barber, t. x. (1965). physiological effects of 'hypnotic suggestions' - a critical review...

VOL. 63, No. 4 APRIL 1965

Psychologica l Bul le t in

PHYSIOLOGICAL EFFECTS OF "HYPNOTIC SUGGESTIONS":

A CRITICAL REVIEW OF RECENT RESEARCH (1960-64)1

THEODORE XENOPHON BARBER

Medfield Foundation, Harding, Massachusetts

Recent studies are reviewed which were concerned with the effectiveness ofsuggestions given under "hypnosis" and "waking" experimental treatments inalleviating allergies, ichthyosis, myopia, and other conditions and in elicitingdeafness, blindness, hallucinations, analgesia, cardiac acceleration and decelera-tion, emotional responses, urine secretion to sham water ingestion, narcotic-like drug effects, and other phenomena. The review indicates that a widevariety of physiological functions can be influenced by suggestions administeredunder either hypnosis or waking experimental treatments, and direct andindirect suggestions to show the particular physiological manifestations arecrucial variables in producing the effects.

Research studies completed prior to 1960which pertained to the effects of "hypnoticsuggestions" on physiological variables werereviewed previously in this journal by thewriter (Barber, 1961b). The present papercritically reviews subsequent investigationsconducted during the years 1960-64.2 Twoquestions are at the forefront of discussion:(a) What physiological functions can beinfluenced by suggestions given under"hypnosis" and "waking" experimental treat-ments? (b) Of the many independent vari-ables subsumed under the labels hypnosisand waking, which are effective and whichirrelevant to producing the physiologicaleffects observed?

1 Writing of this paper was supported by Re-search Grant MH-07003 ("Physiological Effects ofHypnotic Stimulation") from the National Instituteof Mental Health, United States Public HealthService.

2 An attempt is made to review all pertinentstudies with the exception of those concerned withthe effect of hypnotic suggestions on muscularstrength and endurance (reviewed elsewhere, Barber,in press-a) and those concerned with the physiolog-ical correlates of "hypnotic trance per se" (alsoreviewed elsewhere, Barber, 1965b).

HYPNOSIS EXPERIMENTAL TREATMENTS ANDTHE PRESUMED "HYPNOTIC TRANCE STATE"

In general, the investigations summarizedin this paper compared results obtained undertwo experimental treatments: a hypnosistreatment, and a waking treatment. Thehypnosis experimental treatment, but not thewaking treatment, typically incorporated oneset of variables that was subsumed under theterm "hypnotic induction procedure" and asecond set of confounded variables. Thehypnotic induction variables characteristicallyincluded: (a) instructions designed to pro-duce positive motivation to respond to sug-gestions, (b) suggestions of relaxation anddrowsiness, (c) suggestions of entering "deeptrance" or a "hypnotic state," and (d) sug-gestions that it is easy to respond to furthersuggestions (Barber, in press-b; Barber &Calverley, 1964f, in press-a). The variablesconfounded with the hypnosis experimentaltreatment typically included: (a) preselectionof subjects as meeting criteria for high sug-gestibility or "hypnotizability," (b) prelimi-nary practice sessions in which subjects weretrained to respond to a wide variety of sug-gestions, (c) assumption by the subject of

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202 THEODORE X. BARBER

an eyes-closed recumbent or semisupine po-sition during the experimental session, and(d) administration of direct or indirect sug-gestions intended to elicit particular physio-logical manifestations.

Although the hypnosis experimental treat-ment, but not the waking treatment, typicallyincluded the four hypnotic induction varia-bles and the four confounded variableslisted above, researchers tended to over-look some of these variables when theyinterpreted their results. In many instances,the effects noted under the hypnosis experi-mental treatment were simply attributed toa presumed altered state of consciousness onthe part of the subject, namely, a hypnoticstate or a trance state, even though no at-tempt was made to exclude the possibilitythat the effects could have been produced byany one or a combination of the eight vari-ables mentioned above regardless of the pres-ence or absence of hypnotic trance. Pertinenthere are recent experiments (Barber, 1964c,196Sa; Barber & Calverley, 1962, 1963b,1963c, 1964c, 1964g, in press-b; Barber,Karacan, & Calverley, 1964; Parker & Barber,1964) which indicate that subjects who havebeen exposed only to the first of the above ex-perimental variables, namely, motivational in-structions, show surprisingly high levels ofresponse to suggestions of thirst hallucination,body immobility, selective amnesia, enhancedstrength and endurance, enhanced learningproficiency, and so on. Whether or not sub-jects who have received only motivationalinstructions are in a hypnotic state remainsto be demonstrated. This raises a crucialquestion: By what criteria can it be statedthat a subject is in hypnosis or in hypnotictrance? To denote the presence of hypnosisor trance researchers in this area generallyuse one or both of the following criteria:

1. The subject is said to be in hypnotictrance if he manifests a "high" level ofresponse to test suggestions of the type in-cluded in the scales devised by Davis andHusband (1931), Friedlander and Sarbin(1938), and Weitzenhoffer and Hilgard(19S9), for example, test suggestions of limbor body rigidity, hallucination, and amnesia.However, when the supposed causal variable(hypnotic trance) is inferred from the

dependent variable (response to test sug-gestions), it is difficult to avoid the tautologythat subjects respond to test suggestions be-cause they are in trance and we know thatthey are in trance because they respond totest suggestions.

2. In other instances, the presence of hyp-notic trance is denoted by such criteria asrigid facial expression, lack of spontaneityand initiative, disinclination to talk, lack ofhumor, "literal-mindedness," etc. (Erickson,Hershman, & Secter, 1961, pp. 55-58; Gill& Brenman, 1959, pp. 38-39; Pattie, 1956,p. 21; Weitzenhoffer, 1957, pp. 211-212).However, the same investigators who usethese characteristics to denote trance also donot hesitate to state that (a) such charac-teristics can be removed, by explicitly orimplicitly suggesting to the subject that heno longer show them, and many subjects willcontinue to remain in hypnotic trance and,furthermore, (b) some hypnotized subjectsnever manifest such characteristics (Erickson,1962; Gill & Brenman, 1959, p. 36; Pattie,1956, p. 21). By what criteria is it statedthat subjects who do not manifest suchcharacteristics are in hypnosis or trance?Because they manifest a high level of re-sponse to test suggestions. And why are theyresponsive to suggestions? Because they arein trance.

Even if researchers agreed as to what theymeant by and how they were to denotehypnosis or hypnotic trance, and even if theycould avoid circular reasons when employingthis construct, it would still remain to bedemonstrated that the physiological effectswhich will be described below are due prima-rily to the presence of a trance state withinthe subject and not due to one or more ofthe external manipulable variables that arepart of or are confounded with the hypnosisexperimental treatment (Barber, 1964a).

In brief, hypnosis experimental treatments,as opposed to waking treatments, incorporatemany variables. In the discussion which fol-lows we shall ask continuously: Which ofthe multitude of variables included in orconfounded with the hypnosis experimentaltreatment were effective and which irrele-vant to producing the physiological effectsobserved?

PHYSIOLOGICAL EFFECTS OF "HYPNOTIC SUGGESTIONS" 203

SENSORY-PERCEPTUAL PROCESSES

During the years 1960-64 substantialprogress was made in delineating the vari-ables which are instrumental in the hypnoticproduction of ostensible sensory-perceptualalterations such as deafness, blindness, andanalgesia. In general, the evidence obtainedstrongly indicates that the instrumental vari-ables in eliciting these effects may consistsimply of suggestions to try not to hear, totry not to see, and to try not to respond topainful stimulation, and that the numerousother variables incorporated into hypnosisexperimental treatments may play only asmall or negligible role.

Deafness

A series of pre-1960 studies (Erickson,1938a, 1938b; Kline, Guze, & Haggerty,19 54; Malmo, Boag, & Raginsky, 1954;Pattie, 19SO) demonstrated that suggestionsof deafness given under a hypnosis experi-mental treatment are at times effective ineliciting apparent "deafness." However, aspointed out previously (Barber, 1961b), theseinvestigations did not demonstrate that thehypnosis experimental treatment was neces-sary to produce this effect. Barber andCalverley (1964d) recently presented an ex-periment, described below, that was designedto ascertain (a) whether suggestions to trynot to hear or to be deaf are effective inproducing "subjective deafness" when givenunder both hypnosis and waking experimentaltreatments and (b) whether "suggesteddeafness" produces similar objective conse-quences as actual deafness.

