Journal oj Abnormal Psychology1972, Vol. 80, No. 2, 132-140

SOCIAL FACILITATION OF MARIJUANA INTOXICATION:IMPACT OF SOCIAL SET AND PHARMACOLOGICAL ACTIVITY J

ALBERT S. CARLIN,2 CORNELIS B. BAKKER, LAWRENCE HALPERN, AND ROBIN DEE POST

University of Washington

To determine to what extent marijuana intoxication is the result of (a) drugeffects, (b) expectancy and social setting, or (c) an interaction of all thesefactors, two experiments were devised. In Experiment I, Ss first swallowed aplacebo pill and then smoked either two placebo cigarettes or two marijuanacigarettes containing a total of 15 mg. of A9 tetrahydrocannabnol (THC). Thecigarettes were smoked in a setting designed to either facilitate intoxication(up night) or interfere with it (down night) through manipulation of S's ex-pectancy and through modeling. Results indicate that the amount of marijuanasmoked impaired cognitive functioning and was rated as more intoxicating thanwas the placebo. Manipulations of setting and belief had no effect. In Experi-ment II, Ss smoked two cigarettes containing either (a) placebo, or (b) 7.5 mg.of THC, or (c) 15 mg. of THC. The 5s who smoked placebo cigarettes firstswallowed a pill containing either 10 mg. of Librium or 25 mg. of Librium. TheSs who smoked cigarettes containing THC received placebo pills. Smoking wasdone in either up night or down night contexts. Results suggest that socialsetting and belief interact with smaller doses of marijuana, but not with largedoses nor with placebo.

One of the major difficulties in researchingthe effects of marijuana on humans is in de-fining intoxicated behavior and its correlates.At a most simple level, the question is "Whatis a marijuana high?" With this question un-resolved, it is difficult to integrate the ephem-eral effect of the drug described by somerecent researchers (Jones & Stone, 1969;Weil, Zinberg, & Nelsen, 1968) with thesocietal concerns of either those who prosely-tize the use of the drug or those who cham-pion the protection of society from it. Perhapsa significant portion of this confusion couldbe resolved by the hypothesis that marijuanaintoxication is a mixture of psychological,social, as well as pharmacological effects.

Becker (1963) has recounted in detail howone becomes a marijuana user. The new useris taught by friends in a drug culture whatto expect: to interpret drug effects as positiveand to ignore discomfort. This teaching pro-cess takes place in the context of previous

1 This research was supported by Grant 2R01 MH

19015-01 from the National Institute of MentalHealth. The authors thank Randall Williams, LarryPrice, Tim Gillis, Patty Larsen, Scott Forney, andRenata Shaw for various and vigorous help.

2 Requests for reprints should be sent to Albert

S. Carlin, Department of Psychiatry, University ofWashington.

learning from society that this drug is bothpowerful and potentially dangerous. The needfor this teaching process to take place mayaccount for the common observation that thenaive user does not become intoxicated thefirst two or three times he smokes marijuana,a finding which is difficult to account for onthe basis of drug effects alone. Another phe-nomenon illustrating the complex effects ofmarijuana is the "contact high" experiencedby chronic smokers who become intoxicatedmerely on exposure to another person's in-toxication. To dismiss this latter phenomenonas only placebo effect is to overlook whatmay be a major component of social drug use.

The past few years have seen the emergenceof the first carefully controlled experimentalstudies of marijuana on humans. These studies,which are reviewed by Hollister (1971), aredifficult to generalize from. The Ss were runindividually in what can best be describedas a sterile laboratory setting. Many of thestudies relied on oral administration of can-nabis and these are difficult to compare withstudies utilizing the inhalation route of drugadministration. In almost all of these studies,5s were told of the possibility of receivinga placebo substance, thus inducing suspicionand altered expectations. Although these

132

SOCIAL FACILITATION OF MARIJUANA INTOXICATION 133

studies, for the most part, were carried outin a double-blind design, it is not possibleto assess the impact of expectancy and de-mand characteristics of the situation on theeffect of drug or placebo. Variations in dosage,procedure, and experimental design furthercomplicate generalization.

