SOCIAL FACILITATION OF MARIJUANA INTOXICATION:

Transcription

1 Journal oj Abnormal Psychology 1972, Vol. 80, No. 2, 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) drug effects, (b) expectancy and social setting, or (c) an interaction of all these factors, two experiments were devised. In Experiment I, Ss first swallowed a placebo pill and then smoked either two placebo cigarettes or two marijuana cigarettes containing a total of 15 mg. of A9 tetrahydrocannabnol (). The cigarettes were smoked in a setting designed to either facilitate intoxication (up night) or interfere with it ( night) through manipulation of S's expectancy and through modeling. Results indicate that the amount of marijuana smoked impaired cognitive functioning and was rated as more intoxicating than was the placebo. Manipulations of setting and belief had no effect. In Experiment II, Ss smoked two cigarettes containing either (a) placebo, or (b) 7.5 mg. of, or (c) 15 mg. of. The 5s who smoked placebo cigarettes first swallowed a pill containing either 10 mg. of or 25 mg. of. The Ss who smoked cigarettes containing received placebo pills. Smoking was done in either up night or night contexts. Results suggest that social setting and belief interact with smaller doses of marijuana, but not with large doses nor with placebo. One of the major difficulties in researching the effects of marijuana on humans is in defining intoxicated behavior and its correlates. At a most simple level, the question is "What is a marijuana high?" With this question unresolved, it is difficult to integrate the ephemeral effect of the drug described by some recent researchers (Jones & Stone, 1969; Weil, Zinberg, & Nelsen, 1968) with the societal concerns of either those who proselytize the use of the drug or those who champion the protection of society from it. Perhaps a significant portion of this confusion could be resolved by the hypothesis that marijuana intoxication is a mixture of psychological, social, as well as pharmacological effects. Becker (1963) has recounted in detail how one becomes a marijuana user. The new user is taught by friends in a drug culture what to expect: to interpret drug effects as positive and to ignore discomfort. This teaching process takes place in the context of previous 1 This research was supported by Grant 2R01 MH from the National Institute of Mental Health. The authors thank Randall Williams, Larry Price, Tim Gillis, Patty Larsen, Scott Forney, and Renata Shaw for various and vigorous help. 2 Requests for reprints should be sent to Albert S. Carlin, Department of Psychiatry, University of Washington. 132 learning from society that this drug is both powerful and potentially dangerous. The need for this teaching process to take place may account for the common observation that the naive user does not become intoxicated the first two or three times he smokes marijuana, a finding which is difficult to account for on the basis of drug effects alone. Another phenomenon illustrating the complex effects of marijuana is the "contact high" experienced by chronic smokers who become intoxicated merely on exposure to another person's intoxication. To dismiss this latter phenomenon as only placebo effect is to overlook what may be a major component of social drug use. The past few years have seen the emergence of the first carefully controlled experimental studies of marijuana on humans. These studies, which are reviewed by Hollister (1971), are difficult to generalize from. The Ss were run individually in what can best be described as a sterile laboratory setting. Many of the studies relied on oral administration of cannabis and these are difficult to compare with studies utilizing the inhalation route of drug administration. In almost all of these studies, 5s were told of the possibility of receiving a placebo substance, thus inducing suspicion and altered expectations. Although these

2 SOCIAL FACILITATION OF MARIJUANA INTOXICATION 133 studies, for the most part, were carried out in a double-blind design, it is not possible to assess the impact of expectancy and demand characteristics of the situation on the effect of drug or placebo. Variations in dosage, procedure, and experimental design further complicate generalization. At least four separate factors can be seen to contribute to marijuana intoxication. Any attempt to understand the impact of the drug must take all four factors into account. The four factors are: (a) Marijuana smoking behavior itself, which includes smoking as well as the knowledge (which may be erroneous in the case of the placebo) that it is marijuana that is being smoked. Jones and Stone (1969) compared the impact of oral administration of the active ingredient of marijuana, A 9 tetrahydrocannabinol (), smoked placebo, oral placebo, and smoked marijuana. They found evidence suggesting that the smoking behavior itself may be sufficient to have an impact on self-rating and that it