In factor analyses of the hypnosis scales, the essential result is that the items form a continuous, 2-dimensional fan-shaped pattern. This continuum is referred to as the “spectrum of hypnotic performance.” “Spectral analysis” is introduced as an exploratory procedure which makes use of this notion of continuum or spectrum. Spectral analysis consists of a graphical display of the level of latent correlation between a variable and individual hypnotic performances when the latter are arranged according to their position in the spectrum. The spectral analysis of hypnotic performance with respect to absorption is illustrated using data from a sample of 160 Ss. The results indicate that absorption is more strongly related to difficult hypnotic performances than to easy ones. In particular, illustrative item characteristic curves are presented to show that although easy hypnotic performances do not require the processes tapped by individual differences in absorption, a certain level of absorption is necessary to pass difficult hypnotic items. In addition, a high level of absorption may be sufficient in and of itself for difficult hypnotic performances. These results are discussed in light of some speculations by Shor, M. T. Orne, and O’Connell (1962) and Tellegen (1978/1979) concerning the differential contribution of ability components to performance on difficult hypnotic suggestions. The results are also related to a variety of work in social psychological models of hypnotic performance.

Spectral analysis “consists of a graphical display of the level of latent correlation between a variable and individual hypnotic performances when these hypnotic performances are arranged according to their position in the spectrum—which is indexed by item difficulty” (p. 25). Difficulty (the proportion of Ss that pass a given item) is on the X-axis; the degree of latent correlation is on the Y-axis. “It is necessary to differentiate between the manifest and the latent relationship of a variable to a dichotomously scored hypnotic performance. The manifest relationship is given by the point biserial correlation and the latent relationship is given by the biserial correlation. … By inspecting the overall pattern of these biserial correlations as a function of item difficulty, it is possible to overcome the difficulty-content confound, because the biserial correlations are not affected by item difficulty” (p. 25).
“Throughout the easy and middle ranges [of item difficulty], the biserial correlation of hypnotic performance with absorption remains slightly above .2, then it rises sharply in the difficult range–beginning roughly where only one in four Ss can pass the item–to a value slightly above .5 ” (p. 27). “In essence, the proportion of Ss that pass a particular hypnosis suggestion given a particular score on the absorption scale is being plotted” (p. 30).
In their discussion, the authors relate their position to that of other theorists. Shor, Orne, & O’Connell (1962) proposed that both ability and nonability components contributed to hypnosis, with ability being the primary determinant of hypnotic performance at deeper levels. Shor et al. found a correlation between depth ratings and a questionnaire that tapped ‘hypnotic-like experiences’ to be .45; the correlation was .84 when computed for only the Ss who became deeply hypnotized, but only .17 for Ss who were only lightly or medium-level hypnotized. They concluded that their questionnaire predicted hypnotizability only for the “deeper region” of hypnosis.
Tellegen (1978/1979) proposed a two-factor model, one factor being genuine responsiveness and the other being compliance . He suggested that various hypnosis test items draw on the two factors in differing degrees. Tellegen’s genuine responsiveness factor would be similar to Shor et al.’s ability components, and Tellegen’s compliance factor would be similar to Shor et al.’s non-ability components. (The Shor model goes farther than Tellegen in positing a gradual shift in the relative contributions of the two components as one moves form easy to difficult items, and this gradualness is part of the authors’ spectrum model.)
The two-factor model is different from the general factor (plus special factors) model suggested by E. R. Hilgard (1965)); Hilgard’s general factor would probably correspond better to the Tellegen genuine responsiveness factor and the Shor et al. ability component than to the compliance factor or nonability component, which probably would correspond more to the easier items on hypnotizability scales.
Spanos et al. (1980) suggested that cooperativeness and expectation might be more important with ideomotor and challenge suggestions, and ability to treat imaginings as real (i.e. absorption) more important for more difficult cognitive items. Sarbin (1984) developed a typology with two types of individuals–those who respond to the hypnosis context by “joining the game” and knowingly create an illusion that their response is involuntary (the compliance kind of response), and those who convince themselves and others that their response is involuntary (the genuine responsiveness factor kind of response).
[Speaking of the context effects observed but not replicated 100% of the time, on the correlation between absorption and hypnotizability.] “It is possible that context effects may depend on the difficulty of the hypnotic suggestions and the latent abilities of the sample used. For relatively good hypnotic Ss performing relatively difficult suggestions, the correlation of absorption with hypnotizability may be stable across different contexts; however, for less able Ss performing relatively easy suggestions, the correlation, depending more on the ‘non-ability’ component, may be quite responsive to context manipulations. It might also be mentioned parenthetically that details of the instructions used to introduce the particular hypnosis scale employed may differentially pull for one kind of component or the other” (p. 39).

