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Self Hypnosis Online

This is science. It's a way in which we
can use our own brains to help ourselves feel better.
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In the movies, hypnosis usually involves someone falling
under the magical spell of a villainous character. The hypnotized person
then goes into a trace and carries out the hypnotizer's nefarious plans.
In a medical setting, however, self-hypnosis—in which people induce a
hypnotic state by themselves—is a tool that people can use to achieve a
sense of control, rather than lose it. In fact, studies show
self-hypnosis can help people manage pain, anxiety, addiction and
phobias, among other problems.
"There is nothing mystical or magical about hypnosis," explains David
Spiegel, MD, a professor at the Stanford University School of Medicine
in California. "It's just a state of altered and highly focused
attention."
Dr. Spiegel, the past president of the Society for Clinical and
Experimental Hypnosis, says that by learning how to attain a hypnotic
state on their own, people can gain control over what's happening in
their bodies. Below, he discusses the role of self-hypnosis in pain
management.
What is self-hypnosis?
All hypnosis is really self-hypnosis. The person inducing hypnosis
doesn't do anything to a person or control them in any way. Medical
professionals are just teaching people how to narrow their focus of
attention, turn inward and put outside of conscious their awareness of
some things that would ordinarily be in consciousness.
The only time I formally hypnotize a patient is the first time when I
am assessing their hypnotizability. After that, I teach people how to
enter the state for themselves. Since hypnosis is not sleep, but rather
highly focused attention, it's a state you can enter into very quickly
if you've got the ability. You can monitor what you're doing while
you're in it, and you can choose to end it when you want to.
How do you determine someone's receptiveness
to hypnosis?
I do a five-minute test called the hypnotic induction profile. I give
people a series of standard instructions for hypnotic experience. I'm
basically seeing whether they have the capacity to experience these
hypnotically instructed alterations in perception, sensation and motor
control. To evaluate their sensory alternation, for example, I ask them
to imagine that their hand is light and floating up in the air. If they
pull it down, it will float right back up.
It turns out that hypnotizability in adult life is an extremely
stable trait. It's as stable as IQ. The peak period of hypnotizability
in the human life cycle is children between the ages of 5 and 10. Most
8-year-olds are in trances most of the time. You know, you call them in
for dinner and they don't hear you. So it's actually quite easy for most
children to go into hypnotic state.
Some people have it as adults, some don't, and it's easy to measure.
It's not affiliated with a lot of personality characteristics, but
people who are more hypnotizable tend to rate themselves as more
trusting of others. They are more likely to get absorbed in movies or
novels or plays. They are people who have had early life experiences of
imaginative involvement with parents. But people who have experienced
physical punishment are more likely to be hypnotizable as well.
What are some of the techniques you use to
teach self-hypnosis?
Typically we ask people to look up and close their eyes. There is
something about disengaging from the usual scanning visual awareness
that seems to help people cut off their usual anxious preoccupation with
the world outside, and turn inward. So we recommend that they close
their eyes, take a deep breath, let their bodies float and then imagine
they are floating or looking at an imaginary screen or hearing sounds
that they may not ordinarily hear.
How can hypnosis be used to alter someone's
perception of pain?
There are three main strategies. One is physical relaxation. When people
are in pain, they are also often tense. Muscle tension tends to
exacerbate the pain by pulling on the area that hurts. So rather than
fighting the pain, if one can focus on an image that conveys relaxation,
like floating, the pain can be reduced.
The second strategy is sensory alteration. You can actually change
your perception of pain. For example, you can imagine that your hand
that hurts is in a pool of cold ice water in an icy mountain stream. If
you focus on the cool tingly numbness instead of the pain, you learn to
filter the hurt out.
Another technique is distraction. You can focus on sensations in some
other part of your body, and therefore reduce the attention you're
paying to the pain.
How often do you have to self-hypnotize to
maintain pain relief?
I encourage my patients to do it for two to three minutes every one to
three hours if they've got pain, and then anytime the pain starts to get
worse. So it is a technique you can carry with you anywhere and use when
you need it.
Has the effect of hypnosis on pain been
studied?
There is really solid evidence that self-hypnosis is helpful. We did a
trial some years ago for women with metastatic breast cancer that showed
that teaching self-hypnosis resulted in a significant reduction in pain
compared to patients who were not taught self-hypnosis.
Elvira Lang, MD, at Harvard Medical School, did a trial involving 240
people who were having a painful invasive interventional radiology
procedure that involved having little cameras inserted through the
arteries. All participants were offered pain medication. One group was
also offered training in self-hypnosis. Another group had a nurse
assigned to them, but no training in self-hypnosis, and the third group
had routine care.
The study showed that the patients who received the hypnosis training
had far less pain and virtually no anxiety, whereas anxiety was going
through the roof for the other patients. The hypnosis patients had fewer
complications with the procedure. They used far less medication, and it
took 17 minutes on average less time to get through the procedures. So
they were more comfortable, less anxious, had fewer problems and got out
sooner.
What kind of studies still need to be done?
We need more studies evaluating outcome in different contexts, as we
would with any other medical treatment. We need to look at pain in
children undergoing medical procedures; pain control during surgery;
pain for different sorts of problems, from gastrointestinal to arthritis
to other serious chronic pain problems.
Secondly, we need more studies about how hypnosis affects people's
perception of pain. We're learning that there are specific parts of the
brain that are affected by hypnosis for pain relief. One of them is the
anterior singular gyrus, a part of the brain that helps us focus
attention. That seems to be actively involved in hypnotic analgesia.
Parts of the brain that actually process physical sensation also appear
to be involved.
Thirdly, I think we need some studies of the effect of hypnotic
interventions on the practice and cost of healthcare. In Dr. Lane's
hypnosis study, for example, she found that each procedure cost, on
average, $338 less if you taught the patient self-hypnosis. So there are
tremendous economic implications, which also need to be studied more.
Do you think that self-hypnosis should be
taught more regularly?
Absolutely. It's a safe, effective procedure with virtually no side
effects. A lot of people get scared about the idea of hypnosis or think
they are being controlled. It's really a way of enhancing your control
over your body. I think it ought to be part of any pain treatment
program. I also think it should be more a part of medical education.
I do think as we do more studies on hypnosis, medicine will become
more accepting of the idea that this isn't mumbo jumbo. This is science.
It's a way in which we can use our own brains to help ourselves feel
better. |
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1.
What is
hypnosis? Does hypnosis exist? How and why did the concept of hypnosis evolve?
"In the author's
experience there can be developed in a person a special state of awareness
that is termed, for the sake of convenience and historical considerations,
hypnosis or trance.
"This state is
characterized by the subject's ability to retain the same capacities possessed
in the waking state and to manifest these capacities in ways possibly, though
not necessarily, dissimilar to the usual actions of conscious awareness.
"Trance permits the
operator to evoke in a controlled manner the same mental mechanisms that are
operative spontaneously in everyday life."
The late master clinical
Hypnotherapist, Milton Erickson
Modern theories of
hypnosis have drastically changed the way we view this subject. Because the most
common popular view of hypnosis is as an altered state of consciousness of some
kind (i.e. trance), this will be used as a departure point to explain how
hypnosis (1) has been viewed since the 18th Century when it was first
systematically studied and mass interest first arose, and (2) has been
deconstructed as a unitary concept by some modern scientific theorists of the
subject.
