Adjunctive behavior and smoking induced by a maze solving schedule in humans

Adjunctive behavior and smoking induced by a maze solving schedule in humans

Physiology & Behavior, Vol. 17, pp. 849--852. Pergamon Press and Brain Research Publ., 1976. Printed in the U.S.A. Adjunctive Behavior and Smoking In...

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Physiology & Behavior, Vol. 17, pp. 849--852. Pergamon Press and Brain Research Publ., 1976. Printed in the U.S.A.

Adjunctive Behavior and Smoking Induced by a Maze Solving Schedule in Humans ' MEREDITH WALLACE AND GEORGE SINGER 2

Department o f Psychology, La Trobe University, Bundoora, Victoria, A USTRALIA, 3083 (Received 6 July 1976) WALLACE, M. AND G. SINGER. Adjunctive behavior and smoking induced by a maze solving schedule in humans. PHYSIOL. BEHAV. 17(5)849-,852; 1976. - . Adjunctive behavior has been reported as occurring in a variety of species and has been described primarily as a phenomenon of excessive drinking in the rat (schedule induced polydipsia). In an earlier study [9] it was shown that adjunctive behavior occurs in adult human subjects with an FI 60 schedule controlling game playing on a poker machine. In the present study 20 subjects, all University personnel or students, were paid to participate in an experiment where they were required to solve a maze under conditions of scheduled access (8 sec maze drawing). Four subjects were tested with 8, 60, 120 and 300 sec intervals, and 4 with FI 120 on all test sessions. An additional 12 subjects, who were all habitual smokers, were tested with FI 60 sec intervals on all test sessions. A comparison with baseline conditions, consisting of either listening to a tape recording or continuous problem solving, showed an increase in the amount of subjects' motor activity under schedule conditions. There was a significant increase in movement scores with an increase in schedule length, but no increase with repeated scheduled trials of equal duration. The amount of smoking during test sessions was significantly greater than during smoking baseline sessions. Allowing the subject to smoke or not to smoke on maze schedule sessions made no difference to the movement scores. Eight of the subjects were also given instructions to keep still. These instructions had no effect in reducing the amount of activity. These data show that the scheduling of cognitive tasks can also lead to adjunctive behavior. Adjunctive behavior


Schedule induced

Since i n s t r u c t i o n s b y t h e e x p e r i m e n t e r are a p o w e r f u l d e t e r m i n a n t o f b e h a v i o r in t h e l a b o r a t o r y , it is possible t h a t instructions not to move may eliminate the occurrence of s c h e d u l e i n d u c e d behavior. In t h e t h i r d e x p e r i m e n t , the effects o n s c h e d u l e i n d u c e d b e h a v i o r of i n s t r u c t i o n s to keep still were also e x a m i n e d .