Forty-two female students were pretestedon an oral reading test with delayed audi-tory feedback, that is, while their utteranceswere delayed for a fraction of a second,amplified, and returned to their ears througha headphone. In harmony with previousstudies (Yates, 1963), the delayed auditoryfeedback produced stuttering and otherspeech disturbances in these individuals whopossessed normal hearing. Retests on anequivalent form of the oral reading test werethen given, again with delayed auditory feed-back, under three experimental treatmentswith 14 subjects randomly assigned to each

treatment. Subjects assigned to Treatment 1first received a 15-minute hypnotic inductionprocedure, patterned after the procedures ofFriedlander and Sarbin (1938), Marcuse(1959 pp. 52-53), and Weitzenhoffer andHilgard (1959), and then received sug-gestions of deafness. Subjects assigned toTreatment 2 were simply told to try to thebest of their ability not to hear and to bedeaf. Subjects allocated to Treatment 3(control) were retested without receivingeither a hypnotic induction or deafness sug-gestions. Significantly more subjects reportedpartial deafness (sounds were perceived asreduced in intensity) or total deafness(sounds were not heard at all) under Treat-ment 2 (93%) than under Treatment 1(64%). Subjects under both Treatments 1and 2 who claimed partial or total deafnessresponded to the delayed auditory feedbackof their speech in the same way as subjectsunder Treatment 3 (control) who heardnormally, that is, with stuttering, mispro-nunciations, increased vocal intensity, andslowed rate of speaking. In brief, this experi-ment indicated that: (a) subjective reportsof partial or total deafness can be elicitedmore effectively by simply instructing sub-jects under a waking experimental treatmentto try to the best of their ability not to hearrather than by administering suggestions ofdeafness under a hypnosis experimental treat-ment; and (b) the objective effects of partialor total suggested deafness, as evaluated bythe method of delayed auditory feedback,closely resemble the objective effects ofnormal hearing and appear to be markedlydissimilar to the effects of actual deafness.Further studies are clearly needed to confirmthese unexpected experimental results.

Sutcliffe (1961) also used delayed auditoryfeedback to assess hypnotic deafness objec-tively. The test performance consisted ofadding aloud a series of 2-digit numbersunder auditory feedback distraction. Thepertinent comparison in this complex experi-ment was the one made between (a) eightsubjects who were exposed to a hypnoticinduction procedure and then given sugges-tions of deafness for the auditory feedbackand (b) eight subjects who were tested undera waking treatment that did not include


special suggestions or instructions. Hypnoticdeafness did not prevent the impairment inperformance which normally results fromdelayed auditory feedback; subjects whoappeared to be in deep trance and who statedthat they could not hear the feedback of theirspeech performed on the oral arithmetic taskas poorly as the waking subjects who heardnormally.

Black and Wigan (1961) reported that anautonomic response, which had been condi-tioned to an auditory stimulus, could notbe elicited when deafness for the stimuluswas suggested under a hypnosis experimentaltreatment. The procedure was as follows.Two selected subjects were presented with atone paired with an electric shock until theyshowed cardiac acceleration when presentedwith the tone alone without shock. Ahypnotic induction procedure was then ad-ministered and, when the subjects appearedto be in a trance state, deafness for the tonewas suggested and the tone was presentedfour times without shock. The subjects nowdid not show the conditioned cardiac accelera-tion response. Black and Wigan concludedthat although "the case is still in some re-spects unproven" it seems that "deafness totones of specific frequency" can be producedby suggestions of deafness given under hyp-notic trance. However, since the experimentdid not include a waking comparison group,it appears inappropriate to draw conclusionswith respect to the effects of hypnotic trance.The experiment requires replication with theaddition of a waking group that is simplyinstructed to try to ignore and not hear theconditioned tone (cf. Barber & Calverley,1964d, as described above). Furthermore,respiration should be monitored continuouslyin all subjects. Since deep inhalation andexhalation produce cardiac acceleration anddeceleration, respectively, of the same orderof magnitude as is commonly found in studiesof cardiac conditioning (Shearn, 1961; West-cott & Huttenlocher, 1961; Wood & Obrist,1964; Zeaman & Wegner, 1957), the ab-sence and presence of the conditioned cardiacacceleration may prove to be a function ofvariations in respiration.

Color Blindness

Erickson (1939) and Harriman (1942)demonstrated that responses to the Ishiharatest resembling those given by congenitallycolor-blind individuals can be elicited bysuggestions of color blindness given under ahypnosis experimental treatment. Barber andDeeley (1961) subsequently demonstratedthat similar color-blind responses can beelicited under a waking experimental treat-ment by simple instructions to try to ignoreand to try not to see the colors red andgreen on the Ishihara cards.

The findings of Barber and Deeley wereconfirmed by Rock and Shipley (1961) inan experiment with eight subjects. The latterinvestigators administered the Ishihara sixtimes to each subject individually under awaking treatment. On the first four trialsthe subject was asked to respond as if hewere green, red, red-green, and totally color-blind. On the fifth trial he was asked to givehis normal responses. On the sixth trial hewas asked to report all of the numerals thathe could detect on the Ishihara cards. On thefirst four trials the subjects read many of theIshihara cards in the manner expected fromcongenitally color-blind individuals. (Theseunselected "awake" subjects gave approxi-mately as many color-blind responses as weregiven by the highly selected hypnotizedsubjects participating in Erickson's, 1939,experiment.) The fifth trial showed that allsubjects possessed normal color vision. Thesixth trial showed that seven of the eightsubjects had no difficulty in detecting all ofthe numerals seen by color-blind individuals.Rock and Shipley concluded that since "coloranomalies can be induced simply by askingthe subject to do so, hypnotically inducedcolor blindness as a deep sensory alterationstill needs to be proven."

Bravin (19S9) had previously reportedcomparable findings. In preliminary sessionshis subjects were tested for normality of colorvision, and were shown how color-blind indi-viduals perceive red and green as variousshades of the same color by exhibiting onecard of the Ishihara under colored lights.Thirty subjects, selected as capable of "deeptrance," were then randomly assigned to three


hypnosis treatment groups with 10 to eachgroup. After the administration of a hypnoticinduction procedure plus 40 minutes of addi-tional suggestions intended to deepen the hyp-notic trance, subjects in one group were givensuggestions of red-green color blindness to beexecuted after awakening, subjects in the sec-ond group were instructed to role play colorblindness after awakening, and subjects in thethird group were tested in the hypnotic trancestate without suggestions of color blindness.An additional group of 10 unselected wakingsubjects were simply instructed to role playcolor blindness. Subjects in the hypnotic color-blind group, the hypnotic role-play group, andthe waking role-play group gave some re-sponses to the Pseudo-Isochromatic test whichresembled those expected from persons withred-green blindness. Surprisingly, the wakingrole-play group gave more color-blind re-sponses (p < .10) than either the hypnoticcolor-blind or the hypnotic role-play groups.Further research is clearly needed to confirmthe latter unexpected finding.

In summary, the experimental evidenceavailable at present strongly indicates thatsome responses resembling those expectedfrom congenitally color-blind individuals canbe elicited either by (a) suggesting colorblindness to selected subjects under a hyp-nosis experimental treatment (Erickson,1939; Harriman, 1942) or by (b) simplyinstructing unselected subjects under awaking treatment to try to ignore red andgreen or to try to respond as if color-blind(Barber & Deeley, 1961; Bravin, 1959;Rock & Shipley, 1961).

Blindness

Underwood (1960) set out to ascertainwhether "hypnotic blindness" for a specifiedobject produces objective consequences thatare similar to those produced by actual blind-ness. He used two optical illusions in whicha pattern of lines distorts a superimposedfigure. Twelve highly trained hypnotic sub-jects were exposed to a hypnotic inductionprocedure and, when they appeared to be inhypnotic trance were shown the figures super-imposed on the patterns and given the sug-gestion that the patterns were absent. If thesuggestions produced objective effects similar

to those found when the patterns are actuallyabsent, the subjects should perceive thefigures as undistorted. Although 9 of the 12hypnotized subjects claimed that they couldnot see the patterns, they responded as if theycould see them; all subjects reported thedegree of distortion which is normally pro-duced by the patterns on each optical illusion.

Beck and co-workers (Beck, 1963; Beck,Dustman, & Beier, 1964) used 18 subjects,selected as manifesting "high hypnotic sug-gestibility," to study the effects of hypnoticsuggestions on the evoked electrocortical po-tentials that follow a brief flash of light. (Theevoked potentials are known to change withthe intensity of the stimulus and to disap-pear in the absence of sensation.) Under acontrol condition, the evoked potential re-sponses to a flashing light (1/second) were ledoff the occipital area, amplified, and thenaveraged by electronic computer. The evokedresponses were also recorded in the same wayunder a counterbalanced hypnosis treatmentwhich included suggestions that the flashinglight was bright and then dim. Contrary tothe expectations of the experimenters, thesuggestions given under the hypnosis treat-ment failed to affect the potentials; althoughthe subjects testified that the light appearedbright and then dim, there was no significantincrease in the averaged evoked potentials tothe light flashes during suggested brightnessnor was there observable diminution duringsuggested dimness.

