Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A failure to observe schedule-induced polydipsia during schedules of brain stimulation reinforcement Ramer, Donald Gordon 1975

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1975_A8 R34.pdf [ 3.13MB ]
Metadata
JSON: 831-1.0093419.json
JSON-LD: 831-1.0093419-ld.json
RDF/XML (Pretty): 831-1.0093419-rdf.xml
RDF/JSON: 831-1.0093419-rdf.json
Turtle: 831-1.0093419-turtle.txt
N-Triples: 831-1.0093419-rdf-ntriples.txt
Original Record: 831-1.0093419-source.json
Full Text
831-1.0093419-fulltext.txt
Citation
831-1.0093419.ris

Full Text

A FAILURE TO OBSERVE SCHEDULE-INDUCED POLYDIPSIA DURING SCHEDULES OF BRAIN S TIMULATION REINFO RC EMENT by DONALD GORDON RAKER B.A., U n i v e r s i t y of British»Columbia, 1972 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n the Department of Psychology We accept t h i s t h e s i s as conforming to the requ i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA October, 1975 In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I agre e that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and st u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f '* '.. / <- A . • •' \ -The U n i v e r s i t y o f B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1WS Date '<"/.:''></ / ABSTRACT An attempt was made to observe schedule-induced p o l y d i p s i a i n r a t s whose l e v e r p r e s s i n g was r e i n f o r c e d w i t h e l e c t r i c a l b r a i n s t i m u l a t i o n . Eleven food-deprived, water-sated r a t s drank f r e e l y a v a i l a b l e water e x c e s s i v e l y during sessions i n which Noyes food p e l l e t s were d e l i v e r e d i n t e r m i t t e n t l y . When b r a i n s t i m u l a t i o n r e i n -forcement was s u b s t i t u t e d f o r food reinforcement, d r i n k i n g dropped immediately to near zero. D e l i v e r i n g b r a i n s t i m u l a t i o n according to a v a r i e t y of schedules, p a i r i n g b r a i n s t i m u l a t i o n w i t h food r e i n -forcement, p r o v i d i n g s a c c h a r i n s o l u t i o n i n a d d i t i o n to water, and s u b s t i t u t i n g an a i r stream f o r water each f a i l e d to produce schedule-induced p o l y d i p s i c l i c k i n g during b r a i n s t i m u l a t i o n reinforcement sessions. These r e s u l t s suggest that food i n g e s t i o n i s a necessary stimulus f o r schedule-induced p o l y d i p s i c d r i n k i n g . Theories of schedule-induced p o l y d i p s i a are discussed and evaluated. i i . TABLE OF CONTENTS Page Abs t r a c t ; ' i L i s t of Tables i v L i s t of Figures v. Acknowledgement v i . I n t r o d u c t i o n • 1 Schedule-Induced P o l y d i p s i a 1 Dry Mouth Hypothesis ~ 6 A d v e n t i t i o u s Reinforcement Hypothesis 8 Mediating Behaviour Hypothesis 11 Arousal Hypothesis 12 Post-Reinforcement P e r i o d Aversiveness — 13 Ad j u n c t i v e Behaviour-- 15 Purpose of Present Research 19 General Method- — • • 20 Subjects : 20 Surgery and H i s t o l o g y 21 Apparatus ; 22 Procedure : ; 24 Experiment 1. . 25 Method ; 26 Results and D i s c u s s i o n - ; 27 . Experiment 2.- 33 Method 34 Results and Discussion-^ 35 Experiment 3. r 39 Method : '• 40 Results and D i s c u s s i o n 40 i i i . Experiment 4. 