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Social and solitary drinking: Effects on consumption and mood in male social drinkers
Physiology & Behavior, Vol. 28, pp. 1093--1095. Pergamon Press and Brain Research Publ., 1982. Printed in the U.S.A.
Social and Solitary Drinking: Effects on Consumption and Mood in Male Social Drinkers RALF LINDMAN
Department of Psychology, ftbo Akademi, Vdrdbergsgatan 1, SF-20700 ,~BO 70, Finland R e c e i v e d 17 M a r c h 1980 LINDMAN, R. Social and solitary drinking: Effects on consumption and mood in male social drinkers. PHYSIOL. BEHAV. 28(6) 1093-1095, 1982.--Rates of alcohol consumption and mood development were studied in four male social
drinkers serving as their own controls: (a) in a real life social drinking situation of the subject's choice, and (b) under artificial solitary drinking conditions. Almost twice as much alcohol was consumed during patty drinking, while solitary drinking was experienced as aversive and failed to induce the euphoric effects reported at the party. Implications for tension reduction theory and adjunctive behaviour theory were discussed. Alcohol consumption
Emotion
Adjunctive behaviour
MOST social drinkers would probably agree that their alcohol consumption will vary with the context in which drinking takes place, just as their affective adjustment will vary. Experimental interest in the environmental determinants of human drinking behaviour is nevertheless fairly recent, the state-trait models implied by tension reduction theory (TRT) having dominated much of the earlier work [1, 2, 3]. Drinking in a natural setting was apparently first studied systematically in a Canadian beer parlor [20] where group drinkers reportedly consumed twice as much as isolated drinkers. The results have since been confLrmed [6], with similar trends among college students [18], but not with alcoholics [9]. In another recent approach, the drinking behaviour of confederate models has proved a good predictor of subject drinking, suggesting that human alcohol intake can be modified by time-dependent external events [4, 7, 8, 10, 12]. But even acknowledging the importance of environmental events, unexplained issues remain: Why do people initially search for surroundings where they can meet for drinking [17], thus establishing the conditions where subsequent external influences can exert their modifying effects? And why would group drinkers typically describe the symptoms of their intoxication in affective terms, where solitary drinkers reportedly choose clinical terms [17]? These are problems closely related to levels of subjective experience, and the present experiment was designed as a pilot study to investigate (a) effects of elements characteristically present in a real-life social drinking situation, compared to (b) the effects of their absence in an artificial solitary drinking situation, on rates of intake and concurrent affective adjustment. Behaviour and self-estimated mood changes were studied in male moderate social drinkers in a social drinking situation of the subject's own choice, with ad lib access to alcohol, and compared with observations made in social isolation where alcohol was made available to the same subjects, serv-
ing as their own controls, in quantities identical to those that had been consumed by preference in the party situation. The aim of the study was represented to the subjects as a study in mood development. METHOD
Subjects Four male students volunteered as unpaid subjects. They were moderate social drinkers of approximately matched drinking habits and 22-25 years of age.
Procedure Pre-experimental. All subjects elected to spend their social evening at the local Student Union House where dancing and entertainment were available between 7:30 p.m. and 1 a.m. and a generally convivial atmosphere prevailed. The subjects were briefed and instructed in the use of the mood rating scales. They were also weighed, and baseline Alcometer readings were obtained. The subjects had been instructed to have their normal meals. Alcohol administration. Based on body weight, alternative doses were available for each subject: "single shot" (0.2 g ethanol/kg body weight) or "double" (0.4 g/kg), in the form of Finnish Vaakuna distilled spirit (28% weight/34% volume) which was served in 1:3 (v/v) solution with orange juice. Social drinking. The subjects were instructed to ask for single or double drinks at a rate which they felt would make them optimally happy. Individual records were kept of their consumption rates, and Alcometer readings were obtained at 45 rain intervals, as were direct magnitude estimates of mood change on nine variables. All subjects elected to terminate drinking at closing time and were subsequently transported home.