is difficult for even experienced Ss to differentiate smoked marijuana from smoked placebo, but this differentiation was clear for orally administered. (b) The set-inducing aspects of the environment, which include the presence of others who seem to be intoxicated (or not intoxicated) as well as either a congenial setting, neutral setting, or perhaps a negative setting such as a sterile laboratory. (c) The past learning, which is the result of previous experiences with marijuana and intoxicated behavior, both of the 5s themselves and of others observed by S. This factor would lead naive Ss to respond differently to the entire marijuana smoking context than moderately experienced Ss, who may in turn differ from heavy users of the drug, (d) The pharmacological effect of the drug itself. Each pharmacological compound will have it's own specific effect on the individual. This factor is dose related and to some extent varies with the individual's base-line condition and personal responses to the drug. The present studies are an attempt to establish the differential impact of two of these factors, social set and pharmacological effect, on the induction of marjjuana intoxication. Experiment I was designed to determine (a) whether the selected measures of intoxication are sensitive to marijuana, (b) to what extent psychological factors can react with placebo to create intoxication, and (c) to what extent they can overwhelm large doses of the drug. Experiment II can be considered a more finely tuned replication of Experiment I which was designed to determine to what extent a psychotropic, nonintoxicating drug can interact with psychological conditions and be construed by the individual as an intoxicant and also whether these psychological conditions can effect marijuana intoxication at moderate and at large doses. Method EXPERIMENT I Subjects. The Ss were solicited through an advertisement in a university newspaper requesting the services of males who were 21 yr. of age or older for psychological research in exchange for financial remuneration. Respondents to the advertisement were asked if they had had any previous experience smoking marijuana, and screening interviews were scheduled for those who acknowledged such experiences. The Ss were screened by two experienced clinical psychologists. If both agreed that S was free from psychological difficulties, S was told that the experiment's major concern was with marijuana and that he was invited to smoke some marijuana in a socially comfortable and legal setting. If S agreed to participate in the study, he was next seen by a psychiatrist for a final medical decision regarding inclusion in the study as an S. In this manner, 40 experienced marijuana smokers were selected to serve as 5s. These 40 Ss varied in any given characteristic except that all were young adults and all were experienced marijuana smokers. The average age of this group was 24 (ranging from 21 to 32) and the average rate of current marijuana usage was three times a week, varying from daily use to use once or twice a month. Manipulation of social setting. Twenty experimental sessions were held in each of which two Ss participated. The experimental sessions were held evenings and Sunday afternoons. The setting was a comfortably carpeted room furnished with couches, pillows, and subdued lighting. Tape recordings of contemporary music were available for Ss to play and food was served. The setting was not garishly psychedelic, but comfortable and homelike. Unknown to the two'5s present, an apparent third S in the situation was actually an accomplice of the E, who had been trained to become intoxicated on cue. His role was to relate to the other Ss, smoke what appeared to be marijuana cigarettes, and then to appear either intoxicated or remain unaffected by the drug. The major responsibility of the accomplice was to form a majority and exert influence on the minority member of the group. Thus, when $'s

3 134 CARLIN, BAKKER, HALPERN, AND POST accomplice appeared intoxicated, he modeled intoxication for the S who received the marijuana, and then both he and that 5 served as a majority influence on the 5 who received the placebo (up night). When E's accomplice appeared nonintoxicated, he and the 5 who received the placebo served as an influence to inhibit the intoxication of the S who did receive the active drug ( night). The accomplice's behavior was not carefully scripted, but a general scenario was constructed which allowed the accomplice to relate to the Ss in a responsive and relevant fashion. Careful postexperimental debriefing indicated that no S suspected that E's accomplice was playing a role. Each S also received a #1 pink gelatin capsule containing lactose. This was introduced to the subject as imiproxin, a new nonpsychedelic drug. In alternate sessions, Ss were told that it was a potentiator of marijuana intoxication (up night) or an attenuator of intoxication ( night). The