The most popular
traditional view of hypnosis is a sleep-like state induced by a procedure of
some kind by an operator and in which certain special behaviors seem to result;
particularly extreme responsiveness to suggestions made during the hypnotic
process, including physiological responses, and where anomalies of the
experience of volition and memory are consistently reported by subjects.
Therapeutic interest in
hypnosis results mostly from the fact that response to suggestions apparently
includes some increased capacity to access functions which are normally
considered outside of conscious control and memory. Popular interest in hypnosis
stems from the therapeutic interest, and because of the long associations of
hypnosis with spiritual and secular traditions of self-improvement,
self-insight, or self-fulfillment. There has also been interest in hypnotic
methods in various areas of medical and scientific research.
A truly balanced and
comprehensive study of hypnotic phenomena would probably have to include its
relationship with neuroscience, cognitive science, models of subjective
experience, models of creative thinking processes, theories of psycho-social
development, theories of human language and symbol processing, and various
philosophical stances that are still of interest today (such as moral and
ethical considerations of various conceptions of the human will and
responsibility for actions, and such as the legal status of testimony revealed
with the help of hypnosis).
Based on a list developed
by Zeig in 1988, the following frameworks can be identified:
- Janet (and later
Hilgard) thought of hypnosis as dissociation, meaning splitting off of
aspects of consciousness from each other in some way, with one seemingly being
dominant at any given time, but others able to influence behavior at the same
time, or to replace the dominant aspect. This is related to certain theories
of how Multiple Personality Disorder develops. Traditional theories of
spiritualist trances have often involved some notion of dissociation as well.
- Sarbin and Coe describe
hypnosis in terms of role playing, acting out the expected role of a
hypnotized subject in response to the relationship with the hypnotist. Spanos
is also a leading proponent of this view.
- T.X. Barber defined
hypnosis in terms of non-hypnotic behavioral parameters, such as task
motivation and the labeling of a situations as 'hypnotic.'
- Weitzenhoffer first
considered hypnosis a state of enhanced suggestibility, but later a form of
interpersonal influence via suggestion.
- Gil and Brenmand
described hypnosis in psychoanalytic terms as regression in service of the
ego. Freud, though not highly important in the history of hypnosis, had great
interest in it initially, and concluded, once he deviated from Charcot's
neurological theories, that it represented an eroticized dependent
relationship between hypnotist and subject.
- Edmonston assessed
hypnosis as relaxation (based on a Pavlovian theory of sleep as partial
cortical inhibition). This is linked historically to various physiological
theories of how 'conversion' works in fervent religious activities, such as
that of psychiatrist William Sargant.
- Spiegel and Spiegel
implied that hypnosis was a distinct biological capacity.
- Milton Erickson held
that hypnosis was a unique, inner-directed altered state of functioning.
- Various followers of
Erickson's lead have proposed that hypnosis is best defined subjectively and
phenomenologically as a process between individuals, and a communications
strategy for the achievement of therapeutic goals, with or without recourse to
'trance.'
- We should also reserve
at least one category for the numerous esoteric, non-scientific, or archaic
models which view hypnosis in general as a condition of subtle unidentified or
unobservable bodily fluids, a unique electromagnetic field phenomenon, or the
result of supernatural influences or contacts, or contact with alternate
realms of existence (in a non-metaphorical sense).
The creation of a distinct
concept of hypnosis owes its existence mostly to a charismatic 18th
century healer named Franz Anton Mesmer (1734-1815).
Mesmer had a deep interest
in Paracelsan astrological principles, and the supposed direct influence of
heavenly bodies on human health, by means of what were believed by Mesmer and
others to be measurable physical forces (as opposed to the subtle forces of
later occult doctrines interpreting Mesmerism).
Mesmer first applied
magnets to patient's bodies in elaborate theatrical rituals that often resulted
in expected spasmodic muscular contractions and collapse, and often the cure of
various kinds of illness. Mesmer favored the rationalist views of his time,
taking on terms like gravitation and magnetism to originally
describe his theories of his healing work, and how the subtle fluids within the
body could be influenced by him.
Mesmerism caught on
widely, attracting followers to many spiritualist, religious, and scientific
variations of mesmerism, as well as to 'mesmerism' as a dramatic form of
entertainment for its own sake ('stage hypnosis').
It was highly influential
in a number of popular movements, some of which are still very popular today.
The clearest transition
between Mesmer's animal magnetism and modern therapeutic hypnosis was
represented by Manchester surgeon James Braid, who coined the term hypnosis
(from previous use by French researchers) in 1843. The term refers to Hypnos,
the Greek god of sleep, because most forms of mesmerism at that time involved
the production of an apparently sleep-like condition.
Braid, as many scientists
and physicians before and after him, recognized in hypnosis certain legitimate
psychological phenomena of interest, but requiring much more systematic
investigation to understand. Mesmer had come to believe that it was not physical
forces via magnets but he himself that was producing the cures he produced.
Others not long after Mesmer soon began to suspect that the human imagination
played a much larger role in the process than did any physical forces or
capacities of the mesmerist. This was important, because mesmerism went through
a number of periods of great disrepute due to associations with occultism and
various kinds of blatant charlatanism.
A split arose between
those interested in hypnosis as a subject of scientific investigation and as an
adjunct to medical treatment, and those who considered it a tool for personal or
spiritual fulfillment, or for esoteric investigations of religious or 'magical'
nature. Faith healing, mind cure, and Christian Science were all heavily
influenced by hypnosis, and derived much of their impetus in the late 19th
century from the reputation of Mesmer and later mesmerists. Various followers of
the highly influential Theosophical Society and of the Hermetic Order of the
Golden Dawn magical fraternity found great affinity for the magnetic theories of
mesmerism, which they often interpreted in a semi-metaphorical way rather than
as literal electromagnetism.
In the early scientific
study, Braid at first thought that hypnotic induction would yield a unique
condition of the nervous system that was linked somehow to certain cures by
suggestion. He later rejected this, and other physiological explanations of
hypnosis, and emphasized "mental" factors almost exclusively. The theory of
neural inhibition has never been completely rejected as applicable, however,
though often considered insufficient by itself. Ivan Pavlov later greatly
expanded on the neural inhibition theory in his concept of the physiology of
sleep (as a progressive cortical inhibition, which turns out to be fairly
accurate - in general if not in detail).
This neurological
explanation of hypnosis was strongly rejected by Charcot, who believed that the
best hypnotic subjects were 'hysterics,' and that hypnosis was therefore a
manifestation of what was then considered the mental illness of hysteria. His
belief turned out to be wrong, and his view of hysteria as a distinct mental
illness as well, and his psychopathological view was rejected by the end of the
19th century. Two legacies of the neurological pathological theories of Charcot
and the so-called "Paris school" of hypnosis that have endured are cortical
inhibition theory and the later development of dissociation theory, though
neither one serves as a complete theory of hypnosis on its own.
In the early 20th century,
the foundation for most hypnotic theory was laid by the members of the so-called
"Nancy school" of hypnosis (such as Liebault and Bernheim) who elaborated a
theory of hypnotic suggestion based onideomotor action.
This theory had eventually
replaced not only the early neuropathological view, but also Braid's early
psychological theory, "monoideism," the theory that unconflicted ideas
automatically lead to actions. Ideomotor action theory says that ideas suggested
by the hypnotist lead automatically to actions, which are then experienced by
the subject as unwilled. Ideomotor action is another example of a useful but
incomplete model of hypnotic responding. The Nancy school was perhaps most
notable in their deemphasis of hypnotic ritual and their strong emphasis on
suggestion as a mundane though useful psychological process.