C o p y r i g h t © 1982 Brain R e s e a r c h Publications Inc.--0031-9384/82/0601093-03503.00/0
1094
LINDMAN
TABLE 1 MEAN ALCOHOL VOLUMES (28%/34%w/v) CONSUMED UNDER SOCIAL AND SOLITARYDRINKING CONDITIONS (ml) Mean
S.E.
t
p
150
c o
an
Social drinking Solitary drinking
493.7 290.5
90.7 26.2
'4~
2.68
0.075
100
D
MJ
Two-tailed t-test for paired data (N=4).
50
n ! m I
0 Drinking alone. About one week after the party, the subjects were invited to the Department of Psychology to participate in the control condition. This extended over the same period as each subject's social evening, i.e., typically from 7:30 p.m. to I a.m., the critical differences being that the time was spent alone in an office-type room, and that drinks were not served ad lib but at identical rates and in the same quantities that they had been requested in the social drinking condition. Refused drinks were left with the subject. Radio, TV, and magazines were available, but the experimenter engaged in only minimal conversation with the subjects while serving drinks, collecting mood estimates, and obtaining Alcometer readings. Pre- and postexperimental procedures were identical to those in the party condition. Mood estimation. The subjects were asked to produce subjective estimates o f their mood changes at intervals throughout each evening. These were obtained by direct magnitude estimation for several mood scales, so that the state experienced at the time of the first of two consecutive estimates was assigned the standard value of I00, allowing the estimates to be expressed in terms of a simple percentage scale [14,15]. RESULTS None of the subjects consumed as much alcohol in isolation as in the party situation, and most consumed considerably less. The mean volumes are presented in Table l, expressed in ml of Finnish Vaakuna distilled spirit (28% w/34% v). In spontaneous terms, the social isolation condition was described by the subjects as "unnatural," " a v e r s i v e , " and as " n o t inspiring for drinking." These unsolicited impressions were supported by the mood estimation data, as significant euphoric effects were reported in the party situation but not in the social isolation condition which typically induced below-baseline values instead. The trend is clearly shown in Fig. 1 for the self-estimated changes in subjective elation under the two conditions. The means are based on data reduced to percentage change relative to a common baseline [14] for the first three estimations, when rates of alcohol intake were still identical over conditions, with a calculated scaling consistency [ 15] of r =.92 (p <0.001) for the series of three estimates. The treatment effect was highly significant, F(I, 18) =24,76, p <0.001 up to this point, beyond which statistical analysis was not extended since systematic differences in blood alcohol levels over conditions were introduced by the increasingly frequent drink refusals by subjects drinking alone.
I
[ ] Party Im Alone
I
45 90 Time in min.
FIG. I. Self-estimated changes in subjective elation following the first drink under social and solitary drinking conditions. Ordinate in percent to baseline 100.
DISCUSSION The results were similar to those observed by others [4] in that the mean consumption level was almost doubled (170%) in surroundings conducive to social drinking, compared to intake when drinking alone. The least satisfying explanation of this result is the one provided by TRT: if drinking behaviour were critically determined by the learned avoidance of aversive experience [2,3], then social isolation would have been expected to induce more drinking, not less. Any speculative argument that aversive " t e n s i o n " must nevertheless have been present during social drinking seems particularly unwarranted in the present case, since it would be contradicted by the explicit statements by the subjects. Since critical determinants of mood and drinking were obviously at hand in the party situation, but absent when drinking alone, some explanations based on purely environmental influences may be considered first. The presence of a light drinking or heavy drinking model has been shown to be sufficient to alter subject drinking rates correspondingly in many experiments [4, 7, 8, 10, 13] and in the presence of multiple models, subject drinking matched that o f the majority [7]. The effects o f modelling have been found regardless of whether the subjects have been informed of the presence of models or not [8]. If modelling