introduction served to create a social set and served also to cue 's accomplice to act "stoned" or "straight." There were, then, two aspects to the manipulation of social setting: (a) the modeling by E's accomplice and (b) the introduction of Imiproxin as an intoxication facilitator or attentuator. Drug-placebo conditions. Twenty 5s each smoked two marijuana cigarettes. The marijuana was supplied by the National Institute of Mental Health (NIMH) and was assayed by them to contain 1.5%. Each cigarette contained 500 rag. of natural cannabis material and was rolled on a small hand roller (Rizla model), the ends twisted to prevent loss of material and to enable S to smoke the butt end. Each S who smoked marijuana had available to him 15 mg. of. It is difficult to ascertain the exact dosage received, but all Ss smoked both of the cigarettes completely. No attempt was made to pace the smoking in order to establish a standard amount of time for the smoke to be held in the lungs since this would interfere with the creation of a naturalistic setting. Twenty of the Ss, as well as 's accomplice, each night smoked placebo-filled cigarettes. These each contained 500 mg. of cannabis material from which all had been extracted. This material was also supplied and assayed by NIMH. Smell and taste, when smoked, were identical to those of the untreated material. Drug assignment was performed in a double-blind fashion and neither E, E's accomplice, nor S was aware of who received marijuana and who received placebo. All Ss interviewed during the debriefing sessions assumed that they were given marijuana to smoke, and although many Ss had initial suspicions that they might be given a placebo during the evening, once they began to smoke the cigarettes none actually determined that they were given placebo. Measures of intoxication. The effects of marijuana intoxication can manifest themselves in two ways: changes in self-perception and changes in performance. This investigation focuses primarily on measures of various aspects of cognitive and motor functioning to determine changes in performance while limiting the recording of changes in selfperception to the statements by Ss themselves about their perception of their own intoxication. One hour after the smoking sessions began, Ss were placed in individual testing rooms. A variety of tests was administered to determine the impact of marijuana and the impact of social set and expectancy on cognitive and motor functioning. The tests and measures were administered in randomized sequence so that order effects and time since the administration of the drug cannot be considered as contaminating variables. Self-ratings. Prior to beginning the formal testing, each S was asked to rate the quality of the marijuana he smoked and his current degree of intoxication. This was done by means of a 20-cm. line with anchor points of 1 and 100 at either end. The Ss were told that a rating of 1 would indicate that the marijuana was of very poor quality, the worst they had ever smoked; that ratings of 100 would indicate that it was the best they had ever smoked. Similar ratings were carried out for intoxication. The Ss were told that 1 represented a "straight, normal state" and 100 represented a very high degree of intoxication, "stoned as you have ever been." Performance measures. Two tests, Alternate Uses (Christiansen, Guilford, Merrifield, & Wilson, I960) and Association IV (Guilford, 1963) were both selected for inclusion in the test battery because they require associational fluency and a degree of conceptual flexibility. The folklore surrounding marijuana and the traditional reports of greater perceptiveness, creativity, and insight suggested that Ss under the influence of marijuana might do better on these tasks believed to be related to creativity. Color Naming, developed by J. Hain, E. Miller, and A. Reis (Personal communication, 1970) s can be seen as a measure of cognitive control and the ability to resist distraction. After testing for reading ability and color discrimination, S is asked to read a list of color names from a 14 X-4i in. card. The names 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 reads the words and is then asked to call out the color in which the words are printed. The score on this task is the time in seconds required for S to name the colors, plus the number of errors in naming the colors on each of four trials. Digit Symbol is a measure 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 described in detail by Weil, Zinberg, and Nelsen (1968) and by Jones and Stone (1969). However, the procedure used in this investigation was somewhat different than that used by the latter two sets of investigators. Both of them had their Ss practice the task to asymptote of performance prior to the testing situation. The Ss in this investigation re- 3 The authors thank Dr. Hain for supplying norms, instruments, and materials for the Color Naming test.