Sigmund Freud had
originally studied under Charcot and had a deep interest in hypnosis for much of
his life. In 1889, he shifted from Charcot's view to that of the Nancy school's
emphasis on suggestion rather than hysteria, believing that patients often
remembered repressed memories in a beneficial process under hypnosis. Freud was
reportedly a very poor hypnotist, being limited to a simple authoritarian style
of induction, and in 1896, he rejected hypnotic induction ritual as unnecessary
and too likely to foster unwanted amorous advances by patients ('transference,'
and the theory of hypnosis as an eroticized dependent relationship). Freud
replaced the hypnotic procedure with simply placing his hand on the subject's
forehead to help establish what he believed was the proper social relationship
of doctor in dominance over patient.
What qualified acceptance
of hypnosis in medicine that we have today is largely due to the efforts of
pioneers in the experimental study of hypnosis, starting in the 1920's and 30's.
Foremost early researchers were Clark Hull and his then student, Milton
Erickson. Hull's 1933 discussion of scientific research into hypnosis (Hypnosis
and Suggestibility) is still considered a classic.
Erickson later came to
disagree with Hull on the important issue of fundamental approach, stressing the
complex subjective inner processes operating in hypnosis, rather than the
measurable correlates and standardized procedures promoted by Hull. Hull went on
to make important contributions in learning theory, while Erickson went on to
become the name most closely associated with clinical hypnosis today.
Milton Erickson died in
1980, but left a legacy of often zealous followers, a number of important
contributions to the field, and several offshoot schools of applied psychology
based on his core principles of indirect strategic therapy and suggestion, and
based on hypothetical unconscious processes and indirect forms of human
communication. Examples include Jay Haley's strategic model of therapy, the MRI
Interactional model, the Erickson-Rossi hypnotic theories, Neurolinguistic
Programming (NLP), and a number of later frameworks such as that of Lankton
(1983) and Gilligan (1987). The 'Ericksonian' models deliberately blur the
traditional distinction between hypnosis and other forms of therapy, and share
this basic idea with the 'skeptical' view of hypnosis, which we will consider in
the next section.
In addition to Erickson
and Hull, modern scientific research into hypnosis is often associated with a
period of intense experimental research in the late 1950's and early 1960's by
notables such as J.P Sutcliffe, T.X. Barber, M.T.Orne, E.R. Hilgard, R.E. Shor,
and T.R. Sarbin. The work of these researchers had been particularly influential
on the current scientific view of hypnosis, especially as viewed in medicine.
The 'skeptical' modern
conception of hypnosis was pioneered by Theodore Sarbinin 1950, as a
social-psychological alternative to the views that (1) a single
distinctive neurological and psychological state underlies all hypnotic
phenomena (Paris school), and (2) that suggestions somehow mechanically produce
responses without the participation of the subject (Nancy school).
Sarbin instead saw
hypnosis as a social encounter, in which the hypnotist and subject play out
pre-determined roles. Sarbin's role theory was influenced by R.W. White, who in
his "A Preface to a Theory of Hypnotism," in The Journal of Abnormal and
Social Psychology in 1941 discussed various serious limitations of both the
Ideomotor action and dissociation theories. He pointed out that the responses of
hypnotic subjects are too complex to consider them as automatic results of
suggestions, that subjects often creatively and actively improvise a performance
based on their interpretation of suggestions. Thus for just about the first time
posing hypnotic behavior as creative and goal directed, rather
than mechanical.
In addition to the use of
social role theory to replace mechanistic theories of hypnotic response,
'skeptical' theories of hypnosis often refer to empirical research to illustrate
that hypnotic subjects do not in fact transcend the behavioral capabilities of
non-hypnotic subjects. The empirical objective approach to hypnosis, effectively
introduced to the study of hypnosis by Clark Hull in the 1930's, involves an
implicit mistrust of verbal reports of subjective experience, and the use of
quantifiable response indicies.
Key questions remaining in
the modern study of hypnosis within active role theory and other
non-special-state frameworks include: (1) whether a hypnotic procedure is
necessary (first studied by T.X. Barber in the late 1960's and in the 1970's);
(2) in what specific ways active cognitive functioning might be altered in
hypnotic contexts (studied by Orne and by Shor starting in the late 1950's), and
(3) the degree to which dissociation of aspects of consciousness actually
occurs in each of the various hypnotic phenomena(Janet, Prince, later E.R.
Hilgard).
All this leads to the
crucial theoretical distinction of whether it is meaningful and useful to
postulate such a thing as unconscious goal directed activity, and the global
psychological questions of what exactly are the nature of volition, compliance,
belief, and imagination.
Graham Wagstaff of the
University of Liverpool expresses the non-special-state view of hypnosis:
"... studies of hypnosis
have drawn our attention to a number of mundane yet fascinating phenomena that
do beg for explanations, even though, as I have pointed out, a theory of
hypnosis per se doesn't need to provide such explanations.
"For example, we need to
know how a placebo works; how suggestions can affect dermatological responses;
how imagination can produce the experience of a dry mouth, an itch, or nausea;
how coping strategies can affect the experience of pain; and so on.
"However, I would
consider these phenomena to be best investigated without any reference to
'hypnosis' because placing them in a context called 'hypnosis' probably serves
only to confound them with extra demand characteristics."
At another point,
Wag staff
acknowledges the practical consideration:
"... for some patients
there may actually be unique advantages to defining a context as 'hypnosis,'
for example, 'hypnotic amnesia,' if only pretended is a potentially useful
device not only for saving face but also for providing a legitimate context
for controlling the vivid remembering of traumatic experience."
2.
What
is a hypnotic 'trance'?
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 necessary in the production of
hypnotic phenomena) would lead to a state in which the subject's awareness and
behavioral responding was somehow altered from the usual.
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 necessarily 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.
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
hypnosis.'
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.
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 judgment 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 reproduce.
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:
- 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.
- 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.')
- 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.'
- 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.
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 94(1985):611-623.
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 kind 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 stimuli in other
situations. And certainly hypnotic response does not rely upon the generalized
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 suggest.
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 Suggestibility describes a number of experimental
setups for distinguishing the mental characteristics of sleep from those
of hypnotic trance.
One thing suggested by
this is that if sleep can be viewed as largely a generalized 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).
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 necessary 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 MACACA RHESUS IS
CHARACTERIZED BY DIFFERENT PHASES AND INTERHEMISPHERIC 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 humans.
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 state."
Milton Erickson, circa
1944.
The most obvious reason to
make this distinction is to dispel 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
trance.
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 necessarily relaxation.
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."
Milton Erickson
T.X. Barber, a highly
respected researcher into human functioning under hypnosis has long promoted the
view that people can bring out their own inner capabilities by direct requests
to think, feel, and experience in a suggested way, without any need for hypnotic
induction. He says that the secret of hypnosis involves the ability to fantasize
in a hallucinatory way and provide the drama and excitement. Also important,
according to Barber, is the way in which suggestions are given, language which
gives firm but metaphorical suggestions.
Keith Harary, in his
March/April 1992 Psychology Today article, "The trouble with HYPNOSIS.
