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The Harvard Group Scale of Hypnotic Susceptibility and related instruments: individual and group administrations

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The Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A), Tellegen's Absorption Scale (TAS); Dissociative Experiences Scale (DES); and Phenomenology of Consciousness Inventory (PCI) were administered either individually or in groups. Eighty students from undergraduate Introduction to Psychology classes were randomly assigned to 1 of the 2 administration conditions with 40 students each. Although there was a general trend of differential item difficulty levels across the 2 administration conditions, a variety of results (descriptive characteristics, reliability, and validity) point to the similarity of behavioral and subjective responses to hypnosis in the 2 conditions. The TAS, DES, and PCI also produced similar results across both conditions of administration.
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International Journal of
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The harvard group scale of
hypnotic susceptibility and
related instruments: Individual
and group administrations
Frank J. Angelini a , V. K. Kumar b & Louis Chandler a
a University of Pittsburgh ,
b West Chester University of Pennsylvania ,
Published online: 31 Jan 2008.
To cite this article: Frank J. Angelini , V. K. Kumar & Louis Chandler (1999) The
harvard group scale of hypnotic susceptibility and related instruments: Individual and
group administrations, International Journal of Clinical and Experimental Hypnosis,
47:3, 236-250, DOI: 10.1080/00207149908410035
To link to this article: http://dx.doi.org/10.1080/00207149908410035
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THE
HARVARD
GROUP
SCALE
OF
HYPNOTIC SUSCEPTIBILITY
AND RELATED INSTRUMENTS:
Individual and
Group
Administrations’
FRANK
J.
ANGELINI’
University
of
Pittsburgh
V.
K.
KUMAR
West
Chester University
of
Pennsylvania
LOUIS CHANDLER
University
of
Pittsburgh
Abstract: The Harvard Group Scale of Hypnotic Susceptibility, Form A
(HGSHS:A); Tellegen’s Absorption Scale (TAS); Dissociative Experi-
ences Scale
(DES);
and Phenomenology
of
Consciousness Inventory
(PCI) were administered either individually or in groups. Eighty stu-
dents
from
undergraduate Introduction to Psychology classes were
randomly assigned to
1
of
the
2
administration conditions with
40
stu-
dents each. Although there was a general trend of differential item dif-
ficulty levels across the
2
administration conditions, a variety
of
results
(descriptive characteristics, reliability, and validity) point to the simi-
larity of behavioral
and
subjective responses to hypnosis in the
2
condi-
tions. The
TAS,
DES,
and
PCI
also produced similar results across both
conditions of administration.
INDIVIDUAL
AND GROUP
ADMINISTRATIONS
Shor and Orne’s
(1962)
construction
of
the Harvard Group Scale
of
Hypnotic Susceptibility:
Form
A
(HGSHS:A or the Harvard Scale) as a
group version of Weitzenhoffer and Hilgard’s
(1959)
Stanford Hyp-
notic Susceptibility Scale: Form
A
(SHSS:A) may be regarded
as
a land-
mark
in
hypnosis research. Register and Kihlstrom
(1986)
noted that
the
Harvard Scale “represents an ideal instrument for its intended use:
Manuscript submitted November 11,1997; final revision received January
7,1999.
‘The authors appreaate the feedback from three anonymous reviewers
on
earlier ver-
sions
of
this article. Frank
J.
Angelini
is
now
at the Veterans Administration Medical Cen-
ter, Coatesville,
PA.
2Address correspondence to Frank
J.
Angelini, 337
N.
Woodmont Dr., Downingtown,
PA
19355.
The
International
Jouml
ofClinical
nnd
Eqmimentnl
Hypnosis,
Vol.
47,
No.
3,
July
1999
236-250
0
1999
The
Intmtional
Jouml
ofclinical
and
Experimental
Hypnosis
236
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HARVARD SCALE
237
as an initial introduction to hypnosis for naive individuals and as a prel-
ude to a more rigorous classification of hypnotizability by means of such
advanced procedures as
SHSS:C”
(Weitzenhoffer
&
Hilgard, 1962, p. 85).
There is little doubt that the Harvard Scale
is
the most widely used instru-
ment in hypnosis research, perhaps because of its cost-effectiveness as a
self-report measure for testing groups of people simultaneously. How-
ever, Register and Kihlstrom (1986) observed that “since the HGSHS:A
was introduced, there has been an increasing tendency toward reliance
on
it alone, without proceeding to SHSSC for a final criterion assess-
ment” (p. 85). Perry, Nadon, and Button (1992) likewise noted that ”one
major result of this successful development of the HGSHS:A as a group
administered scale is that nowadays its forerunners
(SHSS:A
and
SHSS:B) are rarely utilized, at least by laboratory researchers” (p. 461).
Although it appears that the HGSHS:A is typically used for group
administration, there are research studies that have used it for individ-
ual
administration. Shor and Ome (1963) tested groups of
5
to 40 partici-
pants simultaneously for gathering their normative data.
In
addition,
they examined data obtained from four reference samples that received
”individually-administered versions of the scale” (p. 40).
John,
Hol-
lander, and Perry (1983) tested groups of 8 to 20 normal participants for
their normative data, but they tested a sample of phobics individually.
The present study assessed the effects
of
individual and group
administration of HGSHS:A
on
behavioral and subjective responses to
hypnosis.
