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Schedule induced behavior in humans
Physiology and Behavior, Vol. 11, pp. 395-398. Brain Research Publications Inc., 1973. Printed in the U.S.A.
BRIEF COMMUNICATION Schedule Induced Behavior in Humans R. K A C H A N O F F , ~ R. L E V E I L L E , J. P. M C L E L L A N D A N D M. J. W A Y N E R
Douglas Hospital, Department o f Psychiatry, McGill University, Montreal 204, Quebec, Canada
( R e c e i v e d 11 April 1 9 7 3 ) KACHANOFF, R., R. LEVEILLE, J. P. MCLELLAND AND M. J. WAYNER. Schedule induced behavior in humans. PHYSIOL. BEHAV. 11(3) 3 9 5 - 3 9 8 , 1973.-Schedule induced pacing and drinking was demonstrated in hospitalized humans under a variety of fixed interval schedule conditions. The subjects were not food or fluid deprived and the schedule induced behavior was maintained through the use of secondary reinforcement. The relationship between psychotic and schedule induced behaviors and the implications of these findings for behavior modification programs are discussed. Schedule induced human behavior
Secondary reinforcement
Adjunctive behavior
Psychotic behavior
Behavior modification
S E V E R A L i n t e r m i t t e n t s c h e d u l e s of r e i n f o r c e m e n t have b e e n s h o w n to i n d u c e a v a r i e t y o f b e h a v i o r s w h i c h are n o t r e l e v a n t or necessary to o b t a i n the r e i n f o r c e m e n t a n d a p p e a r as a d j u n c t s to t h e b e h a v i o r u n d e r m o r e direct c o n t r o l o f t h e schedule. Hence, t h e t e r m a d j u n c t i v e b e h a v i o r [ 2 ] . This i n t e r e s t i n g class of b e h a v i o r , p a r t i c u l a r l y s c h e d u l e i n d u c e d polydipsia [ 1 ] , has b e e n studied e x t e n sively in animals such as the l a b o r a t o r y rat b u t little is k n o w n c o n c e r n i n g this b e h a v i o r in m a n . Naturalistic observ a t i o n a n d c o m m o n sense i n d i c a t e t h a t m a n y t y p e s of bizarre h u m a n b e h a v i o r in c h i l d r e n , p s y c h o t i c s and t h e so-called p s y c h o p a t h o l o g i e s of every d a y life m i g h t b e a d j u n c t i v e in n a t u r e . In m o s t o f these e x a m p l e s t h e s c h e d u l e c o n t r o l l i n g t h e time of o c c u r r e n c e is o b s c u r e a n d t h e p r e v i o u s r e i n f o r c e m e n t h i s t o r y o f the individual is u n k n o w n . As a d j u n c t i v e b e h a v i o r seems to arise f r o m a n o n s p e c i f i c increase in m o t o r e x c i t a b i l i t y [41, t h e stimuli effective at t h e m o m e n t are p a r t i c u l a r l y i m p o r t a n t in the f u t u r e d e t e r m i n a t i o n of b e h a v i o r . Drugs w h i c h e n h a n c e the efficacy o f this m e c h a n i s m , such as e t h y l alcohol a n d / , 9 . t e t r a h y d r o c a n n a b i n o l , t h e r e b y result in a f a c i l i t a t i o n of t h e i r s e l f - a d m i n i s t r a t i o n [ 5 ] . In h u m a n and a n i m a l b e h a v i o r sufficient time m u s t elapse b e t w e e n r e i n f o r c e m e n t s and c o n c u r r e n t c o m p e t i n g activities for the a d j u n c t i v e b e h a v i o r to appear. W h e n direct o b s e r v a t i o n of a n i m a l b e h a v i o r is n o t e m p h a s i z e d , t h e b e l i e f t h a t a n a n i m a l does n o t h i n g d u r i n g periods o f so-called low rates of r e s p o n d i n g is a c o m m o n a s s u m p t i o n w h i c h t e n d s to be c o n f i r m e d in b a r r e n test e n v i r o n m e n t s w h e r e a n i m a l s d o n o t have an o p p o r t u n i t y to engage in o t h e r activities. C o n s e q u e n t l y , some i n t e r e s t i n g possibilities have b e e n o v e r l o o k e d in m a n y a n i m a l studies.