Whose power is it, anyway?" reviews a number of critical studies of hypnosis and
concludes a similar view:
"Packaging them [the
true claims made about hypnosis] under the label 'hypnosis' conceals what is
really going on. It doesn't even begin to suggest that they are our very own
powers and there might be ways to get at them directly and entirely on our
own."
We see that there is
little of any consistency that can be said about light trance objectively, and
possibly only 'trance logic' (if that) as a common characteristic of deep
trance. Yet the subjective experience of the individual is sometimes very
profoundly altered.
And some phenomena can be
reliably reproduced in good subjects which are medically considered very unusual
and hard to explain (though not necessarily limited to hypnosis situations). The
working medical framework that had traditionally cleanly separated psychogenic
from physiological effects has been revised in parts to allow for some of the
mechanisms related to effects found in good hypnotic subjects; such as
influences between neural and immunological systems, dermatological (skin)
responses that were previously believed not to be able to be influenced by the
brain and nervous system, and the difficult but demonstrable 'biofeedback'
ability to indirectly control very small neural units previously considered
completely autonomic.
In terms of the prevailing
medical paradigm, numerous functional interconnections within the brain and
between the nervous system and other body systems have been found that may
gradually help to explain such remarkable effects as we see in hypnosis and
under various other seemingly special psychological conditions. Among other key
discoveries, the study of neuropeptides and their distribution throughout the
body as well as the brain provides some potential answers for some of the more
perplexing questions arising from effects due to suggestion.
Richard Benson's
"relaxation response" research pioneered in this area, and a great many studies
since then have validated his ideas about psychological and physiological
functions greatly influencing each other. Two recent article that are fairly
typical are in the June 1989 issue of the mainstream medical specialty journal
Gastroenterology, "Hypnosis and the relaxation response" and "Modulation
of gastric acid secretion by hypnosis."
An excellent review of the
research into the exact physiological effects found to result from hypnotic
suggestions in particular may be found in these two of T.X. Barber's articles
...
- "Physiological effects
of 'hypnosis,' Psychological Bulletin, 58: 390-419, 1961.
- "Physiological effects
of 'hypnotic suggestions': a critical review of recent research (1960-1964),"
Psychological Bulletin, 63: 201-222, 1965.
In addition to these
general references, the following sections may help to follow-up on any interest
into various specific apparent unusual effects of suggestion.
Hypermnesia is perceived
enhanced recall of memories. See also the later section on the reliability of
hypnotic recall.
An excellent overview of
experimental and clinical studies of hypermnesia, perceptual distortions, and
hallucinations under hypnosis may be found in the hypnosis section of the
Annual Review of Psychology, especially these issues spanning 20 years of
research into hypnotic phenomena:
- Vol 16, 1965, E.
Hilgard, p. 157-180
- Vol 26, 1975, E.
Hilgard, p. 19-44
- Vol 36, 1985, J.R.
Kihlstrom, p. 385-418
Another related area is
the remarkable phenomena of eidetic imagery, or 'photographic memory.' In recent
years, this formerly controversial phenomenon has been demonstrated by means of
computer generated random pixel patterns which stereoscopically encode a visual
image. There would be two images which, one seen by each eye at the same time,
produce a three dimensional visual image. It is considered virtually impossible
to detect the encoded image by looking at the separate encoded patterns at
different times. People with eidetic imagery can memorize one pattern, and then
mentally project it with one eye while looking at the other pattern with the
other eye. The result is that they can see the three dimensional image, while
apparently no amount of motivation will permit someone without eidetic imagery
to see the final image.
It is now known that many
five year old children can experience eidetic imagery, and that it is very rare
in adults. A study published in the Journal of Abnormal Psychology in 1975 (and
a follow-up three years later) demonstrated that the rate of eidetic imagery in
adults hypnotically regressed to age five was comparable to that in actual five
year olds.
This could be interpreted
as evidence of true temporal regression in hypnosis in some sense, although that
interpretation seems unlikely in the face of evidence in other areas. It is more
likely to provide unique evidence of state-specific abilities accessible through
hypnotic suggestion.
The following are the
studies quoted above:
- Walker, Garrett, &
Wallace, 1976, "Restoration of Eidetic Imagery via Hypnotic Age Regression: A
Preliminary Report," Journal of Abnormal Psychology, 85, 335-337.
- Wallace, 1978,
"Restoration of Eidetic Imagery via Hypnotic Age Regression: More Evidence,"
Journal of Abnormal Psychology, 87, 673-675.
In addition, Michael Nash
in his chapter "Hypnosis as Psychological Regression," in Lynn and Rhue's 1991
Theories of Hypnosis discusses the evidence around different kinds of
psychological regression and also refers to an unpublished manuscript by
Crawford, Wallace, Katsuhiko, and Slater, from 1985, which is said to also
discuss positive evidence for the facilitation of eidetic imagery phenomenon
with hypnotic techniques: "Eidetic Images in Hypnosis, Rare but There."
Amnesia (basically
selective forgetting in this case) sometimes occurs spontaneously in hypnosis,
and sometimes happens as the result of a direct or indirect suggestion to forget
something. The amnesia effect may last a variable time, possibly months or
longer, depending on the psychological significance of the amnesia and the
forgotten material and on the intensity of attempts to recall and availability
of recall cues in the environment.
A posthypnotic suggestion
in general is a response to hypnotic suggestion that extends beyond the boundary
of the actual trance period. Posthypnotic suggestions are often performed
without any knowledge that they were previously suggested (thus the necessary
link to hypnotic amnesia of this phenomena). The individual responding to a
posthypnotic suggestion and with amnesia for the source of the suggestion will
generally incorporate the response into their ongoing activities without
disruption, in a similar manner to ritualized actions that we pay little
attention to such as brushing our teeth in the morning or making the right
sequence of turns in our well established route to work each morning. If the
response involves some bizarre action, the individual will either be confused or
typically will come up with a creative rationalization for the behavior. Very
rarely will there be any awareness of the action resulting from a previous
suggestion.
It is the contention of
many experts in hypnotic work that individuals can and do resist posthypnotic
suggestions that they do not wish to perform, except that implicit trust of the
hypnotist may promote a behavior out of the ordinary. This is sometimes
(especially per Orne) considered more a factor of the relationship between the
hypnotist and subject than a matter of any capacity to use hypnosis to coerce a
person without their knowledge. The later section on hypnosis and volition will
cover this in grater detail.
See the following sources
of information on post-hypnotic research, in addition to the Hilgard article in
Vol. 16 of Annual Reviews (1965), cited above:
- W. Wells, 1940, "The
extent and duration of post-hypnotic amnesia," Journal of Psychology,
9:137-151.
- Edwards, 1963,
"Duration of post-hypnotic effect," British Journal of Psychiatry, 109:
259-266.
- Dixon, 1981,
"Preconscious Processing" (book)
Various studies have also
been done to try to determine what kinds of psychological pressure will cause
hypnotic amnesia to be breached, and under what conditions.
Schuyler & Coe, "A
physiological investigation of volitional and no volitional experience during
posthypnotic amnesia," Journal of Personality & Social Psychology,
40(6):1160-9, 1981 Jun was a good example.