44 Method— '- 44 Results,and D i s c u s s i o n -—-— 45 Experiment 5. : - 48 Method 49 Re s u l t s and D i s c u s s i o n ; 50 General D i s c u s s i o n • 52 Conclusion' References' 59 60 i v . LIST OF TABLES Page Table 1 Summary of Procedure and Results -Experiment 1 28 Table 2 Pearson c o r r e l a t i o n c o e f f i c i e n t s between number of p e l l e t s d e l i v e r e d and volume of water consumed -Experiment 1 —• • 33 Table 3 Summary of Procedure and Results -Experiment 2 36 Table 4 Summary of Procedure and Results -Experiment 3 41 Table 5 Summary of Procedure and Results -Experiment 4 • 46 Table 6 Summary of Procedure and Results -Experiment 5 50 LIST OF FIGURES Page Figure 1 El e c t r o d e s i t e s of animals SI through S l l 23 Figure 2 Water consumption of SI during sessions of ESB and food reinforcement -Experiment 1 30 Figure 3 Mean d a i l y water consumption of S6, S7, and S8 p r i o r to experimentation and during sessions of ESB and food reinforcement -Experiment 1 31 Figure 4 Cumulative recordings of S10 during c o n d i t i o n s of ESB and food reinforcement -Experiment 2 ; 37 Figure 5 Cumulative recordings of S4 and S6 -Experiment 3 • 42 Figure 6 Cumulative recordings of S7 and S9 -Experiment 4 47 Figure 7 Cumulative recordings of S4 and S6 -Experiment 5 ;• 51 ACKNOWLEDGEMENT Many people c o n t r i b u t e d to the f i n a l outcome of t h i s study. S u r g i c a l a s s i s t a n c e was provided by Dick Clouston and Roy Nikaido. Derek Vanderkooy a s s i s t e d w i t h the h i s t o l o g i e s . Tony P h i l l i p s and John P i n e l provided s u r g i c a l s u p p l i e s . Don W l l k i e and Rod Wong generously provided experimental equipment and sound advice. Expert t y p i n g was provided by J a c k i e Whitehorse. The author i s indebted to these people f o r t h e i r help. F i n a l l y , a d d i t i o n a l g r a t i t u d e i s due Don W i l k i e f o r h i s u n r e l e n t i n g support of a l l stages of the study. 1. INTRODUCTION Schedule-Induced P o l y d i p s i a When small food p e l l e t s are d e l i v e r e d i n t e r m i t t e n t l y to food, but otherwise undeprived r a t s , and water i s f r e e l y a v a i l a b l e , a curious phenomenon develops. W i t h i n s e v e r a l d a i l y sessions of a few hours each, the animals w i l l r e l i a b l y and c o n s i s t e n t l y d r i n k a small draught of water f o l l o w i n g the i n g e s t i o n of each p e l l e t . I f a l a r g e number of p e l l e t s i s d e l i v e r e d during a s e s s i o n , the amount of water consumed i s . e x t r a o r d i n a r i l y l a r g e , o f t e n being s e v e r a l times the normal d a i l y i n t a k e . This phenomenon was f i r s t reported by Fa l k i n 1961 and was c a l l e d schedule-induced p o l y d i p s i a (SIP). One reason i t i s described as "schedule-induced" i s to d i s t i n g u i s h i t from other types of p o l y d i p s i a , such as f o o d - d e p r i v a t i o n p o l y d i p s i a i n g e r b i l s (Kutscher, S t i l l m a n , and Weiss, 1968). Since 1961 SIP has a t t r a c t e d a good deal of experimental i n v e s t i g a t i o n . The phenomenon seems worthy of study because of i t s nonadaptive nature. Rats normally consume 25g of food and 36 ml of water each day under ad l i b feeding c o n d i t i o n s ( C o l l i e r and Knarr, 1966). Food d e p r i v a t i o n decreases water i n t a k e ( F a l k , 1964) . F o l l o w i n g 22 hr food d e p r i v a t i o n , r a t s have been observed to in g e s t a 1:1 r a t i o of water to food, and maintain t h i s p r o p o r t i o n i n t h e i r stomach contents during feeding (Lepkovsky, Lyman, Fleming, Nagumo and Dimick, 1957). During c o n d i t i o n s which produce SIP, t h i s r a t i o has been observed to reach 7:1, concurrent w i t h extreme c e l l u l a r t i s s u e overhydration ( S t r i e k e r and A d a i r , 1966). Food-deprived r a t s can s c a r c e l y a f f o r d the energy r e q u i r e d to heat copious amounts of water from ambient temperature to body temperature before e x p e l