The spectral analysis of hypnotic performance with respect to "absorption".

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The Spectral Analysis of Hypnotic Performance with Respect to “Absorption” a

Claude G. Balthazard & Erik Z. Woody a

b

Peat Marwick Stevenson and Kellogg , Toronto, Ontario, Canada

b

University of Waterloo , Waterloo, Ontario, Canada Published online: 31 Jan 2008.

To cite this article: Claude G. Balthazard & Erik Z. Woody (1992) The Spectral Analysis of Hypnotic Performance with Respect to “Absorption”, International Journal of Clinical and Experimental Hypnosis, 40:1, 21-43, DOI: 10.1080/00207149208409644 To link to this article: http://dx.doi.org/10.1080/00207149208409644

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THE SPECTRAL ANALYSIS OF HYPNOTIC PERFORMANCE WITH RESPECT TO ABSORPTION"'^^ CLAUDE C. BALTHAZARD AND Peat Marwick Stevenson and Kellogg. Toronto, Ontario. Canada

ERIK Z. WOODY3“ Unioersity of Waterloo, Wuterloo, Ontario, Canada

Abstract: 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. Special 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 (197811979) 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. I.

..

The “classic psychometric paradigm” has had a profound yet sometimes tacit influence on how hypnotic phenomena have been conceptualized and on the methods of inquiry that have been used in the investigation Manuscript submitted April 30, 1990; final revision received June 5, 1991. ‘Some of the ideas that appear in this paper were presented at the 94th Annual Meeting of the American Psychological Association, Washington, DC, August 1986. ‘Preparation of this article was supported in part by a grant from the Spencer Foundation of Chicago to Kenneth S. Bowers. 3Special thanks to Kenneth S. Bowers for his continued support and encouragement. We gratefully acknowledge the assistance of Patricia Murray and Debra Hughes in the collection of the questionnaire data, and of Glenn Regehr, Evlyn Cledhill, Tom Davidson, and Eric Rothmar in the administration of the hypnosis scales. ‘Reprint requests should be addressed to Erik 2.Woody, Ph.D., Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.

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of hypnosis. It is a paradigm which has been borrowed from the area of intelligence and which refers to a set of constructs, procedures, and heuristics aimed at providing a mathematical description of performance. Latent traits, such as factors, are an essential part of this description. Although a fair amount of factor analytic work has been done with the hypnosis scales (see Balthazard & Woody, 1985, for a review), this work appears to be at an impasse methodologically, and it has failed to yield any consistent picture of the mechanisms that underlie performance on the hypnosis scales. In the present paper, the authors’ aims are both methodological and substantive. First, with regard to the methodological impasse in factor analysis of these hypnosis scales, we present a new dataanalytic technique, which we have called “spectral analysis.”‘ It addresses some of the implications of factor analysis of the scales in a new way that is better attuned to important conceptual and theoretical issues. Second, we apply this technique to the analysis of the relationship of the personality trait of “absorption” to hypnotic performance. This analysis sheds some new light on the differing mechanisms underlying different kinds of hypnotic performance.

Making Sense of Factors Cronbach (1970) has noted that “no factor analytic scheme should be taken too seriously [p. 3341.” The reason is that factors, or latent traits more generally, are mathematical frames of reference that may not map well onto underlying psychological processes or mechanisms. In particular, it is not necessary for a factor to correspond to any single mechanism or process. Yet, in the history of factor analysis, it was always the intention to explain “latent traits” in terms of psychological mechanisms. Thurstone (1940) himself stated that his preference would be to “head as soon as possible to direct forms of laboratory experiments in terms of which the primary factors may eventually be better understood [p. 2041.” Unfortunately, such promise was never realized; and partly as a consequence, there has been widespread disappointment with the kind of description provided by factor analysis with respect to cognitive abilities. The same conclusions appear to be true of the contributions of factor analysis to our understanding of hypnotic performance. The point here is that “factors” need to be validated like any other construct; it is not enough to identify “factors” on the basis of the content of the items that load on them. The traditional way of exploring the external relations of factors is to derive factor scores for all Ss and then to correlate these factor scores with other variables. For some reason, this approach has not often been used in hypnosis research (Evans & Thorn, 1964; Farthing, Venturino, ‘Our use of the term “spectral analysis” has nothing whatever to do with spectral decomposition techniques, such as Fourier analysis, used with time-series data (e.g., Cottman, 1981).


SPECTRAL ANALYSIS

23

FIG.1. The spectrum of hypnotic performance.

& Brown, 1983; Spanos, Mah, Pawlak, D’Eon, & Ritchie, 19806).Unfortunately, the same aspects of the hypnosis scales that complicate factor analytic investigations also complicate the calculation of factor scores (cf. Balthazard & Woody, 1985). In addition to the usual indeterminancies, such as whether one should use orthogonal or oblique solutions, one must also contend with the considerable complications introduced by the dichotomous item format and the broad range of item difficulties. In what follows, the present authors will propose an alternative to the use of factor scores. Before that, however, we will present what we consider to be the gist of the factor analytic description of the hypnosis scales. Our argument makes use of a number of graphical representations, including factor space, the spectral-analysis plot itself, and item characteristic curves. Although a conceptual scheme links these together, it is useful to keep in mind that what the axes represent is often quite different from one figure to the next.

The Spectrum of Hypnotic Performance The present approach considers “factors” as frames of reference rather than necessarily meaningful entities - that is, as mathematical rather than conceptual entities. Figure 1 gives what we consider to be the ‘Spanos. N . P., Mah, C. D.. Pawlak, A. E., D’Eon, J. L., & Ritchie, C. A multivariate factor analytic study of hypnotic susceptibility. Unpublished manuscript. Carleton University, 1980.


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essential description or main theme in factor analysis of the hypnosis scales (cf. Balthazard & Woody, 1985; Tellegen & Atkinson, 1976). The axes are the first and second unrotated factors; and in this factor space the hypnosis scale items fall into a 2-dimensional fan-shaped pattern, represented by the shaded area. It may be noted that axes corresponding to the rotated factors would fall roughly along the top and bottom edges respectively of this fan shape; however, for our argument, the reference axes are more or less arbitrary - what is essential is the shape of the factor space encompassing the items. The items fall along a continuum defined by a pie-wedge-Iike angular sweep. We refer to this continuum as the “spectrum of hypnotic performance.” The term spectrum is here used descriptively in a manner consistent with the usage of Cronbach (1970, pp. 281-283).’As indicated in Figure 1, this spectrum is related to item difficulty - the correlation between an item’s difficulty and its position (top to bottom) in the spectrum has often been found to be in the .go’s. Although one interpretation of this pattern has been that it is an artifact of item difficulty (Coe & Sarbin, 1971; Sarbin & Coe, 1972), it has been argued elsewhere that this pattern is likely not to be the result of such an artifact (Balthmrd & Woody, 1985; Tellegen & Atkinson, 1976); further empirical evidence for this position will be presented later in this paper. Note that in referring to hypnotic performance as a continuum which is related to item difficulty, we are doing so in a manner much different from Coe and Sarbin (1971). Our use of the term continuum does not imply that there is a single underlying process. Item dimculty is taken as a surface manifestation which happens to be related to an item’s position in the spectrum. This relation is close enough that item difficulty may be taken as a “position marker” with respect to the continuum or spectrum. In other words, item difficulty is not the “cause” of the spectrum, but it reflects, as does the spectrum itself, the processes underlying performance. The presence of a spectrum of this kind suggests that hypnotic performance is complex, and that simply correlating a variable with the total hypnosis scale score is not a good strategy for the exploration of the underlying nature of hypnotic performance.