To
the authors’ knowledge, no study has specifically exam-
ined, using a true experimental design, the effects of individual and
group administration of the HGSHS:A on its psychometric properties,
that
is,
its descriptive characteristics, reliability, and validity
in
terms of
its pattern of external relationships. The earlier studies by Shor and Ome
(1963) and
John
et al. (1983) employed quasi-experimental designs. Fur-
thermore, we are not aware
of
any
study
that has examined if the subjec-
tive experiences of research participants differed as a function of indi-
vidual and group administrations.
According to Register and Kihlstrom (1986), there are several poten-
tially contaminating factors that are present during a group, as opposed
to an individual, administration: (a) social interaction among partici-
pants may distort the scores by increasing or decreasing behavioral com-
pliance,
(b)
the mere presence of others may increase motivation to per-
form in some individuals and decrease it in others, and
(c)
social
comparison may occur during the eyes-open portion of the induction,
biasing the results.
Individual testing may have its own weaknesses. For example, it is
possible that (a) ”eager to please” or ”contribute to science” (Ome,
1959,
p. 278) feelings may be more easily engendered by the experimenters in
the context of individual testing
and
(b)
experimenter interactions with
the individual participant may be more unpredictable than with a larger
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238
FRANK
J.
ANGELINI
ET
AL.
group, contributing to distortion of scores in unpredictable ways.
On
the
other hand, one might argue that preexperimental expectancies con-
cerning hypnosis are
so
strong that what happens in the individual or
group session may have little impact on performance. Furthermore, the
experimenter has little control over how individual participants influ-
ence other potential participants by way of discussing their experiences,
regardless
of
whether they were tested individually
or
in a group.
Despite the postulated differences concerning individual versus
group administration, there are reasons to expect that the psychometric
properties of the HGSHSA would be unaffected by the context of ad-
ministration (individual vs. group). Shor and Orne (1963) reported that
the reliability
of
the HGSHS:A was
.80,
comparable to that of the SHSSA
(.83).
The
item difficulty levels were reasonably stable across their four
reference samples in which individual versions of the scale were admin-
istered. Furthermore,
John
et al. (1983) found evidence for the discrimi-
nant validity of the HGSHS:A when administered individually. They in-
dividually tested 20 phobic women and found, consistent with previous
evidence, that the phobics were more likely to score in the high suscepti-
ble (8-12) category rather than the medium (5-7) and low (0-4) categories.
Furthermore, the proportion of phobics who scored as high susceptibles
(55%) was sigruficantly higher than in the normative group of 357
women (29%).
John
et al. also compared the item difficulty levels in the
phobics and normative samples. They found that although the propor-
tions of phobics were consistently higher on the items, only two items
differentiated the
two
groups. The Spearman rank-order correlation for
the item difficulty distributions in the two groups was
.65
@
<
.05),
sug-
gesting that these distributions were
similar.
From these results,
John
et al.
concluded that the
performance
of
the phobic
subjects
was
more
a
reflection of their hypnotic
abilities than
of
their perception
of
the
demands of the susceptibility test-
ing,
inasmuch as the
data
on
HGSHSA
item
difficulty is not well known to
volunteers
for either experimental
or
clinical studies.
(p.
392)
To
examine the effects of the context of administration on validity, it
was decided to include three commonly used instruments: The Tellegen
Absorption Scale
(TAS;
Tellegen
&
Atkinson, 1974), Bemstein and Put-
nam’s (1986) Dissociative Experiences Scale
(DES),
and Pekala’s
(1982/1991a) Phenomenology of Consciousness Inventory (PCI).
The relationships of the HGSHSA with the TAS and
DES
have been
studied extensively. Nadon (1997) noted a wide range of correlations
between hypnotizability and the TAS from close to
0
to as high as .50 and
that the “observed variability among the sample correlations is
consis-
tent with random sampling error and
sampling
differences across stud-
ies” (p. 319). According
to
Nadon (1997), the estimated population corre-
lation between hypnotizability
and
absorption is small, approximately
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HARVARD
SCALE
239
.20.
The same may be said of the correlation between the HGSHS:A and
DES. Kumar, Pekala, and Marcano (1996) noted that the typical correla-
tions reported in different studies range between
-03
and .26. van IJzen-
doom and Schuengel (1996) reported an average correlation
of
.13
between the HGSHS:A
and
DES
in a
meta-analysis of the studies.
If
the
validity of the HGSHS:A is unaffected by the context of administration
(individual vs. group), then we would expect that its correlation with
the TAS and DES would not differ across the two contexts. Further-
more, the correlations in this study are not expected to differ signifi-
cantly from the estimated population values
(.20
for
the TAS and .13 for
the DES) in the
two
conditions.
The relationship of the PCI with hypnotizability is well documented
(see Pekala, 1991b). Because the PCI is a state instrument, its inclusion
allowed the investigation of changes in subjective aspects of a hypnotic
experience as a result
of
individual and group testing.
In
a recent study,
Kumar, Pekala, and Cummings (1996) found the following five state-
effects factors from
a
factor analysis of the PCI data: dissociated control,
positive affect, negative affect, visual imagery, and attention to internal
processes. They found that the state effects factors of dissociated control
state, positive affect, and attention to internal processes were signifi-
cantly correlated with the HGSHS:A-results that were replicated in
two
other studies (see Kumar, Pekala,
&
McCloskey, 1997). It is of inter-
est to
this
study to see
if
the same pattern
of
correlations is obtained
across the individual and group administration contexts.
