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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

Phenomenological Aspects of Hypnotic Interactions: The Effect of Kinship

This study analyzes the relationship of various measures of hypnosis as a function of kinship. Subjects with varying degrees of kinship (mono- and dizygotic twins, siblings, and parent–child pairs) participated. The Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A), as well as other measures—including the Dyadic Interactional Harmony (DIH) and the Phenomenology of Consciousness Inventory (PCI)—were used with both subjects and hypnosis practitioners. Findings indicated that the phenomenological experience of hypnosis is not determined genetically. The subjects apparently evaluated the session as related to the degree of kinship. MZ twins—on the basis of reactive interactional pattern—evaluate the hypnotic interaction similarly. This was not true for SHSS:A scores or the phenomenological aspects of the state (PCI). These findings were interpreted within the sociopsychobiological model of hypnosis.     

Mexican Norms For The Stanford Hypnotic Susceptibility Scale,Form C

Normative data for the Mexican adaptation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) are presented. Twenty-seven raters administered the scale to 513 Mexican volunteers. Score distribution, item analysis, and reliability of the SHSS:C are presented and compared to other international norming studies. The findings show that the Mexican adaptation of the SHSS:C has psychometric properties essentially comparable to those of the Dutch, German, Italian, and United States reference samples. However, the elevated sample mean suggests Mexicans may have an elevated ability to engage in hypnotic behavior, thus they would likely be especially good candidates for hypnotherapeutic interventions that would better the health options currently available.     

Further norms on the harvard group scale of hypnotic susceptibility,form A

The Harvard Group Scale of Hypnotic Susceptibility, Form A was administered to 168 upper level college students. Findings are congruent with the original normative data reported by Shor and E. C. Orne. Differences between the two samples' mean scores and distributions are discussed in terms of sample composition. Further support for the group scale as an accurate predictor of hypnotic susceptibility was indicated by a significant relationship between the group scale and the individually-administered Stanford Hypnotic Susceptibility Scale, Form C.     

Mexican norms for the Stanford Hypnotic Susceptibility Scale, Form C

Normative data for the Mexican adaptation of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) are presented. Twenty-seven raters administered the scale to 513 Mexican volunteers. Score distribution, item analysis, and reliability of the SHSS:C are presented and compared to other international norming studies. The findings show that the Mexican adaptation of the SHSS:C has psychometric properties essentially comparable to those of the Dutch, German, Italian, and United States reference samples. However, the elevated sample mean suggests Mexicans may have an elevated ability to engage in hypnotic behavior, thus they would likely be especially good candidates for hypnotherapeutic interventions that would better the health options currently available.     

Belgian norms for the Waterloo-Stanford Group C (WSGC) Scale of Hypnotic Susceptibility

Belgian norms of the Waterloo-Stanford Group C Scale of Hypnotic Susceptibility (WSGC) are presented. A French translation of the WSGC was administered to 150 Belgium college students between October and December 2009. Belgium has 2 main linguistic groups, Dutch and French speakers. The present translation was conceived for all French-speaking populations. Score distribution, item analysis, and reliability of the WSGC are presented and compared to the normative sample of the WSGC. The results were also compared with 2 North American norms (University of Connecticut and Seton Hall University) and a Portuguese (translated) norm. The findings show that normative data from the French (Belgium) sample are in line with the reference samples. The only significant difference was the lower proportion of participants scoring within the high range of hypnotic suggestibility on the WSGC.     

Belgian Norms for the Waterloo-Stanford Group C (WSGC) Scale of Hypnotic Susceptibility

Belgian norms of the Waterloo-Stanford Group C Scale of Hypnotic Susceptibility (WSGC) are presented. A French translation of the WSGC was administered to 150 Belgium college students between October and December 2009. Belgium has 2 main linguistic groups, Dutch and French speakers. The present translation was conceived for all French-speaking populations. Score distribution, item analysis, and reliability of the WSGC are presented and compared to the normative sample of the WSGC. The results were also compared with 2 North American norms (University of Connecticut and Seton Hall University) and a Portuguese (translated) norm. The findings show that normative data from the French (Belgium) sample are in line with the reference samples. The only significant difference was the lower proportion of participants scoring within the high range of hypnotic suggestibility on the WSGC.     

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.