The Spectral Analysis of Hypnotic Performance Although the factors identified by factor analysis need not correspond to any underlying process or mechanism, one is left with an observation which may be of great heuristic value - that is, that the processes that underlie hypnotic performance change with the level of hypnotic performance. Let us introduce here an exploratory procedure which makes use of this notion of “continuum” or “spectrum.” This exploratory ’Many writers have elaborated ideas similar to Cronbachi (1970)spectrum, although each uses different terminology (cf. Guttman. 1965; Horn & Cattell, 1966; Hurnphreys, 1962; Schlesinger & Cuttman, 1969).


SPECTRAL ANALYSIS

25

procedure can best be described as a “spectral analysis.” The gist of this spectral analysis is rather simple: it 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. Note that this sort of graph, although conceptually related to the notion of factor space, is of quite a different type. On the abscissa, or X-axis, is the difficulty of the hypnotic performance. Item difficulty is simply the proportion of Ss that pass a given item and is taken here as an index of the item’s position in the spectrum. From left to right, hypnotic performances become more difficult and the proportion of Ss passing the item is decreasing. This procedure requires that the sample be an unselected one in order to get estimates of item difficulties. On the ordinate, or Y-axis, is the degree of latent correlation. It is necessary to differentiate between the man$est and the latent relationship of a variable to a dichotomously scored hypnotic performance. The manifest relationship is given by the point biseriul correlation and the latent relationship is given by the biserial correlation. The point biserial correlation is a special case of the general Pearson product-moment correlation. As a measure of an item’s ability to discriminate levels of the latent attribute, the point biserial correlation is confounded by item difficulty. The biserial coefficient is an estimate of what the Pearson coefficient would have been if the dichotomous variable had been measured on a continuous scale.” 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. “Absorption” as a Correlate of Hypnotic Performance Although any correlate of hypnotic performance might well be submitted to such a spectral analysis, in a number of respects the variable of “absorption” is the obvious first choice. The construct of absorption or imaginative involvement has a long, well-established history in hypnosis research, stemming especially from the work of Shor and his colleagues (Shor, M . T. Orne, & O’Connell, 1962) and J. R. Hilgard (1970, 1979). Borrowing from and refining previous work, Tellegen and Atkinson (1974) developed the most widely used scale to measure this construct, and it has proven to be one of the very few consistent correlates of performance on the hypnosis scales. In addition, the centrality of “absorption” is suggested by the fact that when this measure is partialled out of the relationship of hypnotic performance with its other correlates, these other correlates often contribute no significant unique variance (e.g., Kihlstrom, Register, Hoyt, Albright, Grigorian, Heindel, & Morrison, 1989). There‘The biserinl correlation is discussed in Nunnally (1978, pp. 135-137); Chiselli. Campbell, and Zedeck (1981, pp. 118-119); and Thorndike (1982, pp. 70-73) among other sources.

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fore, attempting to clarify the nature of the bearing of “absorption” on hypnotic performance would be particularly interesting, and so this is what was done in the present study.


METHOD The present sample consists of 160 undergraduate students who were enrolled in introductory psychology courses at the University of Waterloo. The Ss were paid to participate in an administration of both the Harvard Croup Scale of Hypnotic Susceptibility, Form A (HCSHS:A) of Shor and E. C. Orne (1962), and an adaptation for small groupsg of the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and E. R. Hilgard (1962), which shall be referred to as the “Group C.” This was done in two sessions. The HGSHS:A was administered to large groups in classrooms. The Croup C was administered in smaller groups of 6-8 Ss in a more comfortable setting. Our sample of 160 Ss was taken from this larger set of individuals and consists of two subsamples. One subsample of 120 Ss completed the Multidimensional Personality Questionnaire (MPQ) Absorption Scale (Tellegen, 1980’4, a more recent revision of the Tellegen and Atkinson Absorption Scale (Tellegen & Atkinson, 1974), in the context of a questionnaire study. The 34 true/false MPQ items were embedded in a larger questionnaire, itself one of many questionnaires which were to be completed by Ss. These Ss were not paid to fill out the questionnaires, and no connection between the questionnaire study and the previous hypnosis assessment was made. The remaining subsample of 40 Ss completed the absorption scale within the context of an experiment that did involve the use of hypnosis. Once again, the absorption items were embedded in a larger questionnaire. RESULTS Spectral Analysis For each hypnosis suggestion appearing on either HCSHS:A or the Croup C scale, the biserial correlation with the absorption scores was %is group adaptation of SHSS:C has been in use at the University of Waterloo for a number of years now. In this adaptation, a posthypnotic suggestion item was added to SHSS:C. and the hallucinated voice item was replaced by a hallucinated music item. In addition, only 11 HGSHS:A items were administered, as listed in Table 1. The manual and scoring booklet for the group version of SHSS:C (W-SGSHS:C) used in the present study (revised 9/82) as well as data concerning the adaptation for small group administration of the Stanford Hypnotic Susceptibility Scale, Form C have been deposited with the National Auxiliary Publications Service (NAPS). For 38 pages. order document No. 04632 from ASIS-NAPS, do Microfiche Publications, P.0. Box 3513,Grand Central Station, New York, NY 101634513. Remit in advance in U.S. funds only $13.15for photocopies or $4.00 for microfiche and make checks payable to Microfiche Publications NAPS. Outside the United States and Canada, add postage of $6.50 for a photocopy and $1.50for a fiche. There is a $15.00 invoicing fee for orders not,prepaid; this includes POXs. 10 Tellegen, A. The multidimensional personality questionnaire. Unpublished test materials, University of Minnesota, 1980.