l i n g i t . F a l k (1972) has f u r t h e r discussed the nonadaptiyeness of an animal d r i n k i n g i t s e l f i n t o a d i l u t i o n a l hyponatremia which borders on water i n t o x i c a t i o n . F a l k considers t h i s a c t i v i t y to be "psychogenic". Many experiments show that SIP occurs under a v a r i e t y of c o n d i t i o n s . P o l y d i p s i c r a t s w i l l d r i n k from any of s e v e r a l d i f f e r e n t water dispensing devices ( F a l k , 1966a.) . The e f f e c t w i l l occur w i t h d i f f e r e n t operant response requirements f o r the food p e l l e t ( F a l k , 1969) , and i n the absense of a s p e c i f i e d operant response, when food p e l l e t s are d e l i v e r e d f r e e l y to the animal (Burks, 1970). F a l k (1969) has observed SIP i n both sexes of d i f f e r e n t s t r a i n s of r a t s . F u r t h e r -more, the e f f e c t i s not confined to the r a t . Schedule-induced p o l y d i p s i a has a l s o been reported i n the rhesus monkey (Schuster and Woods, 1966), chimpanzee ( K e l l e h e r , c i t e d i n F a l k , 1972), and pigeon (Shanab and Peterson, 1969; but see Whalen, 1975). Schedule-induced p o l y d i p s i a i s not simply e l i c i t e d by the i n g e s t i o n of food. The animal must be food deprived f o r the phenomenon to occur. F a l k (1969) found that r a i s i n g a r a t ' s weight from 80 to 95% of normal had l i t t l e e f f e c t on the degree of SIP d r i n k i n g . Above 95%, however, such d r i n k i n g decreased r a p i d l y even though the animal's operant responding f o r food p e l l e t s on a f i x e d -i n t e r v a l (FI) schedule was s c a r c e l y a f f e c t e d . This i n v e r s e r e l a t i o n s h i p between body weight and SIP d r i n k i n g i s p a r t i c u l a r l y i n t e r e s t i n g because food d e p r i v a t i o n normally decreases d r i n k i n g i n the home cage (Falk,1964). Intermittency of food p e l l e t d e l i v e r y i s a l s o an important f a c t o r i n SIP d r i n k i n g . Schedule-induced p o l y d i p s i a does not occur during continuous reinforcement (CRF) schedules ( F a l k , 1966a.) , except when a CRF schedule a l t e r n a t e s w i t h periods of e x t i n c t i o n (Keehn and C o l o t l a , 1971). In t h i s case, d r i n k i n g only occurs at the onset of e x t i n c t i o n (EXT). On i n t e r m i t t e n t schedules, i n t e r - r e i n f o r c e m e n t time (IRT) and amount of SIP d r i n k i n g are r e l a t e d i n a b i t o n i c f a s h i o n . F a l k (1966b_) has observed SIP to increase as the IRT was increased to 150 sec. An IRT of 300 sec, however, produced l e s s SIP. The importance of such schedule parameter c o n s i d e r a t i o n s i n the SIP phenomenon i s another reason f o r the use of the term "schedule-induced". I t has been suggested t h a t - r e i n f o r c e r magnitude a l s o a f f e c t s SIP. D e l i v e r i n g two p e l l e t s r a t h e r than one during both v a r i a b l e -i n t e r v a l (VI) 1-min and VI 2-min schedules g r e a t l y reduced the t o t a l volume of water consumed w i t h i n each s e s s i o n ( F a l k , 1967) . However, Keehn and C o l o t l a (1971) found that d r i n k d urations f o l l o w i n g 1-, 3-, 6-, or 9- p e l l e t meals are e s s e n t i a l l y the same. Only f o l l o w i n g 21-p e l l e t meals d i d the d r i n k d u r a t i o n i n c r e a s e . I f simultaneous d e l i v e r y of two p e l l e t s i n the F a l k experiment can be considered to comprise one meal, then volume consumed f o l l o w i n g each meal was approximately the same. The d i s t i n c t i o n between p e l l e t and meal