Brentar, John P.; Lynn, Steven J. (1992, August). The Post-Hypnotic Experience Scale: Validity and reliability. [Paper] Presented at the annual meeting of the American Psychological Association, Washington, DC.

This paper describes the development of the Posthypnotic Experiences Scale (PES), a 57-item scale comprised of four subscales labeled Pleasant, Somatic- Kinesthetic, Irritability/Anger, and Anxiety. It was derived by way of an initial factor analysis using 444 subjects and refined by a second factor analysis using 288 subjects. In three data collection phases, the subscales were found to be internally consistent and to exhibit low to moderate test-retest reliabilities. The PES was also found to evidence excellent content, convergent, and discriminant validity, as measured by indices of hypnotizability, positive affect, depression, anxiety, hostility, sensation seeking, dysphoria, social desirability, perceptual aberration, absorption, and physical symptomatology. Behavioral validity was demonstrated in so far as subjects who were willing to volunteer for a second experiment, without reimbursement, scored higher on the Pleasant subscale than did nonvolunteers. (ABSTRACT from the Bulletin of Division 30, Psychological Hypnosis, Fall, 1992, Vol. 1, No. 3.)

Frischholz, Edward (1992, October). The dimensionality of hypnotic performance. [Paper] Presented at the annual meeting of the Society for Clinical and Experimental Hypnosis, Arlington, VA.

A 1985 article by Balthazar & Woody in Psychological Bulletin is the best I have read on this topic, and on how factor analysis can be used fruitfully.
Many people using the same data sets have arrived at difference conclusions. My results are based on two data sets: Balthazar & Woody’s, in which they created a unidimensional scale. (If you factor analyze a simplex matrix you obtain a 3 factor matrix; yet you knew it was unidimensional. They pointed out the 2nd factor correlated with item difficulty, and the 3rd factor had a U-shaped correlation with item difficulty.)
Factor analysis may not be best way to demonstrate unidimensionality.
I decided to use non metric multidimensional analysis to confirm unidimension. By this, Form A appears to be multidimensional. The same holds true for Stanford Form C scale.
Interpretability of the different dimensions? I agree with Dr. Stone: unidimensions are better for interpreting tests. But you should start out by constructing one in the first place.
I argue that Form C is unidimensional, because the items were selected by using item/full score correlations, hence a first component was built into it. But what does the scale measure? The only way to know is to correlate it with external measures, like Woody does. There are no studies using factor analysis showing that different factors on hypnotizability tests have different correlations with external measures (e.g. Factor 1 doesn’t correlate differently with Absorption than Factor 3).
We might better start with a theory if we are going to construct new hypnotizability scales. Don’t just use item total correlations. It would be better to find items representing different dimensions, scale the items, then correlate them with different external referents.
Then when we do collect data, make sure the items are unidimensional representations.
Third, we should appropriately validate these dimensions.

Stone, Mark H. (1992, October). Rasch scaling of hypnotizability. [Paper] Presented at the annual meeting of the Society for Clinical and Experimental Hypnosis, Arlington, VA.

The author calibrated responses to the Stanford Scales of hypnotizability, which have not been used much by clinicians. Much of the data collected by Hilgard and Weitzenhoffer on the development of those scales was not published.
Rasch measurement techniques analyzed item data taken from the individual Form A and B manuals.
The Rasch measurement involves natural Log odds, adjusted by variance of the respective persons. Thorndike’s text explains this procedure taken from Wright & Stone, 1979, Best Test Design.
The calibration of items on Forms A and B of the Stanford scales indicates they differ greatly on difficulty and order of items. Items 1, 2, 3 are among the most difficult. Yet, items should follow item difficulty order.
For practicing clinicians, the mean and SD are inadequate to guide treatment. The practitioner wants to know how the patient responds to each item, compared with what would be expected (Like a Chi square). When data from misfit analysis is combined with clinical observation, we would get more understanding [of the patient’s capabilities].
Not only are the 12 items not in order of difficulty, but there is redundancy. We could shorten the scale by selecting only items that span the same range of item difficulty: 4, 8, 10, 11, 2, 1 or 7, and 3. This would give a screening scale with wider range measured, more finely graduated, better suited to diagnosing misfit. We could connect seemingly disparate scale items.
Form C has a perfect correlation between order of difficulty and order of administration, except for 12 which must be administered earlier.
Forms I and II [the Profile scales] deviate from the administration order and the difficulty order.
Only Form C seems to be located in the way the author would want, a Guttman type scale (which is Like Rasch’s analysis).