In
summary,
this
exploratory study's primary aim was to examine
if
an
individual versus a group administration affected behavioral
and
subjective response to hypnosis. More specifically, the study addressed
the questions of whether the
type
of administration affected (a) the psy-
chometric properties of the HGSHSA in terms of its descriptive charac-
teristics, reliability, and pattern
of
external relationships with the TAS
and DES;
@)
the subjective response to hypnosis on the PCI; and (c) the
psychometric properties of the TAS, DES, and PCI.
No
hypotheses were
advanced in terms of expected group differences given that the nature of
this study was exploratory.
METHOD
Participants
Participants were
80
University of Pittsburgh undergraduates solic-
ited from the Psychology Department's Introductory Psychology
research pool of approximately
300
students. Students participated in
the experiment voluntarily, albeit to complete a departmental research
requirement. Participants knew ahead of time that they were signing up
for a study on hypnosis.
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240
FRANK
J.
ANGELINI
ET
AL,
Instruments
1.
The HGSHSA (Shor
&
Ome, 1962) was used to assess participants’ hyp-
notic susceptibility. The HGSHS:A has been found to have adequate in-
ternal consistency reliability. The
K-R
20 values reported in different
studies are .80 (Shor
&
Ome, 1963), .74 (Kirsch, Council,
&
Wickless,
1990), and .72 (Kumar, Marcano,
&
Pekala, 1996). In this study, the
HGSHSA was modified to accommodate a 2-minute sitting quietly inter-
val to allow the administration of the PCI in reference to this interval (see
Procedure section).
2.
The
TAS
(Tellegen
&
Atkinson, 1974) was used
to
measure participants’
tendency to become absorbed
in
objects of attention. Tellegen (1982)
found an internal consistency reliability for the TAS
of
.82 and a test-retest
reliability of .91 (30-day interval between administrations).
3.
The
DES
(Bernstein
&
Putnam, 1986) was used
to
measure the frequency
of dissociative experiences. There are three DES subscales for use with
nonclinical populations: Absorption and Changeability (AbC), Dereali-
zation and Depersonalization
(D
&
D),
and Amnestic Experiences
(AE).
Carlson and Armstrong (1994), reviewing reliability data concerning
DES
from
various studies, pointed out that the (a) test-retest reliability coeffi-
cients have ranged between .84 to .96 and
@)
split-half reliability coeffi-
cients have ranged between .83 and .93. Frischholz et al. (1990) reported a
Cronbach’s alpha of .95. van IJzendoom and Schuengel(l996) reported
an average alpha reliability of .93 in 16 studies.
4.
The PCI (Pekala, 1982/1991a) was used to map phenomenological
experi-
ence. The
PCI
is
a 53-item self-report instrument completed retrospec-
tively
in
reference to a preceding stimulus condition.
The PCI is composed of the following 12 major and
14
minor dimen-
sions of consciousness: positive affect (joy, sexual excitement, and love),
negative affect (anger, sadness, and fear), altered experience (body im-
age, time sense, perception, and meaning), visual imagery (amount,
vividness), attention (direction-inward, absorption), self-awareness,
altered state
of
awareness, internal dialogue, rationality, volitional con-
trol, memory, and arousal (relaxation).
In
addition, the PCI
can
be used
to compute the five state-effects scores pertaining to dissociated control,
positive affect, negative affect, visual imagery, and attention to internal
processes (Kumar, Pekala,
&
Cummings, 1996).
The PCI has been shown to be a reliable measure of phenomenologi-
cal experience. Pekala, Steinberg, and Kumar (1986) found coefficient al-
phas for PCI (sub)dimensions to range from .71 to .92, with an average of
.82
when administered
in
reference to a period of sitting quietly with
one’s eyes open. Pekala
and
Forbes (1988) found mean coefficient alphas
across all major dimensions of 81,
.81,
32,
and
.83
in
reference to eyes
closed, progressive relaxation, deep abdominal breathing, and hypnosis
conditions, respectively. The PCI’s discriminant validity has been estab-
lished through its abillty
to
reliably discriminate between such contexts
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HAFWARD
SCALE
241
as a hypnotic induction and a period
of
sitting quietly with one's eyes
closed (Kumar
&
Pekala, 1988,1989). Pekala, Forbes, and Constrisciani
(1989) found the PCI to discriminate between a number of contexts, in-
cluding a baseline condition of sitting quietly with one's eyes closed,
deep abdominal breathing, progressive relaxation,
and
the induction
procedure of the HGSHSA.
DesignProcedure
Eighty students were randomly assigned to either the individual
or
group administration condition. Participants
(n
=
40)
in
the group condi-
tion were tested in
two
groups of
20
individuals each. Before the experi-
ment began, all participants were informed that (a) the study's purpose
was to examine the relationship between personality and hypnosis (thus
avoiding reference to the
main
purpose of the study);
@)
they would be
asked
to
complete some questionnaires, following which they would
receive a hypnotic induction; and
(c)
they would complete a question-
naire in reference to their hypnotic experience. Participants were
assured that their responses would be treated confidentially and their
identifying information would be removed from the questionnaires
soon after the data from different questionnaires were collated. Partici-
pants signed an informed consent form before the study began.
Participants first completed the TAS and DES and then received either
the standard
or
a modified (for individual administration) audiotaped
version of the Harvard Scale induction.