w i l l be more f u l l y discussed l a t e r . Schedule-induced p o l y d i p s i c d r i n k i n g depends on the type of food used as reinforcement. Noyes 45 mg r a t p e l l e t s produce the l a r g e s t amount of d r i n k i n g . Twenty-two mg p o r t i o n s of l i q u i d monkey d i e t dispensed according to a VI 1-min schedule engender only s l i g h t l y l e s s d r i n k i n g . F o r t y - f i v e mg sucrose and glucose p e l l e t s produce low l e v e l s of d r i n k i n g . L i q u i d M e t r e c a l and p o r t i o n s of 30% sucrose produce even l e s s d r i n k i n g ( F a l k , 1967) . Freed (1971) found that SIP d r i n k i n g was g r e a t l y decreased when sweetened n o n n u t r i t i v e p e l l e t s were s u b s t i t u t e d f o r 45 mg Noyes food p e l l e t s . This suggests a r e l a t i o n s h i p between the n u t r i t i v e value of the food reinforcement and the q u a n t i t y of water consumed. The dependence of SIP upon type of reinforcement w i l l be more f u l l y discussed l a t e r . Experiments concerned w i t h the SIP phenomenon have t y p i c a l l y provided water i n the. experimental space. The q u a n t i t y of l i q u i d consumed has been shown to depend i n part on type of l i q u i d . F a l k (1966c) found that more s a l i n e than water was consumed p o l y -d i p s i c a l l y . V a l e n s t e i n , Cox, and Kakolewski (1967) found that r a t s drank a greater q u a n t i t y of a s o l u t i o n of s a c c h a r i n and glucose than of water. Segal and Deadwyler (1965b) obtained greater consumption of s o l u t i o n s of s a l i n e and s a c c h a r i n , and smaller consumption of q u i n i n e , than water. The excessive consumption of glucose and perhaps s a c c h a r i n may be due i n part to the food-deprived c o n d i t i o n of the animals ( c f . G i l b e r t and Sherman, 1970). Indeed, Keehn, C o l o t l a , and Beaton (1970) found that r a t s drank s a c c h a r i n throughout the IRT i n a d d i t i o n to during the p o s t - p e l l e t p e r i o d as normally occurs during SIP. Schedule-induced p o l y d i p s i a does not occur only when water i s e a s i l y a c c e s s i b l e . Rats have been shown to work, by p r e s s i n g a l e v e r f o r example, i n order to produce access to water f o l l o w i n g p e l l e t d e l i v e r y ( F a l k , 1966a). , Schedule-induced p o l y d i p s i a appears s i m i l a r to normal d r i n k i n g except f o r i t s excessiveness and i t s c l o s e temporal r e l a t i o n to food i n g e s t i o n . While r a t s normally d r i n k approximately 70% of t h e i r t o t a l water i n t a k e c l o s e l y a s s o c i a t e d w i t h food ( F i t z s i m o n s and Le Magnen, 1969) , the r e l i a b l e d r i n k i n g and volume consumed a f t e r each p e l l e t i n SIP s i t u a t i o n s i s absent. The excessive volume of water consumed w i t h i n a short time demands e x p l a n a t i o n . From the research on SIP have evolved s e v e r a l explanatory hypotheses. Each of these w i l l be examined. 6. Dry Mouth Hypothesis Schedule-induced p o l y d i p s i a u s u a l l y occurs during experimental sessions i n which r a t s r e c e i v e dry Noyes food p e l l e t s . S t e i n , i n 1964, suggested what i s perhaps the obvious: r a t s d r i n k i n response to the i n g e s t i o n of dry food. According to t h i s n o t i o n , the r a t d r i n k s to e l i m i n a t e supposedly a v e r s i v e p o s t - p r a n d i a l o r a l e f f e c t s of the i n g e s t i o n of dry food p e l l e t s ( S t r i e k e r and A d a i r , 1966). Thus SIP d r i n k i n g may serve the f u n c t i o n of " g a