Woody, Erik Z.; Oakman, Jonathan; Drugovic, Mira (1992, October). Fleshing out a two-component view of individual differences underlying hypnotic responsiveness. [Paper] Presented at the annual meeting of the Society for Clinical and Experimental Hypnosis, Arlington, VA.

Balthazar and I pointed out that different psychological processes are implicated in hypnotizability scale items, depending on the difficulty of the item. One process is more important on easy items, the other on difficult items.
We correlated an external variable as a function of difficulty of the items. Used the Absorption scale as the non-hypnotic measure for the latent correlation (biserial correlations). As item difficulty increases, the correlation with Absorption increases (from .2 to .5).
This suggests a high level of Absorption is needed to pass difficult items on the hypnotizability scale. We argued that Absorption is connected to true hypnotic responsiveness.
Now we are looking for indicators of easy item responsiveness. Last year I tried to explain anomalies in the data, anomalies that disappeared with a full complement of Ss.
Another possible external variable to correlate with item difficulty is a social compliance type of attribute, but in the history of hypnosis those variables are not found. Therefore we used a model from alcohol research that investigates an expectancy type of suggestion.
In that model, Ss drank two drinks that were alcohol free, but one drink purportedly had alcohol. Ss were told that large amounts of alcohol affect changes in perception, and that we were testing whether small amounts did. They were tested for “feeling of sluggishness in limbs,” etc. They rated a list of experiences they might be having. The 109 Ss had been tested on Harvard A scale in separate research.
Ratings in the alcohol model had high internal consistency; this suggestion score correlated with hypnotizability in .2-.3 range.
The pattern of latent correlations would be predicted to be a graph with a negative slope, which the researchers obtained. R = -.77
The easier the hypnosis item, the stronger the correlation with the expectancy measure. The easiest Harvard A scale items tap little more than those expectancy effects, and the hardest items have almost nothing to do with the expectancy effect.
What does this mean? We thought it was evidence of a social influence factor. Further work suggests we need to be more specific.
We measured the other putative variables: 1. Compliance Questionnaire (Gudionsson, 1989); it evaluates the tendency to comply with requests, and to obey instructions; e.g., “I tend to go along even when someone is wrong.” It has correlated with a measure of social conformity. 2. Suggestibility Questionnaire (which we developed). Items were based on interviews in which Ss told about everyday suggestible things–e.g. “When I hear about an illness I tend to get it. When someone tells me they smell something, I tend to also.”
These Compliance and General Suggestibility tests correlated .12 and .07 respectively with the alcohol expectancy measure; nor did they correlate with each other. They do not measure the same trait. Also, though they correlated .18 and .26 with hypnotizability, neither variable showed the spectral pattern on latent correlation analysis.
Thus, we need to be more specific in linking the alcohol expectancy measure to hypnosis.
Most items on Harvard A scale are motor items of either direct suggestion or inhibition (challenge) type. The relationship of alcohol expectancy to direct motor items is strong; the relationship is weaker with motor challenge items (for which another process must be important).
We can think of will vs automatic control of behavior, as in the theory presented by Normal and Shallice. For well-learned behavior there are two levels of control: 1. low level – doesn’t require conscious attention and control 2. higher level – relevant to initiation of action, planning
Direct motor suggestion response requires little attentional effort and the role of will is not important. There exists ambiguity for indeterminacy of the role of will and attention. Ambiguity offers an opportunity to attribute one’s action to hypnosis. What happens in alcohol expectancy is different, but an ambiguous experience is happening due to “alcohol” in the drink–ambiguous experience is interpreted according to the context.
This differs from the neodissociation theory explanation, according to which the suggested behavior is enacted voluntarily but the voluntary aspect is separated from consciousness. To me, for simple motor acts the causality is inferred rather than perceived. For simple motor acts, no such higher level control is needed.
Motor challenge items have instructions to “try” to overcome; S must exert will. “Try to raise your arm” is different from “Raise your arm.” The S could remain role consistent and not try; ambiguity is maintained and the S could look to the context for an explanation.
In the Normal and Shallice model, hypnosis weakens the higher system relative to the lower system. The S might be trying to exert will but experience it as less [influential] than in the normal state. Such capacity would not be tapped by an alcohol expectancy measure.
We think of individual differences in hypnotizability as multiple processes, like a tree that consists of more than one healthy branch but has plenty of dead wood to be pruned out.