Visual Thresholds

Kliman and Goldberg (1962) measuredvisual word-recognition thresholds, first undera base-line condition and then under counter-balanced hypnosis and waking experimentaltreatments. There was no overall difference inthe ease of recognition of the tachistoscopi-cally presented words under the hypnosis andwaking treatments. However, words that wereoriginally difficult to perceive (words withhigh base-line thresholds) were perceived moreeasily under the hypnosis treatment; and,under the waking treatment, there was atendency toward reduction in thresholds forwords that were originally easy to perceive(words with low base-line thresholds).

In a series of subsequent studies, Zamansky


and collaborators (Scharf & Zamansky, 1963;Zamansky & Brightbill, 1964; Zamansky,Scharf, & Brightbill, 1964) presented evi-dence indicating that the degree of reductionin word-recognition thresholds obtained underboth hypnosis and waking experimental treat-ments is highly correlated with the initialthreshold level. Subjects with low initialthresholds showed little or no reduction inthresholds under any of the experimentaltreatments. Subjects with high initial thresh-olds tended to show reduced thresholds underall experimental treatments. (The treatmentsincluded hypnosis with suggestions that thewords would be perceived easily and quickly;a waking treatment with monetary rewardfor improved performance; a waking treat-ment in which the subjects were told, incor-rectly, that the apparatus was being tempo-rarily modified so as to facilitate theiridentification of the words; and a wakingtreatment with no special incentives.)

Myopia (Nearsightedness)

Kelley (1958, 1961) attempted to improvevisual acuity in 14 myopic subjects by sug-gestions given with and without a precedinghypnotic induction procedure. Seven subjectswho could not be hypnotized constituted thewaking-suggestion group, and one deep-trancesubject and six light-trance subjects consti-tuted the hypnosis group. Subjects partici-pated in from one to three experimentalsessions. The following types of indirect sug-gestions were used to improve visual acuity:(a) With the subject's eyes closed, theexperimenter described pleasant scenes in de-tail and then suggested to the subject thathe should keep the frame of mind developedin the imagining situation as he opened hiseyes, (b) It was suggested that the subjectwould look at the visual figures on the chartwith an attitude of relaxed interest andeffortlessness, without making any particulareffort to "see." (c) It was suggested thatthe subject would feel as if he were lookingover great distances when he looked at thechart. Although each type of suggestion waseffective with some subjects, the suggestionsto imagine pleasant scenes were the most ef-fective and were used most often. Twelve ofthe 14 subjects showed improved visual acuity

for distant objects. The waking-suggestiongroup improved as easily and as quickly asthe hypnosis group. The overall average im-provement was equivalent to the differencebetween 20/50 and 20/20 acuity.

In an additional series of studies withthree to five myopic subjects (Kelley, 1958),the same suggestive techniques were used toimprove visual acuity while various opticalprocedures (haploscopy, retinoscopy, cyclo-plegia) were employed to delineate themechanisms underlying the changes induced.These studies excluded the possibilities thatthe improvement in visual acuity induced bysuggestion was cerebral ("improved interpre-tation"), pupillary ("increased depth offield"), or due to lens changes, and stronglyindicated that the improvement was due tochanges in eyeball shape (refractive changes)produced by the action of the extrinsic eyemuscles.

Vestibular Nystagmus

Aschan, Finer, & Hagbarth (1962) studiedthe effects of hypnotic suggestions on therapid eye movements produced by vestibularstimulation (vestibular nystagmus). Seven-teen persons who were "known to be goodhypnotic subjects" were selected for theexperiment. Rapid eye movements producedby two types of vestibular stimulation (rotaryand caloric stimulation) were measured withsubjects' eyes closed under four experimentaltreatments: a control treatment, a hypnosistreatment, a hypnosis treatment which in-cluded suggestions of decreased rotary sensa-tion, and a hypnosis treatment which in-cluded suggestions of increased rotary sensa-tion. In most subjects the intensity of the in-duced nystagmus was lowest under Treatment3 and highest under Treatment 4. No attemptwas made to ascertain whether the intensityof the induced nystagmus could be alteredin the desired direction by simply suggestingto unselected awake subjects that they wouldexperience reduced and enhanced rotarysensations.

Visual Hallucination

Barber and Calverley (1964e) confirmedprevious studies indicating that direct sug-gestions to see objects (that are not actually


present) are effective when given under ahypnosis treatment in eliciting testimony thatthe objects are perceived. However, theseinvestigators also found that ostensible"visual hallucinations" could be elicited asreadily under a waking treatment which in-cluded (a) suggestions that it was easy tosee objects that are not present and (b) in-structions to try to perform maximally onassigned experimental tasks.

Prior to the above study, Erickson (1958)and other investigators had contended thathypnotic visual hallucinations are similar ifnot identical with visual perceptions. Thiscontention received indirect support from theexperiments of Erickson and Erickson(1938), Rosenthal and Mele (1952), andBarber (1959), which indicated that hypnoticcolor hallucinations resemble actual colorperceptions in that they give rise to negativeafterimages. In interpreting this finding theauthors stated or implied that the comple-mentary color afterimages were due to in-voluntary neurophysiological processes thatwere associated with or that were broughtabout by the hypnotic hallucination. How-ever, the possibility was not excluded thatthe subjects, who were college students, mayhave had prior knowledge of complementarycolored afterimages even though, in most in-stances, they denied such knowledge. Tobegin to demonstrate that negative after-images associated with hypnotic color halluci-nations are due to involuntary neurophysio-logical processes it is first necessary to excludethe possibility that subjects have prior knowl-edge of the phenomenon. Elsea (1961) recentlypresented a rigorous study along these linesconducted with adolescents attending an in-dustrial training school. In the first part ofthe experiment, Elsea carefully excluded thepossibility that subjects from this populationpossesed knowledge of complementary colorphenomena. In the second part of the experi-ment, 32 volunteers who met criteria for"deep trance," were assigned to the experi-mental group, and 32 volunteers who werenot seen for hypnotic testing were assignedto the control group. The effects of severalvariables were investigated, including thefollowing: (a) the duration of the hypnoticinduction procedure (the control group was

not exposed to a hypnotic induction, halfof the experimental group was exposed to abrief 5-minute "induction" and the other halfto a 30-minute "induction"); (b) subject'sknowledge of negative afterimages. Half ofthe subjects in each group were given in-formation concerning complementary coloredafterimages and the others were not givensuch information. Results were: Subjectsexposed to the extended hypnotic inductionprocedure reported no more "correct" after-images to the hallucinated colors than thoseexposed to the brief induction; hypnotizedsubjects did not report a greater number ofcorrect afterimages than expected by chance;subjects given information concerning thenegative afterimage phenomenon did notreport a greater number of correct after-images to the hallucinated colors than thosenot given such information.

Elsea's negative results do not obviate thepossibility that hypnotic color hallucinationsmay resemble actual color perceptions ingiving rise to complementary colored after-images. However, Elsea's null findings, takentogether with the negative findings ofBernheim (1957), Dorcus (1937), Hibler(1935), Naruse (1962), Sidis (1906), andothers, recently reviewed in detail elsewhere(Barber, 1964b, 1964d), clearly place theburden of proof upon those who wish tomake this claim.

Hallucinated (Imagined) Pain

Barber and Hahn (1964) conducted anexperiment to determine whether suggestedpainful stimulation evokes physiological andsubjective responses which resemble thoseproduced by actual painful stimulation. Inthe preliminary noncritical phase of theexperiment, four groups of 12 subjects wereexposed to a noxious stimulus (immersionof a hand in water at 2 degrees centigradefor 1 minute). Both Group 1, which hadreceived a hypnotic induction prior to stimu-lation, and Groups 2, 3, and 4 which hadnot received an induction, showed increasedheart rate, elevated forehead muscle tension,and heightened levels of skin conductanceduring the stimulus period and subsequentlystated that the stimulus had been experiencedas painful. In the critical phase of the experi-


ment the hypnosis group (Group 1) and awaking group (Group 2) were exposed tononpainful stimulation (immersion of thehand in water at room temperature) afterreceiving suggestions to imagine vividly thatthe nonpainful stimulus was the same painfulstimulus that was received in the first phaseof the experiment. Groups 3 and 4 wereexposed to the painful stimulus (water at2 degrees centigrade) and the nonpainfulstimulus (water at room temperature), re-spectively, without special instructions. Sug-gestions to imagine painful stimulation weremore effective in eliciting subjective reportsof discomfort and pain in the group thathad received the hypnotic induction (Group1) rather than in the group that had not(Group 2). However, Groups 1 and 2 didnot differ in physiological reactions toimagined pain; both groups manifestedphysiological responses (significantly in-creased heart rate and forehead muscle ten-sion and a tendency toward increased skinconductance) which differed from the re-sponses of the group exposed to the non-painful stimulus (Group 4) and were similarto the responses of the group exposed to thepainful stimulus (Group 3).