4 SOCIAL FACILITATION OF MARIJUANA INTOXICATION 135 TABLE 1 MEAN PERCEPTION OF ACCOMPLICE INTOXICATION TABLE 3 MEAN RATING OF PERCEPTION OF OWN INTOXICATION Perception of intoxication Drug Mean score Placebo Rating of own intoxication Drug Mean score Placebo ceived no practice. They were given 90 sec. to perform the task. Hidden Figures requires S to decide which of five geometric figures is embedded in a complex pattern. The test is an adaptation of the Gottschaldt test and is believed to be related to Witkin's concept of field dependence (Thurstone, 1963; Witkin, Dyk, Faterson, Goodenough, & Karp, 1962). The pursuit rotor was used in this investigation as a measure of motor learning. Each S received eight trials of 20 sec., with a 20-sec. intertrial interval. Again the use of this instrument was different than that described by Weil et al., (1968). They used the pursuit rotor as a measure of attention and coordination rather than as a measure of motor learning by having Ss first practice the task to asymptotic performance. Each S was given the task of estimating a time interval generated by E. The S was asked to guess the amount of time elapsing from E saying "start" and the E saying "stop." No attempt was made to prevent 5 from counting since no control over compliance was possible. The actual time interval was IS sec. The S was then asked to generate a 15-sec. time interval by telling E when to start and stop his watch so that 15 sec. elapsed. As part of the debriefing, but prior to revealing any of the deceptions to S, he was asked to rate the degree of intoxication experienced by E's accomplice and the other S. This was done on a scale similar to the one 5 used to rate his own intoxication. Results Ratings of accomplice's intoxication and the results of a 2 X 2 ANOVA carried out on these data are presented in Table 1, The accomplice was judged to be more intoxicated when he played that role than when he TABLE 2 MEAN RATING OF MARIJUANA POTENCY BY SUBJECTS Rating of potency H p Drug Mean score Placebo attempted to appear nonintoxicated (F = U.22,df = 1/34, p<.01) The ratings of marijuana quality and the degree to which S rated himself as intoxicated are presented in Tables 2 and 3. Ratings of marijuana potency and of own intoxication were a function of whether one received drug or placebo only and not significantly by social setting (F , df = 1/36; F , dj = 1/36, p <.01, respectively), Scores on the various measures of cognitive functioning are presented in Table 4. While the initial N in the study was 10 Ss per cell, at the time of statistical analysis, several pieces of data were found to be either unavailable or inadequate (e.g., several Ss were color blind and could not take the color test). Thus, ANOVAS in several of the measures were performed with unequal TVs. All measures except time perception and pursuit rotor performance reveal a significant decrement when performance of Ss who smoked marijuana was compared with Ss who smoked placebo substance. (Hidden Figures: Drug F = 12.11, dj~ 1/34, p <.01; Digit Sym- TABLE 4 MEAN SCORES or COGNITIVE MEASURES Measure Hidden Figures Digit Symbol Associations UP Alternate Uses Color Naming Drug Placebo

5 136 CARLIN, BAKKEE, HALPEEN, AND POST bol: Drug F = 9.87, df = 1/36, p <.01; Associations: Drug/? = 13.24, df =1/36, p <.01.) Alternate Uses and Color Naming both also showed a significant effect on social setting, but these differences are in opposite directions, one supporting the hypothesis and one in the reverse direction. (Alternate Uses: Drug F = 24.05, df = 1/36, p <.01; Set F = 5.19, df - 1/36, p <.05; Color Naming: Drug F-21.16, df =1/34, p <.01; Set F = 5.88, df - 1/34, p <.05.) Method EXPERIMENT II Subject. Experiment II was carried out with a procedure similar to Experiment I. The Ss were solicited and interviewed in the same fashion. The 5s selected for