In h u m a n s some " . . . I n t e r e s t i n g e x a m p l e s are f o u n d in t h e field of p s y c h o t i c b e h a v i o r , w h e r e the p a t i e n t engages in compulsive or o t h e r i d i o s y n c r a t i c ways o n l y w h e n he is n o t e x e c u t i n g t h e b e h a v i o r u n d e r t h e c o n t r o l of a given s c h e d u l e . " [3, p. 2 7 9 ] . T h e p u r p o s e o f the c u r r e n t research p r o g r a m is to s t u d y t h e e s t a b l i s h m e n t a n d c o n t r o l of a d j u n c t i v e b e h a v i o r in h o s p i t a l p a t i e n t s u n d e r c o n t r o l l e d c o n d i t i o n s . T h e p r e s e n t r e p o r t relates some of the prelimin a r y results o n s c h e d u l e i n d u c e d p o l y d i p s i a and s c h e d u l e i n d u c e d pacing. METHOD
Subjects T w o female a n d five male p a t i e n t s diagnosed as schizop h r e n i c were e m p l o y e d . T h e i r ages were f r o m 1 8 - 4 1 years and l e n g t h o f h o s p i t a l i z a t i o n varied from 1 . 5 - 1 1 years. T w o o f t h e p a t i e n t s , S-14 and S-11, received b i m o n t h l y m a i n t e n a n c e doses of p h e n o t h i a z i n e . T h e p a t i e n t s were o n a prescribed o p e r a n t t o k e n e c o n o m y p r o g r a m a n d were a c c u s t o m e d to a t t e n d i n g sessions.
Procedure T h e e x p e r i m e n t a l c h a m b e r consisted o f a 1.82 x 3.05 x 2.44 m e t e r r o o m w i t h tiled floor and a b l a c k e n e d w i n d o w . S i t u a t e d inside t h e e x p e r i m e n t a l c h a m b e r was a pull cord m a n i p u l a n d u m , a p e n n y dispenser, and a s t a n d a r d d r i n k i n g f o u n t a i n . T h e f o u n t a i n was designed to retain w a t e r n o t c o n s u m e d so t h a t v o l u m e ingested could be calculated. Solid s t a t e p r o g r a m i n g e q u i p m e n t was fixed to a table in an
Reprint requests to: Dr. R. Kachanoff, Douglas Hospital, 6875 LaSalle Boulevard, Montreal 204, Quebec, Canada. 395
396
KACHANOFF, LEVEILLE, MCLELLAND AND WAYNER
o b s e r v a t i o n r o o m outside the e x p e r i m e n t a l c h a m b e r . The d r i n k i n g f o u n t a i n , p e n n y dispenser, and pull cord were arranged so t h a t n u m b e r of pulls, drinks, p e n n i e s p r e s e n t e d and the d u r a t i o n of d r i n k i n g and pacing in s e c o n d s were r e c o r d e d on e l e c t r o n i c c o u n t e r s . Drinks, pulls, and p e n n i e s p r e s e n t e d were r e c o r d e d on a LVE c u m u l a t i v e recorder. A t e c h n i c i a n in the o b s e r v a t i o n r o o m m o n i t o r e d t h e equipm e n t and the p a t i e n t d u r i n g test sessions and r e c o r d e d the n u m b e r of pacing events. A pacing event was defined as a walking m o v e m e n t w h i c h did n o t t e r m i n a t e at the d r i n k i n g f o u n t a i n or p e n n y dispenser. A f t e r t h r e e a d a p t a t i o n sessions in w h i c h p a t i e n t s were i n t r o d u c e d to the e x p e r i m e n t a l r o o m for 30 min w i t h o u t i n s t r u c t i o n s and n o p e n n i e s p r e s e n t e d , t h e y were t h e n told t h a t pulling t h e cord w o u l d enable t h e m to earn p e n n i e s from time to t i m e and t h a t t h e