Neuroscience Letters 380 (2005) 346–347
A response to Granqvist et al. “Sensed presence and mys-
We are assuming that they followed our usual protocol and
tical experiences are predicted by suggestibility, not by
verified the presence of the field and the appropriate acoustic
the application of transcranial weak magnetic fields”
signature (timing) of the field before each subject. If thiswas followed, there are three possible explanations for the
discrepancy between the results of our multiple studies over20 years involving dozens of experimenters and the results of
We have read Granqvist et al.’s article “Sensed
Granqvist et al. of these possibilities assume that there
presence and mystical experiences are predicted by sug-
are no nuances in local geomagnetic or structurally recondite
gestibility, not by the application of transcranial weak com-
factors, at present not measured, that are responsible for the
plex magnetic fields”. Double blind studies are essential
when exploring these phenomena. In all of our major stud-
First, the software we gave them to generate the magnetic
ies volving more than 400 subjects during the
field configurations was designed for XT and 286 IBM PCs
last 20 years the subjects were not aware of their experimen-
using DOS. Specific calibration programs are required when
tal conditions and experimenters were not familiar with the
more advanced PCs or WINDOWS is employed. Faster com-
hypotheses being tested or both were not aware of the exper-
puters and WINDOWS in particular distort the timing of the
imental condition. Subjects had volunteered for “memory”
point durations and disconfigure the temporal patterns of the
or “relaxation” studies and were randomly or serially allo-
applied magnetic fields real time values for the
cated to conditions. The “sensed presence” issue was never
point durations are critical in this research For
discussed. The person generating the hypothesis never had
example, even the “Thomas” pattern, when presented in the
reversed temporal sequence, is less effective for producing
These precautions are essential because application of spe-
the sensed presence. In several rat studies potency of
cific patterns of weak (1 T at distances equivalent to intrac-
analgesia from these applied fields can be eliminated, similar
erebral space) complex magnetic fields over the right hemi-
to changing the impact of a drug by changing the position of
sphere enhances suggestibility We have repeatedly em-
an atom, by subtle changes in timing.
phasized the importance of the context and the participants’
Second, Larsson and his colleagues had told us in 2000
beliefs, expectancies, and temporal lobe “sensitivities” with
when they visited the lab that they would be employing the
respect to how they interpret the experiences once they have
equipment to discern the effects of weak magnetic fields for
been elicited by the experimental fields Although we
a PET (Positron Emission Tomography) study. Exposure for
applaud the enthusiasm of Granqvist et al. replicate our
15 min to a particular pattern was suggested for this context,
research, their methodology deviated significantly from the
not for a phenomenological or experiential study. Both our
procedures known to evoke an experimental sensed presence.
rat and human studies indicate that exposures of between
The mean and standard deviation for the score for the in-
20 and 40 min are required for maximum response to weak
cidence of sensed presence for the Granqvist et al.
magnetic fields time required for electroen-
for both their experimental (magnetic field) and sham groups
cephalographic changes, such as altered proportions in alpha
(M = 0.3, S.D. = 0.5 and M = 0.3, S.D. = 0.5) were identical
rhythms or “entrainment” requires more than 15 min of ex-
to scores for sham field groups in our studies (M = 0.3,
S.D. = 0.5). The mean scores for this scale when the appro-
Third, our basic protocol is for the subject to be blind-
priate fields are applied are 0.8 or higher. The likelihood that
folded and to sit in a comfortable arm chair that is housed
Swedish and Canadian students differ in their temporal lobe
within a completely darkened acoustic chamber (which
sensitivity is minimum because the equivalent scores for the
is also a grounded Faraday cage with the dimensions
former were .34 (10.3/30) and for the Canadians (n = 1500
2.74 m × 2.54 m × 1.98 m, high). The authors did not indi-
over a 20-year period) have been 0.32 (S.D. = .15). We sug-
cate the instructions given to the subjects. Our instructions
gest the subjects in their experimental group never received
always emphasize that the phenomena are subtle and request
the subject to just experience whatever happens without la-
0304-3940/$ – see front matter 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2005.03.060
Letter to the Editor / Neuroscience Letters 380 (2005) 346–347
belling the experiences. Although our subjects’ ratings of ex-
[7] S.A. Koren, M.A. Persinger, Possible disruption of remote view-
otic beliefs and temporal lobe sensitivities were moderately
ing by complex weak magnetic fields around the stimulus site and
correlated (rhos between .40 and .45) with lifetime histories
the possibility of accessing real phase space: a pilot study, Percept. Motor Skills 95 (2002) 989–998.