influences are regarded as a way of introducing schedules into a drinking situation, it is interesting to note that several activities have been identified as schedule-dependent in humans [5, l l , 21, 22, 23, 24], and that in an animal study ethanol self-injection behaviour which had been induced by schedule was not maintained once the schedule was removed [16]. N o explicit schedules were, of course, identifiable in the present experiment, apart from the experiments' standard activities which were identical in both conditions. Any social drinking occasion could nevertheless be structured according to subtle schedules, dependent on sequences of social events, or even according to self-imposed schedules of which the subjects themselves may or may not be aware. F o r this reason the extent to which social drinking behaviour might be regarded as essentially adjunctive to other reinforcing events would appear to merit further investigation. The notion that alcohol may serve as a reinforcer in the sense of the TRT due to pharmacological action also appears less likely for another reason. There is consistent evidence
SOCIAL AND SOLITARY DRINKING
1095
that the euphoric effects observed in relaxed surroundings can be reversed in clinical and impersonal settings [12,19]. The present results agree with these reports, furthermore suggesting an interesting linkage between euphoric mood and increased drinking. Since the trends for different mood developments were established before the first drink refusals took place in isolation, i.e., increasing subjective elation at the party but decreasing elation in isolation, and elation then continued to decline in isolation over the period of comparable drinking, the pharmacological effects were obviously insufficient to create either euphoria or an increased desire for drinking. Circumstances associated with the social drink-
ing situation were apparently necessary for both, and subjective elation may thus logically have been part of the factors that precipitated party drinking. Although euphoria has traditionally been regarded as a main consequence of alcohol intake, the effects of subjective well-being o n intake might also prove an interesting subject of study in the light of the present results. ACKNOWLEDGMENTS The participation of Mr. Pertti J~rvinen and Mr. Jan Widjeskog as experimenters is gratefully acknowledged. The study was supported by a grant from the Finnish Foundation for Alcohol Studies.
REFERENCES 1. Allman, L. R., H. A. Taylor and P. E. Nathan. Group drinking during stress: Effects on drinking behaviour, affect, and psychopathology. Am. J. Psychiat. 129: 669-678, 1972. 2. Cappell, H. An evaluation of tension models of alcohol consumption. In: Research Advances in Alcohol and Drug Problems, voi. 2, edited by R. J. Gibbins, Y. Israel, H. Kalant, R. E. Popham, W. Schmidt and R. G. Smart. New York: Wiley, 1975, pp. 177-209. 3. Cappell, H. and C. P. Herman. Alcohol and tension reduction. Q. Jl. Stud. Alcohol 33: 33-64, 1972. 4. Caudill, B. D. and G. A. Marlatt. Modeling influences in social drinking: an experimental analogue. J. consult, clin. Psychol. 43: 405-415, 1975. 5. Clarke, J., M. Gannon, I. Hughes, C. Keogh, G. Singer and M. Wallace. Adjunctive behaviour in humans in a group gambling situation. Physiol. Behav. 18: 159-161, 1977. 6. Cutler, R. E. and T. Storm. Observational study of alcohol consumption in natural settings: the Vancouver beer parlor. J. Stud. Alcohol 36: 1173-1183, 1975. 7. DeRicco, D. A. Effects of peer majority on drinking rate. Addict. Behav. 3: 29-34, 1978. 8. DeRicco, D. A. and W. K. Garlington. The effects of modeling and disclosure of experimenter's intent on drinking rate of college students. Addict. Behav. 2: 135-139, 1977. 9. Foy, D. W. and S. J. Simon. Alcoholic drinking topography as a function of solitary vs. social context. Addict. Behav. 3: 39-41, 1978. 10. Garlington, W. K. and D. A. DeRicco. The effect of modeling on drinking rate. J. appl. Behav. Anal. 10: 207-211, 1977. 11. Kachanoff, R., R. Leveille, J. P. McLelland and M. J. Wayner. Schedule induced behaviour in humans. Physiol. Behav. 11: 395-398, 1973. 12. Kalin, R. Social drinking in different settings. In: The Drinking Man, edited by D. C. McClelland, W. N. Davis, R. Kalin and E. Wanner. New York: Free Press, 1972, pp. 21-47. 13. Lied, E. R. and G. A. Marlatt. Modeling as a determinant of alcohol consumption: Effect of subject sex and prior drinking history. Addict. Behav. 4: 47-54, 1979.