y were n o t to try to leave or talk to the t e c h n i c i a n . T h e y were also i n s t r u c t e d t h a t the t e c h n i c i a n would o p e n the d o o r at the t e r m i n a t i o n of the session. A variety of FI schedules o f r e i n f o r c e m e n t were studied as well as extinction sessions. E x p e r i m e n t a l sessions were c o n d u c t e d daily for 30 min at a fixed time, five days a week. FI schedule intervals were a d j u s t e d in small a s c e n d i n g i n c r e m e n t s
t h r o u g h o u t the course of the e x p e r i m e n t and at times certain FI schedules were r e i n s t a t e d after e x t i n c t i o n sessions. P a t i e n t s were n o t deprived of food or water. RESULTS Of t h e seven p a t i e n t s w h o s t a r t e d , five displayed schedule i n d u c e d pacing. T w o of these five also displayed s c h e d u l e i n d u c e d drinking. One of the p a t i e n t s did n o t display e i t h e r of these behaviors and o n e p a t i e n t was discharged from the h o s p i t a l b e f o r e schedule m a n i p u l a t i o n s were c o m p l e t e d . Schedule i n d u c e d b e h a v i o r was greatest w h e n FI values were varied from FI 30 sec to El 120 sec and generally decreased with values of FI 135 sec to Fl 150 sec. Schedule i n d u c e d b e h a v i o r was m a r k e d l y r e d u c e d d u r i n g e x t i n c t i o n sessions. R e d u c t i o n of adjunctive behavior d u r i n g e x t i n c t i o n was n o t as p r o n o u n c e d w i t h those subjects having a long h i s t o r y in the e x p e r i m e n t a l situation. T h e data o n s c h e d u l e i n d u c e d polydipsia for Subject S-02 are p r e s e n t e d in Figs. 1, 2 and 3. The n u m b e r of drinks for c o n s e c u t i v e test sessions d u r i n g the course of the e x p e r i m e n t are illustrated in Fig. 1 w h e r e the n u m b e r of drinks in each sessions are p r e s e n t e d as a functiQ~ of the
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SCHEDULE INDUCED BEHAVIOR
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S-D2 FI 45 369 PULLS 42 DRINKS 23 PENNIES
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FIG. 3. A sample cumulative record, session 12 FI 45. Hash marks indicate delivery of pennies. Drinking indicated by the downward deflection of the pen in the lower tracing.
fixed interval schedule in seconds (FI schedule in seconds) and extinction (E). The amounts of water consumed in g are presented similarly in Fig. 2. The letter B denotes the three days of baseline and the numbers indicate the fixed interval in seconds and the day on which the schedule was changed. An example of an actual cumulative record, the twelfth session FI 45, is illustrated in Fig. 3. The top tracing represents cumulative pulls on the cord. The delivery of each penny is indicated by a hash mark. In the lower tracing drinks are indicated by a downward deflection of the pen. There were 369 pulls, 42 drinks, and the subject earned 23 pennies. Schedule induced pacing in two subjects, S-11 and S-14, is illustrated in Figs. 4 and 5 where the number of paces, solid lines, and the time spent pacing in seconds per session, broken line, are plotted as a function of the fixed interval schedule and during extinction.
