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Ganzfeld Studies
The low -absorption subjects simply increased their rate of speech
quite slowly throughout the session.
These findings indicate a
characteristic,
discriminative "signature" of high-absorption per-
sons
as individuals who rapidly develop
a strong involvement with
Ganzfeld mentation
(as
reflected in speech
rate) and who sustain
it
through at least the third quadrant of the session.
Subjects who,
as evidenced by this temporal "signature,"
quickly become involved with Ganzfeld mentation and sustain that
involvement
for a considerable period should,
as a consequence,
experience the session as shorter in subjective duration than those
who do not.
This was confirmed when quadratic trend
for words
per minute was correlated with subjective time estimates:
rg =
.197,
110 df, p =
.019,
one-tailed.
Transcript-based verbal indicators can elucidate both the
cognitive consequences of arousal and the development of internal
attention
states.
This methodology
is objective, unobtrusive, non-
reactive,
and
free from the potential biases of self-report methods.
A PROTOTYPICAL GANZFELD PSI EXPERIMENT WITH A
CONTROL CONDITION
A.C. van Dalen, L.R.B.
Dias, J.M.J. Murre, and
S.A.
Schouten"*" (Parapsychology Laboratory,
University
of Utrecht, Sorbonnelaan 16, 3584CA Utrecht, The
Netherlands)
The present experiment
is an attempt to bring some further
evidence into the Ganzfeld debate.
One of the claims made
for
Ganzfeld studies
is that they are supposed to be more successful
in detecting ESP compared
to non-Ganzfeld conditions.
Therefore,
it seems strange that so few experiments include a control condition
in which Ganzfeld stimulation is compared directly with a non-
Ganzfeld condition, because such a comparison is directly relevant
to the question whether Ganzfeld stimulation is psi conducive.
Schouten
(Research Letter , Parapsychology Laboratory, Univ. of
Utrecht, [No.
11],
1981, 67-96) gives an overview of Ganzfeld studies
which included
34 reports.
The main objective of the present study was to investigate
the supposed psi conduciveness of the Ganzfeld by directly compar-
ing subjects' performance in Ganzfeld and non-Ganzfeld conditions.
In order
to be able to generalize the results as much as possible
we went over the details of all experiments reported in Schouten
(1981)
that showed a significant result.
By taking the average,
the maximum
, or the soundest possibility of the
total of listed
particulars, we arrived
at a sort of "prototypical" successful Ganz-
feld experiment.
In addition, we tried
to incorporate as much as
possible the critique expressed by Hyman
(JP,
1985,
3-49) concern-
ing flaws
in methods and procedures.
We decided in advance that we would conclude that
this experi-
ment would offer support
for the claim that Ganzfeld stimulation is
psi conducive only in the case we would
find both
(1)
a significant
difference between the Ganzfeld and the non-Ganzfeld condition
(in
a positive direction for the Ganzfeld condition), and
(2)
significant
psi-hitting in the Ganzfeld condition separately.
A secondary aim of the study was to
gain more insight into
the
effect of the Ganzfeld stimulation on subjects.
To assess the
way subjects experienced the Ganzfeld we asked them to go over a
list of words that we expected be relevant to the conditions, and to
indicate which words they considered appropriate for their experi-
ence.
We also asked the subjects to make a prediction of their
success in both conditions.
This was done because we wanted to
investigate the influence of the subject's expectancies on psi-hitting.
To
test
for possible paranormal experimenter effects, two of the
experimenters made predictions
for every subject regarding his or
her ESP scoring.
All subjects
(41) were tested
for GESP in a Ganzfeld and a
non-Ganzfeld condition, which served as a control condition in this
experiment.
The non-Ganzfeld condition was equal to the Ganzfeld
condition in
all respects except that no halves of ping-pong balls,
red light, headphones, and white noise were used.
All subjects
took part in one
trial in each condition.
The order of the condi-
tions was randomized over the subjects.
No subject had former
experience in Ganzfeld experiments.
Every subject was offered an
optional compensation of maximally
guilders, and later feedback
of their results.
A target pool of 80 targets , which had been developed by
Schouten, was used.
It consisted of pictures taken from National
Geographic Magazine ,
glued on white pieces of cardboard measuring
eight by eleven inches.
A second,
parallel target pool of small
copies
(four by six inches) was used
for judging.
A Schmidt generator was used to generate a random
list ac-
cording to which target sets were to be selected.
A second random
list was generated containing only numbers one to four
for the se-
lection of a target picture from
a set.
The
lists were known
to the
experimenter-coordinator and
to one external person (S.S.), but
not to anyone else.
A three-experimenter plan was employed to minimize possible
accidental leakage of information.
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For the scoring procedure the target set was placed in front
of the subject in a left-to-right order and the subject was asked
to
rate each picture on a 31-point
scale
(0-30)
for similarity between
the picture and her experience during the previous
35-minute
period.