A D J U N C T I V E b e h a v i o r as a result of i n t e r m i t t e n t f o o d delivery s c h e d u l e s has b e e n r e p o r t e d in a variety Of species, a n d has b e e n described p r i m a r i l y as a p h e n o m e n o n of excessive d r i n k i n g in t h e rat [ 1 ] . R e c e n t l y it has b e e n s h o w n t h a t schedules w h i c h do n o t involve f o o d delivery also g e n e r a t e a v a r i e t y of a d j u n c t i v e b e h a v i o r s [ 3 , 7 ] . In an earlier s t u d y [9] it was s h o w n t h a t s c h e d u l e i n d u c e d b e h a v i o r o c c u r s in a d u l t h u m a n s u b j e c t s o n an FI 6 0 s c h e d u l e c o n t r o l l i n g g a m e p l a y i n g o n a slot m a c h i n e . Subjects h a d to barpress to o b t a i n a s y m b o l display, b u t a new display w o u l d a p p e a r o n l y a f t e r a o n e m i n u t e interval. F o r s o m e of t h e s y m b o l c o m b i n a t i o n s subjects received p a y o u t s as in a n o r m a l slot m a c h i n e . It is t h e r e f o r e possible t h a t t h e a d j u n c t i v e b e h a v i o r o b s e r v e d was g e n e r a t e d e i t h e r b y t h e m o n e t a r y r e w a r d s or b y t h e i n t e r m i t t e n t displays. In t h e p r e s e n t s t u d y this c o m p l e x i t y is e l i m i n a t e d b y using s c h e d u l e c o n t r o l l e d maze solving. Cigarette s m o k i n g is a b e h a v i o r w h o s e f r e q u e n c y is t h o u g h t to d e p e n d o n w h a t o t h e r a c t i v i t y t h e s m o k e r is engaged in. If a s u b j e c t is p e r f o r m i n g a s c h e d u l e d task it is possible t h a t s m o k i n g will e i t h e r replace o t h e r s c h e d u l e i n d u c e d b e h a v i o r s or t h a t it will s i m p l y o c c u r as a d d i t i o n a l a d j u n c t i v e behavior. A n o p p o r t u n i t y for s c h e d u l e i n d u c e d s m o k i n g is p r o v i d e d in a t h i r d e x p e r i m e n t w h e r e h a b i t u a l s m o k e r s were able to s m o k e cigarettes d u r i n g s c h e d u l e intervals.

EXPERIMENT 1 In this e x p e r i m e n t subjects were t e s t e d u n d e r 4 condit i o n s o f s c h e d u l e intervals, FI 8, 60, 120, 3 0 0 secs, a n d a baseline session. This last c o n s i s t e d of listening to a tape recording, b o t h b e f o r e a n d a f t e r the schedule sessions.


Subjects F o u r first y e a r p s y c h o l o g y s t u d e n t s , 2 male and 2 female, were used. T h e y were paid a small sum at t h e completion of the experiment.

Apparatus A maze was displayed in a box, 76 cm x 46 cm x 20 cm, lit f r o m w i t h i n b y 5 small lights. T h e b o x was f i t t e d w i t h a lid of t i n t e d p e r s p e x over a sheet of t r a n s l u c e n t perspex. A

1 This project was supported by a grant from the Australian Tobacco Research Foundation in 1976. 2 We thank Mrs. Ann Sanson for her assistance in collecting the data. 849



maze inserted b e t w e e n the perspex sheets could not be seen by the subjects when the lights were off. When the lights were on, the subjects could trace a path through the maze with a chinagraph pencil on the tinted perspex and see b o t h maze and pencil tracing. The box stood on a table in a large, s o u n d p r o o f e d r o o m . A cassette recorder with tapes was used during listening sessions. A one-way mirror allowed vision into the experimental r o o m from an observation room. A wide-angle TV camera in the observation r o o m televised subjects' activity through the one-way mirror. The maze light and auditory signals (beeps) were controlled by a Hales logic system in the observation room. Two stop-watches were used by the experimenter to record any m o v e m e n t by the subject.

for listening, FI 60, 120 and 300 sessions showed an overall significant effect, F = 4.47, df 12,3. A t-test comparing FI 60 and baseline listening shows that all schedule conditions are significantly different f r o m the baseline (t = 3.15, df 6, p < 0 . 0 5 ) . A trend analysis indicates a significant linear trend, F = 10.34, df 3,12 and a significant quadratic c o m p o n e n t , F = 4.53, df 3,12. The results demonstrate an increase in m o v e m e n t when maze solving is scheduled which does not involve the p a y o u t c o m p o n e n t of the game playing experiment. Even m o r e interesting is the increase in m o v e m e n t scores as a f u n c t i o n of schedule length. Although only very few data points were involved in the analysis, the results are in agreement with those reported for polydipsic rats [2].