r g l i n g " f o l l o w i n g the i n g e s t i o n of dry food. Another i n t e r p r e t a t i o n , however, i s that dry food serves simply as a stimulus f o r the i n i t i a t i o n of d r i n k i n g (Teitelbaum and E p s t e i n , 1962) . Support f o r the dry mouth n o t i o n i s provided by s t u d i e s i n which substances other than Noyes p e l l e t s served as r e i n f o r c e r s . S t e i n (1964) f a i l e d to observe SIP when d i l u t e sweetened condensed m i l k was used. S t r i e k e r and Adair (1966) f a i l e d to e i t h e r i n i t i a t e or maintain SIP i n r a t s when vegetable o i l served as reinforcement. In the l a t t e r case vegetable o i l was s u b s t i t u t e d f o r food p e l l e t s f o l l o w i n g - t h e establishment of SIP. F i t z s i m o n s and Le Magnen (1969) found that normal r a t s consume at l e a s t 70% of t h e i r t o t a l d a i l y water requirement w i t h meals. This holds f o r both f r e e feeding or scheduled feeding condi-t i o n s . While normal r a t s eat and d r i n k i n c l e a r l y d i s c e r n i b l e bouts, both recovered l a t e r a l h y p o t h a l a m i c a l l y l e s i o n e d r a t s and n e u r o l o g i c a l l y normal d e s a l i v a t e r a t s d i s p l a y the t y p i c a l p r a n d i a l d r i n k i n g p a t t e r n c h a r a c t e r i s t i c of SIP ( K i s s i l e f f , 1969a.; K i s s i l e f f and E p s t e i n , 1969) . " P r a n d i a l " d r i n k i n g has t y p i c a l l y r e f e r r e d to d r i n k i n g bouts which immediately f o l l o w food i n g e s t i o n and which i n v o l v e consumption of l e s s than 0.5 ml of water. "Normal" d r i n k i n g bouts both precede and f o l l o w food i n g e s t i o n and i n v o l v e consumption of between 0.5 and 2.5 ml of water. Vance (1965) provides a d d i t i o n a l support f o r the dry mouth hypothesis. I f d e s a l i v a t e r a t s e a t i n g dry food are deprived of water, food inta k e f a l l s more p r e c i p i t o u s l y than does food i n t a k e of i n t a c t r a t s which are water deprived. F u r t h e r , the t r a n s i t i o n from normal to p r a n d i a l d r i n k i n g i n the d e s a l i v a t e r a t occurs over s e v e r a l days, s i m i l a r to the i n i t i a t i o n of SIP d r i n k i n g . When the s a l i v a r y flow i s i n t e r r u p t e d i n recovered l a t e r a l r a t s , t h e i r t o t a l water consumption increases i n the absense of a corresponding increase i n food consumption ( K i s s i l e f f and E p s t e i n , 1969). This i n c r e a s e i s due e n t i r e l y to an exaggeration of the p r a n d i a l p a t t e r n of d r i n k i n g t y p i c a l of recovered l a t e r a l r a t s . I f a small amount (0.015 to 0.05 ml) of water i s i n j e c t e d d i r e c t l y i n t o th mouths of e i t h e r recovered l a t e r a l r a t s or n e u r o l o g i c a l l y normal d e s a l -i v a t e r a t s during i n g e s t i o n of a food p e l l e t , p r a n d i a l d r i n k i n g i s a b o l i s h e d . I n j e c t i o n s of s i m i l a r volumes of water d i r e c t l y i n t o the stomachs of these animals produced no s i g n i f i c a n t r e d u c t i o n of p r a n d i a l d r i n k i n g . Water i n t a k e of normal r a t s was p r o p o r t i o n a l l y reduced by i n j e c t i o n s of water v i a e i t h e r route ( K i s s i l e f f , 1969b). These f i n d i n g s s t r o n g l y support the n o t i o n that oropharyngeal s t i m u l i a s s o c i a t e d w i t h the i n g e s t i o n of dry food c o n t r o l p r a n d i a l d r i n k i n g . Normal d r i n k i n g appears to be p a r t i a l l y under the c o