DISCUSSION These results demonstrate schedule induced behavior in humans and the feasibility of further studies under laboratory conditions. These subjects were not deprived of food or fluids and indicate that schedule induced human behavior can be controlled by secondary reinforcement. The schedule induced behavior appeared to be schedule dependent with frequent verbalization, jumping, pacing, drinking, and self-directed activities such as grooming occurring during the session. As soon as the session was terminated, these behaviors ceased and the subjects counted their money and left the laboratory. It is interesting that the schedule induced behavior persists to a certain extent during extinction even when the schedule dependent behavior has diminished fully. If psychotic behavior is schedule induced, then resistance to treatment might be
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398
KACHANOFF, LEVEtLLE, MCLELLAND AND WAYNER
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FI SCHEDULE IN SECONDS FIG. 5. Same as Fig. 4 except for Subject S-14. e x p e c t e d . Some h a b i t u a t i o n seems to o c c u r with each s c h e d u l e w h e n r e p e a t e d for several sessions, as illustrated in Figs. 1, 2, 4 and 5, w h i c h is o v e r c o m e w h e n the n e x t s c h e d u l e is i n t r o d u c e d . A similar increase in a d j u n c t i v e b e h a v i o r o c c u r r e d w h e n an FI 45 s c h e d u l e was i n t r o d u c e d following e x t i n c t i o n , as illustrated in Fig. 5. C h a n g i n g the s c h e d u l e is a n o t h e r f o r m of i n t e r m i t t e n c e . These results
also i n d i c a t e t h a t dense schedules o f r e i n f o r c e m e n t s h o u l d be used cautiously in b e h a v i o r m o d i f i c a t i o n t r e a t m e n t programs because of the possibility o f i n a d v e r t e n t develo p m e n t of i n a p p r o p r i a t e behaviors. A l t h o u g h m a n y anecdotal e x a m p l e s could be cited, a clear d e m o n s t r a t i o n of schedule i n d u c e d b e h a v i o r in n o r m a l h u m a n s u n d e r controlled l a b o r a t o r y c o n d i t i o n s r e m a i n s to be d e t e r m i n e d .
REFERENCES 1. Falk, J. L. Conditions producing psychogenic polydipsia in animals. Ann. N. Y. Aead. Sci. 157: 5 6 9 - 5 9 3 , 1969. 2. Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6: 5 7 7 - 5 8 8 , 1971. 3. Skinner, B. F. and W. H. Morse. Concurrent activity under fixed-interval reinforcement. J. comp. physiol. Psychol. 50: 279 281, 1957.
4. Wayner, M. J. Motor control functions of the lateral hypothalamus and adjunctive behavior. Physiol. Behav. 5: 1319-1325, 1970. 5. Wayner, M. J., I. Greenberg, S. Fraley and S. Fisher. Effects of Ag-tetrahydrocannabinol and ethyl alcohol on adjunctive behavior and the lateral hypothalamus. Physiol. Behav. 10: 109 132, 1973.
BRIEF COMMUNICATION Schedule Induced Behavior in Humans R. K A C H A N O F F , ~ R. L E V E I L L E , J. P. M C L E L L A N D A N D M. J. W A Y N E R
Douglas Hospital, Department o f Psychiatry, McGill University, Montreal 204, Quebec, Canada
( R e c e i v e d 11 April 1 9 7 3 ) KACHANOFF, R., R. LEVEILLE, J. P. MCLELLAND AND M. J. WAYNER. Schedule induced behavior in humans. PHYSIOL. BEHAV. 11(3) 3 9 5 - 3 9 8 , 1973.-Schedule induced pacing and drinking was demonstrated in hospitalized humans under a variety of fixed interval schedule conditions. The subjects were not food or fluid deprived and the schedule induced behavior was maintained through the use of secondary reinforcement. The relationship between psychotic and schedule induced behaviors and the implications of these findings for behavior modification programs are discussed. Schedule induced human behavior
Secondary reinforcement
Adjunctive behavior
Psychotic behavior
Behavior modification
