The Waterloo-Stanford Group C (WSGC) Scale of Hypnotic Susceptibility: Normative and Comparative Data

The Waterloo-Stanford Group C (WSGC) hypnotic susceptibility scale was developed as a substitute for the individually administered Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). A first investigation with WSGC reports normative data on 259 subjects, and the results indicate that it is comparable in most important respects to the norms of SHSS:C. A second investigation directly compared WSGC and SHSS:C in a counterbalanced design on 65 subjects, and the two scales correlated .85. It is argued that, when used as a follow-up to the Harvard Group Scale of Hypnotic Susceptibility, Form A, WSGC provides a valid criterion of hypnotic ability.     

Phenomenological experiences associated with hypnotic susceptibility

Following the administration of a Hungarian translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C), 104 Hungarian subjects completed the Hungarian translation of the Phenomenology of Consciousness Inventory (PCI). Subjects had also been administered the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS: A) about 1 week to 2 months before the SHSS:C The pattern of correlations between hypnotizability (as measured by the HGSHS:A and the SHSS:C) and the 5 factors of the PCI was quite similar to that of previous work carried out using the English language versions on subjects in the United States. SHSS:C and HGSHS:A scores correlated significantly with the PCI factors of dissociated control, positive affect, and attention to internal processes factors. In addition, the SHSS:C score correlated significantly with the visual imagery factor, as found in previous work.     

Italian Norms for the Stanford Hypnotic Susceptibility Scale,Form C1

This paper presents norms for an Italian translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C; Weitzenhoffer & Hilgard, 1962). Archival data on hypnosis research subjects recruited over a 10-year period of research on hypnosis were pooled, resulting in an aggregate sample of 356 participants (263 female and 93 male). Score distribution, item difficulty levels, and reliability of the SHSS:C were computed. Of this group, 218 subjects were administered the Harvard Group Scale of Hypnotic Susceptibility approximately 3 weeks prior to administration of the SHSS:C. The remaining 138 subjects received only the SHSS:C. Results suggest that the Italian version of the SHSS:C is a reliable and valid measure.     

Hypnotic susceptibility scales: are the mean scores increasing?

The Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C), developed and named 37 years ago, is arguably the "gold standard" of hypnotic susceptibility scales. However, it has been the impression of several researchers that means obtained on the SHSS:C are higher now than in previous years. The authors comprehensively review studies using the SHSS:C over a 4-decade period. The findings demonstrate a significant linear trend between year and SHSS:C scores, with higher obtained means in more recent work. The authors also report a similar analysis of research with the Harvard Group Scale of Hypnotic Susceptibility, Form A. Although the mechanisms underlying this trend can only be speculated upon at present, these findings underscore the importance of using local control groups in research on hypnotizability.     

Italian norms for the Stanford Hypnotic Susceptibility Scale, Form C

This paper presents norms for an Italian translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C; Weitzenhoffer & Hilgard, 1962). Archival data on hypnosis research subjects recruited over a 10-year period of research on hypnosis were pooled, resulting in an aggregate sample of 356 participants (263 female and 93 male). Score distribution, item difficulty levels, and reliability of the SHSS:C were computed. Of this group, 218 subjects were administered the Harvard Group Scale of Hypnotic Susceptibility approximately 3 weeks prior to administration of the SHSS:C. The remaining 138 subjects received only the SHSS:C. Results suggest that the Italian version of the SHSS:C is a reliable and valid measure.     

Phenomenological experiences associated with hypnotic susceptibility

Following the administration of a Hungarian translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C), 104 Hungarian subjects completed the Hungarian translation of the Phenomenology of Consciousness Inventory (PCI). Subjects had also been administered the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) about 1 week to 2 months before the SHSS:C. The pattern of correlations between hypnotizability (as measured by the HGSHS:A and the SHSS:C) and the 5 factors of the PCI was quite similar to that of previous work carried out using the English language versions on subjects in the United States. SHSS:C and HGSHS:A scores correlated significantly with the PCI factors of dissociated control, positive affect, and attention to internal processes factors. In addition, the SHSS:C score correlated significantly with the visual imagery factor, as found in previous work.     

In Memoriam: Milton V. Kline 1923-2004

3 subgroups of 20 Ss with high, medium, or low scores on a slightly modified, tape-recorded version of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) were later administered the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and Hilgard (1962). HGSHSrA and SHSSrC correlated .59 which is lower than would be predicted by scale reliabilities. This, together with other data based on item characteristics, indicates that the 2 scales are not equivalent, but in part measure different aspects of hypnotic performance. Scores on HGSHSrA for low Ss are predictive of SHSS:C scores, but the stability of performance between HGSHS:A and SHSS:C is not as marked for medium and high Ss on HGSHS:A. This is partly a result of the failure of passive motor (primary) suggestibility to discriminate between levels of susceptibility, although challenge items do. The 2 clusters of items correlate .23 and .43 in HGSHS:A and SHSS:C respectively. The passive suggestibility items detract from the validity of the 2 scales.     