A
2-minute period was inserted
toward the end
of
the HGSHS:A protocol, subsequent
to
eye catalepsy
but prior to the counting out sequence, during which the participants sat
quietly with their eyes closed.
As
in
other studies with the PCI, the
par-
ticipants were instructed as follows:
For the next several minutes,
I
am
going
to stop talking and
I
want you to
continue to experience the state you are
in
right now. For the next several
minutes,
I
am going to
stop
talking and
I
want you to continue
to
experi-
ence
the
state
you
are in right now. After several minutes,
I
will start talk-
ing again.
OK,
for the next several minutes, continue to experience what-
ever you are experiencing right now.
After the participants were brought out of hypnosis
and
the posthyp-
notic suggestion was removed, they completed the PCI, Form
1,
in refer-
ence to the 2-minute sitting quietly period.
RESULTS
The various results are based on
35
to
40
participants in each group
(individual and group administration) because of
missing
data. Given the
small sample size
in
each condition, we decided to use an alpha level of .20
to minimize the probability of inferring no sigruficant difference when
in
fact there
is
one (a Type
11
error).
Glass
and Hopkins (1984) suggest that
"in
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242
FRANK
J.
ANGELINI
ET
AL.
certain situations it is appropriate to set
a
=
.1 or even higher” (p. 2077,
especially when one wishes to minimize the
risk
of a Type
I1
error (see
also Nash, Hulsey, Sexton, Harralson,
&
Lambert, 1993).
Reliability and Descriptive Characteristics
Table
1
presents the Cronbach’s alpha values, means, and standard
deviations for the Harvard Scale, TAS, and
DES
(including subscales).
The internal consistency reliabilities in the two administration condi-
tions were similar? Table
1
shows that the means did not differ signifi-
cantly
(p
>
.20) between the individual and group administrations for the
Harvard Scale,
TAS,
and DES (including subscales).
In
addition, Levine’s
test for the equality of variances revealed a sigruficant difference for the
HGSHS:A
(F
=
2.16,
p
<
.15) but not for the
TAS
and DES
(F
<
1.0 in both
cases). The finding of decreased variance for the
HGSHS:A
in the indi-
vidual, relative to the group, condition may be regarded as modestly
suggestive of an effect of the context of administration, keeping in mind
that the Bonferroni
p
required equals approximately -067 for any of the
tests to be regarded as significant.
There also were
no
differences in the variances of the
DES
subscales
(p
>
.41 for all three tests). The eta-squared values
in
Table
1
suggest that
the mean differences between the two groups for the dependent vari-
ables were extremely small.
Only
for the HGSHSA did the effect size
exceed
1%
(i.e., 1.4%). Table
1
also indicates that the power to detect such
small differences was extremely low.
To
avoid problems of multicollinearity, two separate multivariate
analyses of variance were done to see
if
there were differences between
the two administration conditions
on
the
PCI
major and minor dimen-
sions. These results are not reported in detail here because the multivari-
ate analyses for both major and minor dimensions were not significant,
exact F(12,61)
=
0.81, exact
F(
14/59)
=
0.63, respectively. Furthermore,
the Levine’s tests for equality of variances were not significant (using the
Bonferroni adjustment) between the two administration conditions for
the
PCI
major and almost all of the minor dimensions (as noted before,
the Levine’s test was significant only for the anger dimension).
3Although not reported
in
detail here, the reliability values
for
the
PCI
major and minor
dimensions also were similar
in
the
two
testing contexts
for
21
out of the
26
(sub)dimen-
sions with differences of
0.15
or
less. The
two
minor dimensions most affected by the con-
text of administration were anger and sadness. Although the individual administration re-
liability values were only
.10
and
20,
respectively, the group values were
.68
and
.61.
The
lowered reliability was most likely due to the rather low variability
in
the individual con-
text
(SD
=
.86
and
.91
for anger and sadness, respectively) as opposed to the group context
(SD
=
1.48
and
1.22
for anger and sadness, respectively). However, it is to be noted that the
means between the
two
conditions did not differ significantly
(p
=
,184
and
,353,
respec-
tively); it may be noted that with
a
Bonferroni adjustment for
14
tests,
p
required for signifi-
cance would be
.014
(for an overall alpha of
.20),
and the variance was significantly differ-
ent for anger only
(p
=
.014).
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Table
1
Reliability, Means, and Standard Deviations for lndividrlal
and
Group Administrations
Individual
Group
Cronbach'sa
M
SD
Cronbach'sa
M
SD
t
P
TI2
1
-
0"
HGSHS:A .74 7.48 2.78 .79 6.78 3.14
1.05
.29 .014
.42
TAS .82 20.20 5.78 .76 21.05 5.16 .69 .49 .006 .52
DES
.92 22.44 12.52
.95
21.27 14.41 .39 .70 .002
.34
AE .70 12.33 14.47 .68 11.00 14.09 .42
.68
.002 .36
AbC
.88
31.50 17.99 .91 29.73 19.54 .42 .67
.002
.37
D&D
.77
8.14 8.78
.81
8.17 11.17 .02 .98
.000
.27
HGSHS:A
=
Harvard Group Scale
of
Hypnotic Susceptibility:
Form
A;
TAS
=
Tellegen's Absorption Scale; DES
=
Dissociative Experiences Scale;
AE
=
Amnes-
tic Experiences;
AbC
=
Absorption
&
Changeability;
D
&
D
=
Derealization and Depersonalization.
a.