Ross, Colin A.; Joshi, S.; Currie, R. (1991). Dissociative experiences in the general population: A factor analysis. Hospital and Community Psychiatry, 42, 297-301.

The 28-item Dissociative Experiences Scale was administered to a stratified cluster sample of 1055 respondents in a general population of Winnipeg. Dissociative experiences were common in the sample and were not related to socioeconomic status, sex, education, religion, or place of birth, although they declined with age in both sexes. A principal components analysis identified three factors accounting for 47.1% of the combined variance of scores. The first factor, absorption-imaginative involvement, is composed of common, benign experiences such as missing part of a conversation, being able to ignore pain, staring into space, absorption in a television program or movie, not being sure if you did something or only thought about it, and remembering things so vividly one seems to be reliving it. The other two factors, activities of dissociated states and depersonalization-derealization, composed of less common experiences such as not recognizing friends or family members and not recognizing one’s own reflection in a mirror, may be powerful predictors of DSM-III-R dissociative disorders.

Fischer, Donald G.; Elnitsky, Sherry (1990). A factor analytic study of two scales measuring dissociation. American Journal of Clinical Hypnosis, 32, 201-207.

The present study was designed to investigate the construct validity of dissociation. We administered the PAS and the DES to 507 male (48%) and female (52%) undergraduate students. Factor analysis on each scale separately showed that neither the PAS nor the DES adequately measures the three dimensions hypothesized to underlie dissociative experience. For both scales, a single factor emerged as replicable and reliable. Use of the scales, in their present form, therefore, should be limited to a single dimension representing disturbances in affect-control in the case of the PAS and disturbances in cognition-control if the DES is used at least with normal populations. Analysis of the combined items showed that the scales are measuring conceptually different but statistically correlated dimensions of dissociation. Further development of both scales is desirable, and further research should investigate the effect of different response formats on the internal structure of the scales. NOTES 1:
NOTES: The stated purpose of this study was to investigate the internal structure of the Perceptual Alterations Scale (PAS) and the Dissociative Experiences Scale (DES) using a large sample from a normal population.
“Sanders (1986) conceived of dissociation as a personality trait that is characterized by modification of connections between affect, cognition, and perception of voluntary control over behavior, as well as modifications in the subjective experience of affect, voluntary control, and perception. She chose items from the MMPI to represent this trait. Bernstein and Putnam (1986), utilizing the DSM-III definition of dissociation, constructed items from information derived from interviews with patients and clinicians to represent a number of different types of dissociative experiences” (0. 202).
“The PAS (Sanders, 1986) is a 27-item scale; subjects respond by checking one of the following categories using a 4-point Likert format: never, sometimes, frequently, almost always. The items related to modifications of regulatory control, changes in self- monitoring, concealment from self and others, and modifications of sensory, perceptual, and affective experiences.
“The DES (Bernstein & Putnam, 1986) contains 28 items. Subjects indicate the percentage of time they experience the feelings or behavior described by the items on a 10- point scale. The items related to the experience of disturbances in identity, memory, awareness and cognition, and feelings of derealization or depersonalization” (pp. 202- 203).
Results were as follows. The one-factor solution for the PAS accounted for 18.5% of the total variance.; 11 of the 28 items did not load significantly on the factor. The one-factor solution for the DES accounted for 26.3% of the total variance; 7 of the 28 items did not load significantly on the factor.
“The 3-factor solution obtained by Sanders (1986) for the PAS was not replicated. An obvious reason for the different is that principal factor extraction was used in the present study, whereas principal components extraction was utilized by Sanders. … Even when principal components analysis is performed on the present data, however, there are difficulties with the 3-factor solution” (pp. 204-205).
“All of the criteria suggest that a single factor best represents the latent structure of dissociative experience as measured by the PAS and DES. Although the total amount of variance accounted for is low, the one-factor solutions for both scales are interpretable, replicable, and have high internal consistency. The items for the PAS appear to represent primarily the affect and control dimensions, whereas those for the DES represent the cognitive dimension” (pp. 205-206).
“Overall, both scales contain similar items, although the DES has more items relating to disturbances in memory and altered perception of time (i.e., cognition), whereas the PAS has more items reflecting specific disturbances in identity and control. It appears, therefore, that the scales are measuring conceptually separate but statistically correlated dimensions of dissociation” (p. 206).