At least four separate factors can be seento contribute to marijuana intoxication. Anyattempt to understand the impact of thedrug must take all four factors into account.The four factors are: (a) Marijuana smokingbehavior itself, which includes smoking aswell as the knowledge (which may be erron-eous in the case of the placebo) that it ismarijuana that is being smoked. Jones andStone (1969) compared the impact of oraladministration of the active ingredient ofmarijuana, A 9 tetrahydrocannabinol (THC),smoked placebo, oral placebo, and smokedmarijuana. They found evidence suggestingthat the smoking behavior itself may be suffi-cient to have an impact on self-rating andthat it is difficult for even experienced Ss todifferentiate smoked marijuana from smokedplacebo, but this differentiation was clear fororally administered THC. (b) The set-induc-ing aspects of the environment, which includethe presence of others who seem to be intoxi-cated (or not intoxicated) as well as either acongenial setting, neutral setting, or perhaps anegative setting such as a sterile laboratory.(c) The past learning, which is the result ofprevious experiences with marijuana and in-toxicated behavior, both of the 5s themselvesand of others observed by S. This factorwould lead naive Ss to respond differently tothe entire marijuana smoking context thanmoderately experienced Ss, who may in turndiffer from heavy users of the drug, (d) Thepharmacological effect of the drug itself. Eachpharmacological compound will have it's ownspecific effect on the individual. This factoris dose related and to some extent varies withthe individual's base-line condition and per-sonal responses to the drug.

The present studies are an attempt toestablish the differential impact of two ofthese factors, social set and pharmacologicaleffect, on the induction of marjjuana intoxica-tion. Experiment I was designed to determine(a) whether the selected measures of intoxi-

cation are sensitive to marijuana, (b) to whatextent psychological factors can react withplacebo to create intoxication, and (c) towhat extent they can overwhelm large doses ofthe drug. Experiment II can be considereda more finely tuned replication of ExperimentI which was designed to determine to whatextent a psychotropic, nonintoxicating drugcan interact with psychological conditions andbe construed by the individual as an intoxi-cant and also whether these psychologicalconditions can effect marijuana intoxicationat moderate and at large doses.

EXPERIMENT I

MethodSubjects. The Ss were solicited through an ad-

vertisement in a university newspaper requestingthe services of males who were 21 yr. of age or olderfor psychological research in exchange for financialremuneration. Respondents to the advertisementwere asked if they had had any previous experiencesmoking marijuana, and screening interviews werescheduled for those who acknowledged such ex-periences. The Ss were screened by two experiencedclinical psychologists. If both agreed that S wasfree from psychological difficulties, S was told thatthe experiment's major concern was with marijuanaand that he was invited to smoke some marijuanain a socially comfortable and legal setting. If Sagreed to participate in the study, he was next seenby a psychiatrist for a final medical decision regard-ing inclusion in the study as an S. In this manner,40 experienced marijuana smokers were selected toserve as 5s. These 40 Ss varied in any given char-acteristic except that all were young adults andall were experienced marijuana smokers. The averageage of this group was 24 (ranging from 21 to 32)and the average rate of current marijuana usage wasthree times a week, varying from daily use to useonce or twice a month.

Manipulation of social setting. Twenty experi-mental sessions were held in each of which twoSs participated. The experimental sessions were heldevenings and Sunday afternoons. The setting wasa comfortably carpeted room furnished with couches,pillows, and subdued lighting. Tape recordings ofcontemporary music were available for Ss to playand food was served. The setting was not garishlypsychedelic, but comfortable and homelike.

Unknown to the two'5s present, an apparent thirdS in the situation was actually an accomplice of theE, who had been trained to become intoxicated oncue. His role was to relate to the other Ss, smokewhat appeared to be marijuana cigarettes, and thento appear either intoxicated or remain unaffected bythe drug. The major responsibility of the accomplicewas to form a majority and exert influence on theminority member of the group. Thus, when $'s

134 CARLIN, BAKKER, HALPERN, AND POST

accomplice appeared intoxicated, he modeled intoxi-cation for the S who received the marijuana, andthen both he and that 5 served as a majority in-fluence on the 5 who received the placebo (up night).When E's accomplice appeared nonintoxicated, heand the 5 who received the placebo served as aninfluence to inhibit the intoxication of the S who didreceive the active drug (down night). The accom-plice's behavior was not carefully scripted, but ageneral scenario was constructed which allowed theaccomplice to relate to the Ss in a responsive andrelevant fashion. Careful postexperimental debriefingindicated that no S suspected that E's accomplicewas playing a role.