S E V E R A L i n t e r m i t t e n t s c h e d u l e s of r e i n f o r c e m e n t have b e e n s h o w n to i n d u c e a v a r i e t y o f b e h a v i o r s w h i c h are n o t r e l e v a n t or necessary to o b t a i n the r e i n f o r c e m e n t a n d a p p e a r as a d j u n c t s to t h e b e h a v i o r u n d e r m o r e direct c o n t r o l o f t h e schedule. Hence, t h e t e r m a d j u n c t i v e b e h a v i o r [ 2 ] . This i n t e r e s t i n g class of b e h a v i o r , p a r t i c u l a r l y s c h e d u l e i n d u c e d polydipsia [ 1 ] , has b e e n studied e x t e n sively in animals such as the l a b o r a t o r y rat b u t little is k n o w n c o n c e r n i n g this b e h a v i o r in m a n . Naturalistic observ a t i o n a n d c o m m o n sense i n d i c a t e t h a t m a n y t y p e s of bizarre h u m a n b e h a v i o r in c h i l d r e n , p s y c h o t i c s and t h e so-called p s y c h o p a t h o l o g i e s of every d a y life m i g h t b e a d j u n c t i v e in n a t u r e . In m o s t o f these e x a m p l e s t h e s c h e d u l e c o n t r o l l i n g t h e time of o c c u r r e n c e is o b s c u r e a n d t h e p r e v i o u s r e i n f o r c e m e n t h i s t o r y o f the individual is u n k n o w n . As a d j u n c t i v e b e h a v i o r seems to arise f r o m a n o n s p e c i f i c increase in m o t o r e x c i t a b i l i t y [41, t h e stimuli effective at t h e m o m e n t are p a r t i c u l a r l y i m p o r t a n t in the f u t u r e d e t e r m i n a t i o n of b e h a v i o r . Drugs w h i c h e n h a n c e the efficacy o f this m e c h a n i s m , such as e t h y l alcohol a n d / , 9 . t e t r a h y d r o c a n n a b i n o l , t h e r e b y result in a f a c i l i t a t i o n of t h e i r s e l f - a d m i n i s t r a t i o n [ 5 ] . In h u m a n and a n i m a l b e h a v i o r sufficient time m u s t elapse b e t w e e n r e i n f o r c e m e n t s and c o n c u r r e n t c o m p e t i n g activities for the a d j u n c t i v e b e h a v i o r to appear. W h e n direct o b s e r v a t i o n of a n i m a l b e h a v i o r is n o t e m p h a s i z e d , t h e b e l i e f t h a t a n a n i m a l does n o t h i n g d u r i n g periods o f so-called low rates of r e s p o n d i n g is a c o m m o n a s s u m p t i o n w h i c h t e n d s to be c o n f i r m e d in b a r r e n test e n v i r o n m e n t s w h e r e a n i m a l s d o n o t have an o p p o r t u n i t y to engage in o t h e r activities. C o n s e q u e n t l y , some i n t e r e s t i n g possibilities have b e e n o v e r l o o k e d in m a n y a n i m a l studies.
In h u m a n s some " . . . I n t e r e s t i n g e x a m p l e s are f o u n d in t h e field of p s y c h o t i c b e h a v i o r , w h e r e the p a t i e n t engages in compulsive or o t h e r i d i o s y n c r a t i c ways o n l y w h e n he is n o t e x e c u t i n g t h e b e h a v i o r u n d e r t h e c o n t r o l of a given s c h e d u l e . " [3, p. 2 7 9 ] . T h e p u r p o s e o f the c u r r e n t research p r o g r a m is to s t u d y t h e e s t a b l i s h m e n t a n d c o n t r o l of a d j u n c t i v e b e h a v i o r in h o s p i t a l p a t i e n t s u n d e r c o n t r o l l e d c o n d i t i o n s . T h e p r e s e n t r e p o r t relates some of the prelimin a r y results o n s c h e d u l e i n d u c e d p o l y d i p s i a and s c h e d u l e i n d u c e d pacing. METHOD
Subjects T w o female a n d five male p a t i e n t s diagnosed as schizop h r e n i c were e m p l o y e d . T h e i r ages were f r o m 1 8 - 4 1 years and l e n g t h o f h o s p i t a l i z a t i o n varied from 1 . 5 - 1 1 years. T w o o f t h e p a t i e n t s , S-14 and S-11, received b i m o n t h l y m a i n t e n a n c e doses of p h e n o t h i a z i n e . T h e p a t i e n t s were o n a prescribed o p e r a n t t o k e n e c o n o m y p r o g r a m a n d were a c c u s t o m e d to a t t e n d i n g sessions.