The subject was informed that his task was to trace the maze while the light was on. The onset of light was signalled by a short beep occurring at a p r e d e t e r m i n e d interval beforehand. In all maze solving sessions the light was on for 8 seconds at a time. Subjects were tested individually on the following conditions: FI 8 sec, where the light was off for 8 seconds, and FI 60, FI 120 and FI 300, where the light was off for 60, 120 and 300 secs respectively. In the FI 8 sec c o n d i t i o n the warning signal occurred 0.5 sec before the light, and in the other conditions it occurred 5 secs before the light to give the subject time to return to the maze if somewhere else in the r o o m at that time. Listening sessions, where subjects listened to a h u m o r o u s tape recording, were also included. The order of conditions was: FI 8, a listening session, 6 experimental sessions (order of schedule intervals systematically varied across subjects), followed by a second listening session. The FI 8 condition was used as a familiarisation session. All sessions lasted 30 minutes and were held on different days. The duration of any activity occurring in intertrial intervals which was not directly related to the experimental task was timed in b o t h baseline and experimental sessions, and constituted a subject's m o v e m e n t score. M o v e m e n t scores are expressed as a percentage of total intertrial interval duration. EXPERIMENT 1: RESULTS Table 1 shows the mean percentage m o v e m e n t scores and SD for the four schedule conditions and the baseline listening sessions. The data for the FI 8 session were not used in the analysis of results because of the e x t r e m e l y short intertrial interval. An analysis of variance of the data TABLE1 MEANS AND STANDARD DEVIATIONS OF PERCENTAGE MOVEMENT SCORES FOR ALL SUBJECTS UNDER BASELINE AND SCHEDULE CONTROLLED CONDITIONS (EXPERIMENT 1) Mean m o v e m e n t




FI 8 Listening FI 60 FI 120 FI 300

7.55 27.07 50.79 69.28 78.55

5.76 10.14 15.39 28.87 14.59

In E x p e r i m e n t 2 the effects of six consecutive FI 120 sessions on m o v e m e n t scores were tested. A different baseline consisting of nonscheduled problem solving was used in addition to a listening session. METHOD

Subjects F o u r n o n p s y c h o l o g y students, all male, were used. Subjects were paid a nominal a m o u n t for attending each session.

Apparatus The same experimental r o o m and apparatus as for E x p e r i m e n t 1 were used. In addition, a stool was placed in front of the maze box. On another table was a programmed e l e c t r o - s p h y g m o m a n o m e t e r which simulated blood pressure readings, and a stop watch. This apparatus was also used in Experiments 3a and b.

Procedure The subjects were told that the purpose of the experiment was to investigate the relationship b e t w e e n physiological measures, interruption and problem solving abilities. Therefore before and after each session, m e a s u r e m e n t of pulse and blood pressure was simulated. The 9 sessions for each subject were each of 30 min duration and as in E x p e r i m e n t 1 were held on different days. Sessions 1, 2 and 9 were c o n d u c t e d to obtain a baseline for m o v e m e n t . Sessions 1 and 9 consisted of problem solving: subjects were presented with a series of lateral thinking problems and told to w o r k through t h e m continuously for the whole session. Session 2 was a listening session as in E x p e r i m e n t 1. Sessions 3 - 8 were the experimental sessions. As in E x p e r i m e n t I, subjects were told their task was to trace the maze while the light was on. FI 120 sec was used as the schedule for all sessions, with a warning beep 5 sec before the light went on. Exposure time of the maze was 8 sec. (Exposure time was reduced to 5 sec for one subject who was particularly fast at the task.) In this experiment, and also in E x p e r i m e n t s 3a and 3b, a time sampling m e t h o d was used. The experimenter recorded the subject's m o v e m e n t every 10 sec. Movements specifically relating to the experimental task were deleted to obtain a total m o v e m e n t score for each subject, expressed as a percentage of all samples recorded in one session.