14. Lindman, R. On the direct estimation of mood change. In: Anxiety and Alcohol: Limitations of Tension Reduction Theory in Nonalcoholics, Reports from the Department of Psychology at Abo Akademi. Monograph suppl. 1, edited by R. Lindman. Abo: Abo Akademi, 1980, pp. 119-120. 15. Lindman, R. and A.-M. Stenh~ill. An interdimensional test of the direct estimation of alcohol-induced mood change. In: Anxiety and Alcohol: Limitations of Tension Reduction Theory in Nonalcoholics, Reports from the Department of Psychology at Abo Akademi. Monograph suppl. 1, edited by R. Lindman. Abo: Abo Akademi, 1980, pp. 121-127. 16. Oei, T. P. S. and G. Singer. Effects of a fixed time schedule and body weight on ethanol self-administration. Pharmac. Biochem. Behav. 10: 767-770, 1979. 17. Pliner, P. and H. Cappell. Modification of affective consequences of alcohol: a comparison of social and solitary drinking. J. abnorm. Psychol. 83: 418-425, 1974. 18. Rosenbluth, J., P. E. Nathan and D. M. Lawson. Environmental influences on drinking by college students in a college pub: behavioral observation in the natural environment. Addict. Behav. 3: 117-121, 1978. 19. Russell, J. A. and A. Mehrabian. The mediating role of emotions in alcohol use. J. Stud. Alcohol 36: 1508-1536, 1975. 20. Sommer, R. The isolated drinker in the Edmonton beer parlor. Q. Jl. Stud. Alcohol 26: 95-110, 1965. 21. Wallace, M. and G. Singer. Adjunctive behaviour and smoking induced by a maze solving schedule in humans. Physiol. Behav. 17: 849-852, 1976. 22. Wallace, M. and G. Singer. Schedule induced behaviour: a review of its generality, determinants and pharmacological data. Pharmac. Biochem. Behav. 5: 483-490, 1976. 23. Wallace, M., A. Sanson and G. Singer. Adjunctive behaviour in humans on a food delivery schedule. Physiol. Behav. 20: 203204, 1978. 24. Wallace, M., G. Singer, M. J. Wayner and P. Cook. Adjunctive behaviour in humans during game playing. Physiol. Behav. 14: 651-654, 1975.
Social and Solitary Drinking: Effects on Consumption and Mood in Male Social Drinkers RALF LINDMAN
Department of Psychology, ftbo Akademi, Vdrdbergsgatan 1, SF-20700 ,~BO 70, Finland R e c e i v e d 17 M a r c h 1980 LINDMAN, R. Social and solitary drinking: Effects on consumption and mood in male social drinkers. PHYSIOL. BEHAV. 28(6) 1093-1095, 1982.--Rates of alcohol consumption and mood development were studied in four male social
drinkers serving as their own controls: (a) in a real life social drinking situation of the subject's choice, and (b) under artificial solitary drinking conditions. Almost twice as much alcohol was consumed during patty drinking, while solitary drinking was experienced as aversive and failed to induce the euphoric effects reported at the party. Implications for tension reduction theory and adjunctive behaviour theory were discussed. Alcohol consumption
Emotion
Adjunctive behaviour
MOST social drinkers would probably agree that their alcohol consumption will vary with the context in which drinking takes place, just as their affective adjustment will vary. Experimental interest in the environmental determinants of human drinking behaviour is nevertheless fairly recent, the state-trait models implied by tension reduction theory (TRT) having dominated much of the earlier work [1, 2, 3]. Drinking in a natural setting was apparently first studied systematically in a Canadian beer parlor [20] where group drinkers reportedly consumed twice as much as isolated drinkers. The results have since been confLrmed [6], with similar trends among college students [18], but not with alcoholics [9]. In another recent approach, the drinking behaviour of confederate models has proved a good predictor of subject drinking, suggesting that human alcohol intake can be modified by time-dependent external events [4, 7, 8, 10, 12]. But even acknowledging the importance of environmental events, unexplained issues remain: Why do people initially search for surroundings where they can meet for drinking [17], thus establishing the conditions where subsequent external influences can exert their modifying effects? And why would group drinkers typically describe the symptoms of their intoxication in affective terms, where solitary drinkers reportedly choose clinical terms [17]? These are problems closely related to levels of subjective experience, and the present experiment was designed as a pilot study to investigate (a) effects of elements characteristically present in a real-life social drinking situation, compared to (b) the effects of their absence in an artificial solitary drinking situation, on rates of intake and concurrent affective adjustment. Behaviour and self-estimated mood changes were studied in male moderate social drinkers in a social drinking situation of the subject's own choice, with ad lib access to alcohol, and compared with observations made in social isolation where alcohol was made available to the same subjects, serv-
ing as their own controls, in quantities identical to those that had been consumed by preference in the party situation. The aim of the study was represented to the subjects as a study in mood development. METHOD
Subjects Four male students volunteered as unpaid subjects. They were moderate social drinkers of approximately matched drinking habits and 22-25 years of age.