Before the subject made her ratings she was given
a
spoken semi-standardized instruction.
It was decided in advance
to evaluate the data by means of Stanford's Z-scores.
than an
aid in the selection
of possibly relevant
,
characterizing
words.
For the non-Ganzfeld condition two differentiating words
were selected:
annoying
(6)
and ordinary
(8), where the numbers
within parentheses represent the number of entries in the indicated
condition.
Although some words received
far higher scores, such
as distracting (21),
stimulating fantasy
(14),
mentally relaxing
(22),
bodily relaxing (19),
and quiet making
(21), these words
Using these scores no difference between the Ganzfeld and
the non-Ganzfeld conditions was found (Wilcoxon T = 344.5, Z - - .11,
p
>
. 90)
.
We also carried out
a few post-hoc analyses (these had
been planned in advance
for the most part as
well).
First
the correlation of direct hits in the two conditions was
investigated.
A positive correlation of hits might be interpreted
as
(weak) evidence for the hypothesis that psi effects are more
e-
pendent on the persons involved than on the method of
mduci
g
and testing such effects.
The test of association tended toward
significance (chi-square =5.48,
1 df, p
<
.02),
so that
e
a ov
hypothesis
finds some support.
However,
it should be taken into
account that in neither condition evidence for psi was observed.
We
also checked whether the order of conditions
(i.e.
,
Ganzfeld
first vs.
Ganzfeld last) had any influence on psi- hitting.
This did
not seem
to be the case (chi-square =
.0315,
1 df.
P
>
.85).
In
the course of the experiment the "sender" changed his method of
concentration, employing auto-hypnosis from Subjects
18 to
4i
Comparing direct
hits in both conditions no
significant
effect of
this change in method was found (chi-square
-
1.95,
1 d
,
p
>
rl5)
The expectancies of the subjects with respect to their scoring
behavior were divided almost evenly:
17 subjects thought they
would do best
in the Ganzfeld condition,
14 subjects predicted high-
er scoring in the non-Ganzfeld condition, and
10 subjects did not
want
to make a prediction.
Comparing the predictions with the rela
five magnitudes of the Stanford scores we were able to
arrive
at the
Sb« of correct predictions,
16 out o£ , possible «">»”*
significant
(binomial p
>
.85)
of course, because the probability of
a correct prediction is one-half.
Two of the experimenters (A.v.D.
and L.D.)
had made pre-
dictions as
well for the probability of scoring for every subject m
both conditions.
None of these predictions was successful (A.v.D.
Ganzfeld:
chi-square = .0189,
1 df, p
> -85s non-Ganzfeld:
chi-
=
0001,
1 df, p
> .99; L.D. Ganzfeld:
chi-square - -5831,
1 df, p
> .40; non-Ganzfeld:
chi-square = .0205,
1 df, p
> .60).
We then evaluated the checklists of words.
In order to
find
clusters of words that maximally differentiated between the two con-
ditions we did a binomial test for every word comparing the total
number of entries in both conditions.
These tests were no more
For the Ganzfeld condition more differentiating words were
found.
Three of them had negative connotations:
dizzy making
(9),
irritating (10),
and confusing
(7),
while sleepy making
(18)
was more neutral.
Two words were found which were close to be-
ing antonyms to the words that differentiated positively for the
non-Ganzfeld condition:
captivating (19) and interesting (20).
Finally, we tested whether there was a correlation between
the magnitude of Stanford scores
(either above or below
zero) and
preference for certain words so that these words could serve as
predictors
for scoring in either condition.
Again exact binomial
tests were used.
No striking results were found.
It
will be clear from the results that this study
is
to be
counted as an unsuccessful replication of other Ganzfeld experi
ments.
Unfortunately, no evidence of psi was found in either
condition,
so that we cannot reach a (tentative)
conclusion about
a possible,
differential advantage of Ganzfeld stimulation.
The
only rather weak effect found
in the post-hoc analysis speaks
against such an advantage.
We may ask ourselves why Ganzfeld
stimulation would,
if
at
all,
be conducive
to psi-hitting.
It may be important that the
stimulus input
is strongly reduced and the attention
is, perhaps,
directed more inwardly.
However,
to a certain extent this
is also
the case
if a subject is merely sitting comfortably in a chair.
From
our query
it can be seen that in both conditions words
like
fantasy
stimulating,
mentally relaxing ,
and
quiet making received approxi-
mately equal scores.
Quite
a number of subjects
(almost ten) ex-
perienced the Ganzfeld stimulation as rather negative.
Added to
this
is the
fact that the Ganzfeld stimulation may specifically in-
fluence the experiences of the subject.
For example, some subjects
reported having thought of running water or of sitting in an
air-
plane, experiences which they related
to the white noise.
Some of
them reported that they found
this very confusing in the rating
procedure *
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