Involuntariness of Response on the Harvard Group Scale of Hypnotic Susceptibility

Following a tape-recorded administration of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962), some 272 Ss recorded their objective responses in the standard scoring booklet and then rated the voluntariness-involuntari-ness of their responses to each HGSHS:A item. The ratings indicated that in about 75% of the instances where HCSHS:A items were objectively passed, Ss experienced their response as completely or mostly involuntary, and this percentage did not differ between ideomotor items and the more difficult challenge items. For a subset of 35 Ss tested on the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitz-enhoffer and Hilgard (1962), SHSS:C score was predicted reliably by HGSHS:A objective score. Thus, HGSHS:A is an adequate predictor of hypnotic susceptibility according to a criterion measure (SHSS:C), in spite of the fact that individual HGSHS:A items are not perfect measures of the classical suggestion effect according to the criterion of involuntar-iness. Ss with higher HCSHS:A scores had significantly higher mean involuntariness ratings for passed items than did lower scoring Ss.     

Finding the Hypnotic Virtuoso

Measures of hypnotizability based on the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) correlate only moderately with those based on Stanford Hypnotic Susceptibility Scale, Form C(SHSS:C). Ss(N = 148) scoring in the high range (10-12) on HGSHS:A were classified according to whether they scored in the “virtuoso” range (11-12) or not on a subsequent administration of SHSS:C. Significant group differences were found on items comprising the cognitive distortion subscale of HGSHS:A, whether assessed in terms of overt behavior or subjective impressions of success. The 2 groups also differed on global self-ratings of hypnotic depth and on those subscales of Field's Inventory Scale of Hypnotic Depth concerned with subjective feelings of loss of control, automaticity, transcendence of normal functioning, and fluctuating depth. Assessments of hypnotizability are enhanced when investigators consider subjective involvement as well as behavioral measures of hypnotic response. This is particularly important when the more dissociative aspects of hypnosis are under scrutiny.     

Book review

To overcome problems with previous psychometric approaches to hypnosis scales, the authors applied full-information factor analysis, based on multidimensional item-response theory (IRT), to a 39-year sample of 11,517 records of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A). They also performed a comparable analysis on the standardization sample of the Waterloo-Stanford Group C Scale (WSGC). The HGSHS:A emerges as two-factored, whereas the WSGC more closely approaches unidimensionality. The HGSHS:A factor structure and means show very little change over 4 decades. However, IRT-based item analysis on the HGSHS:A indicates that problems such as “pseudoguessing” on 2 items limit the quality of the item set. The authors propose alternative substantive interpretations of the traits that may underlie the two-factor structure.     

Four decades of group hypnosis scales: what does item-response theory tell us about what we've been measuring?

To overcome problems with previous psychometric approaches to hypnosis scales, the authors applied full-information factor analysis, based on multidimensional item-response theory (IRT), to a 39-year sample of 11,517 records of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A). They also performed a comparable analysis on the standardization sample of the Waterloo-Stanford Group C Scale (WSGC). The HGSHS:A emerges as two-factored, whereas the WSGC more closely approaches unidimensionality. The HGSHS:A factor structure and means show very little change over 4 decades. However, IRT-based item analysis on the HGSHS:A indicates that problems such as "pseudoguessing" on 2 items limit the quality of the item set. The authors propose alternative substantive interpretations of the traits that may underlie the two-factor structure.     

The Stanford Hypnotic Susceptibility Scale, Form C: normative data of a Dutch student sample

Norms for the Dutch language version of the Standford Hypnotic Susceptibility Scale, Form C (SHSS:C; Weitzenhoffer & Hilgard, 1962) are presented. These norms are based upon a sample of 135 students at a Dutch university. Generally, the psychometric properties of the Dutch version of the SHSS:C are similar to other language versions. However, the mean score was somewhat lower than that found in the original norming studies at Stanford University.     

The stanford hypnotic susceptibility scale,form C: Normative data of a dutch student sample

Norms for the Dutch language version of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C; Weitzenhoffer & Hilgard, 1962) are presented. These norms are based upon a sample of 135 students at a Dutch university. Generally, the psychometric properties of the Dutch version of the SHSS:C are similar to other language versions. However, the mean score was somewhat lower than that found in the original norming studies at Stanford University.     