n t r o l of these oropharyngeal mechanisms, as food-associated p r a n d i a l d r i n k i n g appears to be one of the major components of normal d r i n k i n g . The dry mouth hypothesis has encountered d i f f i c u l t i e s from s e v e r a l sources. F a l k (1969) notes that r a t s show no performance decrement from beginning of s e s s i o n to end when r e i n f o r c e d w i t h dry food p e l l e t s , d e s p i t e an absense of water i n the experimental space. Thus the apparently a v e r s i v e a f t e r e f f e c t s of dry food are not such that they decrease the r e i n f o r c i n g value of the food. When a CRF schedul i s i n e f f e c t , and water i s co n c u r r e n t l y a v a i l a b l e , l i t t l e p r a n d i a l d r i n k i n g occurs and SIP does not develop ( F a l k , 1966a.). Schedule-induced p o l y d i p s i a has been observed when 22 mg p o r t i o n s of l i q u i d monkey d i e t , o n e - t h i r d water by weight, served as reinforcement ( F a l k , 1967). F a l k (1969) b e l i e v e s that d i l u t e sweetened condensed m i l k and vegetable o i l as used by S t e i n (1964) and S t r i e k e r and Adair (1966) were dispensed i n q u a n t i t i e s too l a r g e to produce SIP. Indeed, F a l k (1967) found that l i q u i d monkey d i e t only produced a high degree of SIP when reinforcement magnitude was s m a l l . A d v e n t i t i o u s Reinforcement Hypothesis Schedule-induced p o l y d i p s i a has a l s o been viewed i n terms of a d v e n t i t i o u s , or s u p e r s t i t i o u s ( c f . Skinner, 1948) reinforcement. C l a r k (1962) suggested that bouts of d r i n k i n g which occurred during short IRTs on a VI schedule were o f t e n followed by r e i n f o r c e d bar presses. Thus an a d v e n t i t i o u s l y r e i n f o r c e d chain c o n s i s t i n g of dr i n k - bar press - food reinforcement could be e s t a b l i s h e d . C l a r k found some evidence f o r t h i s a d v e n t i t i o u s chaining n o t i o n . When the animals were switched to f i x e d - r a t i o (FR) schedules i n which the l i k e -l i h o o d of a response being r e i n f o r c e d was unaffected by d r i n k i n g , SIP d r i n k i n g was g r e a t l y attenuated. When the r a t s were returned to a VI schedule f o l l o w i n g FR, a p a t t e r n of post-reinforcement d r i n k i n g soon redeveloped. Other manipulations have provided some support f o r the con-t e n t i o n that SIP i s an operantly maintained response. When food p e l l e t s are d e l i v e r e d independent of the r a t ' s behaviour, according to e i t h e r f i x e d - t i m e (FT) or variable-time(VT) schedules, p o s t - p e l l e t d r i n k i n g occurs (Segal, 1965; Segal, Oden and Deadwyler, 1965b_; and Mot t i n , 1969). This p a t t e r n takes, s e v e r a l days to develop, suggesting the establishment of an a d v e n t i t i o u s l y r e i n f o r c e d response. When food reinforcement i s w i t h h e l d , the d r i n k i n g undergoes e x t i n c t i o n . I t g r a d u a l l y recovers f o l l o w i n g reinstatement of the o r i g i n a l schedule (Segal, Oden, and Deadwyler, 1965a). F u r t h e r , the number of l i c k s during EXT appears to be r e l a t e d to "the number of l i c k s emitted during " t r a i n i n g " , on a VT schedule ( M o t t i n , 1969). There i s evidence to suggest that SIP i s not e s t a b l i s h e d and 10. maintained a d v e n t i t i o u s l y by reinforcement. Schedule-induced p o l y -d i p s i a i s an extremely s t a b l e and r e l i a b l e phenomenon. S u p e r s t i t i o u s behaviour, on the other hand, has been c h a r a c t e r i z e d by i t s i d e o s