Responding and Failing to Respond to Both Hypnosis and a Kinesthetic Illusion, Chevreul's Pendulum

Abstract

In this study, participants who failed to exhibit pendulum movement in response to Chevreul's Pendulum (CP) instructions had lower Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A) scores and reported experiencing less subjective response to hypnosis than did their counterparts who exhibited CP movement. However, intensity scores on Shor's Personal Experiences Questionnaire (PEQ) did not differ between pass- and fail-CP groups. Additionally, pass-CP participants showed positive correlations between PEQ intensity scores and hypnotizability scores, while fail-CP participants showed negative correlations among these measures. These findings are consistent with the notion that CP failure may reflect a situation-specific unwillingness to become imaginatively involved rather than a general inability to do so. Additional analyses revealed that 5 of 10 participants who had failed the CP task scored 0 or 1 on the SHSS:A, while only 3 of 65 pass-CP participants scored 0 or 1.

Zusammenfassung

Im Rahmen dieser Untersuchung zeigte sich, dass Teilnehmer, die bei der Instruktion zu einem Chevreul-Pendel-Versuch (CP) keine Pendelbewegung aufwiesen auch geringere Werte auf der Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A) erzielten und berichteten, in Hypnose subjektiv weniger erlebt zu haben als die Gruppen, die CP Bewegungen aufwies. Die Werte auf Shors Personal Experiences Questionnaire (PEQ) unterschieden sich jedoch nicht zwischen diesen Gruppen. Darüber hinaus zeigte sich ein positiver Zusammenhang zwischen PEQ und Hypnotisierbarkeitswerten für die Gruppe mit CP Pendelbewegungen, während innerhalb der Gruppe ohne CP Bewegung eine negative Korrelation zwischen diesen beiden Werten bestand. Diese Befunde stimmen überein mit der Annahme, dass das Fehlen von CP Bewegungen eher eine situationsspezifische Unwilligkeit gegenüber imaginativem Eintauchen als einer generellen Unfähigkeit dazu widerspiegelt. Zusätzliche Analysen ergaben, dass 5 der 10 Teilnehmer, die keine Bewegungen bei der CP Aufgabe aufwiesen, bei der SHSS:A einen Wert von 0 oder 1 erreichten. Demgegenüber erreichten lediglich 3 der 65 Teilnehmer mit CP Bewegungen solche die Werte 0 oder 1.

Ralf Schmaelzle University of KonstanzKonstanz Germany

Résumé

Dans cette étude, les sujets n'ayant pas fait de mouvement du pendule en réponse aux directives données dans le test du pendule de Chevreul (PC) ont obtenu des résultats plus faibles sur l'échelle de susceptibilité hypnotique de Stanford, formulaire A (SHSS:A), et ont dit avoir réagi de façon moins subjective à l'hypnose que les sujets qui avaient réagi au test du PC. Toutefois, les scores d'intensité au Questionnaire sur les expériences personnelles de Shor (QEP) n'ont montré aucune différence entre les groupes ayant réussi le test du PC et ceux qui y ont échoué. De plus, les sujets ayant réussi le test du PC montraient une corrélation positive entre le QEP et leurs scores d'hypnotisabilité, tandis que ceux qui l'avaient raté montraient une corrélation négative entre ces évaluations. Ces résultats appuient la notion selon laquelle l'échec au test du PC peut indiquer un refus ponctuel d'engager son imagination, plutôt qu'une incapacité totale de le faire. Des analyses complémentaires ont révélé que 5 sujets sur 10 ayant échoué au test du PC ont obtenu un score de 0 ou de 1 au test ESHS:A, tandis que, sur les 65 sujets ayant passé le test du PC, 3 seulement des sujets l'ayant réussi ont obtenu un score de 0 ou de 1 au test ESHS:A.

Johanne Reynault C. Tr. (STIBC)

Resumen: En este estudio, los participantes que fracasaron en mostrar movimiento de péndulo en el Péndulo de Chevreul (PC), tuvieron puntuaciones más bajas en la Escala de Susceptibilidad Hipnótica de Stanford, Forma A (SHSS:A) y puntuaron más bajo en reacciones subjetivas a la hipnosis en comparación con quienes mostraron movimiento en el PC. Sin embargo, las puntuaciones en el Cuestionario de Experiencias Personales de Shor (PEQ) no difirieron entre los dos grupos. Asimismo, quienes pasaron el PC mostraron correlaciones positivas entre las puntuaciones del PEQ y la hipnotizabilidad, en tanto que quienes no pasaron el PC mostraron correlaciones negativas entre estas medidas. Estos resultados son consistentes con la noción de que el fracaso en el PC puede reflejar una falta de voluntad para involucrarse imaginativamente específica a la situación más que una falta de habilidad general para involucrarse. Los análisis adicionales revelaron que 5 de 10 que fallaron el PC puntuaron 0 ó 1 en el SHSS:C, mientras que sólo 3 de 65 que lo pasaron puntuaron 0 ó 1.