An investigation of Taiwanese norms for the Stanford Hypnotic Susceptibility Scale: Form C (Mandarin Chinese Translation)

This study establishes normative data for the Mandarin Chinese Translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C-MCT). Fourteen administrators gave the SHSS:C-MCT as well as demographic and meditation questionnaires to 322 participants of Taiwanese nationality. Score distributions, normality, internal consistency, item difficulty, and comparisons with other SHSS:C samples are presented. Scores on the SHSS:C-MCT were compared to both demographic and meditation practice data. The psychometric properties of the SHSS:C-MCT were found to be similar to those of other samples, and the Taiwanese mean score was found to be higher than most other samples, providing support for continued and expanded use of hypnosis in relative treatment applications in Taiwan.     

Finding the hypnotic virtuoso--another look: a brief communication.

Student volunteers who scored 9 (N = 20), 10 (N = 19), 11 (N = 26), and 12 (N = 15) on a live-administered Harvard Group Scale of Hypnotic Susceptibility (HGSHS:A) of Shor and E. Orne (1962) were retested with the individually administered Stanford Hypnotic Susceptibility Scale (SHSS:C) of Weitzenhoffer and Hilgard (1962). There appeared to be a break in HGSHS:A's predictive ability at 11 suggestions passed. Whereas a majority of Ss who passed at least 11 HGSHS:A suggestions retested in SHSS:C "virtuoso" range (i.e., passed at least 11 suggestions), a relatively small percentage of Ss who passed fewer than 11 HGSHS:A suggestions retested as SHSS:C virtuosos. These results are generally consistent with previous research (Register & Kihlstrom, 1986) using a standard taped-recorded HGSHS:A induction.     

An Investigation of Taiwanese Norms for the Stanford Hypnotic Susceptibility Scale: Form C (Mandarin Chinese Translation)

This study establishes normative data for the Mandarin Chinese Translation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C–MCT). Fourteen administrators gave the SHSS:C–MCT as well as demographic and meditation questionnaires to 322 participants of Taiwanese nationality. Score distributions, normality, internal consistency, item difficulty, and comparisons with other SHSS:C samples are presented. Scores on the SHSS:C–MCT were compared to both demographic and meditation practice data. The psychometric properties of the SHSS:C–MCT were found to be similar to those of other samples, and the Taiwanese mean score was found to be higher than most other samples, providing support for continued and expanded use of hypnosis in relative treatment applications in Taiwan.     

A Rasch Analysis of the Stanford Hypnotic Susceptibility Scale,Form C

The psychometric structure of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) was tested in a Rasch analysis using data from 279 subjects. The Rasch model is the model of choice because it justifies the use of the sum of the item scores as a measure for the underlying construct. Rasch analysis revealed that use of a single sum score (number of suggestions passed) to express hypnotic ability is not sufficiently justified. However, the omission of the mosquito-hallucination and anosmia items (Items 3 and 9) rendered this short 10-item form of the SHSS:C sufficiently compatible with requirements of one-dimensionality, local stochastic independence, and equi-discriminability. Hence, the 10-item form justifies use of a sum score.     

A. comparison of hypnotic susceptibility as assessed by diagnostic ratings and initial standardized test scores

In a nonrandom sample of 63 Ss, a correlation of .79 was found between Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A) of Weitzenhoffer and Hilgard (1959) scores and diagnostic ratings of hypnotizability. This degree of correlation corresponds to an index of forecasting efficiency of 36.8%. Limitations on the interpretation of this finding both as a validity coefficient and as an indicant of the predictive value of SHSS: A are discussed.     

Hypnotizability and Sensorimotor Gating: A Dopaminergic Mechanism of Hypnosis

Dopaminergic mechanisms have been theorized to influence hypnotizability and sensorimotor gating. In this study, the authors investigated an association between sensorimotor gating, as measured by prepulse inhibition (PPI), and hypnotizability, as assessed by the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). They found an inverse correlation between the SSHS:C and PPI. This finding, which replicates an earlier study, provides further evidence for a dopaminergic basis for hypnotizability and suggests additional avenues for research, including a method for possibly enhancing hypnotizability through pharmacological interventions.     

CAN SUBJECTIVE RATINGS OF ABSORPTION,DISSOCIATION, AND TIME PERCEPTION DURING “NEUTRAL HYPNOSIS” PREDICT HYPNOTIZABILITY?: An exploratory study

This study explored absorption, dissociation, and time perception on visual analogue scales (VAS) after a neutral hypnosis session to predict hypnotizability. Sixty-two subjects completed the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) and, during a neutral hypnosis session, VAS ratings of absorption, dissociation, and time perception. The findings indicated that 44% of subjects scored high, 35% medium, and 21% low on hypnotizability, as determined by scores on the SHSS:C. Dissociation VAS ratings significantly differed when comparing low to high and medium to high hypnotizable subjects. However, ratings were not significantly different between medium and low subjects. Significant positive correlation was found between dissociation VAS ratings and SHSS:C total scores. Future research is needed to validate this proof-of-concept study.