Fate of an Uncomplete Posthypnotic Suggestion

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loiirnal of Abnormal Psychology1970, Vol. 75, N o . 3, 278-285

FATE OF AN UNCOMPLETED POSTHYPNOTIC SUGGESTION'

E D GA R P. N A C E

Institute of the Pennsylvania Hospital

M A R T I N T. O R N E *

Institute o f the Pennsylvania Hospital andUniversity of Pennsylvania

This study was designed to test th e possibility that 5s who resist completing apos t h ypno t i c s u g g es t io n m a y , at a la ter t ime, in a si tuat ion which is not seenas related to the hypnotic session, carry out the earlier suggested behavior.

Such Ss were f o u n d to fa l l within th e m e d i u m r a n g e of hypnot izabi l i ty asevaluated over three sessions by the Stanford Scales of Hy pnotizabi l i ty . The5s with low hypnotizability failed to complete the posthypnotic suggestion an ddid no t demons t ra te a subsequent t endency toward the ea r l i er sugges ted be-havior . The 5s with high hypnotizabi l i ty tended to complete th e pos thypnot icsuggestion and, in about hal f of the cases, demonstrated a subsequent tendencyt o wa rd th e ear l ier sugges ted beh avior . W i thin th e m ed i u m ra n g e of hypnotiza-bility were f o u n d t ho s e 5s who did not complete th e posthypnotic suggest ion,bu t subsequent ly, in the ex t rahypnot ic se t t ing , behaved in accordance wi th

the earl ier suggest ion. Hy pno tizabi l i ty as an overal l characteris t ic was clearlyrelated to the demonstration of this action tendency.

A suggestion given to a hypnotized S that

he will, after trance has terminated, carry outa certain behavior in response to a specif iedcue is refer red to as posthypnotic suggestion.The phenomenon of posthypnotic suggestionprovides a foca l po in t for the s tudy of issueswhich are relevant to hypnosis at both th eclinical and the theoretical levels.

Classically, posthypnotic suggestion, ha sbeen conceptual ized as an isolated idea whichwas automatically carried out by S , usuallywithout his conscious awareness of i ts origin(Erickson & Erickson, 1941; Forel, 1907;Gurney, 1886-1887). It has been consideredanalogous to an impulse by such early in-ves t igators as Moll (1890) and, more re-cently, Guze (1951) . Clinicians concernedwith the possible consequences of posthyp-notic suggestions have long advocated that

pr ior to dismissing an S, he should be re-hypnot ized and all posthypnotic suggestionsremoved, regardless of whether or not theyhad been carried out, This precautionary mea-

1The s tudy was suppor ted in part by Cont rac t

4731(00) f r o m th e United States Office o f NavalRe s e a r c h .

2The authors wish to thank their colleagues

E u g en e C o g a n , F. J. Evans, C. H. Hol land , J. J.

L y n c h , Emi ly C . Orne , D. A. Paskewi tz , and JoAnneL. With ington for their help fu l comments an d criti-

cisms in the p r e p a r a t i o n of th i s paper .

Reques t s fo r reprints should b e sen t to Martin T,Orne, Institute of the Pennsy lvania Hospi tal , Uni tfo r Exper imenta l Psychia t ry , 111 No. 49th Street,Philadelphia, Pennsylvania 19139.

sure is der ived f rom th e classical conceptionthat a suggestion given during hypnosis willremain active subsequently, even though Swill have no conscious memory for its content(Prince, 19 29) . Fur the r , while the relation-ship with th e hypnotis t might be crucial atthe tim e the sug gestion was given, the re-sponse was considered to be quasi-automatic

in the service of intrapsychic needs, and es-sent ia l ly au tonomous f rom the hypnotist .From such a formula t ion, it would not only

follow that Ss would respond in the absenceof th e hypnotist, but also that there mightwell be a residual effect f rom posthypnoticsuggestions which 5 for some reason hadfa i led to carry out .

This phenomenon is illustrated by an anec-dote reported by White

sabout a classroom

demonstration of hypnosis. The instructor

gave a deeply hypnotized s tudent th e sugges-tion that prior to leaving the lecture hall, hewould place a chair upon th e desk in f r o n t ofthe room. The suggestion was not carried out,presumably because S fel t embarrassed andsuccessfully resisted his impulse . While work-ing late in his o f f i c e that a f te rnoon , the in-structor heard a strange noise and on in-vestigating its source was able to observe thes tudent quietly place a chair on the desk in

the now deserted lecture hall and leave the

room in as quiet a m a n n e r as he had e n t e r e d !8

White , R . W . P er s o n a l co m m u n i ca t i o n to M a r t i nT. Orne, 1959.