Assuming
a
=
.20.
w
P
w
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244
FRANK
J.
ANGELINI
ET
AL.
Table
2
Item
Dificulty Indices
of
the
Hamard Scale
by
Administration Condition
Individual Group
N
Proportion
N
Proportion
x2
P
Postural alteration
24
.600
16
.400 3.20 .07
Eye
closure
33 325 28 .700 1.72 .18
Hand lowering
32
.goo 31 775 0.07 .78
Arm
immobilization
33 .825 30 .750 0.67
.41
Finger
lock
19 .475
18
.450
0.05
.82
Hands
moving
28 .700
22
.550 1.92
.16
Common
inhibition
31 775 30 ,750
0.06
.79
Hallucination
22
.550
24
.600
0.20
.65
Eye
catalepsy
8 ,200 9 225 0.07 .78
Posthypnotic
suggestion
23 .575 20 .500 0.45
.50
Amnesia
20 .500 17 .425 0.45 .50
Note.
N
=
Number
passing
the
item,
Proportion
=
proportion
passing
the
item.
Item
Analysis
of
the
Harvard
Scale
Because the main focus of this study was the effect of individual and
group administrations on the Harvard Scale, this analysis only per-
tained to the Harvard Scale and not to the other instruments used
in
the
study. Table
2
presents the item difficulty levels of the
12
Harvard items
for the two administration contexts.
x'
analyses showed that significant
differences were obtained for only
3
of the
12
items
(p
<
20).
Because the
Bonferronip required equals approximately
.02
for
10
tests (for
a'
=
.20),
these differences may be attributed to chance. These results are further
supported by a strong positive correlation
(Y
=
-92)
between the two sets
of item difficulty levels.
In
addition, the Spearman rank order correla-
tion for the
two
sets was strong
(Y,
=
.83).
These results suggest that item
difficulty levels for the Harvard Scale were largely unaffected by the
condition of administration.
However, for
9
out of the
12
HGSHS:A items, subjects in the individ-
ual condition were more likely to have "passed than were subjects in
the group condition; the probability of this occurring by chance alone
is
p
<
.05
using a sign test (Conover, 1971). These results are similar to those
obtained
in
the study by Shor and Ome
(1963)
when testing the differ-
ences between the original normative group (tested via group admini-
stration) and
a
group of Harvard Medical School
(HMS)
students (tested
individually) who volunteered
in
experiments on hypnosis.
In
their
study, the proportion of individuals passing the items were higher for
each of the
12
items. Thus, even though the parametric comparison of
condition means was not significant, an item-by-item analysis
Arm rigidity
26 .650 26 .650 0.00 1.00
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HARVARD
SCALE
24s
Table
3
Correlations
of
the
HGSHS:A
With Other Instruments:
Differences Between Individual and Group Conditions
Instruments
TAS .235 .053 .83 .41 .19
DES
.017
-.086
.46 .65
so
Amnestic experiences
-.I28
-.078 .23
.82
.05
Absorption
&
changeability
.094 -.027 .54 .59 .12
Derealization
&
depersonalization
-.062
-.
138
.34
.73
.08
Dissociative control
.402* .611** 1.23
.22
29
Positive
affect
.357* .380* .12 .90
.03
Negative
affect
-.149
.188
1.53 .13 .34
Visual
imagery
.254 .244 .05 .96
.01
Individual Group
IZI
p
9
Attention
to
internal
processes
.569** .427** .83
.41
.19
Note.
HGSHS:A
=
Harvard
Group
Scale
of
Hypnotic
Susceptibility: Form
A;
TAS
=
Tellegen’s
Absorption
Scale;
DFS
=
Dissociative
Experiences
Scale;
q
=
Cohen’s
Effect
Size
Index.
*p
<
.05.
*p
<
.01,
two-tailed.
suggested a significant general trend of higher proportions of individu-
als passing the items when tested individually, as opposed to in a group.
Distribution Differences
on
the Harvard Scale
as a Function
of
Administration Conditions
To
further examine possible differences between the administration
conditions, the proportions of participants classified as low, medium,
and high susceptibles were compared across the two conditions. The
cut-off scores suggested by Kirsch et al. (1990) were used for this analy-
sis:
low
susceptible (score of
0-4),
medium susceptible (score
of
5-9),
and
high susceptible (score
of
10-12).
The breakdown of the proportions of
participants in these categories by conditions (individual and group,
respectively) were as follows: low 20% and 22.5%, medium
50%
and
SO%,
and high
30%
and 27.5%.
A
x2
analysis showed that the nature
of
administration did not affect the distribution of membership in the three
susceptible groups, ~’(2)
=
.102,
p
=
.95.
Correlations With
HGSHS:A:
Diferences Between
the Individual and
Group
Administrations
Table
3
presents the correlations between the Harvard Scale and each
of
the other variables, that is, the
TAS,
the
DES
(its subscales), and the
five state-effects scores of the
PCI:
dissociated control, positive affect,
negative affect, visual imagery,
and
attention to internal processes. The
factor-based scores for the five state effects were derived by
using
the
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246
FRANK
J.