Pain Reactivity (Hypnotic Analgesia)

During recent years, Shor (1959, 1962),Sutcliffe (1961), and Barber and Hahn(1962) presented carefully conducted ex-perimental studies pertaining to "hypnoticanalgesia."

Shor's (19S9, 1962) experiment includedtwo groups of eight subjects. One group wascomprised of "somnambulists" and the otherof subjects who had previously demonstratedthat they were not affected by hypnoticinduction procedures. Prior to the experimentall subjects chose a level of electric shockwhich they found painful but which theywere willing to tolerate for an extended seriesof trials. (On the average, the somnambulistschose lower levels of shock than the "poor"hypnotic subjects.) Each subject was thenpresented with his chosen level of shockunder the following counterbalanced experi-mental treatment with continuous monitoringof skin resistance, respiration, and heart rate:(a) waking control, (b) hypnosis control

(the effect of the trance state alone), (c)waking inhibition (voluntary suppression ofreactions to pain in the waking state),(d) hypnosis inhibition (voluntary suppres-sion of reactions to pain in the trance state),and (e) a hypnosis treatment which includedsuggestions of analgesia. Under Conditionsb, d, and e the somnambulists were placedin deep hypnotic trance whereas the non-susceptible subjects were instructed to simu-late hypnotic trance. Several measures wereused to minimize anxiety in the experimentalsituation, for example, the subjects wereallowed to choose their own level of electricshock, they were told what was to occurduring the experiment, and they were givena 2-second warning prior to each shock.Results were: (a) The somnambulists didnot manifest significantly different physio-logical responses to the noxious stimuli underany of the five experimental treatments.(b) The simulators also showed chance dif-ferences in physiological responses under thefive experimental treatments. Shor concludedthat his data offered no support to thehypothesis that "hypnotic analgesia hasspecial effects on physiological responses topainful stimuli that are beyond the boundsof waking volitional control." However, themost striking finding in the experiment wasthat physiological reactivity to painful stimu-lation was small under all experimental treat-ments. Shor (1962) suggested the followinginterpretation of these results:

the lack of large effects anywhere may be theresult of having succeeded in keeping incidentalanxiety minimal. In other words, since incidentalanxiety was artificially kept low, physiologicalresponses to painful stimulation were very small.Under these circumstances neither hypnotic analgesianor any other condition could show further, specialeffects on physiological reactivity [p. 2001.

Galvanic skin response to painful stimula-tion was the dependent variable in Sutcliffe's(1961) experiment. In preexperimental ses-sions, 24 subjects were given a series ofelectric shocks and a level of shock was estab-lished that invariably produced pain. Thesubjects were then randomly assigned tothree experimental groups with 4 somnambu-lists and 4 subjects who were hypnotizablebut not somnambulists to each group. Group


1 received a series of electric shocks at1-minute intervals under a waking experi-mental treatment. Group 2 received theshocks after hypnotic trance was inducedand suggestions of analgesia administered.Group 3 was exposed to the shocks afterreceiving instructions under a waking treat-ment to act as if the shocks were nonpainful.The galvanic skin response to the noxiousstimulation was not significantly differentunder the three experimental treatments. Thesomnambulists did not differ from the non-somnambulists under any of the treatments.

The dependent variables in the Barberand Hahn (1962) experiment included bothphysiological responses and subjective re-sponses to pain produced by immersion of ahand in freezing water, at 2 degrees centi-grade, for 3 minutes. Forty-eight subjects,who had previously manifested high responseto the Barber Suggestibility Scale (Barber& Calverley, 1963a), were randomly assignedto four treatment groups with 12 per group.One group received a hypnotic inductionprocedure, patterned after the procedure ofWeitzenhoffer and Hilgard (1959), followedby suggestions of hand anesthesia (hypnoticanalgesia treatment). A second group wastold to try continuously, during stimulation,to imagine vividly a pleasant situation(waking-imagined analgesia treatment). Theremaining two groups did not receive specialinstructions or suggestions; one group wassimply exposed to the noxious stimulus (un-instructed treatment) and the other groupimmersed the hand in nonpainful water atroom temperature (control treatment). Nosignificant differences were found between thehypnotic analgesia and the waking-imaginedanalgesia treatments in either subjective re-ports of pain experienced or in four physio-logical responses to the noxious stimulus thatwere monitored by a polygraph (heart rate,forehead muscle tension, respiratory irregu-larities, and palmar conductance). As com-pared to the uninstructed treatment, both thehypnotic analgesia and the waking-imaginedanalgesia treatments were effective in attenu-ating pain reactivity as indicated by subjec-tive reports and by reduction in respiratoryirregularities and forehead muscle tension.However, under both the hypnotic analgesia

and the waking-imagined analgesia treat-ments, subjects reported more discomfort andpain and manifested faster heart rate andhigher levels of skin conductance than thecontrols who were exposed to the nonpainfulstimulus. In brief, the results indicated thatsubjective responses and physiological re-sponses to a pain-producing stimulus can bereduced to a comparable degree (but are notabolished) either by (a) administering ahypnotic induction together with suggestionsof anesthesia or by (b) administering instruc-tions, without a hypnotic induction, toimagine vividly a pleasant situation whenexposed to noxious stimulation (cf. Barber,1963).

INDUCTION AND INHIBITION OF LABORCONTRACTIONS

Kelly (1962) used an intrauterine trans-ducer to record the motility of the womb infive postpartum patients when they weregiven suggestions under a hypnosis treatmentto recall vividly the pains that they had re-cently experienced during labor and delivery.Each patient showed a rise in intrauterinepressure which subsided and recurred in har-mony with the remembered pains. No attemptwas made to ascertain whether suggestions torecall previous labor were alone sufficient toproduce these uterine effects or whether othervariables incorporated into the hypnosistreatment also played a role.

Rice (1961) presented data indicating thatsuggestions to reexperience previous laborpains, given under a hypnosis treatment, areeffective with selected multiparous patients ininducing labor contractions, provided that thepatient is at or near term and the cervix is"ripe." Carter (1963) similarly presentedseveral case studies indicating that sugges-tions to recall previous labor given under ahypnosis experimental treatment are sufficientto induce labor in some pregnant women whoare at term. The earlier report (Rice, 1961)included evidence indicating that, in some ofthe patients, voluntary contraction of theabdominal muscles may have indirectlybrought about the uterine contractions.Further studies are needed to ascertainwhether this is the mechanism involved.

Logan (1963) hypnotized two patients


who were apparently in premature labor andsuggested to them that the labor contractionswould cease. (The fetal membranes had notas yet ruptured when the patients receivedthe suggestions.) The contractions stoppedand did not recur until the expected termdate. Schwartz (1963) presented data in-dicating that some good hypnotic subjects inpremature or full-term labor are able to stoputerine contractions "voluntarily." One pa-tient apparently "deliberately stopped hercontractions" and another stopped her con-tractions "on command." It is not clear fromthis report if the administration of a "hyp-notic trance induction" procedure wasrelevant to producing these effects. Schwartz(1963) stated that:

Depth of trance apparently plays little part in thepatient's ability to stop contractions purposefully.Some patients in deep trance are unable to stoplabor; others in light trance are able to do so[p. 213],

It could also be, of course, that some patientswho are not in hypnotic trance are able tostop labor contractions. Further studies areneeded to delineate the necessary and suffi-cient conditions for producing this effect.

CUTANEOUS FUNCTIONS

Ichthyosis

Mason (19S2) reported that a 16-year-oldpatient with fishskin disease (congenitalichthyosiform erythrodermia of Brocq)showed marked improvement in his conditionduring an extended series of hypnosis treat-ment sessions in which direct suggestionswere administered that his skin would im-prove first in one limb and then in another.(The limb-by-limb improvement apparentlyruled out the possibility of spontaneousresolution.) In a follow-up period extendingover 4 years, it was noted that the patientcontinued to manifest improvement in hiscondition without further treatment of anysort (Mason, 19SS). At the termination ofthe 4-year period, the patient was hypnotizedagain and given suggestions that his legswould show further improvement. This timethe suggestions were not efficacious.