278



U N C O M P L E T E D P O S T H Y P N O T I C S U G G E S T I O N 279

The classical view of posthypnotic sugges-t ion has been challenged by Fisher ( 195 4) ,who t r ied to demonstrate that S 's responseaf ter the te rminat ion of t rance is a funct ion

o f his belief in whether or not the exper iment

is still in progress. Extending this view,Barber (1958) showed that trance inductionis not essential to demonstrate posthypnoticsuggestions an d tha t S's response is a func-

tion of implici t an d explicit cues from th ehypnotist an d will persist only so long as 5believes his relationship with E to be that ofsubjec t to hypnotist . Orne, Sheehan, andEvans (1968) , modi fy ing Fisher 's originalprocedure, showed that 5s who are able to re-spond to very difficult hypnotic suggestions inthe presence of the hypnotist would carry outposthypnotic behavior even in his absenceunder circumstances which they believed tobe outside of the experimental context . Usinga variety of control procedures, they showedthat these f indings could not be accountedf o r by differential cues f rom th e hypnotist .

The experimental work on the aforemen-tioned posthypnotic sugg estion, as well asDamaser 's (196 4) study o n the dur ation of

posthypnotic suggestion, differs f rom th e pres-ent study in that the earlier work focuses onthose 5s who carry out a posthypnotic sug-gestion and, fu r ther , is concerned with theirresponse within the context specifically im -plied by the posthypnotic suggestion.

In contrast, th e present study is designedto invest igate the e f f e c t of a posthypnot icsuggestion that is not completed when testedby th e hypnotis t . The authors wished tocreate a laboratory analogue to the si tuation

described by White (see Footnote 3 ) whichwould allow us to observe whether an 5 whohad failed to carry out a posthypnotic sug-gestion would nonetheless show a subsequenttendency toward th e suggested behavior. Inadd i t ion , it was fe lt crucial to provide a si tua-tion where the behavior could be carried outin a manner that would not readily be recog-nized as related to the posthypnotic sugges-

t ion. Such a situation would have to occuraf ter the hypnot ic pa r t of the experimentwas defini tely over and involve an activi tyclearly independent of the hypnotic session

and the hypnotist .It was essential to suggest a task which

could be carried out in response to the post-hypnotic suggestion, but which might equally

well be incorporated into one's behavior afterthe experimental session was finished. The 5swere requi red to f il l out num erous ques t ion-

naires in the course of part ic ipat ing in thepresent research, and the choice of writingimplement seemed potential ly useful as sucha cri terion of response. If an 5 were given asuggestion that he was to play with a bluepencil when the hypnotist removes his glasses,he might or might not carry out the sug-gestion. Subsequently, however, when askedto fill out a quest ionnai re , he might choose touse a blue pencil to do so. Assuming that 5did not perceive -E's interest in his choice ofwrit ing instrument for the quest ionnaire aspar t of the hypnot ic exper iment , his choice ofa blue pencil would provide evidence thatth e posthypnotic suggestion had an effect inde te rmin ing his behavior outside the contexto f th e specifically defined hypnotic session.

If the choice of a blue pencil in order to fill

out a postexperimental quest ionnaire—af terth e hypnot is t has le f t him—is a posthypnot icresponse, th e present authors would predict

it should be closely related to S's response toother, more conve ntional items. In term s ofhypnotizabili ty as measured wi th s tandardscales, th e authors wo uld predict that 5swould rank in hypnotizability between thosewho are highly hypnotizable (and thereforewould originally have carried out the post-hypnotic suggestion) and those who showl i t t le or no hypnot i c e f f e c t on this or any of

the other items. In other words, if the choiceo f a blue pencil in such a si tuat ion is a form

o f posthypnotic response, it should also relatelawfully to S's responses to other hypnotici tems during th e f o rma l testing of hypnosis,even though the pencil choice as such is notpart of the hypnotic session. On the otherhand, if the use of a blue pencil af ter hyp-nosis is not a funct ion of hypnosis, there

should be no lawful relat ionship between i tand hypnot izabi l i ty .