Each S also received a #1 pink gelatin capsulecontaining lactose. This was introduced to the sub-ject as imiproxin, a new nonpsychedelic drug. Inalternate sessions, Ss were told that it was a poten-tiator of marijuana intoxication (up night) or anattenuator of intoxication (down night). The intro-duction served to create a social set and served alsoto cue 's accomplice to act "stoned" or "straight."There were, then, two aspects to the manipulation ofsocial setting: (a) the modeling by E's accompliceand (b) the introduction of Imiproxin as an intoxi-cation facilitator or attentuator.

Drug-placebo conditions. Twenty 5s each smokedtwo marijuana cigarettes. The marijuana was sup-plied by the National Institute of Mental Health(NIMH) and was assayed by them to contain 1.5%THC. Each cigarette contained 500 rag. of naturalcannabis material and was rolled on a small handroller (Rizla model), the ends twisted to preventloss of material and to enable S to smoke the buttend. Each S who smoked marijuana had available tohim 15 mg. of THC. It is difficult to ascertain theexact dosage received, but all Ss smoked both of thecigarettes completely. No attempt was made topace the smoking in order to establish a standardamount of time for the smoke to be held in thelungs since this would interfere with the creationof a naturalistic setting.

Twenty of the Ss, as well as 's accomplice, eachnight smoked placebo-filled cigarettes. These eachcontained 500 mg. of cannabis material from whichall THC had been extracted. This material was alsosupplied and assayed by NIMH. Smell and taste,when smoked, were identical to those of the un-treated material.

Drug assignment was performed in a double-blindfashion and neither E, E's accomplice, nor S wasaware of who received marijuana and who receivedplacebo. All Ss interviewed during the debriefingsessions assumed that they were given marijuana tosmoke, and although many Ss had initial suspicionsthat they might be given a placebo during theevening, once they began to smoke the cigarettesnone actually determined that they were givenplacebo.

Measures of intoxication. The effects of marijuanaintoxication can manifest themselves in two ways:changes in self-perception and changes in perfor-mance. This investigation focuses primarily on mea-

sures of various aspects of cognitive and motorfunctioning to determine changes in performancewhile limiting the recording of changes in self-perception to the statements by Ss themselves abouttheir perception of their own intoxication.

One hour after the smoking sessions began, Sswere placed in individual testing rooms. A varietyof tests was administered to determine the impactof marijuana and the impact of social set and ex-pectancy on cognitive and motor functioning. Thetests and measures were administered in randomizedsequence so that order effects and time since theadministration of the drug cannot be considered ascontaminating variables.

Self-ratings. Prior to beginning the formal testing,each S was asked to rate the quality of the marijuanahe smoked and his current degree of intoxication.This was done by means of a 20-cm. line withanchor points of 1 and 100 at either end. The Ss weretold that a rating of 1 would indicate that themarijuana was of very poor quality, the worst theyhad ever smoked; that ratings of 100 would indi-cate that it was the best they had ever smoked.Similar ratings were carried out for intoxication. TheSs were told that 1 represented a "straight, normalstate" and 100 represented a very high degree ofintoxication, "stoned as you have ever been."

Performance measures. Two tests, Alternate Uses(Christiansen, Guilford, Merrifield, & Wilson, I960)and Association IV (Guilford, 1963) were bothselected for inclusion in the test battery because theyrequire associational fluency and a degree of con-ceptual flexibility. The folklore surrounding mari-juana and the traditional reports of greater per-ceptiveness, creativity, and insight suggested thatSs under the influence of marijuana might do betteron these tasks believed to be related to creativity.

Color Naming, developed by J. Hain, E. Miller,and A. Reis (Personal communication, 1970)s canbe seen as a measure of cognitive control and theability to resist distraction. After testing for readingability and color discrimination, S is asked to read alist of color names from a 14 X-4i in. card. Thenames are printed in a variety of colors; for example,the word "Red" is printed in blue ink, and the word"Blue" is printed in green ink, etc. The S first readsthe words and is then asked to call out the colorin which the words are printed. The score on thistask is the time in seconds required for S to namethe colors, plus the number of errors in namingthe colors on each of four trials. Digit Symbol is ameasure of visual motor speed and, to some extent,learning. This is described in detail by Wechsler(1956). It's use in marijuana studies has been de-scribed in detail by Weil, Zinberg, and Nelsen (1968)and by Jones and Stone (1969). However, the pro-cedure used in this investigation was somewhatdifferent than that used by the latter two sets ofinvestigators. Both of them had their Ss practice thetask to asymptote of performance prior to thetesting situation. The Ss in this investigation re-

3 The authors thank Dr. Hain for supplying norms,

instruments, and materials for the Color Naming test.