the study did not differ significantly in any relevant demographic characteristics. (Mean age was 23.7, ranging from 21 to 34; current smoking rate was approximately three/week, ranging from.25 to seven/week.) Manipulation of social setting. In Experiment II, the cigarettes were again smoked in a setting designed to either facilitate intoxication (on an up night) or interfere with it (on a night). As in Experiment I, the expectancy variable was manipulated by means of (a) introduction of the drug, imiproxin, as a potentiator or inhibitor of marijuana and (b) the actors' performance as intoxicated or nonintoxicated. Drug placebo conditions. The major differences in Experiment II were in the drug-placebo conditions. The Ss smoked two cigarettes containing either (a) placebo substance (for 50% of 5s) or (b) marijuana with the dosage varied so that 25% of the 5s received 7.5 mg. of and 25% received 15 mg. of. The Ss who smoked placebo cigarettes, first swallowed a pill, introduced as imiproxin, but actually containing either 10 or 25 mg. of. The Ss who smoked genuine marijuana cigarettes received placebo pills. In Experiment II, then, three variables were investigated: (a) expectancy and social setting (up versus nights), (6) drug effects (marijuana versus active placebo) and (c) dosage (either low or high). The variables were tested within a 2X2X2 factorial design, yielding a total of eight cells, with 10 Ss per cell. Assignment of drugs, in Experiment II, was again done in a double-blind fashion. The lab technician who maintained the double-blind code, designated which nights were to be up and, and insured equal groups of 10 Ss per cell. The Ss were contacted on the basis of their availability for a given experimental session. RESULTS Ratings of E's accomplice level of intoxication are shown in Figure 1. Social facilitation, dosage, and drug main effects all attained significance (F = 39.86, df - 1/72, p <.01; F = 5.47, df=l/72, p<.05; and F = 16.62, df = 1/72, p <.01, respectively). Ratings of marijuana quality and of own degree of intoxication are presented in Figures 2 and 3. For both of these measures, significant differences were found only for drugplacebo comparisons. Social facilitation and dosage had no effect on the ratings. (Marijuana quality drug effect F = 67,72, df = 1/72, p <.01; own intoxication drug effect F= , df= 1/72, p<.01). In Experiment II, the social facilitation variable entered significantly into the results of a number of tests. The Hidden Figures task data are presented in Figure 4. Analysis of variance revealed significant effects for the variables of social facilitation, drugs, and a Dose X Drug interaction (Fs = 5.4, 14.05, each, df -1/72, p <.05, <.01, <.05, respectively). An a posteriori Duncan's multiple-range test was carried out on these data and revealed that a low dosage of marijuana (7.5 mg. ) on a night was associated with significantly higher scores than any < 1 lomg 25 mg, 7.5 mg 15 mg FIG. 1. Ratings of the accomplice's level of intoxication as a function of drug received and role played by accomplice.

6 SOCIAL FACILITATION OF MARIJUANA INTOXICATION "Pi I ) <D mg I 5 mg FIG. 2. Ratings of marijuana quality as a function of drug received and social set. of the other marijuana conditions. That is to say, (a) low dosage on an up night, (b) high dosage (15 mg. of ) on an up night, or (c) high dosage on a night. These three mg I 5 mg FIG. 4. Hidden Figures scores as a function of drug received and social set. 70^ t I conditions did not differ significantly from one another according to Duncan's test. The data obtained on the Digit Symbol test are presented in Figure S. Analysis of vari ' 7.5 mg I5mg FIG. 3. Ratings of own degree of intoxication as a function of drug received and social set. lomg 25 mg 7.5 mg l.5mg Fio. S. Digit Symbol scores as a function of drug received and social set.