ANGELINI ET AL.
significant factor loadings obtained in
Kumar,
Pekala, and
Cdgs’s
(1996) study. The standardized scores of only those significant variables
were weighted with the corresponding factor loadings from the previ-
ous study
and
then summed to determine the factor-based scores. As
before, the loadings for the dissociated control state factor were reversed
so
that higher scores would reflect greater dissociated control in the
sense of increased alterations in awareness, body image, time sense, per-
ception, and meaning combined with decreased self-awareness, internal
dialogue, rationality, volitional control, and memory. According to
Kumar, Pekala,
and
Cummings, the dissociated control state factor
reflects changes
in
both trance
and
reality orientation of the participants.
Even with
a
liberal cut-off of alpha at
.20,
the group differences failed
to reach significance on
9
of the
10
variables.
Only
for negative affect was
there a significant effect at the
p
<
.13 level; however,
this
also may be
attributed to chance if one adjusts the overall alpha of
.20
for multiple
tests (i.e., Bonferroni
p
will
equal
.02
for 10 tests). Cohen’s (1992)
q
index
for effect sizes
is
also indicated
in
Table 3. For
6
of the 10 variables, the
effect sizes were low
(.lo
or more) to medium
(.34);
for the other
4
vari-
ables, differences were trivial (less than
.lo).
Furthermore, if one
assumes the population correlation between the HGSHS:A and TAS to
be about
.20
(Nadon,
1997)
and between the HGSHS:A and
DES
to be
about
.13
(van IJzendoom
&
Schuengel, 1996), then the respective corre-
lations (either condition) obtained in this study do not differ signifi-
cantly
(Z
values
<
1.00
for both tests) from them.
DISCUSSION
At the very outset, a note of caution
is
warranted in drawing conclu-
sions from largely null findings, especially
in
view of low power
in
the
statistical tests associated with small sample sizes
in
each of the admini-
stration conditions. However, the effect sizes computed were
so
small
that one would need extremely large sample sizes to detect such small
effects. Still, more definitive conclusions concerning the individual ver-
sus group administration must await a large-scale study with more
subjects.
Does
Group
Versus
Individual Administration
Affect the Descriptive Characteristics
of
the
HGSHS:A?
To
a modest degree, our finding of a signrficant (sign test,
p
<
.05)
gen-
eral trend of higher difficulty indices (higher value indicates item easi-
ness) for the HGSHS:A items for individual, vis-a-vis group, administra-
tion was similar to that of Shor and Ome (1963).
In
addition, the
variability of the HGSHS:A
was
somewhat lower for the individual,
than for the group, administration
(p
<
.15).
However, these findings
must be considered provisional, given that the
two
conditions did not
differ in terms of (a) a parametric comparison
of
the overall means
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HARVARD
SCALE
247
(p
>
.20),
(b)
the chi-square tests of item difficulty indices in an item-by-
item analysis (using Bonferroni adjustment for 12 tests), and
(c)
the pro-
portions
of
subjects classified into high, medium,
and
low susceptible
categories. Furthermore, the means and standard deviations of the
HGSHS:A were similar to those found in previous studies (Kirsch et al.,
1990; Shor
&
Ome, 1963; Zachariae, Sommerlund,
&
Molay, 1996).
Does
Group Versus Individual Administration
Affect the Reliability and Validity Configuration
of
the
HGSHS:A?
There is little evidence that the internal consistency was compro-
mised by the individual administration of the HGSHS:A. The reliability
values are similar to those found in other investigations
(Kirsch
et al.,
1990; Shor
&
Ome, 1963; Zachariae et al., 1996). The pattern of correla-
tions with related constructs seems secure across the
two
administration
conditions with the magnitude of correlations similar
to
those reported
in the literature (Kumar, Pekala,
&
Marcano, 1996; Nadon, 1997; van
IJzendoorn
&
Schuengel, 1996). Furthermore, individual and group
administrations resulted in similar phenomenological experi-
ences-greater hypnotizability was associated with greater feelings of
dissociative control, positive affect, and attention. These results parallel
those of other studies (Kumar, Pekala,
&
Cummings,
1996; Kumar,
Pekala,
&
McCloskey, 1997).
Thus,
although there may be an effect
of
administration in terms of a general trend of higher difficulty indices for
the individual administration, the reliability /validity configuration of
the HGSHS:A seems relatively unaffected by the condition of
administration.
Although these results may point to the flexibility of using the
HGSHS:A either for individual or group administration, it would seem
prudent to exercise caution when faced with making chical judgments
or when contemplating how to manage data collected from
both
indi-
vidual
and
group administrations of the HGSHS:A. At
this
point in time,
we would advise that it is best to avoid routinely combining data from
individually tested subjects with data obtained from group testing.
Finally, Shor and Orne (1963) suggested that the HGSHSA can be used
with groups
of
unlimited size. Thus,
an
interesting study would be to
systematically evaluate the effects of group size (including very large
sample sizes of 100 to
200
students or more).
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Die Harvard Gruppenskala der Hypnose-Suggestibilitat und verwandte
Instrumente: individuelle Administration und Gruppenadministration
Frank
J.