of experiencing a sensed presence as discerned by question-
[8] L.J. Martin, S.A. Koren, M.A. Persinger, Thermal analgesic effects
naires completed during lecture periods two to four months
from weak, complex magnetic fields and pharmacological interac-
before the experiments, these variables were not significantly
tions, Pharm. Biochem. Behav. 78 (2004) 217–227.
correlated with the occurrence of sensed presences within
[9] M.A. Persinger, Increased emergence of alpha activity over the left
the chamber during either sham field or magnetic field con-
but not the right temporal lobe within a dark acoustic chamber:differential response to the left but not the right hemisphere to tran-
ditions. The critical factor for the experience of powerful
scerebral magnetic fields, Int. J. Psychophysiol. 34 (1999) 163–169.
sensed presences was the generation of the appropriate con-
[10] M.A. Persinger, The neuropsychiatry of paranormal experiences, J.
figuration of transcerebral magnetic fields.
Neuropsychiatry Clin. Neurosci. 13 (2001) 515–524.
We congratulate our colleagues in Sweden for the courage
[11] M.A. Persinger, The sensed presence within experimental settings:
to begin the steps to replicate experiments that may allow
implications for the male and female concept of self, J. Psychol. 137(2003) 5–16.
neuroscience to systematically explore experiences hereto
[12] M.A. Persinger, F. Healey, Experimental facilitation of the sensed
attributed to mystical or religious sources. However, the im-
presence: possible intercalation between the hemispheres induced
portance of replicating the specific timing and pattern of the
by complex magnetic fields, J. Nervous Mental Dis. 190 (2002)
magnetic field is as critical in this area of science as care-
fully adhering to the steps of synthesizing a compound is in
[13] M.A. Persinger, P.M. Richards, S.A. Koren, Differential entrainment
of electroencephalographic activity by weak complex electromag-
netic fields, Percept. Motor Skills 85 (1997) 527–536.
[14] M.A. Persinger, S.G. Tiller, S.A. Koren, Experimental simulation of
a haunt experience and elicitation of paroxysmal electroencephalo-
References
graphic activity by transcerebral complex magnetic fields: inductionof a synthetic “ghost”? Percept. Motor Skills 90 (2000) 659–674.
[15] P.M. Richards, S.A. Koren, M.A. Persinger, Experimental stimulation
[1] L. Baker-Price, M.A. Persinger, Weak but complex pulsed magnetic
by burst-firing weak magnetic fields over the right temporal lobe may
fields may reduce depression following traumatic brain injury, Per-
facilitate apprehension in women, Percept. Motor Skills 75 (1992)
cept. Motor Skills 83 (1996) 491–498.
[2] L. Baker-Price, M.A. Persinger, Intermittent bust-firing weak (1 mi-
[16] L. Sculthorpe, M.A. Persinger, Does phase-modulation of applied
croTesla) magnetic fields reduce psychometric depression in patients
40 Hz transcerebral magnetic fields affect subjective experiences and
who sustained closed head injuries: a replication and electroen-
hypnotic induction? Percept. Motor Skills 97 (2003) 1031–1037.
cephalographic validation, Percept. Motor Skills 96 (2003) 965–974.