RESULTS The mean percentage movement score (X = 75.2, SD 13.5) for schedule sessions was significantly larger than that for the unscheduled problem solving sessions (X =43.5, SD 6.77), t = 2.71, df 6, p<0.05). Individual scores are shown in Fig. 1. It appears that subjects reach their maximum activity level for a specific schedule interval in a single session. There is no significant trend within scheduled trials of equal duration. This absence contrasts with the functional relationship between schedule length and movement observed in Experiment 1.

an auditory beep sounded at 60 sec intervals. This session was included as a warm up session. Session 2 was a listening session, similar to that in Experiments 1 and 2 except that subjects were permitted to smoke ad lib. Sessions 3, 4, 9 and 10 were problem solving sessions; ad lib smoking was allowed for 2 sessions and not for the other 2. In sessions 5 to 8 the task was maze solving on a FI 60 sec schedule with 8 sec access to the maze. Ad lib smoking was allowed for 2 sessions and not for 2 sessions. The order of these sessions was systematically varied. Percentage movement scores were obtained in the same manner as in, Experiment 2. In addition the number of cigarette puffs was recorded. EXPERIMENT 3b: METHOD

Sub/ects Eight additional subjects were used, of whom 5 were psychology and 3 were nonpsychology students. All smoked over 20 cigarettes a day. Inducements were similar to Experiment 3a.




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FIG,. 1. Percentage movement scores for 4 subjects on all sessions.

EXPERIMENTS 3a AND 3b In the following experiments cigarettes were made available to subjects selected because they were habitual smokers. In experiment 3a subjects were tested with the maze-solving as the schedule controlled behavior as in Experiments 1 and 2, and a nonscheduled problem solving situation was used as a baseline as in Experiment 2. In Experiment 3b, a further 8 smokers were tested on the same scheduled task, but an attempt was made to counteract any possible demand characteristics [5] which might be operating to promote increased movement by explicitly instructing subjects not to move except when necessary to smoke or draw on the maze. These instructions also constitute a test of the persistence of adjunctive behavior. EXPERIMENT 3a: METHOD

Subjects Four subjects were used, all of whom were nonacademic university staff. All were moderate to heavy smokers who had smoked over 20 cigarettes a day for several years. Subjects were paid as in Experiments 1 and 2, and were provided with free cigarettes for each session.

Procedure Subjects were told that the interrelationship of smoking, physiological measures and problem-solving abilities was being investigated. As in Experiment 2, blood pressure and pulse measurements were simulated before and after each session. There were 10 sessions in all. In the first session, smoking was the schedule controlled behavior. Subjects were required to inhale once only when

The procedure was similar to that for Experiment 3a except that the listening session and the nonsmoking problem solving sessions were omitted. There were seven sessions for each subject. In addition, subjects were told to restrict their movements in every session so as not to contaminate the physiological measures. RESULTS Instructions not to move made no difference to mean percentage movement scores under either unscheduled problem solving (PS) or scheduled maze solving, p> 0.05 in both cases. For this reason the data were combined across experiments. Movement scores for maze solving conditions were significantly higher than for problem solving conditions (t = 3.57, df 22, p<0.05). (Mean movement maze = 72.2, SD 12.7; mean movement PS = 53.6, SD 11.7) The amount of smoking behavior as indicated by number of puffs increased in 11 out of 12 subjects, t = 2.603, d.f 22, p<0.05. (Mean puffs maze = 25.0, SD 9.65; mean puffs PS = 16.67, SD 4.43). There were large individual differences in this increase in smoking when compared to baseline. Some subjects showed a minimal increase, others increasing by over 200%. The number of behavior samples on which smoking or smoking related behavior (such as lighting or ashing a cigarette) occurred, was deducted from the total movement scores in maze/ smoking sessions. The residual scores, expressed as a percentage, (Mean = 59.66, SD 12.12) were compared with percentage movement scores (Mean = 68.32, SD 15.25) obtained from maze/nonsmoking sessions, t = 1.47, df 22, p>0.05. That is, smoking did not replace other adjunctive behaviors but simply added to the total amount of adjunctive behaviors. DISCUSSION The results of these experiments show that adjunctive behavior occurs under conditions of schedule controlled maze solving and demonstrates that in human subjects a