-

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SPECTRAL ANALYSIS

TABLE 1 ITEM DIFFICULTYAND BISERIALCORRELATIONS WITH ABSORITION SUGGESTIONS


Suggestion a. Hand Lowering, HCSHS:A and Croup C b. Head Falling, HGSHS:A C . Hands Moving Apart, HGSHS:A and Croup C d. Eye Closure, HCSHS:A e. Communication Inhibition, HGSHS:A f. Arm Rigidity, HCSHS:A and Croup C g. Age Regression, Croup C h. Arm Immobilization, HGSHS:A and Croup C i. Eve Catalepsy. HGSHS:A j. Taste Hallucination. Croup C k. Posthvpnotic Suggestion. HCSHS:A and Croup C 1. Dream. Croup C m blosquito/Flv Hallucination, HCSHS:A and Croup C n. Negative Visual Hallucination. Croup C 0. Amnesia, HCSHS:A and Croup C p. Music Hallucination, Croup C

FOR

HYPNOTIC

Item Biserial Difficulty Correlation .89

.73 .69

.63 .61

.55 .53 .52 .50 .49

..w .43 .34 .23 .23

.I5

.23 .34 .16 .24

.23 .26 .28 .17 .31

.28

.20 .30 .24

.31 .43

.53

Note. - Suggestions are listed in order of increasing difficulty.

calculated. To improve the reliability of individual data points, the observations for suggestions that appear on both HCSHS:A and the Croup C were averaged. Each data point represents either an individual item when it was administered once, or the average values when the item was administered in the context of both scales. Item difficulties and biserial correlations for individual suggestions are given in Table 1. Figure 2 shows the result of the spectral analysis of hypnotic performance with respect to absorption. The pattern of results shows rather clearly that the strength of the relationship of absorption to hypnotic performance is related to the difficulty of the hypnotic performance. Throughout the easy and middle ranges, 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. A regression analysis of these data yielded statistically significant (p < .05) linear and quadratic trends, accounting for 37% and 21% of the variance, respectively. Before moving on to a discussion of these findings, an alternative explanation for the pattern of biserial correlations must be considered. The biserial correlation is sensitive to item reliability. If it could be shown that items of greater difficulty are more reliable than items of average or lesser difficulty, then an alternative explanation for the spectral pattern would be possible. The reliability of an individual hypnosis item is difficult to estimate directly. We will take the highest tetrachoric correlation of a

BALTHAWRD AND WOODY

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FIG.2. The spectral analysis of hypnotic performance with respect to absorption. Note. Circled items are discussed in the text.

given hypnosis item with any of the other items to be a lower bound estimate of what the reliability of the item would be if it were measured on a continuous scale (cf. Gulliksen, 1950).These reliability estimates are given in Table 2. It can be seen that item reliability shows a very slight tendency toward increase as the items become more difficult. The hardest two items, however, which play a crucial role in Figure 2, do not have the highest estimated reliabilities; generally, differential item reliability does not provide a cogent explanation for the observed pattern of biseriai correlations. Incidentally, the results of this spectral analysis provide the best empirical evidence so far that the spectrum of hypnotic performance is not an artifact of some sort.

Beyond the Biserial: The ltem Characteristic Curoe The biserial correlation provides some useful information about the relationship of a given individual performance to some external variable, but it does not provide a complete picture of this relationship. For instance, why is the relationship between some hypnotic performances and absorption lower than for others? Is it that individuals with high absorption scores fail the item, or that people with low absorption scores pass the item? A more complete picture of the relationship between performance on a given hypnosis item and a continuous variable can be given by the item characteristic curve or the item response function (Hambleton & Cook, 1977;Lord, 1980; Thorndike, 1982).The item response function expresses the probability of passing a given item as a function of the level of ability on the latent ability.

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TABLE 2 ESTIMATEDITEM RELIABILITIES Suggestion


a.

Hand Lowering, HGSHS:A and Group C

Estimated Item Reliability .47

h. Head Fdling, HCSHS:A

.44

c. Hands Moving Apart, HCSHS:A and Croup C d . Eye Closure, HCSHS:A e. Comniunicntion Inhibition, HCSHS:A f. Arm Rigidity, HGSHS:A and Croup C g. Age Regression, Croup C h. Arm Immobilization, HCSHS:A and Croup C i. Eye Catalepsy, HCSHS:A j. Taste Hallucination, Croup C k. Posthypnotic Suggestion, HGSHS:A and Croup C 1. Dream, Croup C in. Muscpito/Fly Hallucination. HGSHS:A and Croup C n. Negative Visual Hallucination. Group C 0 . Amnesia. HCSHS:A and Croup C p. Music Hallucination, Croup C

.58 .67 .82 .72 .73 .71 .82 .55

.60 .51

.63 .74 .79 .70

Note. - Suggestions are listed in order of increasing difficulty.

Although the following analyses are inspired by item response theory, they are not intended as a thoroughgoing application of this psychometric theory. Item response theory is mathematically quite complex, yet the basic notion behind the item characteristic curve can be grasped in t u i ti ve 1y. On the ordinate, or Y-axis, is the probability of passing a given hypnosis suggestion. The probability of passing a given hypnotic suggestion is given here by the proportion of S s that have passed the item. On the abscissa, or X-axis, is the level of latent ability. Here, the raw scores on the absorption scale will be used, which can range from 0 to 34. Of course, the absorption score is only an approximation of the latent attribute score, but it is assumed that this approximation is good enough. Note that this score, which is taken to represent the latent attribute, is an independent external criterion of performance, and there exists an item characteristic curve for each hypnotic suggestion. (While item response theory is usually employed to examine the internal structure of a measure, here we look at what might be termed an “external” structural property of absorption, since the hypnosis items are not included as indicators of the latent criterion. The conditions under which such external criterion measures may be appropriate are discussed in Thorndike, 1982, see Chapter 7.) In essence, the proportion of Ss that pass a particular hypnosis suggestion given a particular score on the absorption scale is being plotted. Because there are few Ss with certain absorption scores, especially at both extremes, a moving aueruge procedure was used. The observations for three adjacent absorption scores were combined and assigned to the

BALTHAWRD AND WOODY

PROBABILITY


OF PASSlffi SUGGESTION

0

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.3

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0

5

10

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FIG.3. Item Characteristic curve for Communication Inhibition suggestion. HGSHS:A.

midpoint of the interval. For instance, the number of “passes” on a given hypnosis suggestion for Ss with absorption scores of 11, 12, and 13 were combined, and the resulting proportion was considered the value for an absorption score of 12;then the observations for Ss with scores of 12, 13, and 14 were combined, and the resulting proportion was considered the value for an absorption score of 13,and so on. Although a separate item characteristic curve can be derived for each suggestion, two will be presented here for purposes of our discussion. The first item characteristic curve is for the Communication Znhibition suggestion on HGSHS:A, the second item characteristic curve is for the Music Hallucination suggestion on the Croup C Scale. These suggestions were chosen because of their position in the spectral analysis. The C m munication Inhibition suggestion is in the moderately easy range of hypnotic performance and has a biserial correlation with absorption of .23. The Music Hallucination suggestion falls in the very difficult range of hypnotic performance and has a biserial correlation with absorption of .53. Item characteristic curves are usually assumed to share an ogival shape but vary along three parameters. The first parameter is the “steepness” of the curve. This steepness parameter is related to the biserial correlation coefficient. The steeper the curve, the bigger the biserial correlation. The second parameter represents the difficulty of the item. For the present purposes, the dimculty of a hypnotic suggestion is given by the level of absorption at which the probability of passing the suggestion is .5. The third parameter is the asymptote (usually the lower asymptote) and refers

SPECTRAL ANALYSIS

31


PROBABILITY OF PAsslNG SUGGESTION

5

10

15

20

25

30

ABSORPTION SCORE

FIG.4. Item characteristic curve for Music Hallucination suggestion, Group C.