Angelini, V. K. Kumar, und Louis Chandler
Zusammenfassung: Die folgenden Skalen wurden individuell oder in Grup-
pen administriert: die Harvard Gruppenskala der Hypnose-SuggestibiliGt
(Form :A), Tellegen's Absorption Scale (TAS), Dissociative Experiences Scale
(DES),
und Phenomenology of Consciousness Inventory (PCI). Achtzig Studi-
enanf anger aus einem "Einfiihrungskurs
in
die Psychologie" wurden ran-
dornisiert in zwei Gruppen zu je
40
Studenten individuell bzw. unter Grup-
penbedingungen getestet.Unter den beiden
Administrationsbedingungen
zeigte sich zwar ein unterschiedlicher Trend in bezug darauf, wie schwierig
es war, Elemente auf der Skala zu bestehen, aber es deuten eine Vielzahl von
Resultaten (descriptive characteristics, reliability, validity) auf die Ahn-
lichkeit von verhaltensmagigen und subjektiven Hypnose-Reaktionen unter
beiden
Administrationsbedingungen
hin. Die
TAS-,
DES- und PCI-Tests
erzielten ahnliche Ergebnisse fir die beiden
Administrationsbedingungen.
ROSEMARIE
GREENMAN
University
of
Tennessee, Knoxville,
USA
L'Echelle de Sensibilitk Hypnotique du Groupe Harvard
et ses outils en rapport
:
gestion individuelle
ou
de groupe
Frank
J.
Angelini, V.
K.
Kumar, et Louis Chandler
RCsumC: L'Echelle de SensibilitC Hypnotique du Groupe Harvard, forme A,
1'Cchelle d'absorption de Tellegen (TAS), l'kchelle d'exp6rience dissociative
(DES),
l'inventaire
de
phknomknologie de conscience
(PCI)
ont Ct6 appliqu6s
soit individuellement soit en groupe.
80
ktudiants du niveau de licence "Intro-
duction
B
la psychologie" ont 6th test& de facon randomisee
h
rune des dew
conditions,
40
Ctudiants dans chacune d'entre elles. Bien que il y ait eu une
tendance gkn6rale
h
h
diffiirencier les niveaux de difficult6 des items pendant
Downloaded by [West Chester University Libraries] at 07:01 04 November 2013
250
FRANK
J.
ANGELINI
ET
AL.
les deux conditions d'applications, une vari6t6 de r6sultats (caractCristiques
descriptives, fiabilit6, validit61 montrent la similarit6 des reponses subjec-
tives et comportementales l'hypnose dans ces
2
conditions. Les TAS, DES, et
PCI ont Cgalement produit des rbsultats identiques dans les deux conditions
&administration de ce travail.
VICTOR
SIMON
Psychosomatic Medicine
&
Clinical Hypnosis
Institute, Lille, France
La Escala Grupal de Susceptibilidad Hipn6tica de Harvard
y
otros instrumentos afines: administraciones individual y grupal
Frank
J.
Angelini,
V.
K.
Kumar, y Louis Chandler
Resumen: Administramos individual
o
grupalmente la Escala Grupal de Sus-
ceptibilidad HipnBtica de Harvard, Forma A (HGSHS:A); la Escala de Absor-
ci6n de Tellegen (Tellegen's Absorption Sca1e;TAS); la Escala de Experiencias
Disociativas (Dissociative Experiences Scale; DES);
y
el Inventario Fenome-
nol6gico de Conciencia (Phenomenology of Consciousness Inventory; PCI).
Asignamos aleatoriamente a
1
de las
2
las condiciones de adrninistracion a
ochenta estudiantes del curso universitario "Introduccibn a la Psicologia" con
40
estudiantes en cada grupo. Aunque hub0 una tendencia general a tener dis-
tintos niveles de dificultad de 10s items en las
2
condiciones de administra-
ci6n, varios resultados (caracteristicas descriptivas, confiabilidad, validez)
subrayan la semejanza en las respuestas subjetiva
y
conductual a la hipnosis
en las
2
condiciones. El TAS, DES,
y
PCI tambi6n produjeron resultados simi-
lares en ambas condiciones de administracibn.
ETZEL
CARDERA
Uniformed Services University
of
the Health
Sciences, Bethesda, Ma yland, USA
Downloaded by [West Chester University Libraries] at 07:01 04 November 2013
... The Harvard Group Scale of Hypnotic Susceptibility (HGSHS: A) [30] is the most widely used in hypnosis research because of its cost effectiveness and the ability to test several people at the same time [30]. However, as Angelini et al. [30] pointed out, both group testing and individual testing of hypnotic responsiveness have their limitations. ...
... The Harvard Group Scale of Hypnotic Susceptibility (HGSHS: A) [30] is the most widely used in hypnosis research because of its cost effectiveness and the ability to test several people at the same time [30]. However, as Angelini et al. [30] pointed out, both group testing and individual testing of hypnotic responsiveness have their limitations. ...
... The Harvard Group Scale of Hypnotic Susceptibility (HGSHS: A) [30] is the most widely used in hypnosis research because of its cost effectiveness and the ability to test several people at the same time [30]. However, as Angelini et al. [30] pointed out, both group testing and individual testing of hypnotic responsiveness have their limitations. They highlighted the fact that social interaction in a group may skew findings by increasing or decreasing the desire to perform in front of others. ...
Article
Full-text available
This article explores the history of the ancient art of hypnosis down through the years. It examines the efficacy of hypnosis as a treatment for chronic pain and outlines theories and models of hypnosis. The biological correlates of hypnosis are delineated and the application of hypnotherapy and its place in modern medicine in the treatment of chronic pain is also discussed.