Procedure Pre-experimental. All subjects elected to spend their social evening at the local Student Union House where dancing and entertainment were available between 7:30 p.m. and 1 a.m. and a generally convivial atmosphere prevailed. The subjects were briefed and instructed in the use of the mood rating scales. They were also weighed, and baseline Alcometer readings were obtained. The subjects had been instructed to have their normal meals. Alcohol administration. Based on body weight, alternative doses were available for each subject: "single shot" (0.2 g ethanol/kg body weight) or "double" (0.4 g/kg), in the form of Finnish Vaakuna distilled spirit (28% weight/34% volume) which was served in 1:3 (v/v) solution with orange juice. Social drinking. The subjects were instructed to ask for single or double drinks at a rate which they felt would make them optimally happy. Individual records were kept of their consumption rates, and Alcometer readings were obtained at 45 rain intervals, as were direct magnitude estimates of mood change on nine variables. All subjects elected to terminate drinking at closing time and were subsequently transported home.
C o p y r i g h t © 1982 Brain R e s e a r c h Publications Inc.--0031-9384/82/0601093-03503.00/0
1094
LINDMAN
TABLE 1 MEAN ALCOHOL VOLUMES (28%/34%w/v) CONSUMED UNDER SOCIAL AND SOLITARYDRINKING CONDITIONS (ml) Mean
S.E.
t
p
150
c o
an
Social drinking Solitary drinking
493.7 290.5
90.7 26.2
'4~
2.68
0.075
100
D
MJ
Two-tailed t-test for paired data (N=4).
50
n ! m I
0 Drinking alone. About one week after the party, the subjects were invited to the Department of Psychology to participate in the control condition. This extended over the same period as each subject's social evening, i.e., typically from 7:30 p.m. to I a.m., the critical differences being that the time was spent alone in an office-type room, and that drinks were not served ad lib but at identical rates and in the same quantities that they had been requested in the social drinking condition. Refused drinks were left with the subject. Radio, TV, and magazines were available, but the experimenter engaged in only minimal conversation with the subjects while serving drinks, collecting mood estimates, and obtaining Alcometer readings. Pre- and postexperimental procedures were identical to those in the party condition. Mood estimation. The subjects were asked to produce subjective estimates o f their mood changes at intervals throughout each evening. These were obtained by direct magnitude estimation for several mood scales, so that the state experienced at the time of the first of two consecutive estimates was assigned the standard value of I00, allowing the estimates to be expressed in terms of a simple percentage scale [14,15]. RESULTS None of the subjects consumed as much alcohol in isolation as in the party situation, and most consumed considerably less. The mean volumes are presented in Table l, expressed in ml of Finnish Vaakuna distilled spirit (28% w/34% v). In spontaneous terms, the social isolation condition was described by the subjects as "unnatural," " a v e r s i v e , " and as " n o t inspiring for drinking." These unsolicited impressions were supported by the mood estimation data, as significant euphoric effects were reported in the party situation but not in the social isolation condition which typically induced below-baseline values instead. The trend is clearly shown in Fig. 1 for the self-estimated changes in subjective elation under the two conditions. The means are based on data reduced to percentage change relative to a common baseline [14] for the first three estimations, when rates of alcohol intake were still identical over conditions, with a calculated scaling consistency [ 15] of r =.92 (p <0.001) for the series of three estimates. The treatment effect was highly significant, F(I, 18) =24,76, p <0.001 up to this point, beyond which statistical analysis was not extended since systematic differences in blood alcohol levels over conditions were introduced by the increasingly frequent drink refusals by subjects drinking alone.
