller,
J.R. Weekes, and L.D. Bertrand, "'Trance logic' duality and
hidden observer responding in hypnotic, imagination control, and
simulating subjects," Journal of Abnormal Psychology

2.5. Trance as distinct from sleep or stupor

I think we can fairly conclude from the research on hypnosis done
so far that 'trance' may in fact have useful meaning for describing
the subjective experience of subjects in hypnotic situations,
but is not explained, or even described, by any one simple theory
yet proposed, either neurological or psychological. All of the
current theories seem to leave aspects unexplained.

Clearly, selective cerebral inhibition and activation of some
is involved at various stages of a hypnotic induction,
but not yet in any way we can uniquely distinguish from other
forms of waking response to changing stimulii in other situations.
And certainly hypnotic response does not rely upon the generallized
inhibition found in the action of depressant drugs or in the normal
sleep state. It is a much more highly specific effect, if indeed
it truly is distinct in some way, as subjective data appear to

The most common neurological theories of hypnosis over the years
as a form of partial sleep have mostly been based on (1) the superficial
resemblance of a classically induced subject to a near-sleeping
person, (2) on the ease with which a deeply hypnotized subject
will fall off to sleep on suggestion or if hypnosis is not explicitly
ended, and (3) because various drugs that induce sleep-like or
stuporous states can produce some of the same characteristics
as hypnotic trance.

It has been very consistently determined that trance itself has
nothing at all to do with sleep, and is much more easily distinguished
from a sleeping state physiologically than from a waking state.
Measurements attempted included a number of famous early experimental
studies in the 1930's, on such variables as EEG measurements,
cerebral circulation, heart rate, respiration, basal metabolism,
and various behavioral parameters. Representative of these experiments
comparing hypnosis and sleep was: M.J. Bass, "Differentiation
of the hypnotic trance from normal sleep," Journal of
Experimental Psychology
, 1931, 14:382-399.

Though the mentation in hypnosis often resembles dreaming, it
appears much closer to daydreaming in character than to
normal night time dreaming.

Clark Hull, in his 1936 classic Hypnosis and Sugestibility
describes a number of experimental setups for distinguishing the
mental characteristics of sleep from those of hypnotic

One thing suggested by this is that if sleep can be viewed as
largely a generallized cortical inhibition, and trance is not
in any determinable way identified with sleep, that trance is
not a form of sleep or a stupor. This is also easily determined
by observing the range of activities possible in hypnotized subjects
(compared to waking subjects and those under the influence of
depressant drugs).

2.6. 'Trance Reflex' and the appearance of stupor

So the question remains, if trance is not sleep or stupor, then
why do hypnotized subjects commonly appear so passive?

The consensus on this subject, from studies of 'waking hypnosis,'
('trance' in which the subject acts normally and does not show
any evidence of the classical relaxed deep trance state), and
from many years of clinical observations, is that the apparent
lethargy and catalepsy are more a result of suggestions used to
deepen hypnosis than a neccessary correlate of suggestibility
or trance itself in general. In a way, a side-effect of trance
rather than a quality or cause of trance. There is also seemingly
a temporary but distinct immobilizing reflex following certain
kinds of stimuli used in some hypnotic inductions. This may help
provide a temporary or initial facilitation of hypnotic suggestibility
in some people, according to some theories.

Monotonous visual stimuli, surprise, fear, physical restraint,
and a number of other factors have long been observed to produce
'trance' with fixation (followed by defocusing) of gaze, narrowing
or attenuation of externally focused attention, general immobility,
and various physiological changes which resemble the correlates
of relaxation and internally directed (visual) attention
in humans.

Perhaps the most routine observance of this is with people gazing
into television sets or in the familiar case of 'highway hypnosis.'
It appears that this type of 'trance' induction often precedes
the production of hypnotic suggestion phenomena, and can occur
prior to any verbal suggestions, from proprioceptive or visual
stimuli alone. It is probably closest to the traditional view
of the hypnotist swinging a watch to put their subjects 'to sleep.'

One means of searching for the basis for this seemingly reflexive
trance response is from phylogenetic data, using animals. A similar
response occurs in monkeys and other animals under both laboratory
and natural conditions, as an apparent passive defensive response
(resembling death) under certain extreme conditions.

Various Russian researchers investigating animal hypnosis seem
to have discovered electroencephalographic correlates of this
animal 'death trance' which resembles the initial trance/inhibition
effect that sometimes precedes human hypnotic suggestibility.
They report an interhemispheric asymmetry of the brain, which
a recent Russian email journal article, (Petrova E.V., Shlyk G.G.,
Kuznetsova G.D., Shirvinska M.A., Pirozhenko A.V., HYPNOSIS IN
EEG ASYMMETRY), summarizes as being

"created as the result of the activation of the right hemisphere."

They cite:

  • Simonov P.V. The Motivation Brain, Gordon a. Breach Pub.,
    N.Y.-L., 1992.
  • Kuznetsova G.D., Nezlina N. I., Petrova E.V. Dokl. Akad. Nauk,
    1988, 302:623.
  • Petrova E.V., Luchkova T.I.,Kuznetsova G.D. Zh. Vyssh. Nerv.
    Deyat. 1992, 42: 129.