Kihlstrom, John F.; Register, Patricia A.; Hoyt, Irene P.; Albright, Jeanne Sumi; Grigorian, Ellen M.; Heindel, William C.; Morrison, Charles R. (1989). Dispositional correlates of hypnosis: A phenomenological approach. International Journal of Clinical and Experimental Hypnosis, 37, 249-263.

Attempted to construct and validate a questionnaire measure of hypnotic- like experiences based on Shor’s (1979) 8-dimension phenomenological analysis of hypnosis. Separate item pools were developed to measure each disposition: Trance, Nonconscious Involvement, Archaic Involvement, Drowsiness, Relaxation, Vividness of Imagery, Absorption, and Access to the Unconscious. Based on preliminary testing (total Number – 856), a final questionnaire was produced containing 5 items measuring normal, everyday experiences in each domain. Results from a standardization sample (Number – 468) showed that each of the subscales, except for Archaic Involvement, possessed satisfactory levels of internal consistency and test-retest reliability. Factor analysis indicated that 6 subscales loaded highly on a common factor similar to the absorption construct (Tellegen & Atkinson, 1974), while items pertaining to Relaxation and Archaic Involvement formed separate factors. Validation testing on 4 samples receiving the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) (total Number = 1855) showed that the Absorption and Trance dimensions correlated most strongly with HGSHS:A; the correlations with Drowsiness, Relaxation, and Nonconscious Involvement approached 0. The scales derived form Shor’s analysis, however, did not improve the prediction of hypnotizability over that obtained with the absorption scale (Tellegen & Atkinson, 1974).

Donovan, David (1988). Factor analytic structure of attitudes towards hypnosis, guided imagery, and relaxation. [Unpublished manuscript] (Paper written for Comrey’s Factor Analysis Course, UCLA)

Factor analysis of semantic differential responses of 212 adults regarding 3 terms (hypnosis, imagery, relaxation) placed imagery in an intermediate position between the extremes of hypnosis and relaxation. Both common and unique factors extracted are discussed.

Pekala, Ronald J. (1988, November). Pattern dissimilarity in phenomenological structures among individuals of different hypnotic levels: Hypnosis and eyes-closed conditions. [Paper] Presented at the annual meeting of the Society for Clinical and Experimental Hypnosis, Asheville, NC.

Hierarchical factor analysis was consistent with the psychograms in showing the same pattern in eyes closed conditions for four levels of hypnotizability; but different patterns during hypnosis for the four level groups. This procedure enables the quantification of different phenomenological states, and to operationalize them.

McConkey, Kevin M. (1983). Behaviour, experience, and effort in hypnosis. Australian Journal of Clinical and Experimental Hypnosis, 11, 73-81.

Subjects were administered the Harvard Group Scale of Hypnotic Susceptibility, Form A, and were afterwards asked to rate the degree to which they experienced the items; subjects also scored their behavioural performance on the items. Data were analyzed to explore the relationships among behaviour, experience, and effort. Findings indicated a significant positive relationship between behaviour and experience on all of the HGSHS:A items, a significant negative relationship between behaviour and effort on the ideomotor items, and a significant positive relationship between behaviour and effort on the cognitive items. A similar pattern was observed between experience and effort. Also, subjects of varying HGSHS:A responsivity differed in terms of overall experience of the scale but not in terms of the overall amount of effort that they expended. Implications of the data are discussed in terms of the factors influencing subjects’ experiential response and behavioural performance as well as the attributions that they make concerning effort during hypnosis.

Kihlstrom, John F. (1982, October). Self appraisals of hypnotic ‘depth’. [Paper] Presented at the annual meeting of the Society for Clinical and Experimental Hypnosis, Indianapolis, IN.

Subjects take both private experience and public behavior into account, and weight the available information according to an implicit theory of hypnosis.

Burns, Ailsa (1977). The distribution and factor structure of hypnosis scores following intervention. International Journal of Clinical and Experimental Hypnosis, 25, 192-201.