I
[ ] Party Im Alone
I
45 90 Time in min.
FIG. I. Self-estimated changes in subjective elation following the first drink under social and solitary drinking conditions. Ordinate in percent to baseline 100.
DISCUSSION The results were similar to those observed by others [4] in that the mean consumption level was almost doubled (170%) in surroundings conducive to social drinking, compared to intake when drinking alone. The least satisfying explanation of this result is the one provided by TRT: if drinking behaviour were critically determined by the learned avoidance of aversive experience [2,3], then social isolation would have been expected to induce more drinking, not less. Any speculative argument that aversive " t e n s i o n " must nevertheless have been present during social drinking seems particularly unwarranted in the present case, since it would be contradicted by the explicit statements by the subjects. Since critical determinants of mood and drinking were obviously at hand in the party situation, but absent when drinking alone, some explanations based on purely environmental influences may be considered first. The presence of a light drinking or heavy drinking model has been shown to be sufficient to alter subject drinking rates correspondingly in many experiments [4, 7, 8, 10, 13] and in the presence of multiple models, subject drinking matched that o f the majority [7]. The effects o f modelling have been found regardless of whether the subjects have been informed of the presence of models or not [8]. If modelling influences are regarded as a way of introducing schedules into a drinking situation, it is interesting to note that several activities have been identified as schedule-dependent in humans [5, l l , 21, 22, 23, 24], and that in an animal study ethanol self-injection behaviour which had been induced by schedule was not maintained once the schedule was removed [16]. N o explicit schedules were, of course, identifiable in the present experiment, apart from the experiments' standard activities which were identical in both conditions. Any social drinking occasion could nevertheless be structured according to subtle schedules, dependent on sequences of social events, or even according to self-imposed schedules of which the subjects themselves may or may not be aware. F o r this reason the extent to which social drinking behaviour might be regarded as essentially adjunctive to other reinforcing events would appear to merit further investigation. The notion that alcohol may serve as a reinforcer in the sense of the TRT due to pharmacological action also appears less likely for another reason. There is consistent evidence
SOCIAL AND SOLITARY DRINKING
1095
that the euphoric effects observed in relaxed surroundings can be reversed in clinical and impersonal settings [12,19]. The present results agree with these reports, furthermore suggesting an interesting linkage between euphoric mood and increased drinking. Since the trends for different mood developments were established before the first drink refusals took place in isolation, i.e., increasing subjective elation at the party but decreasing elation in isolation, and elation then continued to decline in isolation over the period of comparable drinking, the pharmacological effects were obviously insufficient to create either euphoria or an increased desire for drinking. Circumstances associated with the social drink-
ing situation were apparently necessary for both, and subjective elation may thus logically have been part of the factors that precipitated party drinking. Although euphoria has traditionally been regarded as a main consequence of alcohol intake, the effects of subjective well-being o n intake might also prove an interesting subject of study in the light of the present results. ACKNOWLEDGMENTS The participation of Mr. Pertti J~rvinen and Mr. Jan Widjeskog as experimenters is gratefully acknowledged. The study was supported by a grant from the Finnish Foundation for Alcohol Studies.