SOCIAL FACILITATION OF MARIJUANA INTOXICATION 135

TABLE 1MEAN PERCEPTION OF ACCOMPLICE INTOXICATION

Perception ofintoxication

UpDown

Mean score

Drug

78.7738.55

Placebo

57.7234.6

TABLE 3MEAN RATING OF PERCEPTION OF OWN INTOXICATION

Rating of ownintoxication

UpDown

Mean score

Drug

85.7575.85

Placebo

30.5037.45

ceived no practice. They were given 90 sec. to per-form the task. Hidden Figures requires S to decidewhich of five geometric figures is embedded in acomplex pattern. The test is an adaptation of theGottschaldt test and is believed to be related toWitkin's concept of field dependence (Thurstone,1963; Witkin, Dyk, Faterson, Goodenough, & Karp,1962).

The pursuit rotor was used in this investigation asa measure of motor learning. Each S received eighttrials of 20 sec., with a 20-sec. intertrial interval.Again the use of this instrument was different thanthat described by Weil et al., (1968). They usedthe pursuit rotor as a measure of attention and co-ordination rather than as a measure of motor learn-ing by having Ss first practice the task to asymptoticperformance.

Each S was given the task of estimating a timeinterval generated by E. The S was asked to guessthe amount of time elapsing from E saying "start"and the E saying "stop." No attempt was made toprevent 5 from counting since no control over com-pliance was possible. The actual time interval wasIS sec. The S was then asked to generate a 15-sec.time interval by telling E when to start and stop hiswatch so that 15 sec. elapsed.

As part of the debriefing, but prior to revealingany of the deceptions to S, he was asked to ratethe degree of intoxication experienced by E's ac-complice and the other S. This was done on a 1-100scale similar to the one 5 used to rate his own in-toxication.

ResultsRatings of accomplice's intoxication and

the results of a 2 X 2 ANOVA carried out onthese data are presented in Table 1, Theaccomplice was judged to be more intoxicatedwhen he played that role than when he

TABLE 2MEAN RATING OF MARIJUANA POTENCY BY SUBJECTS

Rating of potency

HpDown

Mean score

Drug

86.0574.60

Placebo

44.7053.85

attempted to appear nonintoxicated (F =U.22,df = 1/34, p< .01)

The ratings of marijuana quality and thedegree to which S rated himself as intoxicatedare presented in Tables 2 and 3. Ratings ofmarijuana potency and of own intoxicationwere a function of whether one received drugor placebo only and not significantly by socialsetting (F - 22.06, df = 1/36; F - 60.65, dj= 1/36, p < .01, respectively),

Scores on the various measures of cognitivefunctioning are presented in Table 4. Whilethe initial N in the study was 10 Ss per cell,at the time of statistical analysis, severalpieces of data were found to be either un-available or inadequate (e.g., several Ss werecolor blind and could not take the color test).Thus, ANOVAS in several of the measureswere performed with unequal TVs. All mea-sures except time perception and pursuit rotorperformance reveal a significant decrementwhen performance of Ss who smoked mari-juana was compared with Ss who smokedplacebo substance. (Hidden Figures: DrugF = 12.11, dj~ 1/34, p < .01; Digit Sym-

TABLE 4MEAN SCORES or COGNITIVE MEASURES

Measure

Hidden FiguresUpDown

Digit SymbolUpDown

AssociationsUPDown

Alternate UsesUpDown

Color NamingUpDown

Drug

7.135.56

55.653.6

5.37.3

9.813.6

82.3384.8

Placebo

13.4616.31

68.062.5

10.511.0

18.924.3

56.8863.7

136 CARLIN, BAKKEE, HALPEEN, AND POST

bol: Drug F = 9.87, df = 1/36, p < .01;Associations: Drug/? = 13.24, df =1/36, p