Procedure T h e e x p e r i m e n t a l c h a m b e r consisted o f a 1.82 x 3.05 x 2.44 m e t e r r o o m w i t h tiled floor and a b l a c k e n e d w i n d o w . S i t u a t e d inside t h e e x p e r i m e n t a l c h a m b e r was a pull cord m a n i p u l a n d u m , a p e n n y dispenser, and a s t a n d a r d d r i n k i n g f o u n t a i n . T h e f o u n t a i n was designed to retain w a t e r n o t c o n s u m e d so t h a t v o l u m e ingested could be calculated. Solid s t a t e p r o g r a m i n g e q u i p m e n t was fixed to a table in an
Reprint requests to: Dr. R. Kachanoff, Douglas Hospital, 6875 LaSalle Boulevard, Montreal 204, Quebec, Canada. 395
396
KACHANOFF, LEVEILLE, MCLELLAND AND WAYNER
o b s e r v a t i o n r o o m outside the e x p e r i m e n t a l c h a m b e r . The d r i n k i n g f o u n t a i n , p e n n y dispenser, and pull cord were arranged so t h a t n u m b e r of pulls, drinks, p e n n i e s p r e s e n t e d and the d u r a t i o n of d r i n k i n g and pacing in s e c o n d s were r e c o r d e d on e l e c t r o n i c c o u n t e r s . Drinks, pulls, and p e n n i e s p r e s e n t e d were r e c o r d e d on a LVE c u m u l a t i v e recorder. A t e c h n i c i a n in the o b s e r v a t i o n r o o m m o n i t o r e d t h e equipm e n t and the p a t i e n t d u r i n g test sessions and r e c o r d e d the n u m b e r of pacing events. A pacing event was defined as a walking m o v e m e n t w h i c h did n o t t e r m i n a t e at the d r i n k i n g f o u n t a i n or p e n n y dispenser. A f t e r t h r e e a d a p t a t i o n sessions in w h i c h p a t i e n t s were i n t r o d u c e d to the e x p e r i m e n t a l r o o m for 30 min w i t h o u t i n s t r u c t i o n s and n o p e n n i e s p r e s e n t e d , t h e y were t h e n told t h a t pulling t h e cord w o u l d enable t h e m to earn p e n n i e s from time to t i m e and t h a t t h e y were n o t to try to leave or talk to the t e c h n i c i a n . T h e y were also i n s t r u c t e d t h a t the t e c h n i c i a n would o p e n the d o o r at the t e r m i n a t i o n of the session. A variety of FI schedules o f r e i n f o r c e m e n t were studied as well as extinction sessions. E x p e r i m e n t a l sessions were c o n d u c t e d daily for 30 min at a fixed time, five days a week. FI schedule intervals were a d j u s t e d in small a s c e n d i n g i n c r e m e n t s
t h r o u g h o u t the course of the e x p e r i m e n t and at times certain FI schedules were r e i n s t a t e d after e x t i n c t i o n sessions. P a t i e n t s were n o t deprived of food or water. RESULTS Of t h e seven p a t i e n t s w h o s t a r t e d , five displayed schedule i n d u c e d pacing. T w o of these five also displayed s c h e d u l e i n d u c e d drinking. One of the p a t i e n t s did n o t display e i t h e r of these behaviors and o n e p a t i e n t was discharged from the h o s p i t a l b e f o r e schedule m a n i p u l a t i o n s were c o m p l e t e d . Schedule i n d u c e d b e h a v i o r was greatest w h e n FI values were varied from FI 30 sec to El 120 sec and generally decreased with values of FI 135 sec to Fl 150 sec. Schedule i n d u c e d b e h a v i o r was m a r k e d l y r e d u c e d d u r i n g e x t i n c t i o n sessions. R e d u c t i o n of adjunctive behavior d u r i n g e x t i n c t i o n was n o t as p r o n o u n c e d w i t h those subjects having a long h i s t o r y in the e x p e r i m e n t a l situation. T h e data o n s c h e d u l e i n d u c e d polydipsia for Subject S-02 are p r e s e n t e d in Figs. 1, 2 and 3. The n u m b e r of drinks for c o n s e c u t i v e test sessions d u r i n g the course of the e x p e r i m e n t are illustrated in Fig. 1 w h e r e the n u m b e r of drinks in each sessions are p r e s e n t e d as a functiQ~ of the
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fixed interval schedule in seconds (FI schedule in seconds) and extinction (E). The amounts of water consumed in g are presented similarly in Fig. 2. The letter B denotes the three days of baseline and the numbers indicate the fixed interval in seconds and the day on which the schedule was changed. An example of an actual cumulative record, the twelfth session FI 45, is illustrated in Fig. 3. The top tracing represents cumulative pulls on the cord. The delivery of each penny is indicated by a hash mark. In the lower tracing drinks are indicated by a downward deflection of the pen. There were 369 pulls, 42 drinks, and the subject earned 23 pennies. Schedule induced pacing in two subjects, S-11 and S-14, is illustrated in Figs. 4 and 5 where the number of paces, solid lines, and the time spent pacing in seconds per session, broken line, are plotted as a function of the fixed interval schedule and during extinction.