Wink (1961) recently reported comparablefindings. Two sisters with congenital fishskin

disease were exposed to a hypnotic inductionprocedure at weekly intervals for 8 weeks andgiven suggestions that specific affected skinareas would soon start to grow soft andsmooth and the thick skin would flake off.The skin condition of both patients im-proved in some designated areas but not inothers. At the same time, improvement wasnoted in some undesignated areas. In thenext phase of the experiment the patientswere exposed to a hypnotic induction atfortnightly intervals for 2 months, and thenmonthly for an additional 2 months, andgiven suggestions that all affected areas ofthe skin would improve. Wink stated that:"Attempts at the assessment of skin changescan never be accurate and may be mislead-ing . . . . With these reservations, the im-provement in these two cases is tabulated asfollows": both patients manifested (a) a gen-eral reduction in skin thickness ranging from20% to 75% in various areas (with anaverage reduction of 48% and (b) a reduc-tion in the circumference of specific affectedareas ranging from 0% to 90% (with anaverage reduction of 24%).

Unfortunately, neither Mason nor Winkattempted to ascertain whether the sugges-tions of improvement were effective alone(i.e., with or without hypnosis) or whethervariables included in the hypnotic inductionprocedure also played a role. Further studiesare needed to determine which of the manyvariables incorporated into hypnosis ex-perimental treatments are instrumental andwhich irrelevant in alleviating fishskin disease.Further studies that attempt to delineatethe intervening hormonal, vascular, or neu-ronal mechanisms involved would also be ofgreat interest to both psychologists andphysicians.

Allergic Skin Responses

Fry, Mason, and Bruce-Pearson (1964)presented two studies concerning the effectsof hypnosis on allergic cutaneous responses.In the first study, 18 hypnotizable subjects,selected as manifesting asthma and/or hayfever and as showing positive skin reactionsto extracts of either pollen or house dust,were randomly divided into a control and anexperimental group. Both groups were skin


tested with four strengths of pollen or housedust on two occasions separated by a 2-weekinterval. The experimental subjects, but notthe controls, were exposed to a hypnoticinduction procedure three times during theintervening 2 weeks and given suggestionsthat they would not manifest skin reactionswhen tested again. Both groups showed areduction in the size of the wheals on secondtesting. At the two lower strengths of allergen,but not at the two higher strengths, thehypnosis group manifested significantlysmaller wheal responses than the controls.Although this study indicated that a hypnosisexperimental treatment is effective withselected patients in reducing allergic responsesto low strengths of allergens, it does nothelp in understanding which of the manyvariables subsumed under the term hypnosisare instrumental in producing this effect.Were the suggestions not to react to theallergen effective alone (with or withouthypnotic induction) or did other factors,such as the following, also play a role: selec-tion of subjects as hypnotizable, suggestionsintended to produce relaxation, suggestionsthat the subject was entering a hypnoticstate or trance, etc.?

In the second study, Fry et al. assigned 29patients randomly to three groups. All groupswere exposed to a hypnotic induction onthree occasions at weekly intervals and givensuggestions as follows: to one group it wassuggested that the right arm would notreact to skin tests, to another group it wassuggested that neither arm would react, andto the third group no suggestions were given.Bilateral tests for response to allergens weremade immediately before the first and im-mediately after the final hypnosis session.In general, all three groups showed a reduc-tion in the size of the wheals on both armsduring the second skin test. Since a wakingcontrol group was not employed, it cannotbe stated with certainty whether a reductionin response to the specific allergens used inthis experiment would have occurred onsecond testing if the hypnotic inductionprocedure was not used.

Black (1963a) also evaluated the effectsof hypnosis on an allergic response. Twelvesubjects, comprising the experimental group,

were selected as meeting three criteria: theygave histories of psychosomatic disorders,some of which were allergic; they weretrained hypnotic subjects; and it was thoughtlikely that they would show inhibition of anallergic response when given appropriatesuggestions. The subjects were first tested onone arm for response to the selected allergen.They were subsequently exposed to a hyp-notic induction, given suggestions for 5minutes that they would not react to theallergen, and then skin tested on the alternatearm. Eight of the 12 subjects manifestedreduced response to the allergen on secondtesting, as indicated by temperature measure-ments at the site of the injection and by anobservable reduction in edema. A controlgroup excluded the possibility that subjectsshow reduced response on second testingto the selected allergens used in this experi-ment. However, Black did not attempt toascertain whether suggestions not to reactto the selected allergens, given with or with-out hypnotic induction, were sufficient toreduce the allergic response.

In a second experiment Black (1963b)set out to determine whether hypnotic sug-gestions can inhibit the Prausnitz-Kustnerreaction, that is, the production of local hy-persensitiveness in a nonallergic person bythe intradermal injection of serum from anallergic person. Fourteen subjects wereselected as meeting two criteria: they werenot allergic to horse serum, and they werecapable of hypnotic trance. There were twoexperimental phases. In the first phase thesubject was inoculated on the arm withserial dilutions of a human serum containingskin-sensitizing antibodies against a com-ponent of horse serum. Horse serum wasthen pricked into each injection site and thesize of the resultant wheal was measured.The second phase was carried out after anintervening period of 2 weeks to severalmonths. The procedure was the same as inthe first phase with the exception that beforeassessing the subject's reaction to the horseserum, he was placed in a supine position,exposed to a hypnotic induction, and givensuggestions for 5 minutes that he would notreact. In general, the subjects showed smallerwheals in response to the horse serum in the


second part of the experiment. No attemptwas made to ascertain whether waking con-trol subjects would have manifested a similarreduction in the Prausnitz-Kustner reaction ifthey were placed in a supine position duringthe second session, whether suggestions notto react were necessary and sufficient toproduce the observed effects, or whetherother variables included in or confounded withthe hypnosis experimental treatment alsoplayed a role. These criticisms are also ap-plicable to a further study carried out alongsimilar lines by the same investigators (Black,Humphrey, & Niven, 1963).

West, Kierland, and Litin (1961) studiedthe effects of hypnosis on the following ab-normal vascular responses that are typicallypresent in patients with allergic eczema(atopic dermatitis): the delayed blanch, theabsent histamine flare, and white dermo-graphism. The subjects were 14 patientshospitalized with severe allergic eczema andcapable of deep hypnosis. The vascularresponses were assayed first under a wakingtreatment, then under a hypnosis treatment,and then again under a waking treatment.The hypnosis experimental treatment in-cluded the following confounded variables:the patients were deeply hypnotized, madecomfortable and relaxed by suggestions,given suggestions that their skin was well andwould react normally, and given a descriptionof the expected normal reactions. Vascularresponses were essentially the same in thetwo waking sessions. Results obtained duringthe hypnosis session were: 3 of the 14 pa-tients did not show a delayed blanch reaction,a flare in response to histamine was presentin 3 of the 4 patients who did not previouslyshow a flare, and white dermographism wasunaltered. Most subjects reported subjectiveimprovement during and immediately afterthe hypnosis session, stating that tensenessand itching were relieved. However, there wasno correlation between subjective improve-ment and alteration in the objective vascularresponses. No attempt was made in the studyto ascertain whether the objective effects onthe abnormal vascular responses were pro-duced by the suggestion that the skin wouldreact normally, by the suggestions of com-

fort and relaxation, or by these suggestionsin interaction with other suggestions includedin the hypnosis experimental treatment.

Ikemi and Nakagawa (1962) included anecessary comparison group that was lackingin the above studies, namely, a waking groupgiven suggestions not to react. These in-vestigators selected 13 subjects who mani-fested high allergic sensitivity to the leavesof two common poisonous trees found inJapan (the lacquer tree and the wax tree).The leaves of the chestnut tree were used asa control. One group of five subjects wereexposed to a hypnotic induction and thengiven suggestions that they were beingtouched by the leaves of the chestnut treewhile they were actually touched with theleaves of one of the allergy-producing trees.Chestnut leaves were applied to the alternatearm while the subjects received the suggestionthat they were being touched by the leavesfrom one of the allergy-producing trees. Eightsubjects assigned to the waking treatmentwere blindfolded and given the same sug-gestions. All hypnosis subjects and all wakingsubjects showed slight to marked degree ofdermatitis—for example, flushing, erythema,papules—when exposed to the control leavesand given the suggestion that they were beingexposed to the allergy-producing leaves.Four of the five subjects under the hypnosistreatment and seven of the eight under thewaking treatment did not manifest noticeableallergic responses to the leaves of the allergy-producing trees when given the suggestionthat they were being exposed to the leavesof the chestnut tree. In brief, the data pre-sented by Ikemi and Nakagawa strongly in-dicated that (a) the effective variables ineliciting an allergic response to an innocuoussubstance were direct suggestions that theinnocuous substance was an allergic sub-stance, (b) the effective variables in inhibit-ing an allergic response to an allergen weredirect suggestions that the allergic substancewas an innocuous substance, and (c) themany other variables incorporated into thehypnosis experimental treatment appeared tobe irrelevant to producing these effects. Fur-ther studies are clearly needed to confirmthese striking experimental results.