response contingent m o n e t a r y reward is not a necessary condition for the occurrence of schedule induced responses. It also demonstrates that conditions which require an intermittent response w i t h o u t material r e i n f o r c e m e n t are sufficient to induce adjunctive behavior. Moreover, the frequency of adjunctive behavior in humans increases as a function of schedule interval. This was previously shown only with regard to schedule induced polydipsia [2] and has been used as a characteristic in defining adjunctive behavior. No increase in the f r e q u e n c y of adjunctive behavior was observed with repeated presentation of the same length maze solving schedule which seems to indicate that the imposition of a schedule has an i m m e d i a t e effect which reaches its m a x i m u m in one session. This is an indication of h o w powerful schedules may be in controlling behavior. The fact that instructions not to move had no effect on the f r e q u e n c y of adjunctive behavior confirms that the responses emitted under schedule conditions were not merely the result of demand characteristics [5] but represent a class of responses which are related to the presence of the schedule. The persistence of adjunctive behavior with contrary instructions is surprising since instructions are usually a powerful determinant of behavior in a h u m a n laboratory [8]. In the third e x p e r i m e n t where smoking was permitted,

other adjunctive behavior also occurred as indicated by an increase of m o v e m e n t scores over baseline to the same extent as in E x p e r i m e n t s 1 and 2. Smoking as measured by n u m b e r of puffs also increased over baseline. Allowing the subject to smoke or not to smoke on maze schedule sessions made no difference to the m o v e m e n t scores after smoking associated behavior was subtracted where appropriate. These data suggest that smoking has no specific effect on the level of adjunctive behavior and that cigarettes merely provide another stimulus for schedule induced responses. The proportional increase of smoking behavior from baseline to schedule conditions is no greater than the proportional increase of any other behavior. Smoking does not seem to be higher in the response hierarchy of habitual smokers than other forms of behavior measured in these experiments. This may be a result of the task chosen for schedule control, since there is some evidence from studies on rats that there are specific preference hierarchies. Rats on f o o d delivery schedules prefer adjunctive drinking to wheel-running [6] and rats on water delivery schedules prefer adjunctive wheel running to eating [ 4 ] . There may be specific sequences where cigarette smoking is the preferred behavior. This is a question for further research. F o o d or caffeine associated smoking may elicit a stronger preference hierarchy than maze solving associated smoking.

REFERENCES 1. Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6: 577-588, 1971. 2. Falk, J. L. Schedule-induced polydipsia as a function of fixed interval length. J. exp. Analysis Behav. 9 : 3 7 - 3 9 , 1966. 3. Kachanoff, R., R. Leveille, J. P. McLeltand and M. J. Wayner. Schedule induced behavior in humans. Physiol. Behav. 11: 395-398, 1973. 4. King, G. D. Wheel running in the rat induced by a fixed-time presentation of water. Animal Learning and Behavior 2: 325-328, 1974. 5. Orne, M. T. The nature of hypnosis artifact and essence. J. abnorm, soc. Psychol. 58: 277-300, 1959.

6. Segal, E. F. The interaction of psychogenic polydipsia with wheel running in rats. Psychon. Sci. 14: 142-144, 1969. 7. Singer, G., M. J. Wayner, J. Stein, K. Cimino and K. King Adjunctive behavior indtaced by wheel running. Physiol. Behav. 12: 493-495, 1974. 8. Singer, G., and P. W. Sheehan. The effect of demand characteristics on the figural after-effect with real and imaged inducing figures. Am. J. PsychoL LXXVlII: 96-101, 1965. 9. Wallace, M., G. Singer, M. J. Wayner and P. Cook. Adjunctive behavior in humans during game playing. Physiol. Behav. 14: 651-654, 1975.