[17] S.G. Tiller, M.A. Persinger, Geophysical variables and behavior:
[3] J.N. Booth, S.A. Koren, M.A. Persinger, Increased proportions of
XCVII. Increased proportions of left-sided sense of presence in-
sensed presences and occipital spikes with 1- and 10-ms point du-
duced experimentally by right hemispheric application of spe-
rations of continuous 7-Hz transcerebral magnetic fields, Percept.
cific (frequency-modulated) complex magnetic fields, Percept. Motor
[4] C.M. Cook, M.A. Persinger, Geophysical variables and behavior:
XCII. Experimental elicitation of the experience of a sentient beingby right hemispheric, weak magnetic fields: interaction with temporal
lobe sensitivity, Percept. Motor Skills 92 (2001) 447–448.
[5] N.P. Granqvist, M. Fredrikson, P. Unge, A. Hagenfeldt, S. Valid, D.
Larhammar, M. Larsson, Sensed presence and mystical experiences
Behavioral Neuroscience Research Group
are predicted by suggestibility, not the application of transcranial
Laurentian University, Sudbury, Ont., Canada P3E 2C6
weak complex magnetic fields, Neurosci. Lett.
∗Corresponding author. Tel.: +1 705 675 4824
[6] F. Healey, M.A. Persinger, S.A. Koren, Enhanced hypnotic sug-
gestibility following application of burst-firing magnetic fields overthe right temporoparietal lobes: a replication, Int. J. Neurosci. 87
E-mail address: mpersinger@laurentian.ca
Neuroscience Letters 380 (2005) 348–350
Reply to M.A. Persinger and S. A. Koren’s response to
abilities distorted by the applied fields depending on which
Granqvist et al. “Sensed presence and mystical experi-
operating system was used. To the best of our knowledge,
ences are predicted by suggestibility,not by the applica-
“remote viewing” still awaits sound scientific verification. tion of transcranial weak magnetic fields”
Moreover, its relation to the sensed presence experience isunclear.
Concerning room size, our chamber was 2 m× 2 m (i.e.,
4 m2, not 2 m2 as erroneously described in our article),
Our team entered this field with the expectation that
marginally smaller than Persinger’s. As the participants were
we would be able to reproduce previous results on sensed
blindfolded throughout the exposures also in our study, we
presence and similar experiences resulting from weak
regard the idea of an influence of room size as far-fetched
magnetic fields applied over the temporal lobe by Persinger
and confusing. Furthermore, the plan was to utilize the de-
and colleagues. Our intention was to use PET to elucidate
vice in PET studies, in which case it would have had to be
the regional blood flow changes associated with sensed
used in a much larger room containing the PET instrument,
presence induced by the so-called “Persinger helmet”. To
but Persinger never expressed any concerns about this.
be able to analyze regional blood flow changes we had to
Regarding double-blindness, which we believe to be the
be sure of the phenomenological effects of the device. We
most important reason for the different results between our
performed a thorough pilot study (N = 89) with equipment
laboratories, we have not read all of the several hundred arti-
and software provided by Persinger’s group.
cles published by Persinger in this and related areas. However,
Two of us (D. Larhammar and M. Larsson) visited Lau-
we have carefully checked the methodological descriptions
rentian University (Sudbury, Canada), where Persinger and
of the studies that were cited in the response by Persinger
Koren demonstrated the equipment to us. A portable version
as representing truly double-blind procedures. As far as we
of the device was then kindly sent to us. To ensure that the
can judge, none of them was double-blind according to the
unit complied with health regulations for the generated fields,
conventional definition of the term, namely an experiment in
we performed magnetic field measurements with the aid of
which (1) neither the experimental subject (2) nor the person
radiophysics expertise, which verified field strengths in the
administering treatment knows which treatment any partic-
magnitude of 1–10 T both before and after the study. For
ular subject is receiving Hence, whether or not exper-
verification of function before each session, we relied on the
imenters know about the hypotheses being tested is in our
diode system that represents the output of the digital to ana-
view irrelevant according to this definition (although appar-
logue converter as described in the instruction manual
ently emphasized as important by Persinger) because double-
Regarding the software, we were given the information by
blindness precludes the possibility of selective interaction
Persinger and Koren that the program version we received,
with participants across conditions.