An intervention procedure was found to produce significant gains in hypnotic performance in a sample of 90 Ss. It was argued that the postintervention scores could be regarded as a measure of asymptotic rather than average hypnotizability. The distribution and factor structure of these scores were then considered to see whether these differed from what is generally found when average hypnotizability is measured. Using Orne and O’Connell’s (1967) Diagnostic Rating Scales, a trimodal distribution was obtained with the modes falling at the top of the ideomotor passive range, the bottom of the cognitive range, and the middle of the “classic somnambulist” range. Analysis of subscale scores based on this distribution indicated the presence of a trait of general hypnotic competence. A 3-factor solution gave a strong general hypnotic factor, best represented by challenge items, a second ideomotor passive factor, and a third factor which could represent either a difficulty or a dissociation dimension. A 4-factor solution reduced the generality of the first factor, gave it more the appearance of a challenge factor, and introduced a strong imagery factor along with a passive ideomotor and a posthypnotic suggestion/negative hallucination factor. The size of the unrotated first factor was found to compare favorably with that obtained in other studies: this could be interperted as meaning that the effect of training is to increase the size of the general factor in hypnotic performance. It is suggested that the 3 modes may represent 3 hierarchically arranged “ideal types” of hypnotic response, and that the effect of training has been to push members of the 3 classes closer towards their paradigm.

Spiegel, Herbert; Aronson, Marc; Fleiss, Joseph L.; Haber, Jerome (1976). Psychometric analysis of the Hypnotic Induction Profile. International Journal of Clinical and Experimental Hypnosis, 24, 300-315.

Psychometric analyses of the Hypnotic Induction Profile (HIP) of Spiegel (1974a), a sixteen point test designed to measure hypnotic capacity, are presented herein. Briefly summarized are the sequential phases of trance experience as monitored by the HIP. On the basis of a factor analysis of individual items entering into the HIP’s of 1674 patients, two distinct factors emerged. One is defined largely by up-gaze and eye-roll, the other by some of the subsequent items. Two methods for scoring the HIP, a configurational method involving both factors (profile scoring) and an actuarial method using only items from the second factor (induction scoring), are defined. As expected from the factor analysis, eye-roll is little related to the HIP graded by either scoring method. The correlation of induction scoring with the eye-roll is .22 in a sample of 1023 patients. Such a correlation is significant, although it accounts for only 5% of the variance that eye- roll and induction scoring have in common. That the low correlation may be a function of the relationship of hypnotizability to psychopathology is shown by a highly significant correlation (r = .52) between eye-roll and induction scores in a population selected as non- psychotic. The usefulness of the HIP in relation to psychodiagnosis has been demonstrated elsewhere and is not the subject of this paper. Evidence is presented bearing on the reliability of the profile and induction scores, both yielding satisfactory reliabilities. Some validity information is given through satisfactory correlations with existing standardized scales. The HIP and Stanford Hypnotic Susceptibility Scale (Weitzenhoffer & Hilgard, 1959) correlate .55.

Field, Peter B.; Palmer, R. (1969). Factor analysis: Hypnosis inventory. International Journal of Clinical and Experimental Hypnosis, 17, 50-61.

An inventory scale of hypnotic depth and the Stanford Hypnotic Susceptibility Scale, Form A were factor analyzed, based on a sample of 223 college students. Both measures yielded a general factor of hypnotic depth. Rotation yielded inventory factors of unawareness, drowsiness, enthusiasm, subjective conviction, and Stanford factors of challenge and ideomotor-posthypnotic suggestibility. Results of an earlier study describing development of the hypnosis inventory were successfully cross-validated. (Spanish & German summaries) (19 ref.) (PsycINFO Database Record (c) 2002 APA, all rights reserved)

Greenleaf, Eric (1969). Developmental-stage regression through hypnosis. American Journal of Clinical Hypnosis, 12, 20-36.

Twenty subjects serving as their own controls were given four developmental tasks under conditions of hypnotic regression (R) and hypnotic simulation (S). Scored interview data were correlated with performances under R and S. Findings: (a) The Ss’ pattern of responses is best conceptualized as a ‘mixed’ regression rather than ‘true’ developmental regression. (b) Even when Ss are used as their own controls, the R condition is productive of a greater mean number of childlike responses than is the S condition, disregarding response patterns. (c) The S condition scores provide measures of a set of relatively independent, the R condition of a set of relatively unitary performance variables; this in the same Ss. (d) Factor analysis yielded three orthogonal factors: ‘outcome by test performance,’ a personality constellation and a factor describing interpersonal actions. The specific situational variable with greatest impact on test performance was the subject’s ability to pretend.

As, Arvid; Lauer, Lillian W. (1962). A factor analytic study of hypnotizability and related personal experiences. International Journal of Clinical and Experimental Hypnosis, 10 (3), 169-181.