Highly responsive hypnotic
subjects, who were classified as having control over remembering (voluntaries)
or not having control over remembering (in voluntaries) during posthypnotic
amnesia, were compared with each other on four physiological measures (heart
rate, electrodermal response, respiration rate, muscle tension) during
posthypnotic recall. Two contextual conditions were employed: One was meant to
create pressure to breach posthypnotic amnesia (lie detector instructions); the
other, a relax condition, served as a control. The recall data confirmed earlier
findings of Howard and Coe and showed that voluntary subjects under the lie
detector condition recalled more than the other three samples that did not
differ from each other. However, using another measure of voluntaries showed
that both voluntary and involuntary subjects breached under lie detector
conditions. Electro dermal response supported the subjects' reports of control in
this case. Physiological measures were otherwise insignificant. The results are
discussed as they relate to (a) studies attempting to breach posthypnotic
amnesia, (b) the voluntary/involuntary classification of subjects, and (c)
theories of hypnosis.
Hypnosis was at one time
frequently and successfully used for surgical anesthesia. It is still sometimes
used effectively for dental work, childbirth, and chronic pain of various types.
Pain control is one of the most reliable and most studied of the hypnotic
phenomena.
In addition to Hilgard's
article in Vol 26 of Annual Reviews (1975) see:
- Hilgard, Hilgard,
Macdonald, Morgan, and Johnson, 1978, "The reality of hypnotic analgesia: a
comparison of highly hypnotizables with simulators." The authors find that
motivated simulation of hypnotic analgesia is easily distinguished from
hypnotic analgesia.
- Hilgard and Hilgard,
1983, "Hypnosis in the relief of pain" (book)
- In 'Evaluation of the
efficacy and neural mechanism of a hypnotic analgesia procedure in
experimental and clinical dental pain,' 4,41-48, Pain, 1977, J. Barber
and D. Mayer reported that effective analgesia was produced by a refinement of
hypnotic technique, and was not reduced by naloxone. J. Barber,
neuropsychiatry at UCLA, seems to have somewhat specialized in this area.
- Another 1977 study,
Stern, Brown, Ulett, and Sletten, 'A comparison of hypnosis, acupuncture,
morphine, Valium, aspirin, and placebo in the management of experimentally
induced pain,' Annals of the New York Academy of Sciences, 296,
175-193, found that acupuncture, morphine, and hypnotic analgesia all produced
significantly reduced pain ratings for cold pressor and ischemic pain.
- Van Gorp, Meyer, and
Dunbar, 'The efficacy of direct versus indirect hypnotic induction techniques
on reduction of experimental pain,' International Journal of Clinical and
Experimental Hypnosis, 33, 319-328, 1985 (with cold pressor pain).
- Tripp and Marks, 1986,
compared hypnosis and relaxation with regard to analgesia for cold pressor
pain in 'Hypnosis, relaxation, and analgesia suggestions for the reduction of
reported pain in high- and low-suggestible subjects,' Austrailian Journal
of Clinical and Experimental Hypnosis, 33, 319-328.
- H.B. Crasilneck et al.,
1955, "Use of hypnosis in the management of patients with burns," Journal
of the American Medical Association, 158: 103-106.
- D. Turk, D.H.
Meichenbaum, and M. Genest, (1983), Pain and behavioral medicine: a
cognitive-behavioral perspective, New York: Guilford Press has a review of
cognitive-behavioral strategies for pain control in general, not limited to
hypnosis.
- In Larbig W. Elbert T.
Lutzenberger W. Rockstroh B. Schnerr G. Birbaumer N. EEG and slow brain
potentials during anticipation and control of painful stimulation.
Electroencephalography & Clinical Neurophysiology. 53(3):298 -309, 1982 Mar.,
EEG corrrelates of pain control were studied.
Cerebral responses in
anticipation of painful stimulation and while coping with it were investigated
in a "fakir" and 12 male volunteers. Experiment 1 consisted of 3 periods of 40
trials each. During period 1, subjects heart one of two acoustic warning stimuli
of 6 sec duration signaling that either an aversive noise or a neutral tone
would be presented at S1 offset. During period 2, subjects were asked to use any
technique for coping with pain that they had ever found to be successful. During
period 3, the neutral S2 was presented simultaneously with a weak electric shock
and the aversive noise was presented simultaneously with a strong, painful
shock. EEG activity within the theta band increased in anticipation of aversive
events. Theta peak was most prominent in the fakir's EEG. A negative slow
potential shift during the S1-82 interval was generally more pronounced in
anticipation of the aversive events that the neutral ones, even though no overt
motor response was required. Negativity tended to increase across the three
periods, opposite to the usually observed diminution. In Experiment 2, all
subjects self- administered 21 strong shock-noise presentations. The fakir again
showed more theta power and more pronounced EEG negativity after stimulus
delivery compared with control subjects. Contrary to the controls,
self-administration of shocks evoked a larger skin conductance response in the
fakir than warned external application.
Some of the most
interesting hypnotic phenomena involve the apparent precision production of
subtle skin responses by suggestion. Allergic reactions, pseudo-sunburns,
blisters, and weals have been produced by suggestion. In addition, it has long
been known that certain highly troublesome skin conditions have been influenced
or healed in some people by suggestion (with or without hypnotic induction).
See the following for
further information on studies of this:
- Ullman & Dudek, 1960,
"On the psyche and warts: II. Hypnotic suggestion and warts," Psychosomatic
Medicine, 22:68-76
- Rulison, 1942, "Warts,
A statistical study of nine hundred and twenty one cases," Archives of
Dermatology and Syphilology, 46:66-81.
- Asher, 1956,
"Respectable Hypnosis," British Medical Journal, 1: 309-312.
- R.F.Q. Johnson and T.X.
Barber, 1976, "Hypnotic suggestions for blister formation: Subjective and
physiological effects," American Journal of Clinical Hypnosis, 18:
172-181.
- Mason, 1955, "Icthyosis
and hypnosis," British Medical Journal, 2: 57-58.
- M. Ullman, 1947,
"Herpes Simplex and second degree burn induced under hypnosis, American
Journal of Psychiatry, 103: 828-830.
Experiments with hypnosis
during surgery have found that suggestion during and after surgery can reduce
bleeding significantly, as well as help with the management of pain.
See Clawson and Swade,
1975, "The hypnotic control of blood flow and pain: The cure of warts and the
potential for the use of hypnosis in the treatment of cancer," American
Journal of Clinical Hypnosis, 17: 160-169.
This is a broad area
covering a number of factors that are difficult to separate. In addition to the
critical review by Barber in 1965 cited above in (1), see G.S. Blum, 1968.
"Effects of hypnotically controlled strength of registration vs. rehearsal,"
Psychonomic Science, 10: 351-352, which discusses hypnosis as a possible way
of reducing rehearsal needed to learn something new.
In some of his
publications, researcher Charles Tart discusses the concept of state-specific
abilities, including the possibility that some might apply to hypnotic
phenomena. See his States of Consciousness, and other related works for
more on this.
The effect of hypnotic
suggestion in apparently enhancing physical performance under certain conditions
seems to relate to the unusual control over focus of attention available in
hypnosis, which permits improved concentration and increased motivation in some
athletes, and can be used to modify or lessen the influence of inhibiting
beliefs or attitudes. Similar effects are seen when athletes are motivated in
other ways, outside of hypnosis.
See T.X. Barber's 1966
paper, "The effects of 'hypnosis' and motivational suggestion on strength and
endurance: a critical review of research studies," British Journal of Social
and Clinical Psychology, 5:42-50.