As evidence of a correlation between right hemisphere cortical
activity and human hypnosis, they cite:

  • Gruzeiler J., Brow T., Perry A. et al. Int. J. Psychophysiol.,
    1984, 2:131.
  • Meszaros J., Growford H.J., Nady-Kovacs A, Szabo Cs., Neuroscience,
    1987, Suppl. 22:472.

One investigation into the relationship of primate behavior and
electrical activity of the brain (EEG) involved 45 male Macaca
Rhesus monkeys seated in a primatologic chair and observing the
oscillation of a shining ball, 4 cm in diameter, placed 15 cm
in front the animal's eyes for 15-20 minutes.

In this experiment, six of the monkeys immediately stopped motor
activity. At first their eyes were fixed on the ball, then muscle
tonus weakened, eyes became unfocused, and respiration slowed.
These same symptoms appeared in the remaining animals, although
they developed slower. During the first 2-3 minutes of the stimulation,
the slower responding monkeys showed a negative reaction to the
ball (a monkey abruptly turned away or tried to push it away).
Then the negativism ceased and the first signs of inhibition appeared:
yawning, scratching, and obtrusive hand motions.

Finally, what the experimenters call the 'hypnotic state' ensued;
eyes fixed on the ball, the animal became calm, and closed its
eyes. This state continued from several seconds to several minutes
and could be observed several times during an experimental session.
In 12 monkeys that displayed orienting or aggressive response
to the ball, visual signs of inhibition were not observed under
these conditions. Further physical restraint (fixation of hands
and trunk) resulted in the 'hypnotized' behavior. This is in contrast
to the more usual behavior of monkeys, what the authors of the
article call the 'freedom reflex' which results when they are
taken from their home cages and placed in the primatologic chair.

As they describe the EEG observations:

"The electrical activity of monkey brain cortex before hypnosis
was characterized by a robust polyrhythmia and presence of theta-
and beta-rhythms. In one monkey the alpha-rhythm was dominate.
During hypnosis, slow activity (delta and theta) with increased
amplitude appeared, periodically alternating with low-amplitude
activity. Power spectrum maps showed that in the low-amplitude
phase the decrease in the power of all rhythms was paralleled
in three monkeys with robust beta-1 rhythm with a predominance
in the left hemisphere. In the high-amplitude phase, delta and
theta-rhythms dominated in the right hemisphere."

"The analysis of the coherence and correlation functions
showed the decreased relationship between hemispheres (especially
in the frontal cortical areas) under hypnosis and its increase
during relaxation (as compared to the background)."

"The analysis of the EEG showed that in the brain of hypnotized
monkeys interhemispheric asymmetry appears: the domination of
the theta- and delta-rhythms in the right hemisphere or beta-rhythm
in the left hemisphere - depending upon the phase of hypnosis."

Factors shown to facilitate this "animal hypnosis" include
vestibular (pose in the chair) and somatosensory (fixation) stimuli
and emotional stress (fear), novelty to the experimental conditions,
and additional proprioceptive (restriction of the motor freedom)
and visual influences. Various sources seem to indicate similar
factors which operate on the corresponding 'trance response' in

In addition to the 'trance reflex' which is seen to sometimes
accompany or precede hypnotic induction, the factor of 'trance
logic' which surfaces under deep trance also adds to the catatonic
appearance, as the primitive language capacity in trance logic
could easily contribute to the appearance of stupor. But the individual
is actually, in general, wide awake and thinking, and in control
of themself, but extraordinarily focused on their internal experience,
and on the voice of the hypnotist.

"... the general tendency of the hypnotic subject to be passive
and receptive is simply expressive of the suggestibility of the
hypnotic subject and hence a direct result of the suggestions
employed to induce hypnosis and not a function of the hypnotic

Milton Erickson, circa 1944.

The most obvious reason to make this distinction is to dispell
the popular myth that a hypnotized person is unconscious or unable
to respond to emergencies, or to oppose the will of the hypnotist
if they should wish to do so. In fact, Erickson did a famous detailed
study of attempts by the hypnotist to force their will on hypnotized
subjects, and observed that not only did the subjects discriminate
what suggestions they would and would not respond to, and refused
to respond to some, but then often came up with ways to hurt or
humiliate the hypnotist in retaliation for the attempt. And that
they were even more selective about what suggestions they would
not respond to under hypnosis than they were normally!

Another reason this distinction is made is because of extraordinary
skills of some hypnotists to 'induce trance' (gain a unique kind
of compliance or communication) with people who had not been prepared
or relaxed by a classical induction, and who in fact steadfastly
and effectively resisted all attempts at classical induction of

A third reason is that we observe in some hypnotic phenomena that
an individual can be hypnotized, with the help of a traditional
progressive relaxation procedure for example, and then "remain
hypnotized" (equally responsive to suggestion) long after
leaving the state of physiological relaxation and classic apparent
catatonia. So, the 'trance,' though it may in fact start with
a process similar to that which commonly leads to sleep, or may
start with the 'trance reflex,' it is not dependent upon stupor,
nor even neccessarily relaxation.

2.7. Evidence of enhanced functioning following

Some of the 'unusual capacities' often claimed of hypnosis are
actually legitimate, but found to be quite normal capacities seen
in various non-hypnotic situations as well, though the hypnotic
'deep trance' context does apparently give a unique kind of access
to those normal capacities. Seemingly a product of the unique
sort of attention control found in hypnotic responding.

"Trance permits the operator to evoke in a controlled manner
the same mental mechanisms that are operative spontaneously in
everyday life."