to the probability of passing a suggestion given very low levels of absorption. Since the item characteristic curve is so closely linked to the biserial correlation and difficulty of the item, the graphs for the two illustrative items used here show the essential features, and the graphs for the other items would necessarily be unsurprising variants of these two cases. Figure 3 gives the item characteristic curve for the Communication Inhibition suggestion. The curve rises slowly throughout the range of absorption scores. The lower asymptote is in the . 2 range, which means that even with no appreciable level of absorption, the probability of passing the Communication Inhibition suggestion is .2. The item characteristic curve for this suggestion crosses the .5 probability level at a score of 13 on absorption. This means that someone with a score of 13 or more on absorption is more likely to pass the Communication Inhibition suggestion than he/she is to fail it, although this probability increases slowly for scores greater than 13 and decreases slowly for scores less than 13. Figure 4 gives the item characteristic curve for the Music Hallucination suggestion. The curve remains at near 0 levels for the first half of the range of absorption scores, then it rises quickly to a final value that approaches 1. The lower asymptote is 0, which tells us that without the requisite skills of absorption the probability of passing the Music Hallucination suggestion is.virtually nil. The item characteristic curve for this suggestion crosses the .5 probability range at a score of 31 on absorption. This means that someone with a score of 31 or more on absorption is more likely to pass the Music Hallucination suggestion than he/she is to fail it. Here, however, this probability goes up sharply for scores above 31 and falls sharply for scores below 31.


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The item characteristic curves extend our understanding of the relationship between absorption and hypnotic performance. The item characteristic curve for the Music Hallucination item suggests that a certain level of “absorption” is necessary to pass difficult hypnotic items. The item characteristic curve for the Communication Znhibition item suggests that processes other than absorption are operative in the easy range of hypnotic performance. These alternative processes do not appear to operate in the dimcult range of hypnotic performance. Results for the other suggestions were entirely consistent with this account.

DISCUSSION Spectral Analysis and Shor et a1.k (1962)Model of Hypnotic Performunce The results of our spectral analysis bring to mind some early work by Shor et al. (1962). These authors suggested that both ability and nonability components contribute to hypnotic performance, and that ability components are the primary determinants of hypnotic performance in the deeper region, whereas non-ability components are the primary determinants in the lighter region. Their speculations were based on evidence of a different kind than presented here, evidence that was challenged by E. R. Hilgard (1965). For this reason, it is important to compare the present evidence with that which had originally been adduced to support the notion that ability components were more relevant to difficult hypnotic performances. Shor et al. (1962) were investigating the relationship between a questionnaire which tapped “hypnotic-like” experiences and hypnotizability assessed both by clinical ratings and the Stanford Hypnotic Susceptibility Scale, Forms A and B (SHSS:A and B) of Weitzenhoffer and E. R. Hilgard (1959). Shor et al.’s (1962) ratings of depth are directly comparable to usual hypnosis scores, and the deep range of hypnotic performance was further subdivided into deep, very deep, and extremely deep ranges on the basis of clinical judgment. For the whole sample of 25 Ss, the correlation between the depth ratings and the questionnaire measure was .45. When this same correlation was computed for the 8 Ss who fell within the deep range, however, it was found to be .84. The correlation between the depth ratings and the questionnaire measure for the 17 Ss who fell in the less than light, light, and medium depth ranges was .17. On the basis of these findings, Shor et al. (1962)argued that “there is reasonable evidence that the questionnaire as evolved predicts hypnotizability, especially in the deeper region of the hypnotizability continuum; it is less predictive, if at all, in the lighter region [p. 711.” Shor et al. (1962)used the scattergram to represent a speculative model of hypnotic performance. Their schematic representation of the shapes of the scattergrams between hypnotic depth and the two major compo-


SPECTRAL ANALYSIS

33

Very L'ghl

CONTINUUM

OF HYPNOTIZABILITY

I Logarithmic Form)

FIG. 5. Schematic representation of Shor et a1.k (1962) model of hypnotic performance. Note. - From "Vdidiltion and cross-validation of self-reported personal experiences which predict hypnotizability" by R. E. Shor. M . T.Orne. & 1).N. O'Connell, / . h y c h o f . . 1962. 5.3. p. 73. Copyright 1962 by The Journal Press. Reproduced by permission.

nents - that is, ability and non-ability components - is reproduced here as Figure 5. Given that the degree of correlation between two variables is inversely related to the amount of error there is in predicting one variable from the other, the scattergram narrows where the correlation is greater. The solid outline refers to the shape of the relationship between ability components and hypnotizability. The bottom of the scattergram is truncated because it was assumed that just about everyone in the normal college population has enough of the ability components to achieve an average level of hypnotic performance given that other conditions are favorable. The important aspect of this solid outline is that it narrows dramatically in the deep range of hypnotizability, reflecting the greater correlation of ability components with hypnotic performance in that region. The broken outline refers to the shape of the relationship between non-ability components and hypnotizability. Here the narrowing of the scattergram occurs in the lighter ranges of hypnotic depth, reflecting the greater correlation of non-ability components with hypnotic performance in that region. E. R. Hilgard (1965) attempted unsuccessfully to replicate the findings of Shor et al. (1962). He selected a sample of 24 Ss who scored 10 or more on SHSS:A and split them into a group of 12 high-highs and 12 low-highs on the basis of their performance on the Stanford Profile Scales (SPS:I and 11) of Weitzenhoffer and E. R. Hilgard (1963). He found that the mean on an experience inventory for the high-high Ss was not significantly higher than that of the low-high Ss, and that the correlation between the scores on the experience inventory and SPS:I and I1 scores was but . l o .


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How are we to reconcile the findings of Shor et al. (1962) and E. R. Hilgard (1965) with our own, given that each purports to address the same issue - that is, whether measures derived from questionnaires are more predictive of hypnotic performance in the difficult range? A major issue in such a reconciliation would appear to be that the method of correlations within a restricted range is less sensitive than our spectral analysis, chiefly because the biserial correlation uses the responses of all Ss, whereas the restricted range correlation is based on the responses of a smaller subset of Ss. For purposes of comparison, Figure 6 presents the scattergram between absorption scores and hypnosis scores for our data, representing a correlation of .38. The hypnosis scores were computed by summing HGSHS:A and Croup C scores. It may be observed that the effects revealed by the spectral analysis yield a plot whose heteroscedasticity is only barely noticeable by visual inspection. The variance of hypnosis scores does get smaller with increasing levels of absorption, as one would predict from the spectral analysis, but this increasing relationship would not translate into effects that are so dramatic as to be picked u p clearly with a correlation within a restricted range. Thus, we consider results such as E. R. Hilgard's (1965) to be broadly consistent with those of our spectral analysis. Also, although this pattern is consistent with Shor et al. (1962), the heteroscedasticity is much less readily apparent than what is

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SPECTRAL ANALYSIS

35

suggested by their conceptual model. Looking at this relationship as one otherwise might, then, nothing very striking is apparent that deviates from the usual bivariate distribution, despite the clear result obtainable with the spectral analysis. In brief, it would appear to be the case that although the evidence of Shor et al. (1962) may have been fortuitous, their speculations may well have been correct. The results of our spectral analysis do support the notion that ability components, if those are what is tapped by the absorption scale, are more strongly related to difficult hypnotic performances than to the easy ones.