7 138 CAELIN, BAKKEE, HALPEEN, AND POST up 8-7 I 6- o <o I i up mg I5mg FIG. 6. Associations IV Test Scores as a function of drug received and social set. ance revealed only a significant social facilitation by drug interaction (F = 4.SO, df = I/ 72, p <.OS). Duncan's multiple-range test on these data revealed that 7.5 mg. of smoked on a night did not differ signifi <S lomg 25 mg 7.5 mg I5mg FIG. 7. Color Naming Test scores as a function of drug received and social set. 7.5mg I 5 mg FIG. 8. Alternate Uses Test scores as a function of drug received and social set. cantly from any of the placebo groups but did differ significantly from the IS-mg.- marijuana groups and from the 7.5-mg. marijuana up night group. The data for the Associations Test are displayed in Figure 6. An analysis of variance on these data revealed a significant drug effect and a significant social facilitation by dosage interaction (F = 17.73, df = 1/72, p <.01; F = 4.76, df = 1/72, p <.05, for a drug effect and interaction, respectively). The Duncan's multiple-range test did not clarify the nature of these data and will not be reported here. Performance on the Color Naming Task summarized in Figure 7 reveals only a drug effect, with the marijuana group doing significantly worse than the placebo group. The Alternate Uses test revealed no significant differences as a function of any of the variables, as illustrated in Figure 8. Although falling short of significance, the pattern of scores is quite similar to those observed for Hidden Figures and Digit Symbol. Both time measures resulted in a drug dose interaction (F , df = 1/72, p <.05;

8 SOCIAL FACILITATION OF MARIJUANA INTOXICATION 139 F = 4.14, dj = 1/72, p <.05, for time estimation and time generation, respectively). These data suggest that time passes more quickly for 5s receiving 2 5 mg. of or 7.5 mg. of than it does for Ss receiving 10 mg. of or 15 mg. of. Motor learning, as measured by pursuit rotor performance over eight trials revealed no significant differences between groups, but all groups displayed significant learning (F = 64.11, df- 7/504, p <.01). DISCUSSION In discussing these data, the first consideration must be the extent to which manipulations of social setting and expectancy were successful. The data indicate that the sources of influence were perceived as intended; that the accomplice successfully appeared as more intoxicated when he intended to and less so when he tried to appear "straight." In Experiment II, this manipulation was somewhat contaminated by what appears to be an assimilation process. Intoxicated individuals saw everyone as more intoxicated than did nonintoxicated individuals, and those who received larger drug doses saw everyone as more intoxicated than did those who received smaller doses; nonetheless, the accomplice's role did significantly effect how he was seen. The imiproxin was also accepted by all Ss as a real drug, and indeed a few asked if it might be available in either pharmacy or black market in the immediate future. It is reasonable on the basis of these data to conclude that these variables were successfully manipulated and were perceived by 5s as they were intended. A second major consideration is the extent to which the chosen measures of intoxication and drug effect are sensitive to these factors. Some recent research on the effects of marijuana have suggested that its effects are ephemeral, while others have seen it as quite potent. For example, the study by Weil et al. (1968) has been reported to indicate that naive users' performance is impaired on a variety of tasks, while the experienced user's performance tends to improve, and Jones and Stone (1969) reported that little impact is found with either smoked or orally consumed. Many of the studies reviewed by Hollister (1970) do, however, report that has significant effects in a variety of areas of functioning; in these studies, 5s were frequently administered orally. Many of the differences that are observed can be ascribed to variations in methodology, design, and dosage between studies. The results of Experiment I clearly indicate that five of the seven performance tasks were responsive to large doses of marijuana and can be taken as indicators of marijuana intoxication. Selfratings differentiated significantly between Ss who received the placebo and those who received marijuana and can also be taken as indicators of intoxication. The manipulations of social setting and expectation carried out in Experiment I had little impact on either functioning or ratings. Only two of the measures, Associations and Color Naming, showed any effect of social manipulations, and even these are difficult to interpret since they are in opposite directions. Associations scores indicate that increasing expectation of intoxication interacts with receipt of the drug to further impair performance, while Color Naming scores show the reverse relationship. The lack of positive results in Experiment I leaves two major questions unanswered: (a) To what extent is the lack of any impact of variations in social setting and expectancy related to dosage? That is, were the social manipulations overwhelmed by large dosage or are they merely irrelevant to the intoxication process? and (b) To what extent is intoxication due to belief that one has smoked marijuana plus the experience of general drug side effects. In other words, is the impairment observed in Experiment I as drug effect specific to marijuana or the result of belief plus side effects? The results of Experiment II suggest that social setting and belief do effect the marijuana experience but only at moderate dosages. The large dosage of the drug, in both experiments, clearly overwhelmed the effects of the social manipulation. In contrast, evidence was provided by three of the six performance measures for a social facilitation effect in low dosage marijuana conditions. It appears that the manipulation did not significantly influence performance under the conditions.