METHOD

Subjects

The Ss were 50 undergraduate males , ages 18-22,

who vo lun te e r e d in response to a poster placed onth e campus of the University of Pennsylvania which



280 E D G A R P. NACE A ND MARTIN T. ORNE

advert ised "Paid Psycholog ica l Exper iments , " andwh ic h expla ined tha t an ini t ia l assessment o f suscept i-bi l i ty to hypnos i s would be i n v o l v ed . The 5s hadparticipated in no previous experiments conducted inth i s l abora tory , nor had they an y previous experi-ence with the Stan fo rd Hy pno tic Suscept ibi l i ty Scales

(Wei tzenhof fe r & Hilgard, 1959, 1952) .

Procedure

The experiment consis ted of three separate sessionsscheduled on 3 di f f e ren t days, a lways at least 3 daysa p a r t . The 5s were scheduled original ly f o r on ly on esession, and f u r t h e r sessions were arranged at theend of each experimental session. The p u r p o s e of theexper iment was expla ined as inves t iga t ing the param-eters of the n o r m a l p h e n o m e n o n o f h ypno t i z ab i l i t yand relat ing the abi l i ty to othe r psycholo gical in-dexes. The 5s f i l led out v a r i o u s q u es t i o n n a i r e s oneach of their successive vis i ts to the laboratory. Nine5s could not be rescheduled an d were excluded f r o m

the da ta ana lys i s . Al tho ugh the c rucia l exper im enta ltest w as m a d e d u r i n g th e third session, 5s were givenno reason to suspect that the third session was par-

t icularly crucial for this exper iment , and, in fact ,many 5s were rescheduled a f t e r this session forf u r t h e r s tud ies .

4

Every exper imenta l room in the l abora tory , aswell as the wa i t i n g ro o m , w as equipped with apencil well that co n t a i n ed a clear plast ic bal l-pointpen, one red penci l , one blue penci l , one green penci l ,one chartreuse penci l , two yel low pencils, and aneraser stick. From th e beginning, an attempt w asm a d e to have th e penci ls seem used and to have th earrangement o f the penci l wel l appear na tura l . Theywere, however , cons i s ten t ly a r ranged in the fo l lowingm a n n er : the two yellow pencils and the ball-point

pen were at the f r o n t of the well closest to whereth e 5 would na tura l ly s i t ; the eraser s t ick an d thegreen and char t re use penci l s were a long the s ides o fth e penci l well; the red and blue pencils were against

the back of the penci l wel l and were least accessibleto 5. The colored pencils had the same kind of eraseras the more widely used yel low pencils , and al l hadth e usual kind of black lead. Pencils were kept

sharpened and were appropr ia te ly a r ranged b e f o r e

each expe rimen tal session. To el im inate s ize as ad e t e rm i n a n t of choice, all penci l s were approximate lyth e same length, though o f suf f icient var ia t ion toappear na tura l .

Experimental Session 1 . Up o n a r r i v i n g at the lab-o ra t o ry , 5 was greeted b y a secre ta ry-recep t ion i s tin th e waiting room and asked to complete a f o rmwh ic h p ro v i d ed i d e n t i f y i n g i n f o rm a t i o n . Un k n o w n t o5, the s ec re t a ry n o t ed whi ch wr i t i n g i n s t ru m en t 5used for this f o r m (Observa t ion la ) .

5

4The schedul ing assistants w ho co n v i n ced all 5s

to return for the three sessions were Rochel le Stein-

fe ld and Mary M c E l r o y .5 If 5 asked dur ing any o f the exper imenta l ses -

sions w h a t he was to wri te wi th , he was di rec tedtoward the pencil wel l wi th the s ta tement , "You mayuse one of these." I f 5 i n q u i r e d as to whether pen

A f t e r complet ing th e a d d en d a f o r m , 5 was in -t r o d u ced to E , w ho took 5 to o ne o f the ex p e r i m en t a lrooms, discussed th e f u n c t i o n s of the l a b o ra t o ry , an danswered any questions 5 might have about hyp-nosis. The E then asked 5 to complete three ques-t i onna i r e s (a s filler i t ems) and l e f t the room. The

5 's choice o f wr i t ing ins t rument fo r these ques t ion-naires was recorded by a research assistant,

0who

observed 5 t h ro u g h a one-way screen (Observa-

t ion Ib).