Complex v.1.5 (inadvertently called 1.15 in our article) could
What is relevant, though, is what Persinger proceeds to
be used with faster PC’s provided that a calibration procedure
claim, namely that “both (i.e., the experimenter and the sub-
was followed This was consequently undertaken with
jects) were not aware of the experimental condition”. He does
the included calibration software. Moreover, Persinger has
not specify which of the five articles cited (four of which
been informed that calibration was indeed performed (e-mail
were empirical studies, one a review) that would meet both
communication, November 27, 2004). We used a DOS-based
of these criteria at the same time. A close inspection of the
operating system (Windows 95) and the program ran stably
methodological descriptions shows that none of them does,
in a DOS shell. The reference Persinger cites as showing that
rendering Persinger’s claim inaccurate at best. Let us give
faster computers and more advanced operating systems alter
two examples: First, his reference 11 was not a between-
the temporal signature of the fields and their phenomenolog-
group experiment, i.e., participants were not randomly as-
ical effects [Ref. 7 in the letter by Persinger and Koren] refer
signed to different treatments. All participants were given
to a single case study (N = 1), in which a “medium” with re-
the same treatments, and were then compared based on sex
mote viewing capability had his claimed “remote viewing”
and handedness. Hence, this is an example of a correlational
0304-3940/$ – see front matter 2005 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.neulet.2005.03.059
Letter to the Editor / Neuroscience Letters 380 (2005) 348–350
study (or at best a “quasi-experiment”). Of course, double-
study, 2 × 15 min exposures would be sufficient to evoke
blindness cannot possibly have been achieved here. Second,
blood flow changes in the relevant brain regions, whereas
his reference 12 is a between-group experiment. However,
an additional 2 × 5 min would be required to generate the
according to the method description, there was only one ex-
experience that we wished to monitor in the PET study.
perimenter present. Hence, she was supposedly responsible
We have an additional comment regarding the magnetic
both for interacting with the participants and for experimen-
field device. After our results had been accepted for publica-
tal condition assignment (i.e., giving left, right, bilateral, or
tion in Neuroscience Letters, we notified Persinger about the
sham-field stimulation). If this was the case, she must have
results. Our groups have since then been exchanging emails,
been aware of which condition the participants were assigned
from Persinger’s side mostly concerning possible method-
ological errors on our part that would account for our null
Unless randomization to conditions is pre-programmed, in
result. In one email Persinger stated that the unit he had sent
double-blind experiments, it is necessary to have two exper-
to us was a portable version of the original equipment with
imenters: One who is blind to condition (the one interacting
slightly different properties than the original unit, as the unit
with the participants) and one who randomly assigns the par-
sent to us had been optimized for a PET study. To us, how-
ticipants to different conditions (who must not interact with
ever, it seems clear that the unit must still have been expected
the participants in any way). None of the studies cited by
to induce the sensed presence or similar experiences as this
Persinger followed such a protocol, whereas ours did.
was the phenomenon to be studied by PET. This statement
The reason we would give some weight to this design dif-
about the equipment came to us as quite a surprise. We would
ference between our studies is that double-blindness, as con-
never have ventured on this rather large and technically com-
ventionally defined, is often a requirement for experimental
plicated double-blind study if we would have had the least
studies published in medical and psychology journals. Need-
indication that the unit would not strictly function as intended.
less to say, there are good reasons for such a design require-
Has the type of unit we received been evaluated for efficacy
ment, the most important being that selective interaction and
by Persinger and colleagues? We, of course, assume this has
other potentially placebo-producing effects explain a large
been the case. Furthermore, all physical measurements of the
part of the variance allegedly accounted for by a given treat-
device that we conducted were consistent with functionality.
ment, as noted in a recent editorial in Science
Of relevance to emphasize again is that we did indeed plan
This is where our concerns about suggestibility originally
to perform a PET study, because we had a sincere interest
arose, and was subsequently supported by our data. Some
in the results presented by Persinger and collaborators over
people are notoriously prone to pick up and respond to cues
several years. This means that if we were biased in any di-
from experimenters. This has been shown for individuals
rection, it would have been towards obtaining similar results
scoring high on absorption to mind-altering experiences
to Persinger’s. However, we felt compelled to rectify what
(Recall that the participants in our study who indicated mys-
we perceived to be the design weaknesses of the previous
tical and somatosensory experiences also were high on this
studies before embarking on a costly and complicated PET
trait as well as on new age spirituality.)