To throw further light on the exclusivity of “primary suggestibility” as reported by other investigators, a factor analysis was performed in a sample of 102 female college students on the basis of the intercorrelations of 23 items of personal experiences earlier shown to be related to hypnotizability, and 19 items from 2 hypnosis scales. No simple factor structure emerged. 2 factors were interpreted: the 1st as a hypnotic factor with special emphasis on the capability to sustain the effect of suggestion over time, and the 2nd as a combination of psychological changeableness and social influencibility. A brief discussion was given of the composite picture of hypnotic susceptibilty emerging from the fact that many hypnotic items loaded on both factors. (PsycINFO Database Record (c) 2002 APA, all rights reserved)


Gravitz, M.A. (2002). The search for Bridey Murphy: Implications for modern hypnosis.. American Journal of Clinical Hypnosis, 45, 3-10.

The 1956 publication of “The Search for Bridey Murphy” was a noteworthy event in the history of hypnosis. This internationally best selling book, written for lay readers, described several recorded sessions of alleged time-regression to a prior life nearly two centuries before 1956. While subsequent investigations disproved that claim, there were a number of important implications for the science and practice of hypnosis. Although it was concluded that the Bridey Murphy interviews were products of cryptomnesia, the book was a significant factor associated with a resurgence of public and professional intrest in the modality.

The author notes that the hypnotist was a layman who did no mental status evaluation prior to the hypnosis. The author also considers and rejects several alternative hypotheses (reincarnation or regression to past lives; fraud or hoax; monetary motivation on the part of the hypnotist; and development of a dissociated identity, i.e. multiple personality disorder. He concludes, “Tighe”s expectancies, her prior hypnotic experiences with Bernstein, her compliance, transference, acquiescence, and heightened suggestibility, could have set the stage for the subsequent behavior of both the hypnotist and subject in a nonconscious interrelationship in which both parites accepted their beliefs as reality” (p. 7).

Gravitz, M.A. (2002). The search for Bridey Murphy: Implications for modern hypnosis.. American Journal of Clinical Hypnosis, 45, 3-10.

The 1956 publication of “The Search for Bridey Murphy” was a noteworthy event in the history of hypnosis. This internationally best selling book, written for lay readers, described several recorded sessions of alleged time-regression to a prior life nearly two centuries before 1956. While subsequent investigations disproved that claim, there were a number of important implications for the science and practice of hypnosis. Although it was concluded that the Bridey Murphy interviews were products of cryptomnesia, the book was a significant factor associated with a resurgence of public and professional intrest in the modality.

The author notes that the hypnotist was a layman who did no mental status evaluation prior to the hypnosis. The author also considers and rejects several alternative hypotheses (reincarnation or regression to past lives; fraud or hoax; monetary motivation on the part of the hypnotist; and development of a dissociated identity, i.e. multiple personality disorder. He concludes, “Tighe”s expectancies, her prior hypnotic experiences with Bernstein, her compliance, transference, acquiescence, and heightened suggestibility, could have set the stage for the subsequent behavior of both the hypnotist and subject in a nonconscious interrelationship in which both parites accepted their beliefs as reality” (p. 7).

Page, R. A. (2002, December). Bridey Murphy: Five decades later.. Hypnos: Swedish Journal of Hypnosis in Psychotherapy and Psychosomatic Medicine, 29 (4), 182-185..

This paper examines the impact and explanations of the case, aided by recordings of some of the actual hypnotic sessions conducted, and comments on a companion paper by Melvin A. Gravitz, Ph.D.

Scorboria, Alan; Mazzoni, Giuliana; Kirsch, Irving; Milling, Leonard S. (2000, August). Evaluating the exclusions: Comparing influences of hypnosis and leading questions on memory reports. [Paper] Presented at the annual meeting of the American Psychological Association, Washington, D. C..

Recall and memory distortion were assessed in a sample of 50 highly hypnotizable participants, using a modified form of the Gudjonsson Suggestibility Scale. After listening to a story, half of the participants were asked a series of leading questions, and the others a corresponding series of nonleading questions. Half of the participants in each condition were asked the questions following a hypnotic induction, and the other half in a nonhypnotic context. All participants were then asked nonleading questions without hypnosis. No increases in correct responses were found. Both leading questions and hypnosis resulted in increased error rates and a decrease in “don’t know” responses. Implications of the findings regarding the per se exclusion of post-hypnotic testimony are discussed. [Abstract in Psychological Hypnosis: Bulletin of Division 30, Volume 10 Issue 1, Winter-Spring 2001.]