It has long been supposed
(and in recent years demonstrated experimentally) that emotions and
psychological state somehow have an effect on human immune response, but even
though detailed mechanisms and the limits of this effect have not been well
understood in modern medical science. A recent article in Science News, Sept.
4,1993, pp. 153, describes 'the first solid evidence that hypnosis can modify
the immune system far more than relaxation alone."
The report concerns the
research of Patricia Ruzyla-Smith of Washington State University in Pullman and
her co-workers, who conclude that "hypnosis strengthens the disease-fighting
capacity of two types of immune cells, particularly among people who enter a
hypnotic trance easily."
This appears to correspond
well with and bolster the previous findings related to enhanced 'placebo'
(psychosomatic) effects in good hypnotic subjects, in the hypnotic induction
situation. However, it does not appear to address the persistent question of
whether highly hypnotizable subjects have a unique capacity for psychosomatic
regulation, or whether they simply exhibit this capacity common to all of us in
a uniquely accessible and convenient way by responding to hypnotic suggestion.
In this research, the
psychologists recruited 33 college students who achieved a hypnotic trance
easily and 32 students who had great difficulty doing so. Volunteers viewed a
brief video describing the immune system and then were assigned to one of three
groups: hypnosis, in which they listened to a hypnotic induction asking them to
imagine their white blood cells attacking "germ cells" in their body and then
performed this exercise through self-hypnosis twice daily for one week;
relaxation, in which they floated effortlessly in a large tank of warm water
containing Epsom salts and repeated the session one week later; or neither
method.
Students who underwent
hypnosis displayed larger jumps in two important classes of white blood cells
than participants in the other groups. The greatest immune enhancement occurred
among highly hypnotizable students in the hypnosis group.
One of the most persistent
of the many controversies surrounding hypnosis is its use in facilitating the
recall or (re)experience of events which are distinctly out of the range of what
most people think of as usual human experiences. For the present discussion, we
might divide these extraordinary experience into three overlapping types:
- Experiences which seem
extraordinary because what is remembered (while under hypnosis) as having
previously happened seems to defy commonly accepted canons of plausibility,
such as the controversial UFO abduction phenomenon,
- Experiences which,
perceived as happening during hypnosis, seem to defy commonly accepted canons
of plausibility, or would require a drastic theoretical revision to accept,
such as psychic phenomena,
- Experiences which seem
extraordinary because they have an unusually powerful or lasting effect on the
individual, such as certain deeply religious or mystical experiences,
The veracity of events
recalled under hypnosis is considered by most experts today to be problematic to
determine. Hypnosis facilitates the recall of details in good subjects, and also
facilitates the manufacture of details during recall that were not necessarily
present previously. This in fact is characteristic of recall in general, which
has been demonstrated to be far from a permanent and unchanging record, but more
a dynamic and adaptive process; a shape-shifting moire pattern of sorts,
conforming to inner needs and ongoing mental activity, more than a videotape
recording of the precise details of perceptual events.
There is also some
evidence that hypnosis may additionally aid in providing 'state-specific'
context to aid in the recall of information and experience of which the
individual is otherwise normally unaware.
Which of these complex and
incompletely understood processes is dominant in the recall of someone's
extraordinary memories of seemingly implausible events is extremely difficult if
not impossible to determine from the hypnotic session alone.
Neither claims of
unimpeachable veracity under hypnosis (the 'hypnosis as truth serum' idea) nor
those of hypnosis being completely unreliable in facilitating recall ('false
memory') stand up to close scrutiny as a general principle applicable to all
cases of controversial hypnotic recall. The best evidence available seems to
indicate that hypnotic methods can sometimes be valuable in a number of ways,
both to the individual's psychological health and in helping to gather factual
information, but that they should not be relied upon by themselves or given
special preference over other kinds of testimony for such things as legal
evidence, nor considered to be accessing anything like a perfectly faithful
permanent record of past perceptual events.
This section closes with
an illustrative philosophical excerpt from a recent book investigating
perception, memory, and consciousness, based on years of observation of
Synesthesia (cross-sensory perception); "The Man Who Tasted Shapes: A Bizarre
Medical Mystery Offers Revolutionary Insights into Reasoning, Emotions, and
Consciousness," Richard E. Cytowic, MD, Jeremy Tarcher/Putnam Publishing 1993,
ISBN 0-87477-738-0:
"While pointing out the
overlap between emotion and memory, I want to emphasize that memory is not
simply a fixed look-up table. It too is a creative process during which the
state of the brain's electrical fields change. The sensory cortices generate a
distinct pattern for each act of recognition and recall, with no two ever
exactly the same. They are close enough to cause the illusion that we
understand and have seen the event before, although this is never quite true.
Each time we recall something it comes tainted with the circumstances of the
recall. When it is recalled again, it carries with it a new kind of baggage,
and so on. So each act of recognition and recall is a fresh creative process
and not merely a retrieval of some fixed item from storage."
"Furthermore, persons,
objects, and events are not perceived in their entirety but only by those
aspects which are, have been, or can be experienced and acted upon by an
observer..."
"... All that we can
know about anything outside ourselves is what the brain creates from raw
sensory fragments, which were actively sought by the limbic brain in the first
place as salient chunks of information..."
"... Put in a more
familiar context, artists and creative writers look at the world in a certain
way. It is the same world that everyone else sees, but seen differently.
Contemporary people often call artists weird because they do not seem to be
seeing the same things that the majority sees. It is critical to realize that
the sensory gateways that feed into the brain establish their own conditions
for the creation of images and knowledge. Artistic giants knew full well that
their visions were not shared by most people. Even when persecuted or
abandoned because of their vision artists persist. That is all the can do
because their visions are their reality, and for many of us they subsequently
become our reality when we experience their art."
(copyright (c) Richard
E. Cytowic, MD)
There are a number of
links between the sorts of situations commonly associated with hypnosis, and the
experience of what are often called 'psychic phenomena,' (herein primarily
meaning apparent extrasensory perceptions, and psychokinesis, but also such
related experiences as apparitions mediumistic phenomena, and such strange
occurrences as the apparent suspension of death).
Hypnosis has a strong
historical connection with spiritualism, as evidenced partly by the shared
traditional emphasis on 'trance,' especially 'trance' appearing as a stupor
(contrasted with the confusing notion of an 'alert trance' or 'waking trance' in
some kinds of hypnotic situation). Spiritualism, in turn, has very strong
associations with both the origins of various schools of psychology, and modern
parapsychology, and the study of 'psychic phenomena' in general. The reason for
quoting that term here is to emphasize that the term originally meant such
subtleties of mental life as what we today often think of as the 'subconscious'
or 'unconscious' mind, rather than specifically and exclusively such things as
ESP, hauntings, or poltergeists. At the time, it seems there had been less of a
feeling that there was a distinct difference in plausibility between
'unconscious processes' and those today generally considered paranormal. Because
of this, the term may tend to be ambiguous when used in a discussion where a
wide variety of experiences are being included.
Early (circa late 19th
century, early 20th century) psychology was largely a philosophical endeavor,
which included a wide range of areas of investigations that were grouped in ways
that might seem a little strange today. For example, the American Society of
Psychical Research (ASPR), today probably thought of mostly as having been a
pioneering organization in the study of the paranormal, devoted a great deal of
its early efforts (and an explicit section of its charter) to studying what we
today usually consider mundane aspects of hypnosis.