Blisters and Wheats

Although the writer's previous review(Barber, 1961b) referred to a relativelylarge number of studies pertaining to theproduction of blisters by hypnosis, no ex-periments in this area were found that wereconducted during the years 1960-64. How-ever, a study that is peripherally related tothis topic was presented by Kaneko andTakaishi (1963). These investigators workedwith four patients who were suffering fromchronic urticaria (hives) and who were goodhypnotic subjects. Two patients were of theopinion that heat was a causative factor inproducing their urticarial wheals, and theother two believed that their wheals wereproduced by emotional conflicts. The formertwo patients were exposed to a hypnotic in-duction and then given suggestions thatwheals would be produced by heat, and thelatter two were exposed to an induction andthen given suggestions intended to produceemotional conflict. Kaneko and Takaishi re-ported that "wheal formations were ap-parently produced in all cases during or rightafter trance." It should be noted that Kanekoand Takaishi did not give suggestions in-tended to produce emotional conflict to awaking comparison group. Previous investi-gators (Brandt, 19SO; Graff & Wallerstein,19S4; Graham & Wolf, 19SO; Moody, 1946,1948) had found that, irrespective of hyp-nosis, some patients suffering from urticariamanifest new urticarial wheals while discuss-ing their emotional problems.

ASTHMA

Several investigators used tests of respir-atory function to measure the effects of hyp-nosis on asthma objectively. Smith and Burns(1960) worked with 25 hypnotizable asthmaticchildren. Suggestions that immediate andprogressive relief from asthma would occurwere given in four hypnosis treatment sessionsconducted at weekly intervals. No evidence ofimprovement was obtained on objective testsof respiratory function (tests of vital capacityand of forced expiratory volume). Edwards(1960) administered suggestions that asthmawould gradually disappear in several hypnosistreatment sessions conducted with six severe

asthmatics. A 1-year follow-up showed thattwo patients were not affected by the hypnosis sessions, two failed to show objectiveimprovement on tests of respiratory functionalthough they reported subjective improve-ment, and two showed both objective andsubjective improvement. Edwards appropri-ately pointed out that, since a waking con-trol group was not used, no clear-cut con-clusions can be deduced from these results.

White (1961) conducted an extended studywith 10 patients suffering from moderate tosevere asthma. Each patient participated infrom 7 to 10 hypnosis treatment sessionsextending over a 4-6-month period, and wassubsequently hypnotized at irregular intervalsfor a further period of 6-11 months. Duringthe hypnosis sessions, easier breathing, lessen-ing of tension and bronchospasm, and in-crease in self-confidence were repeatedly sug-gested to the patient. Vital capacity alongwith mean and peak expiratory flow rateswere measured before and after each hypnosissession. The subjects also made their ownsubjective evaluation of whether their breath-ing was easier, unaltered, or worse. The moststriking finding was the disparity betweenthe objective effects of hypnosis and the sub-jective improvement reported by the sub-jects. Subjective improvement was reportedin 58% of the hypnosis sessions, whereasrespiratory functioning was objectively im-proved in only 19% of the sessions. Thesubjects stated that their condition was worsein only 6% of the sessions, whereas theobjective tests showed deterioration in 29%.(In the remaining sessions there was nochange subjectively or objectively.) Whitespeculated that the frequent objective de-terioration in respiratory function, if not dueto chance, may have been due to the factthat the patients were in a semirecumbentposition during the hypnosis sessions. (Itappears likely that the semirecumbent posi-tion is accompanied by a fall in vital capacitydue to redisposition of abdominal viscera.)However, this explanation is not entirely con-vincing since the patients were tested in thesitting position, 2 minutes after completionof the hypnosis session, when it appearspossible that the effects of recumbency onvital capacity would have ceased.


Maher-Loughnan, MacDonald, Mason, andFry (1962) assigned 55 asthmatic patientsat random to a hypnosis and a control treat-ment. The 27 patients assigned to the hyp-nosis experimental treatment were exposedto a hypnotic induction procedure in 10 ses-sions extending over a 6-month interval.During each hypnosis experimental session,symptom-removal suggestions were adminis-tered and, whenever possible, the patientswere taught "autohypnotic" methods of re-laxation. The 28 patients assigned to thewaking control group were given symptomaticbronchodilators and were seen at the sameintervals and for the same length of time asthe hypnosis group. The hypnosis experi-mental treatment was associated with im-provement in the asthmatic condition accord-ing to subjects' entries in diaries, but not ac-cording to objective measurements. After 2months of treatment and extending up to the6 months duration of the study, the hypnosisgroup reported a greater reduction in wheez-ing and in use of bronchodilators than thecontrol group. With respect to objective meas-urements, both the hypnosis and the controlgroup failed to show clear-cut changes insputum or blood eosinophil counts, and invital capacity, forced expiratory volume, andpeak flow. Further investigations are neededalong similar lines to ascertain whether thesubjective improvement attributed to thehypnosis treatment is accompanied by anyobjectively measured physiological criteria ofimprovement. Further studies should also usean additional waking comparison group givensuggestions of symptom removal, but notgiven the many other suggestions commonlysubsumed under the term hypnosis.

CARDIOVASCULAR FUNCTIONS

Yanovski (1962a, 1962b) presented dataindicating that various types of suggestionsgiven under a hypnosis experimental conditionwere effective in producing alterations on theelectrocardiogram (EKG). For instance, sug-gestions of relaxation at times produced car-diac deceleration and suggestions intended toevoke anxiety at times produced tachycardia,ventricular extrasystoles, and flattening of theT wave. No attempt was made to ascertainwhether the same suggestions would produce

the same EKG effects in a waking comparisongroup.

Klemme (1963) attempted to isolate theeffects of suggestions to accelerate and de-celerate the heart from the effects of themany other variables incorporated into hyp-nosis experimental treatments. The subjectswere 10 unselected volunteers, and 10 se-lected individuals who had previously demon-strated that they were capable of deep trance.All subjects were first asked to accelerate theirheart by simply thinking to themselves, "Myheart is beating faster and faster." Next, allsubjects were asked to accelerate and then todecelerate the heart by any means at theirdisposal. Finally, all subjects were exposed toa hypnotic induction and then received sug-gestions to accelerate and decelerate the heartin the same way as in the waking sessions.Suggestions to accelerate and decelerate theheart produced noticeable effects in the ma-jority of subjects under both the waking andthe hypnosis experimental treatments. Therewas a trend, which did not reach significance,for greater response to suggestions under thewaking treatment. (This trend might havebeen due to failure to counterbalance theexperimental treatments.) Klemme (1963)writes:

In this experiment hypnosis did not enhance theability of subjects to alter the heart rate as suggesteddespite rather deep trance states. This came as a sur-prise, for in the initial phase of the pilot experimentthe author was convinced that contrary results wouldbe obtained. Many of the good trance subjects . . .also expected the heart rate to be more effectivelyaltered in the state of hypnosis.

Klemme also noted that the observed altera-tions in heart rate may have been indirectlyproduced by variations in respiration. Underboth the waking and the hypnosis treatments,respiratory rate was elevated when subjectswere trying to accelerate the heart and wasslowed by nearly 50% when they were tryingto produce cardiac deceleration.

Black, Edholm, Fox, and Kidd (1963)studied the effects of hypnotic suggestions onthe peripheral circulation in nine selecteddeep-trance subjects. The subjects were ex-posed to a hypnotic induction while seated ina bath of water and then given suggestionsthat the bath temperature was being increased


or decreased. In some experiments the bathtemperature was not altered and in other ex-periments it was altered in the opposite direc-tion to the suggested change; for example,suggestions were given that the subject feltcold at the same time as the bath temperaturewas raised. The effects of direct and indirectsuggestions were also compared; for example,"you are hot" versus "you are hot becausethe house is on fire." The dependent vari-ables were forearm and hand blood flow asmeasured by plethysmograph and mouth tem-perature measured by clinical thermometer.Although the hypnotized subjects testifiedthat they felt cold and warm in accordancewith the suggestions, the suggestions failed toexert clear-cut effects on peripheral blood flowand oral temperature.