Etzel Cardeña Lund UniversityLund Sweden

The authors wish to express their appreciation to Emily Carota Orne for her encouragement and thoughtful suggestions about this manuscript.

Notes

³In an initial session, psychoanalytic character type was assessed by means of the Blacky Picture Test (Blum, 1950; Blum & Hunt, 1952) and participants were chosen to participate in the Chevreul Pendulum/hypnosis study on the basis of their performance on the Blacky. However, response to the Blacky was entirely unrelated to response to hypnosis and/or CP. Thus, the sample should be considered randomly selected from the available participant pool.

⁴A copy of the Shor PEQ is available from the first author.

⁵The second author was the sole experimenter. He was not blind to Blacky scores when hypnosis was induced, nor to response to the SHSS:A when CP was administered. He was blind to PEQ responses and responses to the postexperimental inventory until after the end of the experiment. Possible context and expectancy effects are examined in the discussion section of this article.

⁶Standard criteria on the amnesia item require that, during suggested amnesia at the end of the SHSS:A, the participant recalls three or fewer of the suggestions given/responses made during administration of the scale. Reversibility criteria add the requirement that two or more additional items be remembered after the experimenter ends amnesia by saying “Now you can remember everything.” Using reversibility criteria avoids scoring the amnesia item as a pass for those participants whose lack of response is based on unwillingness or disinterest rather than on experiencing some degree of inability to remember in response to hypnotic suggestion (cf. Kihlstrom & Evans, 1976).

⁷Instructions for use of Chevreul's pendulum in a clinical setting are available from the first author.

⁸PEQ data were missing for one subject who passed the CP task. Thus, correlations were based on 64 pass-CP and 10 fail-CP subjects. Total PEQ score equals the number of items checked plus the number of checkmarks. Similar results emerge if total PEQ score, rather than the intensity score, is used. As in previous research, a simple count of number of items checked, without inclusion of the number of checkmarks indicating the intensity of the experience, did not correlate with hypnotizability.

⁹Given the predicted significant difference on the binomial test in respect to the overall pattern, there was only one direction in which the correlations between PEQ scores and each of the three dependent variables could differ. They could only be more negative for fail-CP participants than for their pass-CP counterparts. Thus, one-tailed statistical tests (as opposed to two-tailed tests) were appropriate for this analysis.

¹⁰For example, in this study's total sample only the relationship between PEQ intensity scores and subjective hypnotizability was significant. However, when all data from the 8 participants who scored 0 to 1 are eliminated from analyses, correlations for all remaining participants between scores on Shor's PEQ and the three major dependent variables become significant and were essentially equivalent to those found for the group of participants who passed the CP task. Thus, it seems likely that those scoring 0 or 1 on the SHSS:A added noise that, when removed, avoided two Type 2 errors that we would have made.

¹¹While both quasi-experimental and correlational studies of hypnotizability might benefit from this sort of supplemental analysis, it is most important in the purely correlational studies. In a quasi-experimental design, a group of lows scoring from 0–4 may comprise some participants who are unwilling, not unable, to be deeply hypnotized. However, the heterogeneity produced by the some unwilling low scorers may be ameliorated by the inclusion of those who score 2–4 in the low hypnotizable group. Alternatively, purely correlational studies that use the full range of scores from 0–12 may well make participants who are unwilling to be hypnotized far too influential. The familiar crossproducts formula for Pearson's r is where n _p is the number of t _X,t _Y pairs. With a little algebra, it can be shown that the r formula can also be written as . In English, this means that Pearson's r is a linear transformation of the average squared difference between t _X and t _Y scores. Positive correlations have similar t scores on the two variables, while negative correlations reflect quite different t _X and t _Y scores. Since we are looking at squared differences, a large difference squared becomes a very large difference. Alternatively, when t scores (which are largely decimal fractions) are similar, a small difference almost disappears when squared. Scores that are extreme on either measure may contribute a great deal to the sum of squared differences as, compared with scores close to the mean, they are far more able to widely differ from the t score on the other measure. So, if participants who score at the extremes of a hypnotizability scale (e.g., 0 or 1) are nevertheless heterogeneous, they may add a good deal of noise to or even entirely distort the results of such correlational studies. This is especially problematic as few published reports include scatterplots.

¹²Student volunteers in an experiment and patients in a clinical setting are obviously very different groups. Thus, the following discussion is limited by the degree to which one can extrapolate findings from one group to the other. However, Martin Orne and Robert Karlin's clinical experiences with CP indicate that such extrapolation may be justified, at least as a basis for further clinical exploration. As noted above, a script for administering CP in a clinical setting is available from the first author.

¹³As Arnold Lazarus (personal communication, November 1971) once commented during a group supervision, “There is nothing quite as useless as desensitizing someone to a bridge phobia when they are terrified of their job on the other side of the bridge.”