Hypnosis has thus long had
a popular traditional association with such controversial psychic phenomena as
ESP, PK, poltergeist activity, and clairvoyance, as well as various forms of
occultism and some kinds of religious healing rituals.
Of particular pertinence
here, there is also a tenuous but persistent experimental link between hypnotic
processes and laboratory psi. The link is particularly prominent in anecdotal
evidence, but this is often of questionable reliability, for reasons that will
be described here. It is in the more controlled laboratory psi data that the
more truly demonstrable anomalous results appear that give us cause for further
investigation.
First, the difficulty with
this sort of experiment, and the kinds of protocols and controls required should
be recognized. While the open-minded researcher of anomalies might not wish to
reject the useful subjective verbal reports of hypnotic subjects, they also have
to contend with the remarkable subtlety of non-paranormal (conventional sensory)
human perception and communication.
Milton Erickson, for
example, described an experiment with hearing impaired 'lip readers.' He
discovered that they actually read a much richer panorama of cues than simply
the moving lips. The lip reading subjects would sit with their backs to a
blackboard on which there were various geometric designs. The designs were then
covered with sheets of paper. In front of the lip readers sat a group of
non-hearing-impaired participants, who were instructed to look at the blackboard
and say and do nothing. Someone else removed the paper covering the geometric
symbols, one at a time. The lip readers were instructed to write down anything
that they read from the participants in front of them who were observing the
geometric figures.
The lip readers were able
to "read" the names of the geometric figures apparently from their partner's
faces, with varying degrees of accuracy. One subject, a diagnosed paranoid
psychotic, who believed they heard other people's thoughts about them, was
reported as having perfect accuracy.
Erickson applied this
insight to his hypnotic technique, by recognizing the significance of messages
he himself didn't realize he was giving. A similar analysis has frequently been
applied to anecdotal reports of cases of apparent telepathy, but where 'cold
reading', or the skill of gathering information surreptitiously through subtle
but conventional sensory clues, appears to be a likely factor.
Someone might actually
suggest that the paranoid psychotic patient in this particular experiment, and
some or all of the other hearing-impaired patients, were actually employing some
telepathic faculty to some degree. But most interpretations would probably focus
on the use of subtle clues that the participants observing the blackboard were
unaware of providing. The nature of hypnotic communication ('rapport') is such
that the participants are particularly well attuned to the nuances of each
other's movement, speech and expression. This, combined with the lip readers'
existing capacity for attending to subtle body language, contributes to the
appearance of an even more extraordinary, even paranormal, information transfer,
and makes it more difficult to sort out the precise mechanisms of information
transfer involved.
Modern psychological
reviews might also focus on the hypothesis that the paranoid psychotic subject
was likely dissociating their perception of what they were reading from their
awareness of its source (rather than the obvious appearance of receiving it from
an extrasensory source). This resembles the dissociation theory of how trance
mediumistic (trance channeling) behaviors and some religious experiences (such
as hearing the voice of God) may occur, at least in some cases. The concept of
cognitive dissociation is a central one to many modern psychological
descriptions of hypnotic and peripheral phenomena, as we will see in more detail
later. In particular, we will see that dissociation provides an extremely useful
description, but not necessarily an adequate explanation of all of the data.
Today, most psychologists,
and virtually all of those investigators known as parapsychologists, are aware
of the complexity of human perception under even conventional circumstances.
They would generally tend not to consider a psi hypothesis to be
demonstrated in this sort of situation, given the apparently demonstrated
correlation of exceptional body language reading skills and high hit rates. This
is of course entirely different from demonstrating that a psi faculty is not
operating. Just that the experimental situation in this particular case does
not provide evidence of psi.
But there are other
experimental results, with protocols more specifically designed to rule out
subtle conventional sensory communication. These give us reason to at least
consider and test a psi hypothesis, with an eye toward ruling out subtle body
reading effects, in hypnotic situations. It appears from some results that under
certain kinds of conditions hypnosis may at least be slightly conducive to
anomalous information transfer, even when subtle cues are eliminated.
One well known difficulty
of even this result, though, is that it is not clear whether hypnosis is
facilitating some elusive 'ESP' faculty in some general way, or more
specifically improving the percipient's ability to perform on the particular
kinds of tests in use. In other words, the dramatic interpretation of hypnosis
as an altered state in which paranormal capacities are provided or enhanced may
not be the best or only explanation, even if the psi hypothesis itself were to
receive growing experimental support. There is also the crucially important
matter of just exactly what it is about the process of hypnotic induction
and its effects on the subject that changes hit rates in certain laboratory psi
tests.
In another section, we
briefly review T.X. Barber's work demonstrating that most if not all of the
unusual phenomena reported during hypnosis are also seen under other conditions.
He and his colleague Sheryl Wilson in their work on the theory of the 'Fantasy
Prone Personality' also provide us with another link between psi and hypnosis,
the observation that there are distinct similarities in personality variables
between people who are excellent hypnotic subjects, and those who report large
numbers of psychic experiences.
It should be emphasized
here that this theory does not support the once popular notion that good
hypnotic subjects are simply gullible or neurotic, or otherwise mentally ill; as
no correlation with any of these personality variables has ever been determined.
Rather, the FPP theory paints a picture of natural visionary individuals with a
rich inner life and often extraordinary psychosomatic responses, but who are
perfectly well able to distinguish their vivid fantasy life from reality, just
as most of us can distinguish a dream from a memory of actual events, most of
the time.
In other words, among the
factors that the FPP does NOT correlate with well at all is any diminished
capacity for reality testing. This should be born in mind particularly because
of the popular connotations of the term 'fantasy-prone,' and the questionable
veracity of recollections occurring under hypnotic procedures. A report from an
FPP subject is not inherently either more or less reliable than one from other
subjects, in or out of hypnosis. Their rich mental life does not necessarily
intrude on their external perceptions, except under various very unusual kinds
of conditions, such as spontaneous hallucination triggered by hypnotic
suggestion.
Additionally, there is the
complex psychological question of whether the individual interprets their
experience as 'real' or 'imagined.' When an LSD user comes down from their trip,
they don't generally continue to believe that their face was melting or that the
sky actually changed to fluorescent green during their experience, they
distinguish it as an 'altered state.' However, during the trip, the altered
perception may be quite convincing.
In hypnotic extraordinary
experiences, we find both cases where the individual believes that their
perceptions were due to an altered state, even though it seemed real at the
time, and those where they believe something quite bizarre actually happened,
not the result of an unusual perceptual state. And the two types of cases are
not at all easy to distinguish by any means other than relying on the report of
the subject.
It has also been observed
that even a polygraph is of extremely limited value in distinguishing whether a
bizarre occurrence actually happened to an individual or was hallucinated or
'confabulated.' In many cases, the individual believes that a hallucinated or
hypnotically constructed event happened, when unambiguous independent historical
records indicate that it did not.
The particular conditions
under which spontaneous hallucination can occur, and under which they can be
confused with external perceptual experiences are not well known, nor is there
any known method of distinguishing a spontaneous hallucination from an external
sensory perception. Even theories of how drug action (e.g. LSD) causes
hallucinations are highly speculative, and spontaneous hallucinations are much
more slippery.
Two current theories of
spontaneous hallucination concern changes in the chemical environment of
endogenous neurotransmitters or neuromodulators which influence perception
(endorphins and serotonin being the most commonly cited); and possibly some
unique mode of function of temporal or temporolimbic brain pathways, perhaps
influenced by electromagnetic fields.