9 140 CARLIN, BARKER, HALPERN, AND POST Ratings of the 5s' own degree of intoxication are not effected either by dose or by social setting. The failure of Ss' ratings to discriminate between high and low marijuana dosages may be attributed to one of two factors. Either (a) the scales themselves were not sensitive to finer variations in degree of intoxication or (b) Ss are not capable of fine discriminations of how high they are and tend to make dichotomous judgments, that is, "stoned" or "not stoned." Cognitive performance, in contrast, appears to be a surprisingly sensitive measure of intoxication and of the interaction of drug effects with social set and expectation. The two experiments taken together offer a consistent picture of the impact of marijuana on cognitive functioning and how this effect is mitigated by variations in social setting and expectation. Marijuana in large doses significantly interferes with thinking and controlled associations, with the analytic process associated with field independence, and the ability to control perception and resist distraction. At smaller doses, on many of these tasks, Ss who expect to become intoxicated and who are exposed to others behaving in an intoxicated fashion perform like individuals receiving a larger dose of the drug, while those having negative expectations and being exposed to others who are behaving in a nonintoxicated fashion perform like individuals receiving placebo. Our findings suggest that a dose-drug expectancy relationship exists for the effects of marijuana (at low dosages), but not for either straight placebo or a psychotropically active placebo. Marijuana intoxication for experienced smokers appears to be a function of the drug alone at higher dosages, and a function of drug and set at lower dosages. Thus if someone is not outrageously "stoned," he is likely to be responsive to the social setting in which he finds himself. Lending support for the folk notions about marijuana, an "experienced head" cari be influenced to "get off" more or be "brought by" his social surroundings. Regardless of the social manipulations performed, experienced marijuana users do not seem to respond to a placebo substance with intoxicated behavior or self-reports. Further research into the role of such factors as experience and the process of learning to become intoxicated, as well as the contribution of smoking behavior to intoxication, is required to more clearly ascertain the impact of cognitive and social factors on marijuana intoxication. As a first step, however, the studies described above do suggest that intoxication can be effected by belief and social setting. REFERENCES BECKER, H. S. Outsiders. New York: The Free Press of Glencoe, CHRISTIANSEN, P. R., GUILFORD, J. P., MERRIFIELD, P. R., & WILSON, R. C. Alternate uses, Beverly Hills, Calif.: Sheridan Supply Co., GDILFORD, J. P. Association IV described. In J. W. French et al., Manual for kit of reference tests for cognitive factors. Princeton, N. J.: Educational Testing Service, HOLLISTER, L. E. Marijuana in man: Three years later. Science, 1971, 172, JONES, R. T., STONE, G. C. Psychological studies of marijuana and alcohol in man. Paper read at 125th Annual Meeting of the American Psychiatric Association, May THURSTONE, L. L. Hidden Figures Test. In J. W. French et al., Manual for kit of reference tests for cognitive factors. Princeton, N. J.: Educational Testing Service, WECHSLER, D. The measurement and appraisal of adult intelligence. (4th ed.) Baltimore: Williams and Wilkins, WEIL, A. T., ZINBERG, N. E., & NELSEN, J. M. Clinical and psychological effects of marijuana in man. Science, 1968, 162, WITKIN, H., DYK, R. B., FATEESON, H. F., GOOD- ENOUGH, D. R., & KARP, S. A. Psychological differentiation. New York: Wiley, (Received December 15, 1971)