SECRETORY FUNCTIONS

Salivation

Bowles and Pronko (1949) and Pronko andHill (1949) presented data indicating that,under a hypnosis experimental treatment, sug-gested taste stimuli tended to affect salivarysecretions in a similar manner as actual gusta-tory stimuli. For instance, as compared to thebase-level salivary secretory response to dropsof water placed on the tongue, subjects showedenhanced salivation when it was suggestedthat the water was sour or acid. Barber,Chauncey, and Winer (1964) set out to con-firm and extend these findings, asking: (a)Are suggestions to imagine vividly that wateris sour or that an acidic solution is tastelesseffective in elevating and depressing salivarysecretions, respectively? (b) Are such sug-gestions more effective when given under ahypnosis or a waking experimental treatment?Under counterbalanced hypnosis and wakingtreatments, 16 subjects were given suggestionsto imagine vividly specified taste stimuli("Disregard the actual taste of the solutionwe are using today, and vividly imagine that[water is sour or that a sour solution is taste-less]" ). The parotid gland salivary responseto water was enhanced by the suggestion thatthe water was sour whereas the response to anacidic solution was depressed by the sugges-tion that the solution was tasteless, and theeffects of suggestions on salivation did not

differ significantly when given with and with-out a preceding hypnotic induction procedure.

Urine Secretion

To assess the effects of "hypnotically hal-lucinated water ingestion" on urine flow,Hulet, Shapiro, Schwarcz, and Smith (1963)selected nine hypnotizable subjects (five fe-males from a psychiatric ward and four malesfrom a surgical ward). After 12-15 hours offluid restriction the subjects were put to bedfor 1 hour and then the bladder was catheter-ized and the catheter was left in place. Afteran additional 1^-hour rest period in bed, thebladder was emptied and two or more 20-minute urine samples were collected (base-level measurements). The subject was nextplaced in a deep hypnotic trance for 20 min-utes, an empty glass was then placed in hishand, and satiation of thirst was suggestedrepeatedly while the subject "drank" for aperiod of 10 minutes. Following this, the blad-der was emptied and urine samples were col-lected every IS minutes during an experi-mental period extending over 4S-7S minutes.Four of the five females, but none of themales, manifested an increase in urine flowand a simultaneous decrease in urine osmoticconcentration during the experimental periodas compared to the base-level period. No sig-nificant increase in sodium excretion, sodiumexcretion fraction, or inulin clearance (ameasure of filtration rate) was observed inany instance. No attempt was made to ascer-tain which of the many variables incorporatedinto the hypnosis experimental treatment wereeffective in producing water diuresis in the fe-male subjects. When urine samples were col-lected during the experimental period the sub-jects had been lying down for at least 3^hours. It may be that lying quietly for an ex-tended period of time may itself produce wa-ter diuresis. Best and Taylor (1950) pointout that:

the urine volume is less in the standing position thanin recumbency; this is due chiefly to the concentra-tion of plasma protein which occurs in the formerposition [p. 440].

Further studies are needed to ascertainwhether the water diuresis was due to: thelong-maintained recumbent position, the sug-gestions of water ingestion, or one or more of


the many other variables incorporated intothe hypnosis experimental treatment.3

COLD-STRESS

Reiner (1964) used five trained hypnoticsubjects in an experiment designed to evalu-ate the effects of hypnosis on response to acold-stress situation. The subjects were placedin a thermal chamber at 40 degrees Fahrenheitfor 1 hour under counterbalanced hypnosisand waking experimental treatments. Underthe hypnosis treatment, but not under thewaking treatment, suggestions were adminis-tered "related to techniques which the sub-ject might utilize to increase his feelings ofcomfort." Under both experimental treatmentsthe subjects showed falling skin and rectaltemperatures during the hour in the coldchamber. However, the subjects showed mark-edly reduced shivering, lower levels of skinconductance, and slower heart rate under thehypnosis treatment than under the wakingtreatment. It was not determined whethersuggestions "related to techniques which thesubject might utilize to increase his feelingsof comfort" were alone sufficient (with orwithout hypnotic induction) to reduce shiver-ing, etc., or whether other variables incorpo-rated into the hypnosis treatment also playeda role.

INHIBITION AND ELICITATION OFNARCOTIC DRUG EFFECTS

Ludwig and Lyle (1964) attempted tocounteract the physiological effects of mor-phine by hypnotic suggestions. Five hospital-ized patients, who were being treated for nar-cotic addiction, were first exposed to a hyp-notic induction procedure and then given 15milligrams of morphine. Next, it was sug-gested to the subject that he had receivedonly "sugar water" and that, after "awaken-ing," all of the effects of the shot would leave

3 Corson, Corson, Rosen, Reese, and Dykman(1960) had previously conducted an experimentsimilar to that of Hulet et al. However, the findingsobtained by Corson and co-workers were presentedonly in abstract form and are thus difficult toevaluate. Corson et al. stated simply that "hypnoticsuggestions of drinking water was made to hy-dropenic subjects. This often led to diuresis. In mostcases, the response did not have the characteristicsof a water diuresis. The urine osmolarity did notdecrease: UNI, Uoi, and UK often increased."

and he would feel perfectly normal. Althoughthree of the five subjects stated after awaken-ing that they felt normal, the attempt to re-verse the physiological effects of morphine wasunsuccessful; systolic blood pressure, pulserate, and pupillary constriction were not sig-nificantly different prior to and after the sug-gestions to feel normal.

In another phase of the same investigationLudwig and Lyle set out to ascertain whethersuggestions given with and without a preced-ing hypnotic induction are effective in re-producing the behavioral and physiologicaleffects produced by a narcotic drug and byabrupt narcotic withdrawal. The experimentalsubjects, 11 hospitalized postaddicts, were ex-posed to a hypnotic induction and then giventhe suggestion that they had received a shotof their addicting drug. In a later session thesame subjects were again exposed to a hyp-notic induction and given the suggestion thatthey were going back to a previous time whenthey were experiencing sudden withdrawalfrom the drug and that they would again ex-perience all of the withdrawal symptoms. Ina subsequent session the same subjects wereasked under a "waking-acting" treatment toact as if they had just received the narcoticdrug and, later, to act as if they wereexperiencing withdrawal symptoms. Anothergroup of 5 postaddicts ("faking" group)were first instructed to simulate hypnosis andwere then given suggestions that they had re-ceived the addicting drug and, subsequently,were given suggestions of experiencing with-drawal symptoms. The experimental subjectsbehaved as if they had received a narcoticand also as if they were experiencing absti-nence symptoms more convincingly under thehypnosis experimental treatment than underthe waking-acting treatment. Furthermore, thefaking group did not perform as realisticallyas the experimental group had performed un-der the hypnosis treatment. When given thesuggestion that they had received a narcotic,some subjects under the hypnosis treatmentbut no subjects under the waking-acting orfaking treatments showed flushing, gagging,vomiting, mouth dryness, or slurred speech.When reexperiencing of the narcotic with-drawal syndrome was suggested, some subjectsunder the hypnosis treatment, but no subjectsunder the waking-acting or faking treatments,


cried, hiccuped, yawned, and vomited. How-ever, certain aspects of the narcotic absti-nence syndrome, for example, gooseflesh, pilo-erection, diarrhea, and bowel incontinence,were not observed in any instance.

Ludwig and Lyle pointed out that they wereaware during the experiment as to which sub-jects were "actually hypnotized" and whichwere faking or acting and that it would havebeen preferable if a "blind" condition hadbeen used. They also noted that they mayhave conveyed "a bias to perform in an in-ferior manner" to the faking group and to theexperimental group under the waking-actingtreatment. Further studies are needed to ex-clude the possibility that it was these vari-ables which produced the differences in per-formance.

EMOTIONAL RESPONSESA relatively large number of investigators

have recently attempted to delineate thephysiological concomitants of hypnotically in-duced emotions.

Persky and collaborators reported that sug-gestions intended to produce anxiety, givenunder a hypnosis experimental treatment, wereeffective in one study (Persky, Grosz, Norton,& McMurtry, 1959) but not in another(Levitt, den Breeijen, & Persky, 1960) inproducing a physiological effect commonly ob-served during anxiety or stress, namely, in-creased concentration of plasma hydrocorti-sone. These discrepant results were explainedas due to differences in the preanxiety levelsof hydrocortisone. The degree of increase inthe plasma hydrocortisone level with stressappears to be negatively related to the pre-stress levels. In the first experiment the pre-anxiety level of hydrocortisone was lowwhereas in the second experiment it was rela-tively high.