study. These changes in experimental design have forced us
Therefore, in future replications in this area, employment
to conclude that the weak magnetic fields do not contribute
of a truly double-blind design will be required to test our
to the subjective experiences, at least until a causative role is
interpretation that individual differences in suggestibility is
convincingly demonstrated in double-blind experiments.
involved. Until then, and regardless of the number of studies
Let us jointly hope that science will march on, and that ad-
performed in the past, we think the burden of proof should fall
ditional double-blind replications of Persinger’s studies will
upon those who have not used a truly double-blind design.
be undertaken by independent research groups in the near
Regarding the duration time of the magnetic fields
future. We will be delighted to share our experiences with
(i.e., 15 min versus 20 min of each configuration: the
designing a double-blind protocol if such studies are to be
“Thomas field” and the “burst field”), Persinger initially
recommended 15–20 min exposure with each configuration(personal communication, April, 2001, by e-mail). In thatcommunication, he also claimed that, following the burst
References
exposure, “a presence will be experienced in the remaining
[1] P. Bateson, Editorial: desirable scientific conduct, Science 307 (2005)
individuals” (i.e., those who had not already had a sensed
presence experience). Of course, it was very surprising for
[2] Dorland’s Illustrated Medical Dictionary, 28th ed., W.B. Saunders
us to learn, after Persinger had read our paper showing
Company, Philadelphia, USA, 1994, p. 505.
null-results from 2 × 15 min exposures, that 20 min are now
[3] S.A. Koren, M.A. Persinger, Instruction Manual: Complex Digital
required to evoke a sensed presence. However, according
to Analogue (DAC) Converter System Including Integrated 4 CannelCommutator and ComplexSoftware, 1998, Behavioral Neuroscience
to his letter this is what is required for maximum response.
Laboratory, Laurentian University, Sudbury, Canada.
Regardless, the participants in our study who were exposed
[4] A. Tellegen, G. Atkinson, Openness to absorbing and self-altering
to the active field condition received a total exposure of
experiences (“absorption”), a trait related to hypnotic susceptibility,
30 min (2 × 15). Also, we fail to comprehend why, in a PET
J. Abnorm. Psychol. 83 (1974) 268–277. Letter to the Editor / Neuroscience Letters 380 (2005) 348–350Childrens Hospital, Lund University HospitalDepartment of Psychology, Uppsala UniversityP.O. Box 1225, SE-751 42 Uppsala, SwedenE-mail addresses: marcus.larsson@stemcell.lu.se
Unit of Pharmacology, Uppsala University
(M. Larsson), pehr.granqvist@psyk.uu.se (P. Granqvist)
Convenção que constitui a Organização das Nações Unidas para a Educação, Ciência e Cultura Celebrada em Londres em 16 de Novembro de 1945 e modificada pela Conferência Geral nas suas 2ª, 3ª, 4ª, 5ª, 6ª, 7ª, 8ª, 9ª, 10ª e 12ª sessões Os Governos dos Estados-parte da presente Convenção, em nome dos seus povos, declaram: Que, como as guerras nascem no espírito dos h
ALGAS E ESPONJAS: UMA FONTE DE SUBSTÂNCIAS COM ATIVIDADE ANTIVIRAL Odinéia do S. Pamplona*1; Bruno F. dos Santos2; Suzi M. Ribeiro3; Lísia M. Gestinari1; Maria Teresa V. Email: odineia@ufam.edu.br Instituições: *Universidade Federal do Amazonas (UFAM), Instituto de Ciências Exatas e Tecnologia (ICET); 1 Núcleo em Ecologia e Desenvolvimento Sócio-Ambiental de Macaé/Univers