Stern, Clara; Stern, William (1999). Recollection, testimony, and lying in early childhood. Washington, DC: American Psychological Association. (First published in 1909, in German.)
This book, previously unavailable to American readers, describes a seminal study by William and Clara Stern, first published in Germany in 1909, documenting their own children’s abilities to recollect, recount, testify, and distinguish truth from falsehood” (from publisher statement). Contents: Recognition as the basis of recall; The chronological development of recall and testimonial ability; False testimony–Mistaken recollections, pseudo-lies, and lies; Recognition; Correct recollection; Purposive recall; Mistaken recollections; Experimental studies of testimony in early childhood; The falsification of testimony through fantasy; Pseudo-lies and lies; Educating young children to report on their experiences; The origins of lying and its prevention; The capability of small children as witnesses in legal proceedings.

Karlin, Robert (1997). Illusory safeguards: Legitimizing distortion in recall with guidelines for forensic hypnosis – two case reports. International Journal of Clinical and Experimental Hypnosis, 45, 18-40.

Two amnesic automobile accident victims remembered the information needed for their ongoing lawsuits during hypnosis. Meeting the recording requirements of the Hurd safeguards led to the admission of hypnotically influenced testimony in court in one case, whereas failure to record led to exclusion in the other. In both cases, closed-head trauma almost certainly prevented long-term memory consolidation. Thus adherence to guidelines for forensic hypnosis legitimized distortions in recall instead of preventing them. Hypnosis used to facilitate hypermnesia alters expectations about what can be remembered, makes memory more vulnerable to postevent information, and increases confidence without a corresponding increase in accuracy. Distortion of recall is an inherent problem with the use of hypnosis and hypnotic-like procedures and cannot be adequately prevented by any set of guidelines.

Perry, Campbell; Orne, Martin T.; London, Ray William; Orne, Emily Carota (1996). Rethinking per se exclusions of hypnotically elicited recall as legal testimony. International Journal of Clinical and Experimental Hypnosis, 44 (1), 66-81.

In 1993, Boggs argued for a rethinking of the per se exclusion of hypnotically elicited testimony. This article analyzes the Minnesota v. Mack (1980) case that initiated this exclusion and the two Illinois cases Boggs cites in favor of her position. The scientific data on the effect of hypnosis on memory do not support Boggs’s position. Rather than providing reasons for rethinking this per se position, these data suggest that it should be retained.

Lynn, Steven Jay; Martin, Daniel J.; Frauman, David C. (1996). Does hypnosis pose special risks for negative effects? A master class commentary. International Journal of Clinical and Experimental Hypnosis, 44 (1), 7-19.

The authors review evidence in both experimental and clinical hypnosis situations. They conclude that”the available data do not justify the conclusion that hypnotherapy is any more dangerous, or ultimately less effective, than other psychotherapy and relaxation procedures” (p. 13). However, negative effects do sometimes occur in clinic or in laboratory. They indicate that the following situations and factors suggest need for particular care or vigilence:
Increased Psychopathology
Intensified Transference
Misconceptions About Hypnosis
Suggestions May Instigate or Reveal Unexpected Affect
Difficult or Inappropriate Suggestions
Direct Suggestions to Relinquish Symptoms
Countertransference Reactions
Suggestive Procedures and False Memory Creation
Inadeuate Training in Psychology and Psychotherapy

Maestri, D.; Perry, C.; Laurence, J.-R. (1996, August). Children’s memory for a special event: Exploring the effects of repeated questioning on recall, suggestibility, and photo lineup identification. [Paper] Presented at the annual meeting of the American Psychological Association, Toronto, Canada.

Recollections of a visit at the Montreal Olympic Stadium from two groups of children (4.5- and 5.5-year-old) were elicited on four occasions with free recall, direct questions, and misleading questions. Recall was evaluated in terms of correct, incorrect, neutral, repeated, omitted, and attributional responses. To study the possibility of children choosing one type of suggestion more readily than the other, the misleading questions were further evaluated in terms of the type of suggestion implied. A photo lineup recognition task of familiar and unfamiliar faces present during the visit was also included. Children displayed high degrees of acquiescence to the misleading questions and a clear preference for the suggestion that did not involve their own person. In the photo lineup identification task, 21-37 percent (across trials) of the children mistakenly judged familiar and unfamiliar faces as having been present at the event. Results were discussed in a legal context. (ABSTRACT from Bulletin of Division 30, Psychological Hypnosis, Fall, 1996, Vol. 5, No. 3.)

8025, Ruehle & Zamansky, 1995