REFERENCES 1. Allman, L. R., H. A. Taylor and P. E. Nathan. Group drinking during stress: Effects on drinking behaviour, affect, and psychopathology. Am. J. Psychiat. 129: 669-678, 1972. 2. Cappell, H. An evaluation of tension models of alcohol consumption. In: Research Advances in Alcohol and Drug Problems, voi. 2, edited by R. J. Gibbins, Y. Israel, H. Kalant, R. E. Popham, W. Schmidt and R. G. Smart. New York: Wiley, 1975, pp. 177-209. 3. Cappell, H. and C. P. Herman. Alcohol and tension reduction. Q. Jl. Stud. Alcohol 33: 33-64, 1972. 4. Caudill, B. D. and G. A. Marlatt. Modeling influences in social drinking: an experimental analogue. J. consult, clin. Psychol. 43: 405-415, 1975. 5. Clarke, J., M. Gannon, I. Hughes, C. Keogh, G. Singer and M. Wallace. Adjunctive behaviour in humans in a group gambling situation. Physiol. Behav. 18: 159-161, 1977. 6. Cutler, R. E. and T. Storm. Observational study of alcohol consumption in natural settings: the Vancouver beer parlor. J. Stud. Alcohol 36: 1173-1183, 1975. 7. DeRicco, D. A. Effects of peer majority on drinking rate. Addict. Behav. 3: 29-34, 1978. 8. DeRicco, D. A. and W. K. Garlington. The effects of modeling and disclosure of experimenter's intent on drinking rate of college students. Addict. Behav. 2: 135-139, 1977. 9. Foy, D. W. and S. J. Simon. Alcoholic drinking topography as a function of solitary vs. social context. Addict. Behav. 3: 39-41, 1978. 10. Garlington, W. K. and D. A. DeRicco. The effect of modeling on drinking rate. J. appl. Behav. Anal. 10: 207-211, 1977. 11. Kachanoff, R., R. Leveille, J. P. McLelland and M. J. Wayner. Schedule induced behaviour in humans. Physiol. Behav. 11: 395-398, 1973. 12. Kalin, R. Social drinking in different settings. In: The Drinking Man, edited by D. C. McClelland, W. N. Davis, R. Kalin and E. Wanner. New York: Free Press, 1972, pp. 21-47. 13. Lied, E. R. and G. A. Marlatt. Modeling as a determinant of alcohol consumption: Effect of subject sex and prior drinking history. Addict. Behav. 4: 47-54, 1979.
14. Lindman, R. On the direct estimation of mood change. In: Anxiety and Alcohol: Limitations of Tension Reduction Theory in Nonalcoholics, Reports from the Department of Psychology at Abo Akademi. Monograph suppl. 1, edited by R. Lindman. Abo: Abo Akademi, 1980, pp. 119-120. 15. Lindman, R. and A.-M. Stenh~ill. An interdimensional test of the direct estimation of alcohol-induced mood change. In: Anxiety and Alcohol: Limitations of Tension Reduction Theory in Nonalcoholics, Reports from the Department of Psychology at Abo Akademi. Monograph suppl. 1, edited by R. Lindman. Abo: Abo Akademi, 1980, pp. 121-127. 16. Oei, T. P. S. and G. Singer. Effects of a fixed time schedule and body weight on ethanol self-administration. Pharmac. Biochem. Behav. 10: 767-770, 1979. 17. Pliner, P. and H. Cappell. Modification of affective consequences of alcohol: a comparison of social and solitary drinking. J. abnorm. Psychol. 83: 418-425, 1974. 18. Rosenbluth, J., P. E. Nathan and D. M. Lawson. Environmental influences on drinking by college students in a college pub: behavioral observation in the natural environment. Addict. Behav. 3: 117-121, 1978. 19. Russell, J. A. and A. Mehrabian. The mediating role of emotions in alcohol use. J. Stud. Alcohol 36: 1508-1536, 1975. 20. Sommer, R. The isolated drinker in the Edmonton beer parlor. Q. Jl. Stud. Alcohol 26: 95-110, 1965. 21. Wallace, M. and G. Singer. Adjunctive behaviour and smoking induced by a maze solving schedule in humans. Physiol. Behav. 17: 849-852, 1976. 22. Wallace, M. and G. Singer. Schedule induced behaviour: a review of its generality, determinants and pharmacological data. Pharmac. Biochem. Behav. 5: 483-490, 1976. 23. Wallace, M., A. Sanson and G. Singer. Adjunctive behaviour in humans on a food delivery schedule. Physiol. Behav. 20: 203204, 1978. 24. Wallace, M., G. Singer, M. J. Wayner and P. Cook. Adjunctive behaviour in humans during game playing. Physiol. Behav. 14: 651-654, 1975.