DISCUSSION These results demonstrate schedule induced behavior in humans and the feasibility of further studies under laboratory conditions. These subjects were not deprived of food or fluids and indicate that schedule induced human behavior can be controlled by secondary reinforcement. The schedule induced behavior appeared to be schedule dependent with frequent verbalization, jumping, pacing, drinking, and self-directed activities such as grooming occurring during the session. As soon as the session was terminated, these behaviors ceased and the subjects counted their money and left the laboratory. It is interesting that the schedule induced behavior persists to a certain extent during extinction even when the schedule dependent behavior has diminished fully. If psychotic behavior is schedule induced, then resistance to treatment might be
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398
KACHANOFF, LEVEtLLE, MCLELLAND AND WAYNER
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FI SCHEDULE IN SECONDS FIG. 5. Same as Fig. 4 except for Subject S-14. e x p e c t e d . Some h a b i t u a t i o n seems to o c c u r with each s c h e d u l e w h e n r e p e a t e d for several sessions, as illustrated in Figs. 1, 2, 4 and 5, w h i c h is o v e r c o m e w h e n the n e x t s c h e d u l e is i n t r o d u c e d . A similar increase in a d j u n c t i v e b e h a v i o r o c c u r r e d w h e n an FI 45 s c h e d u l e was i n t r o d u c e d following e x t i n c t i o n , as illustrated in Fig. 5. C h a n g i n g the s c h e d u l e is a n o t h e r f o r m of i n t e r m i t t e n c e . These results
also i n d i c a t e t h a t dense schedules o f r e i n f o r c e m e n t s h o u l d be used cautiously in b e h a v i o r m o d i f i c a t i o n t r e a t m e n t programs because of the possibility o f i n a d v e r t e n t develo p m e n t of i n a p p r o p r i a t e behaviors. A l t h o u g h m a n y anecdotal e x a m p l e s could be cited, a clear d e m o n s t r a t i o n of schedule i n d u c e d b e h a v i o r in n o r m a l h u m a n s u n d e r controlled l a b o r a t o r y c o n d i t i o n s r e m a i n s to be d e t e r m i n e d .
REFERENCES 1. Falk, J. L. Conditions producing psychogenic polydipsia in animals. Ann. N. Y. Aead. Sci. 157: 5 6 9 - 5 9 3 , 1969. 2. Falk, J. L. The nature and determinants of adjunctive behavior. Physiol. Behav. 6: 5 7 7 - 5 8 8 , 1971. 3. Skinner, B. F. and W. H. Morse. Concurrent activity under fixed-interval reinforcement. J. comp. physiol. Psychol. 50: 279 281, 1957.
4. Wayner, M. J. Motor control functions of the lateral hypothalamus and adjunctive behavior. Physiol. Behav. 5: 1319-1325, 1970. 5. Wayner, M. J., I. Greenberg, S. Fraley and S. Fisher. Effects of Ag-tetrahydrocannabinol and ethyl alcohol on adjunctive behavior and the lateral hypothalamus. Physiol. Behav. 10: 109 132, 1973.