Weller, Linder, Nuland, and Kline (1961)reported that hypnotic suggestions intendedto produce anxiety, anger, and excitementfailed to affect blood glucose levels in diabeticpatients and in normal subjects. Dudley,Holmes, Martin, and Ripley (1964) found thathypnotic suggestions of deep relaxation anddepression were associated with decreased re-spiratory ventilation and oxygen consumptionwhereas hypnotic suggestions of exercise,anger, and anxiety or pain were associatedwith elevated ventilation and oxygen con-

sumption. Martin and Grosz (1964) measuredmuscle action potentials, heart rate, andpalmar resistance when it was suggested tothree subjects, who had received a hypnoticinduction, that they were becoming relaxed,anxious, and depressed. In general, physio-logical reactivity was highest during suggestedanxiety and lowest during suggested relaxa-tion. Hirose, Hirayama, and Ikemi (1961)presented data indicating that suggestions ofanxiety and fear given under a hypnosis ex-perimental treatment produced a significantreduction in liver blood flow (as measured in-directly by the disappearance rate of colloidalradiogold). Graham and co-workers (Graham,Kabler, & Graham, 1962; Graham, Stern, &Winokur, 1958; Stern, Winokur, Graham, &Graham, 1961) demonstrated that specificattitudes, suggested under a hypnosis experi-mental treatment, produced specific physio-logical effects. For instance, suggestions thatthe subject felt that he was being treated un-justly but could do nothing about it produceda rise in skin temperature but very little risein blood pressure; whereas suggestions that hefelt as if he had to be on guard against bodilyassault produced a rise in blood pressure, butnot in skin temperature.

It cannot be determined from the above in-vestigations whether the suggestions intendedto induce emotions were the only instrumentalvariables in producing the observed physio-logical effects or whether other variables in-corporated into the hypnosis experimentaltreatment also played a role. Several experi-ments that provide a tentative answer to thisquestion are summarized next.

Vanderhoof and Clancy (1962) asked fiveselected hypnotizable subjects to specify anexperience that they found stressful and emo-tional. The subjects were then asked to recallthe emotional experiences under noncounter-balanced hypnosis and waking experimentaltreatments, while blood flow through a limbwas measured continuously by venous occlu-sion plethysmograph. In general, blood flowwas elevated during recall of the emotional ex-periences under both hypnosis and wakingtreatments, with a greater increase occurringunder the first treatment (hypnosis) in threeof the five subjects.

Kehoe and Ironside (1963) measured thesecretory rate of gastric acid in seven subjects


under noncounterbalanced hypnosis and wak-ing experimental treatments. Under both treat-ments, the subjects were first asked to reporttheir ongoing thoughts and imagery and theirdominant emotional states and, subsequently,were given suggestions to experience a speci-fied emotion. After the experiment was com-pleted, eight judges studied the subjects' tape-recorded verbalizations and, using the methodof paired comparisons, succeeded in ratingreliably several emotional states. Significantcorrelations were obtained between the secre-tory rate of total gastric acid and the domi-nant emotional states, the secretory rate be-ing highest with anger and lowest with help-lessness-hopelessness. Comparable correlationswere obtained between gastric secretory rateand emotional states under both the hypnosisand the waking experimental treatments.

Damaser, Shor, and Orne (1963) suggestedfear, calmness, happiness, and depression toeight trained hypnotic subjects under counter-balanced hypnosis and waking experimentaltreatments. A second group, comprised of ninepoor hypnotic subjects, was given the sameemotion-inducing suggestions under a faking-hypnosis treatment. Consistent alterations inheart rate, forehead muscle activity, andpalmar skin potential were observed in re-sponse to the suggested emotions under thehypnosis treatment, with fear tending to pro-duce the highest and calmness the lowest ac-tivity on the physiological measures. However,very similar physiological responses were ob-served when the good hypnotic subjects wereasked to produce the emotion under the wak-ing treatment and also when the faking sub-jects were asked to simulate the emotion.

In summary, the experiments reviewed inthis section indicate that suggestions designedto evoke emotional responses are at times ef-fective in producing alterations in heart rate,skin conductance, respiration, gastric secre-tions, and other physiological variables. Al-though suggestions to manifest the emotionsare clearly instrumental variables in produc-ing these effects, it remains to be demon-strated that other variables incorporated intohypnosis experimental treatments also play animportant role.

SUMMARY AND CONCLUSIONS

The investigations cited indicate that awide variety of physiological effects can be

elicited by suggestions administered under ahypnosis experimental treatment. Allergic re-sponses can be inhibited, physiological reac-tions to cold-stress can be minimized, laborcontractions can apparently be induced andinhibited in some women at term, some fea-tures of the narcotic withdrawal syndromeand some narcoticlike drug effects can be pro-duced in postaddicts, water diuresis can beelicited in some hydropenic female subjects,ichthyosis can be mitigated, and wheals canbe produced in patients suffering from urti-caria.

However, in most instances, the experi-mental treatment whose consequences wereunder investigation (hypnosis) incorporatedmany variables whose separate contributionswere not assessed. In the majority of investi-gations no attempt was made to evaluate therelative contributions of (a) suggestions thatcertain physiological effects were forthcoming,(b) instructions intended to produce positivemotivation to respond to suggestions, (c) sug-gestions of relaxation, and (d) suggestionsthat the subject was entering a deep tranceor a state of hypnosis. Further, no attemptwas made to ascertain the role of such vari-ables as (e) the practice received by the sub-ject in the preceding "training" sessions, (/)the eyes-closed recumbent position adopted bythe subject during the hypnosis session, and(g) the bias introduced into the experimentby variations in the tone of voice in which thesuggestions were administered to the subjects(Barber, 1961a, 1962, in press-c; Barber &Calverley, 1964a, 1964b).

In a few investigations an attempt wasmade to isolate the effects of one of the manyvariables confounded with the hypnosis ex-perimental treatment, namely, the variablecomprised of direct or indirect suggestions in-tended to elicit behaviors which would giverise to the desired physiological effects. Inmost instances it was found that the direct orindirect suggestions, given under either hyp-nosis or waking experimental treatments, weresufficient to produce the physiological mani-festations. Heart acceleration and heart de-celeration were observed when hypnotizedand awake subjects received direct suggestionsto increase and then to decrease their heartrate. Direct suggestions to try not to see redor green or to try to respond as if color-blind,given to awake subjects, were sufficient to


produce some responses to the Ishihara testwhich resemble those given by congenitallycolor-blind individuals. Direct suggestions totry not to hear were sufficient to producepartial or total "subjective deafness" in themajority of hypnotized and awake subjects.Suggestions to experience specified emotions,given to either hypnotized or awake subjects,were sufficient to produce various autonomicchanges generally associated with emotions.Irrespective of the presence or absence of hyp-notic induction, suggestions to imagine pleas-ant scenes and then to open the eyes and keepthe frame of mind developed during imaginingwere sufficient to improve visual acuity inmyopic subjects. Suggestions to imagine thata sour solution was tasteless or that waterwas sour were sufficient to depress and en-hance salivary secretion rate, respectively, inboth hypnotized and awake subjects. Sugges-tions to try to imagine painful stimulation,given to hypnotized subjects and to awakesubjects, were sufficient to elicit some au-tonomic effects which are commonly observedduring painful stimulation. Waking-imaginedanalgesia was as effective as hypnoticallysuggested analgesia in reducing autonomic andsubjective responses to a pain-producingstimulus. Suggestions to try to see objectsthat are not present, given to hypnotized andawake subjects, were sufficient to elicit ap-parent visual hallucinations. Suggestions givento hypnotized and awake subjects that theywere being exposed to an allergy-producingsubstance (when they were actually exposedto an innocuous substance) were sufficient toproduce allergic dermatitis. Suggestions givento hypnotized and awake subjects that theywere being stimulated by an innocuous sub-stance (when they were actually stimulatedby an allergen) were sufficient to inhibit anallergic response.

In brief, a wide variety of physiologicalfunctions can be influenced by directly or in-directly suggesting to either hypnotized orawake subjects that certain physiological ef-fects are forthcoming. Whether other variablescommonly incorporated into hypnosis experi-mental treatments also play a role in produc-ing these functional alterations remains to bedetermined. Also to be determined are thehormonal, vascular, and neuronal mechanismswhich intervene in the production of thesephysiological manifestations.

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(Received September 29, 1964)

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