A f t e r th e que s t ionn a i res were completed, E ad-ministered the Stanford Hypnotic Susceptibility Scale,

Fo rm A (SHSS: A) o f W e i t z e nh o f f e r an d Hilgard(1959) without modi f ica t ion . Af te r the hypnot ic ses -sion, E asked 5 to check o n a Subject ive D e p t hForm, scaled 1-10, how deeply hypnot ized he fe l the had b e e n . The E n o t e d 5's choice o f wri t i n g in -s t r u m e n t f o r this task (Observat ion I c ) , and 5 w asthen re t u rn ed to the wai t ing room where he was

rescheduled by the ' e c r e t a r y , p a i d , an d asked tosign a receip t . Th e secretary observed S's choice ofwri t ing ins t rument fo r the receip t (Observa t ion Id).

Experimental Session 2. The S was asked by thesecretary to complete a ques t ionna i re in the wait ingr o o m , and she again noted S's choice of wri t ingi n s t r u m e n t (Observa t ion 2a) . Then 5 w a s intro-

duced to a f e ma l e research assistant ,7

who admini s -tered the Stanford Hypnotic Suscept ibi l i ty Scale,Fo rm B (SHSS: B , W e i t z e nh o f f e r & Hilgard , 1959)wi t ho u t m o d i f i ca t i o n . A f t e r th e hypnot ic sess ion , 5again checked th e Subject ive D e p t h F o r m , and h ischoice o f wr i t ing ins t rume nt was observed by the

r e sea rch ass i s tan t (Observa t ion 2b) . The 5 was re-tu rned to the wai t ing room where hi s choice o fwri t ing ins t rument fo r the s igna ture o f a receip tw as noted by the s ec re t a ry ( Ob s e rv a t i o n 2c ) .

Experimental Session 3. The 5 was a d m i n i s t e r edth e S t a n f o r d H y p n o t i c Suscept ibi l i ty Scale, Form C(SHSS: C) of Weitzenhof fe r and Hi lgard (1962)wi th one modi f i ca t ion : the addi t ion o f a pos thypnot icsuggest ion a f te r the first sentence in Item 12. Thepos thypnot ic sugges t ion was as fo l lows:

Soon y o u wil l awaken . A f t e r you are completelyawake, when I take off my glasses you will notice

some penci l s on the desk in f r o n t o f y o u , and you

will have a compel l ing urge to pick up a bluepenci l and p lay with it . W h e n I take o f f m yglasses you will feel a compulsion to pick up a

b lue penc i l . Y ou will have th e urge to do thiswhen I take o f f m y glasses. Y ou need n o t r e m e m -b er t h a t I told you t o do so , j u s t as you mayforge t other things unt i l I tell you 'Now you can

remember every thing . ' Regard less , when I take o f fmy glasses you wil l feel a compe ll ing urg e to picku p a blue penci l an d play with i t .

or penci l were appropr ia te , he was answered with ,"It doesn' t matter." Rachel Wampler served as

secre ta ry-recep t ion i s t and recorded this d a t a .6

Mary L o u i s e B u r k e an d Carole Spencer recordedthe penci l cho ice observ a t ions dur ing b o t h SHSS:Aan d SHSS:C sessions.

7Luise E. Mil ler admin i s tered the SHSS:B scales.





28 2 E D G A R P. N A C E AND MARTIN T. O R N E

TABLE 2

FREQUENCY OF CHOICE OF WRITING INSTRUMENT INSTANFORD HYPNOTIC SUSCEPTIBILITY SCALES,

FORMS A AND B VERSUS S T A N F O R DHYPNOTIC SUSCEPTIBILITY SCALE,

FORM C

W ri t i ngi n s t r u m e n t

Ow nPe nYellowGreenChartreuseRedBl ue

Expectedf r e q u e n c y "

27.7424,3430.41

3.24S.636.911.71

Obse rvedf r e q u e n c y

16.8227.1122.43

6.542.810.93

23.36

x !

4.300.322.103.361.42S.17

274.11

Note . —Xs

to tal = 290.78, p < .001.a

Average of the f r equenc i e s f rom Stan f o rd H ypno t i c Sus -cept ib i l i ty Scales, F o r m s A and B.