Spectral Analysis and Tellegen’s Two-Factor Model of Hypnotic Performance Tellegen (1978/1979) proposed what is in fact a factor analytic counterpart of Shor et al.’s (1962) model. He suggested a model where two general factors are operating jointly. One general factor is a “genuine responsiveness factor,” and the other is a “compliance factor” (Tellegen, 1978/1979, p. 228). Tellegen (1978/1979) defines compliance as “the tendency to comply overtly, regardless of one’s subjective experience, with perceived social demands associated with suggestions [p. 2281.” What changes from item-to-item is the relative strength of the two general factors, with some suggestions tapping mostly the genuine responsiveness factor and others tapping mostly the compliance factor. The close relationship between Tellegen’s (197811979)model and Shor et al.’s (1962) model is readily apparent. Tellegen’s (1978/1979) “genuine responsiveness factor” corresponds to the “ability components” of Shor et al. (1962), and his “compliance factor” corresponds to their “non-ability components.” Tellegen’s notion of relative strength is implicit in Shor’s et al.’s formulations, in that in Shor et al.’s model, performance in the lighter regions reflects non-ability components to a greater extent than ability components, whereas performance in the deeper region reflects ability components to a greater extent than non-ability components. What is more explicit in Shor et al.’s model is the gradualness of the shift in the relative contributions of the two components as one moves from easy to difficult hypnotic performances. It is this gradualness that we have incorporated in the notion of a “spectrum.” Tellegen (1978/1979) noted how decisive empirical evidence concerning the presence and strength of these two broad, hypothetical dimensions would require extension of the network of correlation between traditional hypnotic response measures to include additional and “purer” indicators, reflecting one of the two hypothetical factors without also measuring the other [p. 2281. Our spectral analysis has in fact provided some evidence of this sort that is, the “genuine responsiveness factor” of Tellegen (1978/1979) and the “ability components” of Shor et al. (1962) are what is tapped by the


36


absorption scale. The “compliance factor,” or “non-ability components,” are not addressed with the present findings and their nature remains a matter of speculation. It is important to point out, however, that putative indicators of such a factor or component, whatever its nature, could well be submitted to the spectral analysis technique in an attempt to illuminate the easier ranges of hypnotic performance. Then the biserial correlations for the least difficult items should be higher than those for more dimcult items (the opposite of our result depicted in Figure 2).

Are the Hypnosis Scales Just a Rouna!ubout Way of Measuring Absorption? The absorption scale, as well as other self-report inventories of hypnotic-like experiences, has been found repeatedly to have a moderate correlation with hypnotic performance, roughly in the .35-.40range for SHSS:C.” The meaning of this relationship, however, changes in important ways depending on the underlying model one adopts to relate S’s manifest responses, or hypnotic performance, to S’s latent ability, or hypnotizability. The model that E. R. Hilgard (1965) has favored is a “general factor plus special factors” model, in which all items belonging to the traditional domain of hypnosis share one common “core,” the general factor. Subsets of items of similar content may share something besides the general factor, yielding special factors. By contrast, the model of Tellegen (197811979) and the spectrum representation advocated in the present paper are best described as a “two general factors” model (which, incidentally, does not rule out the possibility of smaller special factors as well). In this type of model, there are two cores, whose relative representation is related, at the manifest level, to the difficulty of the suggestion. It seems almost self-evident in such a model to associate “hypnotizability,” “genuine responsiveness,” “true hypnosis,” “ability components,” or the “essence of hypnosis” with that core that is reflected to a greater degree in the more difficult items, and “non-hypnoticabilities,” “compliance,”or “non-ability components” with that core that is reflected to a greater degree in the easier items (cf. M. T. Orne, 1977). From the viewpoint of the “general plus special factors” model, the moderate correlation between absorption and hypnotic performance is taken to indicate that “absorption” or “imaginative involvement” is just “The reported values for the correlation between “absorption” and hypnotic performance range from - .03 (Council, Kirsch, & Hafner, 1986) to .57 (Crawford, 1982). It should be kept in mind, however, that studies reporting such correlations differ widely in many rbspects: some samples are relatively small or taken from special populations (Chiofalo & Coe, 1981/1982);sometimes the 34 items are imbedded in a larger scale, but quite often they are not; usually the scale is given in such a way that S is aware that there is a connection between the absorption scale and hypnotic performance, but there are exceptions (such as the present study); sometimes the relationship between absorption and hypnotic performance is subject to some experimental manipulation (Council et al., 1986; Spanos & McPeake, 19741975).


SPECTFUL ANALYSIS

37

one part of the package of skills which are used in the enactment of hypnotic suggestions. In the “two general factors model,” however, this same moderate correlation takes on new meaning. Although the correlation of “absorption” with the total hypnosis score is moderate, its correlation with one of the general factors in more substantial. In fact, given the factorial complexity of the hypnosis scales, and attenuation due to unreliability, a correlation of about .35 between the total hypnosis score and a given questionnaire measure is about all that can be expected. A correlation of this magnitude, given the coherence of the spectral pattern, is substantial enough to be able to make the argument that whatever is tapped by the absorption scale and this general factor which represents genuine responsiveness are the same “thing.” It is only somewhat facetious to point out that the practical implication of this is that if one wants to measure true “hypnotizability,” one might be better off using the absorption scale than one of the standard hypnosis scales. Nonetheless, to say that the genuine responsiveness factor is absorption is perhaps to make a misleading statement. In the construction of their scale, Tellegen and Atkinson (1974) factor analyzed items which had been shown previously to predict hypnotic performance and found a single factor. The important aspect here is that the appellation “absorption” derives from Tellegen and Atkinson’s hypothesis as to what may be the core that pulls all these items together (see also Tellegen, 1981), and other constructs may possibly be found to be more appropriate. For example, Crawford’s (Crawford, 1985; Crawford & Allen, 1983) concept of “cognitive flexibility”cou1d be invoked to explain individual differences on the absorption scale, and it might even be possible to question whether the scale actually taps a cognitive ability per se (cf. Kerr & Neisser, 1983; Reisberg, Culver, Heuer, & Fischman, 1986), as opposed to some sort of preference or attitude. Nonetheless, the present findings augment the importance of further efforts to determine more clearly the underlying nature of the individual differences tapped by the absorption scale. Another objection to the identification of “genuine hypnotic responsiveness” with whatever dimension is measured by the absorption scale is that it must somehow fail to capture the richness and complexity of hypnotic responsiveness. In this respect, we must introduce the distinction between macro and micro levels of description.” Approaches that are based on the analysis of manifest relationships, such as factor analysis and spectral analysis, provide descriptions at the macro level. Sometimes such descriptions give a glimpse of the underlying process. Approaches that are based on detailed task analyses, or the identification of the “building blocks” of performance, refer to a micro level of description. As it turns out, mechanisms that are made up of complex interactions of ‘*A good treatment of such a distinction is given in Cronbach (1970. pp. 345-352).