... The TAS, a measure of the trait of absorption, has produced significant correlations that vary across studies with the HGSHS: A; 13-89 by some estimations, 0-50 by others, with an estimation of a mean of roughly .20 (Roche & McConkey, 1990;Angelini, Kumar, & Chandler, 1999). The TAS is a self-test questionnaire consisting of 34 questions regarding subjective states of concentration and fantasy involvement, and has been described as, "openness to self-altering experiences" (Tellegen & Atkinson, 1974). ...
... The Tellegen Absorption Scale (TAS) (Tellegen and Atkinson, 1974) is a 34-item, dichotomous, true/false measure of absorption. It has been correlated with hypnosis, often with hypnotizability at ranges between .13-.89, and with the HGSHS:A in particular from .00-.50, with a mean score of .20 (Roche & McConkey, 1990;Angelini, et al., 1999). Validity is set at .66-.75, and reliability at .85-.95 over various studies (Tellegen & Atkinson). ...
... What was perhaps most striking among the findings was the lack of correlation between the HGSHS: A and the TAS. As per the literature, these two measures were expected to at least produce significant, low correlations, and were predicted to be higher due to the subset of the population studied (Roche & McConkey, 1990;Angelini, Kumar, & Chandler, 1999). However, in some studies, they do not produce a correlation, so the results here were not altogether unexpected. ...
Thesis
Full-text available
Creativity and hypnosis have been considered related traits since the 1960s. A great deal of research supports this through the study of quantitative measures of both traits. This study was undertaken in order to replicate research correlating creativity and hypnotizability, but among individuals considered more creative than the general population. Thirty two subjects (n=32) involved in creative fields were administered a battery of hypnosis and creativity measures consisting of the Harvard Group Scale of Hypnotic Suggestibility Form A, the Tellegen Absorption Scale, the Abbreviated Torrance Tests for Adults, and the O Index of the NEO-PI-R O Index. Six relationships were hypothesized among the variables, and null was rejected only in one; there was a significant correlation between the personality measure of hypnotizability, as represented by the Tellegen Absorption Scale, and the personality measure of creativity, the NEO-PIR O Index. The scores on these two tests individually were both one and two standard deviations above population norms respectively. The sample means for the Harvard Group Scale of Hypnotic Suggestibility Form A and were below the population norms, and the samples means for the Abbreviated Torrance Test for Adults were average. It was concluded that the extremely high scores on the Tellegen Absorption Scale and the O Index skewed the results for correlations among all the scores. A main implication of the results was that populations that rank extremely high in aspects of creativity might produce dissipation in the correlation to hypnotizability.
... All five psychometric measures used in this study are validated and reliable measures of anomalous thinking and experiences in both non-clinical and clinical populations (Angelini, Kumar, & Chandler, 1999). There was one measure for compartmentalisation (HGSHS: A), one for detachment (DES), two for psychotic-like experiences (PDI-21 and CAPS) and finally one measure for absorption (TAS). ...
... The HGSHS: A is a well-validated and reliable measure (Cronbach's alpha = .79; Angelini et al., 1999) that includes a short hypnotic induction session followed by a series of 12 suggestions and a de-induction procedure. It can be psychometrically divided into three factors: ideomotor (e.g. ...
... The total score is a sum of the suggestions responded to (i.e., higher scores indicate greater hypnotizability). It is one of the most commonly applied measures of hypnotizability in group settings, comparable to other standardized hypnotizability measures (Busija et al., 2011) and reliable when delivered in groups or individually (Angelini et al., 1999). In our sample, the HGSHS had adequate internal consistency, Cronbach's ɑ = .71. ...
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... 46 Of the reviewed studies, some reported that patients under the age of 50 and female patients responded better to hypnotherapy, 16,21,27,33 which can be due to higher hypnotizability in females and younger clients. 46 Thus, we suggest assessing hypnotizability with standard scales, such as the Stanford Scales of Hypnotic Susceptibility 47 or the Harvard Group Scale of Hypnotic Susceptibility, 48 in future studies. ...
... Moreover, differences in imagery, vividness, self-awareness, and arousal were found between the meditative and non-meditative states (Venkatesh, Raju, Shivani, Tompkins, & Meti, 1997). When compared with self-report measures of creativity, PCI results were correlated with reported creativity, positive affect, attention to internal processes, visual imagery, and subjective trance depth experienced during hypnosis (Angelini, Kumar, & Chandler, 1999;Kumar et al., 1996). ...
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Presents data from 2 studies with 112 and 263 undergraduates, respectively, suggesting that the Phenomenology of Consciousness Inventory has adequate reliability and validity in assessing alterations in phenomenological experience associated with stimulus conditions (i.e., eyes open and closed, sitting quietly, and a hypnotic induction). (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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300 nursing students experienced 4 stimulus conditions (baseline, progressive relaxation, deep abdominal breathing, and hypnosis) and completed the Phenomenology of Consciousness Inventory in reference to a 2-min period under each condition. Hypnoidal scores, assessing the extent to which Ss endorsed phenomenological experience consistent with what high susceptibles would report during hypnosis, were computed for each condition for low, low-medium, high-medium, and high susceptible Ss. Repeated-measures analyses of variance (ANOVAs) indicated that, although hypnosis and progressive relaxation were associated with near equivalent hypnoidal scores for high susceptibles, low susceptible Ss obtained higher scores during progressive relaxation. Findings have implications for the differential use of stress management techniques in clinical practice. (PsycINFO Database Record (c) 2012 APA, all rights reserved)