Pencil Selection and Hypnotizability8

The 5s were divided into three groups onth e basis of their posthypnotic per formancefollowing SHSS:C: (a ) those who failed tocarry out the posthypnotic suggestion (PHS)and did not use the blue pencil subsequently

( — P H S — p e n c i l ) ; (b ) those who failed tocarry out the posthypnotic suggestion but diduse the blue pencil subsequently ( — P H S +penci l) ; and (c) those who carried out the

posthypnotic suggestion (+PHS ± penci l ) . 9

Table 3 por trays the hypnotizability for eacho f these groups during each of the threesessions. A Kruskal-Wallis one-way analysiso f variance for Session 3 (SHSS:C) shows asignificant difference in hypnotizability ( p <.01) among the three groups which confirmsour predict ion . Fur ther , it should be notedthat the same relative order of hypnotizabili tyappeared in 5s' hypnotic scores that was ob-tained during the first (p < .10) an d second(p < .01) sessions, u s ing th e same statistical

test.The group of 5s who responded to the post-

hypnotic suggestion could, of course, also be

8 The m e a n SHSS:A score for a l l Ss in the presen t

exper iment was signif icantly ( p < .01) lower than acomparab le vo lun te e r g r o u p u s e d in an ear l ie r s t udy(O'Conne l l , 1966) . A compar ison o f the number o fSs passing th e pos thypnot ic sugges t ion or the amnes iai tem in SHSS: A in the presen t s tudy and in O'C o n -nell's (1966) s tudy revealed no s ign i f i can t d i f fe r en ces .

9

Data f r o m Ss ( N=

6) who used a blue penc i ldur ing Sessions 1 or 2 are excluded f r o m the presen tanalysis , as there was no way of asce r ta in ing whe the r

Ss' earlier use of the blue pencil would influence their

choice in Session 3.

divided into those individuals who subse-quently used the blue pencil after they hadcarried out the suggestion (+PHS + pencil;N = 10) and those who did not again usethe blue pencil af ter carrying out the post-

hypnotic suggestion (+PHS — pencil ; N —8). No differences in hypnotizability betweenthese tw o groups were expected, and nonewere observed.

The difference in hypnotizability in SHSS:Cbetween 5s who did not carry out the post-hypnotic suggestion but subsequently usedthe blue pencil ( — P H S + pencil) and the

group that neither carried out the posthyp-notic suggestion nor used th e blue pencil( — P H S — pencil) approached significance (p

< .10, Mann-Whitney U Test). The d i f f e r -

ence in hypnotizability in SHSS:C between5s who carried out the posthypnotic suggest ion(+PHS) and the — P H S + pencil group was

not significant, whereas th e difference in hyp-notizability in SHSS:C between th e +PHS

group and the — P H S — pencil group was

significant (p < .05, Mann-Whi tney U Tes t ) .Of particular interest ar e some of the pat-

te rns which emerged on specific i t ems in d i f -ferentiating the — P H S + pencil group from

the — PHS — pencil group. Applied to am-nesia scored in terms of pass or fail accordingto the criterion used in the Stanford HypnoticSusceptibility Scale, th e Fisher exact proba-bility test (one-tailed) differentiates the twogroups (p < .05) in Session 1, amnesia beingmore frequent in the — P H S + pencil group.In Session 3 ( SHSS: C ) , the difference againemerges, with th e Fisher exact probabilitytest (one-tailed) reaching a probability level

o f p < .10. This difference is relativelystronger if one considers that amnesia is

TABLE 3

H Y P N O T I Z A B I L I T Y OF GROUPS B A S E D ON SHSS:C P O S T H Y P N O T I C RESPONSE

Proiln

-PHS - penc i l(N = 18)— PHS -h penc i l

( 2V = 8)+PI-IS -f c pencil(N = 18)

SHSS: A

X

5.94

7.13

8.SO

SD

3.14

3.52

2 . 4 7

SHSS:B

X

7.17

8.389.78

SD

2.39

1.652.22

SIISSiC

X

5.83

7.758.56

SD

2.65

2.331.27

N ot e .— S H S S re fe r s to Stan f o rd H y pno t i c Suscep t i b i l i tyScale, of which Forms A, B , and C were given.