BALTHAWRD AND WOODY

38


processes may well reveal themselves as unidimensional at the macro level. In other words, “absorption” can be “one thing” at the macro level of description and yet be quite complex at the micro level.

Spectral Analysisfrom a Social Psychological Perspectioe Our present formulation has adopted a “trait” approach to hypnotic performance. Although social psychological approaches tend to focus on the contextual aspects of hypnotic performance, they have also had to come to grips with individual differences. In the various social psychological explanations for individual differences in hypnotic performance we find remarkable and perhaps unanticipated convergence with our results. We shall briefly touch upon the work of Spanos, the work of Sarbin, and the work of Council. In summarizing the results of a multivariate investigation of hypnotic performance, Spanos et al. (1980)13noted “the findings . . . indicate that cooperativeness and expectation may be particularly important in responding to ideomotor and challenge suggestions, while the ability to convincingly treat imaginings as real (i.e., absorption) becomes increasingly important for more difficult ‘cognitive’ items [p. 211.” The analyses of Spanos et al. (1980)14are open to the possibility of difficulty artifact, yet their interpretation shows remarkable convergence with ours. Sarbin (1984) has recently argued for a two-fold typology based on the individual’s approach to the demands of the hypnotic context. A first type of individual interprets the hypnotic context as an invitation to “join the game” and knowingly creates the illusion that the hypnotic enactment is involuntary. A second type of individual convinces himselUherself, as well as others, of the involuntariness or genuineness of hidher enactments. The former type of responsiveness seems clearly linked to “non-hypnotic abilities” or “compliance,” and the latter to “genuine responsivenes.” The typological aspect of Sarbin’s (1984) model refers to the notion that S is consistent in his or her approach. In discussing the “two general factors model,” we noted how hypnotic suggestions differed with respect to the relative contribution of the two factors. In other words, performance on a given item is a “ b l e n d of two factors. The difference between dimensional and typological accounts refers to where this “blending” occurs. In dimensional accounts, the performance of each S on any given item reflects the contributions of both factors in the relative proportions that are characteristic of the item. We could say that the blending of the two fitctors occurs “within Ss.” In the typological account, the performance of a given S on all items reflects either one or the other factor. The loading of a given item on one of the two factors reflects the relative effectiveness of that factor in passing that item. Here, we could say that the blending %ee Footnote 6. “See Footnote 6.


SPECT’RAL ANALYSIS

39

of the two factors occurs “between Ss.” Sarbin (1984) did not elaborate on any connection between type and level of performance. If one were to assume that “joining the game” is a less and less effective strategy as the items become more difficult, however, then such typological accounts could provide a reasonable account for the spectrum of hypnotic performance (Balthazard & Woody, 1989). With respect to the relationship of “absorption” to hypnotic performance, the work of Council and his colleagues (Council & Kirsch, 1983; Council et al., 1986) is truly provocative. They found that the absorption scale correlated with hypnotic performance only when the absorption scale was administered in an hypnotic context. They then argued that such a correlation represents an expectancy-mediated artifact - that is, completing the absorption scale sets up expectancies that carry over into the performance on the hypnosis scales. There has been considerable controversy over the replicability of this context effect. For example, Woody, Bowers, and Oakman (1990) found the context effect very clearly, but they showed that it did not depend on administering the absorption scale prior to the hypnosis scale; whereas Nadon, Hoyt, Register, and Kihlstrom (1991) were repeatedly unable to find any consistent context effect.” One possible resolution to this controversy is suggested by the results of our spectral analysis and the general theme of distinguishing between “ability” and “non-ability” components in hypnotic performance. 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. In conclusion, we would emphasize that the technique of spectral analysis and the results we have obtained point toward a conception of hypnotic performance that offers something of a rapprochement between the special-ability and social-psychological views. It would appear quite unlikely that either view could account for the entire hypnotic spectrum, and the proponents of the two views may be thought of as exploring and offering IS

In the present study, there were 120 Ss for whom the absorption scale was administered in a context utterly divorced from hypnosis, with the items imbedded in a larger questionnaire, 2 months before the administration of the hypnosis scales. Yet these absorption scores correlated very clearly with hypnotic performance, and this correlation was not significantly different from that for the 4 0 4 group to whom the absorption scale was administered in a hypnotic context. Nonetheless, it is only fair to point out that the present study was never designed to evaluate context effects.

BALTHAWRD AND WOODY


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explanations of different parts of this spectrum. Ideally, we would devise purer sets of items that would unconfound the components underlying hypnotic performance; then the two theoretical camps might be seen plainly to be investigating two quite different things. The nature of the spectrum itself, however, suggests that such a hard and fast distinction might be somewhat artificial, in that most of the “classical” hypnotic performances appear to involve both components. In addition, since it seems to be in the nature of the phenomenon for hypnotic items inescapably to suggest their own “correct” responses, it is a considerable challenge to imagine how such purification of performance items could be accomplished. Meanwhile, as an alternative to this alluring but thus far unfulfilled goal, we offer the technique of spectral analysis, with its potential for illuminating the roles of both types of component.

REFERENCES BALTHAZARD,C. G., h WOODY,E. Z. The “stuff” of hypnotic performance: A review of psychometric appronches. Psychol. Bull., 1985. 98,283-296. BALTHAZARD.C. G.. & WOODY,E. Z. Bimodality, dimensionality, and the notion of hypnotic types. [nt. I. din. exp. Hypnosis. 1989, 37. 7 W 9 . CHIOFALO.L. C.. & COE. W. C. A failure to support the relationships of selected traits and hypnotic responsiveness in drima students. Amer. /. clin. Hypnosis, 198111982. 24, 200-203.

COE. W. C., h SARBIN,T. R. An alternate explanation to the multiple composition of hypnotic scales: A single role-relevant skill. /. Pen. soc. Psychol.. 1971, 18. 1-8. COUNCIL, J. R., & KIRSCH, 1. “‘Absorption”:Personality correlate or expectancy-mediated artifact? Paper presented at the 91st Annud Convention of the American Psychological Association, Anaheim. CA. August 1983. COUNCIL, J. R.. KIRSCH. I., h HAFNER,L. P. Expectancy versus absorption in the prediction of hypnotic responding. /. consult. clin. Psychol.. 1986, 50, 182-189. CRAWFORD. H. J. Hypnotizability, daydreaming styles, imagery vividness. and absorption: A multidimensional study. /. P e n . soc. Psychol., 1982, 42, 915-926. CRAWFORD, H. J. Cognitive flexibility, dissociation. and hypnosis. Paper presented at the 93rd Annual Convention of the American psychological Associations. Los Angeles. CA, August 1985. CRAWFORD, H. J.. & ALLEN,S. N. Enhanced visual memory during hypnosis as mediated by hypnotic responsiveness and cognitive strategies. 1.exp. Psycho/.: Cen., 1983. 112, 662-685. CRONBACH, L. J. Essentials of psychological testing. (3rd ed.) New York: Harper & Row, 1970.