How these unusual brain
conditions relate to psychic phenomena and to other observations related to
hypnosis in general is not yet well established.
3.
How
reliable are things remembered under hypnosis?
This has often arisen as
both a legal issue (as in the reliability of testimony obtained during or after
hypnotherapy) and also a social issue(regarding the use of hypnotherapy to
establish evidence of early child abuse, for example).
It is entirely true that
subjects under hypnosis frequently recall past forgotten events (or 'repressed'
memories in the jargon of psychoanalysis indicating an active role of the
individual in forgetting as a defense mechanism).
It is also true that
people under hypnosis often 'remember' things quite vividly that never actually
happened, but which have great personal significance nonetheless. Psychiatrist
William Sargent was one of the first to document the therapeutic benefit of
emotionally charged experience, or abreaction, of fantasized life events.
This is one of defining
characteristics of deep trance hypnosis in fact, the intensity of fantasies as
well as memories, and the inability to distinguish the two. This characteristic
of trance is what makes is possible to usehypnotherapy to alter personal history
in order to reduce the traumaticeffects of past events on an individual's
functioning. Not simply a relivingor 'catharsis' of the trauma, but a sometimes
a lasting modification of theinterpretation of the memory can and does occur in
many cases.
This apparent violability
and fallibility of human memory is frequentlydownplayed in discussions of
hypnotic recall because of the already difficulttime that legitimate victims of
abuse have in proving what happened to them.It's not the intention here to make
life more difficult for abuse victims,only to point out that hypnosis doesn't
neccessarily solve their problem ofdigging out facts from old memories as neatly
as we'd like it to.
The illusion of unusual
veracity of hypnotic recall appears to come from atleast two main sources:
- Older models of human
memory as a simple recording and playback mechanismwhich preserved extreme
details of everything perceived, and which could beplayed back in an enhanced
way under certain conditions, like hypnosis.
- The vividness and
subjective meaningfulness often attributed toexperiences under hypnosis partly
as a result of the unique characteristics ofhypnotic imagery.
Recognizing the potential
difficulties arising from what some call 'falsememory syndrome,' several states
in the U.S. now confine legal testimony tothat obtained prior to any systematic
hypnotic treatment.
In 1985, a committee
commissioned by the American Medical Associationcautioned against the systematic
use of hypnosis for recollection for both itsunreliability (the possibility for
example of 'confabulation,' the creation ofstories out of whole cloth to help
fill in missing memories) and its potentialto create vivid false memories with
an artificially induced sense ofcertainty.
In addition to the
previously provided references for hypermnesia, here aresome more specifically
devoted to the limitations of hypnotic recall:
- D. Spiegel et al, 1989,
"Hypnotic alteration of somatosensory perception,"American Journal of
Psychiatry.
- Loftus and Loftus, "On
the permanence of stored information in the humanbrain," American
Psychologist, 35(5):409-420 (May,1980), criticallyevaluates the data
gathered by neurologist Wilder Penfield who had oncebelieved he had discovered
during the probing of the brains of epilepticpatients a 'sequential record of
consciousness' similar to the oldtape-recorder model of human memory.
No one yet knows exactly
how human memory works in all its details, but theview of hypnotic recall as
potentially highly fallible is also supported byclinical experience and
experimental data.
Milton Erickson called the
vivid experiences under hypnosis 'vivification,'and describes how a vivified
image is experienced, regardless of whetherremembered or constructed:
"... They are
subjectively experienced as external events rather than asinternal processes,
with a consequent endowment of them as realityexperiences."
"... They identified it
with actual past experiences and thus endowed it witha subjective validity."
"... They 'created a
reality' that permitted a responsive functioning inaccord with the demands of
the experiment."
Are there identified
physiological correlates for such vivid recollections orre-creations of past
events? One controversial researcher, Michael Persinger,has written hundreds of
articles on the subject of neurophysiologicalcorrelates of extraordinary
experiences of all kinds. He has reportedlyreproduced something like ecstatic
mystical states with the help ofelectromagnetic stimulation of the cortical
temporal lobes of human subjects,and facilitated vivid imagery akin to UFO
abduction experiences. He is notalone in the observation of what is sometimes
known as 'clinical mysticism,'which is seen in some forms of temporal lobe
epilepsy and in mechanicalstimulation of areas of the temporal lobes, but he is
somewhat unique in hisrepeatedly published insistence that all or virtually all
unexplainedpheonomena and seemingly false memories can be traced to
electromagneticeffects on the brain. For an article particularly pertinent to
the issue ofhypnotic recall, see:
- Persinger MA.
Neuropsychological profiles of adults who report "suddenremembering" of early
childhood memories: implications for claims of sex abuseand alien
visitation/abduction experiences. Perceptual & Motor Skills.75(1):259-66, 1992
Aug.
"Six adults, who had
recently experienced sudden recall of preschool memoriesof sex abuse or alien
abduction/visitation, were given completeneuropsychological assessments. All
experiences "emerged" when hypnosis wasutilized within a context of sex abuse
or New Age religion and were followedby reduction in anxiety. As a group,
these subjects displayed significant (Tgreater than 70) elevations of
childhood imaginings, complex partialepileptic-like signs, and suggestibility.
Neuropsychological data indicatedright frontotemporal anomalies and reduced
access to the right parietal lobe.MMPI profiles were normal. The results
support the hypothesis that enhancedimagery due to temporal lobe lability
within specific contexts can facilitatethe creation of memories; they are
strengthened further if there is alsoreduction in anxiety." (Taken from an
on-line abstract).
If there is anything to
this 'temporal lobe lability' hypothesis, it seemswell worthwhile investigating
its relationship to hypnotic suggestibility, andthe hypothetical 'Fantasy Prone
Personality' of Barber and Wilson.
As for recall under
hypnosis, the experimental observation seems to be thatthe subject is uniquely
motivated to remember details, but also uniquelycapable of making up details and
experiencing them as if they were remembered.
In Lynn and Rhue's 1991
Theories of Hypnosis, Robert Nadon et al.discuss a representative example of
experiments in eyewitness recall with theaid of hypnosis. Subjects were shown a
videotape of a mock armed robbery.They were then asked to recall specific
aspects 6 times:
- Twice immediately after
seeing the film.
- Twice a week after
seeing the film.
- Once during hypnosis.
- Once after hypnosis.
The result was that high
hypnotizability subjects (SHSS:C) recalled morecumulative items in hypnosis than
they did just before hypnosis. Lowhypnotizability subjects did not
remember more during hypnosis. Thismatches our expectation of hypermnesia, that
hypnosis facilitates recall forgood hypnotic subjects.
Most interestingly,
both high and low hypnotizability subjects alsomade more cumulative
errors during hypnosis than just before hypnosis,though the effect was
stronger with highly hypnotizable subjects.
One explanation of this
kind of result from experiments is that the hypnoticcontext causes subjects to
adopt a looser reporting criterion, and they aremotivated to produce more
information, containing both correct and incorrect(where there is no clear
memory) details. See Klatzky and Erdely, 1985, "Theresponse criterion problem in
tests of hypnosis and memory," InternationalJournal of Clinical and
Experimental Hypnosis, 33, 246-257 for furtherdiscussion of this report
criterion issue.
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