U N C O M P L E T E D P O S T H Y P N O T I C S U G G E S T I O N 283

TABLE 4

STANFORD HYPNOTIC SUSCEPTIBILITY SCALE, FORM C, ITEM ANALYSIS C O M P A R I N G PROPORTIONOP Ss IN EACH GROUP PASSING A PARTICULAR ITEM

Item

Hand lower ingMoving hands apartMosquito hallucinationTaste hallucination

A rm rigidityDreamA ge regressionA rm immobilizationAnosm ia to a m m o n i aHallucinated voice

Negative visual hal luc inat ionPosthypnotic amnesia

Groups

-PHS -pencil

1.000.94O.SO0.560,560.560.500.500.390.17

0.110.06

-PHS +pencil

1.001.000.750.380.750.881.000.750.500.25

0.130.38

+PHS ±pencil

1.001.000.890.890.720.610.890.780.560.50

0.220.50

-PHS -pencil vs .-PHS +

pencil

ns *nsnsnsnsns

<.02Snsnsns

ns<.10

+PHS ±pencil vs .-PHS +

pencil

nsnsns

<.025nsnsnsnsnsns

nsns

+PHS ±pencil vs.-PHS -

pencil

nsns

<.025<.05

nsns

<.025nsns

<.025

ns<.OOS

* For all ns values, p > .10.

possibly more difficult to achieve in SHSS:C,since recall of items may be enhanced by 5'sexperience with at least f ive i tems in SHSS:Cwhich are common to SHSS:A an d SHSS:B.This possibility is supported by the fact that

in the present authors ' sample, 60% of 5spassed the amnesia item in SHSS:A, 32% inSHSS:B, and 28% in SHSS:C. The amnesiaitem did not significantly differentiate the-PHS + pencil group f rom the +PHS

groups, but did dif feren t ia te th e — P H S—

pencil group f rom th e +PHS groups ( p <.01, Fisher's t e s t ) .

A f u r t he r distinction between th e — P H S +pencil and — PHS — pencil groups emerged inan analysis of the SHSS.'C ag e regression item .All 8 5s in the — P H S + pencil group passed

this item in contrast to only 9 of 18 in the— P H S — pencil group, result ing in a differ-

ence signif icant at p < .05 by Fisher's test.Th e most difficult i tems in terms of pass-

fail criteria are the aud i to ry hal luc ina t ion and

the negative visual hallucination in SHSS:C.These items were passed by so few of eitherthe -PHS + pencil or the -PHS - pencilgroups that no differences could emerge be-tween th e groups. The auditory hallucinationand the mosquito hallucination in SHSS:C

each significantly dif ferentiated be tween the— P H S — pencil group and the combined+PHS groups (p<.Q5), but did not sig-nif icant ly di f fe ren t ia te the — P H S + pencil

group f rom the combined +PHS groups. Nosignificant differences emerged between an yo f the groups when th e relatively easier hyp-notic items, ideomotor and challenge items,were compared. A breakdown comparing th ethree groups in terms of passing or failing th e

items in Session 3 is contained in Table 4.

DISCUSSION

The present study asks whether 5s who donot carry out a posthypnotic suggestion wouldnonetheless in another context subsequentlydemonstra te a tendency to carry out the sug-gested behavior. The authors felt it essentialto choose an item of behavior apparently un-related to the hypnotic session and to takespecial care to prevent 5 f r o m recognizing

that th e behavior was of interest to the hyp-notist or , for that matter , to the laboratory.The pencil choice appeared to be an unob-trusive measure 5 would not easily identifyas relevant .

W e would have liked to have had directevidence about 5s' perception of the pencilchoice, since it is of considerable importancetheoretically that 5s did not view it as relatedto th e hypnotic tasks, but we chose not to doa detailed inquiry lest we make 5s aware of

our interest in the choice of penc i l—an interestwe felt sufficiently novel to make excellentcampus scut t lebut t . Most of the 5s, however,took part in f u r t he r studies with other in -



284 E D G A R P. N A C E AND M A R T I N T. O R N E

vestigators within th e laboratory, and it is thepresent authors ' practice to discuss 5s' past

experiences with them preceding any f u r t he rhypnotic sessions. Working with another in-vestigator, Ss are typically asked about an y

aspects of their past experiences in the lab-oratory which they felt were striking or par-ticularly interesting. The fac t that no 5 re -ported anything about the choice of pencillends some indirect support to our belief thatwe were successful in making this a truly un-obtrusive criterion measure.

A somewhat related issue is whether S'schoice of blue pencil might not have been afo rm of compliance, because he could some-how have recognized E's interest in his choice

an d responded to i t . We hold this possibilityto be unlikely since 5 had been given a post-hypnotic suggestion to play with th e pencilwhen E removed his glasses. If 5 were in -clined simply to comply with E, he couldhave done so more easily by carrying out theposthypnotic suggest ion . We are cognizantthat special active control procedures (Orne,1969) would be necessary to state abso-lutely that choice of pencil following SHSS:Cwas conceived by 5 to be pr ivate behavior ,

but feel that the concept of pencil choice asprivate behavior is not crucial to the argu-m e n t that an action tendency m ay exist be-yond th e hypnotic context.