EVANS,F. J.. h T~OFIN,W. F. Questionnaire scales correlating with factors of hypnosis: A preliminary report. Psychol. Rep.,1964.14.67-70. FARTHING,G . W.,VENTIJRINO,M.,h BROWN,S. W.Relationship between two different types of imagery vividness questionnaire items and three hypnotic susceptibility factors: A brief communication. Znt. /. clfn. exp. Hypnacis, 1983. 31.8-13. GHISELLI,E. E., CAMPBELL,J.P.. h ZEDECK,S. Measurement theoryfor the behauioral sdences. San Francisco: Freeman, 1981. GOTRUN, J. M.Time-series anulysi.9: A comprehensive introductionfor the sodo/ scientist. Cambridge: Cambridge Univer. Press, 1981. GULLIKSEN. H. Theory ofmental tests. New York: Wiley. 1950.

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GUTTMAN. L. The structure of relations among intelligence tests. Proceedings. Inoitational conference on testing problems, 1964. Princeton, N J: Educational Testing Service, 1963. Pp. 25-36. HAMBLETON, R. K., & COOK,L. L. Latent trait models and their use in the analysis of educational test data. J. educ. Meas., 1977. 14. 75-96. HILGARD.E. R. Hypnotic susceptibility. New York: Harcourt, Brace, & World. 1965. HILGARD,J. R. Personality and hypnosis: A study of imaginatioe inooloement. Chicago: Univer. of Chicago Press, 1970. HILGARD.J. R. Personality and hypnosis: A study of imaginatioe inooloement. (2nd ed.) Chicago: Univer. of Chicago Press, 1979. HORN,J. L., & CATTELL,R. B. Refinement and test of the theory of fluid and crystalized intelligence. 1.educ. Psychol., 1966. 57, 253-276. HUMPHREYS. L. C. The organization of human abilities. Amer. Psychologist, 1962, 17, 47-83,

KERR, N.. & NEISSER. U. Mental images of concealed objects: New evidence. J . exp. Psychol.: Learn. Mem. Cogn., 1983, 9, 212-221. KIHLSTROBI. J. F., REGISTER,P. A., HOYT.1. P., ALBRIGHT, J. S.. CRIGORIAN. E. M.. HEINDEL,IV.C., & MORRISON,C. R. Dispositional correlates of hypnosis: A phenomenological approach. I n f .J. clin. exp. Hypnosis, 1989, 37, 249-263. LORD,F. M. Applications of item response theory to practical testing problems. Hillsdale, N J: Erlbaum. 1980. NADON, R., HOYT. 1. P., REGISTER, P. A., & KIHLSTROM. J. F. Absorption and hypnotizability: Context eKects re-examined. 1.Pers. SOC.Psychol.. 1991. 60,14-t-153. NUNNALLY.J. C. Psychometric theory. (2nd ed.) New York: McCraw-Hill. 1978. ORNE,M . T. The construct of hypnosis: Implications of the definition for research and practice. Ann. NY.Acad. Sci.. 1977, 296. 14-33. L. c . , HEUER.F.,& FISCHMAN, D.visual memory: When imagery REISBERG,D..CULVER, vividness makes a difference. J . ment. Itnag., 1986, lO(4). 51-74. T. R. Nonvolition in hypnosis: A semioticanalysis. Psychol. Rec., 1984,34,537-3.19. SARBIN. SARBIN. T. R., & COE,W. C. Hypnosis: A social psychological unalysis of inJhence communication. New York: Holt. Rinehart & Winston, 1972. SCHLESINCER, I. M.,& GUTTMAN. L. Smallest space analysis of intelligence and achievement tests. Psychol. Bull., 1969, 71. 95-100. SHOR. R. E.. & ORNE,E. C. Harvard Group Scale of Hypnotic Susceptibility, Form A . Pdo Alto, CA: Consulting Psychologists Press, 1962. SHOR. R. E., ORNE,M. T.. & O‘CONNELL. D. N. Validation and cross-validation of selfreported personal experiences which predict hypnotizability. 1. Psychol., 1962, .53, 575. SPANOS.N. P., & MCPEAKE,J. D. The interaction of attitudes towards hypnosis and involvement in everyday imaginative activities on hypnosis. Amer. 1. clin. Hypnosis. 197U1975, 17, 247-252.

TELLECEN,A. On measures and conceptions of hypnosis. Amer. J. clin. Hypnosis. 19781 1979, 21, 219-236.

TELLECEN. A. Practicing the two disciplines for relaxation and enlightenment: Comment on “Role of the feedback signal in electromyograph biofeedback: The relevance of attention” by Qudls and Sheehan. J . exp. Psychol.: Gen., 1981,110, 217-226. DLLEGEN. A,, & ATKINSON,C. Openness to absorbing and self-altering experiences rabsorption”), a trait related to hypnotic susceptibility. 1.abnorm. Psychol., 1974, 83, 268-277.

TELLEGEN.A., & ATKINSON. C. Complexity and measurement of hypnotic susceptibility: A comment on Coe and Sarbin’s alternative interpretation. J. P en . soc. Psychol.. 1976. 33,142-148. THORNDIKE. R. L. Applied psychometrics. Boston: Houghton MifRin, 1982.