In order to validly consider the choice ofthe blue pencil for the questionnaires as anitem of posthypnotic behavior, however, itwould be essential to show a di f ferent ia l re-sponsiveness between the —PHS — pencil an d

the — P H S + pencil groups in other areas of

hypnotic per f orm ance. Such a differenceemerged in relation to posthypnotic amnesia.Factor analytic studies (Evans, 1965; Ham-mer, Evans, & B art le t t, 1963; Hilgard, 1965;Thorn, 1961) have shown that certain hyp-notic i tems tend to cluster. One such clustercomprises posthypnotic suggestion, posthyp-notic amnesia, an d hallucinations. Since th eauthors consider the — P H S + penci l g roup tobe manifesting posthypnotic behavior, it wouldfollow that they should likewise be distin-

guished f rom the — P H S — pencil group interms of posthypnotic amnesia. Such was thecase in SHSS:A, where the -PHS + pencilgroup, in terms of pass-fail criteria, was d i f -

feren t ia ted signif icantly f rom the — P H S —

pencil group in regard to the amnesia item.Th e most d i f f i c u l t items in terms of pass-failcriteria are the auditory and negative visualhallucinations. So few of either group passed

these i tems that no differences could be de-t e rmined . Fur ther substant ia t ion of differen-

t ial hypnotizability between the — P H S —

pencil group and the — P H S + pencil groupis afforded by comparing overall hypnotic per-formance (see Table 3) and by comparingper fo rmance on the age regression item inSHSS:C (see Table 4 ) .

Thus, the use of the blue pen cil, which theauthors interpreted as posthypnotic behavior,showed a remarkably lawful relationship to

S's response within th e hypnotic situation.Not only is hypnotizability as an overallcharacteristic related to this behavior, butspecific kinds of responses to hypnotic sug-gestions show a striking relationship to it.The use of the blue pencil is characteristic ofan S who does not respond as well as thosewho passed th e posthypnotic i tem, but whorespond considerably better than those whofailed this item and did n ot use the blue pencilsubsequently .

Our findings are in line with those repo rtedearlier that highly hypnotizable Ss will carryout a posthypnotic suggestion in an extra-experimental setting (Orne, Sheehan, & Evans ,1968). In the present study, however, th eauthors have been able to extend this ob-servation to show that even in less deeplyhypnot ized individuals, the posthypnotic sug-gestion m ay create an intrapsychic need tocarry out an item of behavior, the execution

o f which may not even be reported to thehypnotist, and which, fo r that mat ter , m ayeven escape S's own awareness. This observa-tion may not be surprising to any clinicianwho has worked with hypnosis or to anyonefamiliar with the classical conception of thephenomenon . It is, however, a crucial demon-stration when viewed in the context of currenttheories which a t t e mpt to explain al l hypnoticphenomena as dependent upon S's playingan interpersonal role which requires cont inu-

in g reinf orcem ent and support of the hyp-noti st. It is difficult to see how such a viewcan explain the f indings reported here.

Of par t icu lar in teres t f rom a theoretical



U N C O M P L E T E D POSTHYPN OTIC SUGGESTION 285

s tandpo in t is the f ac t that the use of the b luepencil outside of the hypnotic relationship islawful ly related to S 's response to hypnot ic

suggestion within th e clearly denned hypnotic

re lat ionship . This suggests that th e effect ofother hypnotic suggestions cannot be ex-pla ined simply on the basis of a face- to- facerelationship between subject and hypnotist,

bu t rather requires us to pos tulate addi t ionalmechanisms fo r the ir u nde rs tand ing .

Final ly , the present s tudy lends support to

the cl in ic ian ' s t radi t ional caut ion that thehypnot is t mus t make cer tain that he has re-moved any posthypnotic suggestion, lest thesesugges t ions co nt in ue to exert a poten t , though

no t necessarily obvious, effect u p o n S af te rthe hypnotic relationship has ceased. If suchan effect can be demonstrated in the laboratory

where th e a m o u n t of S's i n v o l v e m e n t is rarelyanalogous to that obtained in the therapeut icuse of hypnosis , there m ay well be cons ider-able wisdom in this tradit ion al c aveat.

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(Received March 24 , 1969)

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Fate of an Uncomplete Posthypnotic Suggestion