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THURSTONE.L. L. Current issues in factor analysis. Psycbl. Bull., 1940. 37. 189-236. WEITZENHOFFER, A. M.. & HILGARD,E. R.Stanford Hypnotic Susceptibility Scales, Forms A and B . Pa10 Alto. CA: Consulting Psychologists Press, 1959. WEITZENHOFFER, A. M.,& HILGARD,E. R. Stanford Hypnotic Susceptibility Scale, Form C.Palo Alto, CA: Consulting Psychologists Press, 1962. WEITLENHOFFER, A. M., & HILGARD, E. R. Stanford Profile Scales of Hypnotic Susceptibdity, Forms 1 and 11. Palo Alto, CA: Consulting Psychologists Press, 1963. WOODY.E. Z., BOWERS,K. S., & OAKMAN.J. M.Absorption and dissociation as correlates of hypnotic ability: Implications of context effects. Paper presented at the 41st Annual Meeting of the Society for Clinical and Experimental Hypnosis, Tucson, AZ, October 1990. Die Spektrumanalyse der hypnotischen Ausfiihrung in bezug auf "Absorption" Claude G. Balthazard und Erik Z. Woody Abstrakt: Das wesentliche Resultat in Faktorenanalysen der Hypnoseskalen ist, daB die Einzelheiten ein fortlaufendes. 3-dimensionales, flcherartiges Muster bilden. Man bezeichnet dies Kontinuum 01s das "Spektrum der Hypnoseausfiihrung". "Spektrumanalyse" wird als ein erforschendes Verfahren eingefiihrt, das diese Idee des Kontinuums oder Spektrums gebraucht. Die Spektrumanalyse besteht aus einer graphischen Wiedergnbe des latenten Korrelationsniveaus zwischen einer Variablen und individuellen Hypnoseausfiihrungen, wenn die letzteren ihren Positionen gemliIl im Spektrum arrangiert sind. Die Spektrumanalyse der Hypnoseausfiihrung wird hier, mit Hinsicht auf Absorption, durch Gebrauch von Resultaten, die an einem Muster von 160 Vpn. erzielt worden waren, illustriert. Die Resultate deuten an, da6 Absorption mit schwierigen Hypnoseausfiihrungen stiirker verbunden ist als mit den leichten. lnsbesondere werden illustrative, den Einzelheiten charakteristische Kurven prlsentiert, um zu zeigen, d d ein gewisses Ma6 von Absorption nBtig ist, um schwierige Hypnoseeinzelheiten zu bestehen, obgleich einfache Hypnoseausfiihrungen nicht die Verfahren verlangen, die bei individuellen Unterschieden in Absorption angezapft werden. Weiterhin mag ein hohes Absorptionsniveau in rich selbst fiir schwierige Hypnoseausfiihrungen genug sein. Diese Ergebnisse werden hier im Hinblick auf einige Spekulationen von Shor. Orne, O'Connell(1963) und Tellegen (1978/1979) diskutiert, die den unterscheidenden Beitrag der Fahigkeitskomponenten zur Ausfiihrung an schwierigen Hypnosesuggestionen betreffen. Die Resultate werden auch auf eine Anzahl von sozial psychologischen Modellen der Hypnoseausfiihrung bezogen. Analyse spectrale des performances hypnotiques et degrd d "absorption" Claude C.Bnlthazard et Erik Z. Woody Rdsumd: Les analyses factorielles des dchelles daypnose rdvblent essentiellement que les items constituent un continuum P deux dimensions en forme d'dventail. On rtnre h ce continuum comme le "spectre" des performances hypnotiques. L'analyse spectrale est utilisde mmme une procddure exploratoire b a d e sur cette notion de continuum ou spectre. L'analyse spectrale consists en une reprbsentation graphique du niveau de corrdlation latente existent entre une variable et des performances hypnotiques individuelles, quand, ces dernibres sont organis6es selon leur position sur le spectre. Canalyse spectrale de la performance hypnotique en relation evec I'absorption est iUustrh avec un khantillon de 160Ss. Les dsultats montrent que I'absorption est plus fortement relide aux performances hypnotiques difficiles qu'aux fades. Des courbes illustrant des items caractdristiques sont prdsentdes pour ddmontrer que, m&me si les performances hypnotiques f a d e s ne font


SPECTRAL ANALYSIS

43

pas appel ilux processus dabsorption rbveles par les differences individuelles ?a ce niveau, un certain degrk dabsorption est necessaire pour reussir les items hypnotiques difficiles. De plus, un haut niveau dabsorption peut Ctre suffisant, A lui seul, pour des performances hypnotiques difficiles. Ces resultats sont discutes ?a la lumihre de certaines sficulations de Shor, Orne, O'Connell(1962) et Tellegen (1978/1979) en ce qui concerne la contribution differentielle des composantes dhabiletb liees ?a la performance pour les suggestions hypnotiques difficiles. Les resultats sont egalement mis en relation avec une varibtk de modbles psychosociaux de la performance hypnotique. El anPlisis espectral de la actuacidn hipnotica referido a la absorcih Claude G. Balthazard y Erik 2. Woody Resumen: En el a d i s i s factorial de las escalas hipn6ticas. el resultado esencial consiste en que 10s items formen un modelo continuo y bidimensional con forma de abanico. Este continuo es llamado "el espectro de la ejecuci6n hipn6tica". El an6Iisis espectral es introducido como un procedimiento exploratorio que utiliza esta noci6n de continuo o espectro. El analisis espectral consiste en una exhibition gr6fica del nivel d e correlacib latente entre una variable y la ejecucidn hipn6tica individual, cuando esta dltima esth ordenada de acuerdo a su posici6n en el espectro. El analisis espectral de la ejecucion hipn6tica referido a la absorci6n es ilustrado con 10s datos de una muestra d e 160 sujetos. Los resultados indican que la absorci6n esth m6s fuertemente relacionada con las ejecuciones hipnoticas dificiles que con las fhciles. En particular, se presentan curvas caracteristicils de items que muestran que aunque la ejecuci6n hipn6tica f6cil no requiere el registro de las diferencias individuales de absorci611, un cierto nivel de absorci6n es necesario para pasar items hipnoticos dificiles. Ademhs, un alto nivel de absorcion puede ser suficiente por si solo para ejecuciones hipn6ticas dificiles. Se discuten estos resultados teniendo en cuenta algunas especulaciones d e Shor, Orne y O'Connell (1962) y d e Tellegen (1978/1979) referidas a las diferentes contribuciones de 10s componentes de la capacidad para ejecutar sugestiones hipn6ticas dificiles. Tambien se relacionan 10s resultados con una variedad de modelos sociopsicol6gicos de ejecuci6n hipn6tica.

EEG correlates of hypnotic susceptibility and hypnotic trance: spectral analysis and coherence.

The hypnotic induction profile and absorption.

Two personality measures relating hypnotic susceptibility to absorption.

Effects of environmental temperature change on mercury absorption in aquatic organisms with respect to climate warming.

The effect of prior knowledge of hypnotic items on hypnotic performance and depth.

Spectral properties of microwave graphs with local absorption.

Comparative performance of hybrid and elite inbred rice varieties with respect to their source-sink relationship.

Effects of gluteal kinesio-taping on performance with respect to fatigue in rugby players.

Use of direct instructions to modify hypnotic performance: the effects of programmed learning procedures.

[Delays for lung cancer treatment: performance with respect to timeliness and increase of investigations].

Diagnostic performance of ultrasound and ultrasound elastography with respect to physician experience.

The Sensitivity Analysis for the Flow Past Obstacles Problem with Respect to the Reynolds Number.

Free-flow electrophoresis. II. Analysis of the method with respect to preparative cell separation.

The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship.

Individual differences and autonomic control: absorption, hypnotic susceptibility, and the unilateral control of skin temperature.

Adaptive spectral clustering with application to tripeptide conformation analysis.

A controversy with respect to occlusion.

To be respected and to respect: the challenge of mutual respect in intergroup relations.

Cholangiocarcinoma with respect to IgG4 Reaction.

Molecular structure, NBO analysis, electronic absorption and vibrational spectral analysis of 2-Hydroxy-4-Methoxybenzophenone: reassignment of fundamental modes.

Hypnotic procedures and surgery: a critical analysis with applications to "acupuncture analgesia".

The Stanford Hypnotic Susceptibility Scales as related to other measures of hypnotic responsiveness.

Health inequalities: an analysis of hospitalizations with respect to migrant status, gender and geographical area.

Normative Values of Voice Analysis Parameters With Respect to Menstrual Cycle in Healthy Adult Turkish Women.