y n c r a t i c nature, v a r i a b i l i t y , and i n s t a b i l i t y (Skinner, 1948; but see Staddon and Simmelhag, 1971). A l s o , the chain of responding during SIP s i t u -a t i o n s i s somewhat backwards f o r an a d v e n t i t i o u s e x p l a n a t i o n to h o l d . Should a d v e n t i t i o u s reinforcement maintain SIP, d r i n k i n g should then occur b e f o r e , not Immediately f o l l o w i n g , food p e l l e t d e l i v e r y . Schedule-induced p o l y d i p s i a has been observed i n rhesus monkeys to f o l l o w food reinforcement which was d e l i v e r e d at one hour, and longer, i n t e r v a l s (Schuster and Woods, 1966). To suggest that d r i n k i n g which occurs d u r i n g the pe r i o d of lowest p r o b a b i l i t y of reinforcement i s maintained a d v e n t i t i o u s l y seems to be s t r e t c h i n g the p o i n t . Schedule-induced p o l y d i p s i a has a l s o been observed to occur i n s i t u a t i o n s which punish d r i n k i n g i n c l o s e antecedent p r o x i m i t y to food reinforcement. F a l k (1964) programmed a changeover delay (COD) during a VI 60-sec food reinforcement schedule. The COD prevented d e l i v e r y of a food p e l l e t when scheduled food d e l i v e r y was preceded by a l i c k at the d r i n k i n g spout w i t h i n 15 sec. Despite the f a c t that d r i n k i n g was never immediately r e i n f o r c e d , SIP was e s t a b l i s h e d and maintained. Segal and Oden (1969) extended t h i s f i n d i n g by the i m p o s i t i o n of a 30 and 60 sec COD on a FT 60-sec schedule. This a l s o f a i l e d to prevent SIP. 11. Schedule-induced p o l y d i p s i a has been r e l i a b l y demonstrated during a FR 30 schedule which r e i n f o r c e d every 30th bar press ( F a l k , 1969). In t h i s case, p o s t - p e l l e t d r i n k i n g postponed reinforcement, which occurred only f o l l o w i n g the r e q u i r e d t h i r t y bar press responses. I t i s u n l i k e l y that d r i n k i n g during t h i s c o n d i t i o n could be a d v e n t i t i o u s l y r e i n f o r c e d . The evidence, then, supporting an a d v e n t i t i o u s reinforcement i n t e r p r e t a t i o n of SIP i s tenuous. i Mediating Behaviour Hypothesis. I t has been suggested t h a t SIP occurs to serve as a cue i n timing reinforcement a v a i l a b i l i t y . Segal and Holloway (1963) found that r a t s r e i n f o r c e d w i t h food f o r spacing t h e i r key press responses at l e a s t 20 sec apart (DRL 20-sec schedule) soon engaged i n a p a t t e r n of key press - p e l l e t - d r i n k i n g . Premature responses were not followed by d r i n k i n g , as were r e i n f o r c e d key presses. When d r i n k i n g d i d not occur, responses were seldom s u f f i c i e n t l y separated i n time to be r e i n f o r c e d . Once r a t s had developed SIP under a DRL schedule, removing the water b o t t l e (Deadwyler and Segal, 1965) or r e p l a c i n g i t w i t h an empty b o t t l e (Segal and Oden, 1965) tended to d i s r u p t the DRL performance, thus decreasing the number of p e l l e t s r e c e i v e d . These r e s u l t s suggest that SIP plays an important r o l e i n the mediation, or t i m i n g , of i n t e r -m i t t e n t l y r e i n f o r c e d responding. The n o t i o n that SIP serves only to mediate responding, however, cannot be s e r i o u s l y e n t e r t a i n e d . As F a l k (1969) has pointed s out, that d r i n k i n g can serve a mediating f u n c t i o n does not n e c e s s a r i l y imply that i t i s necessary f o r t h i s f u n c t i o n . Schedule-induced p o l y -d i p s i a occurs on a v a r i e t y of schedules, i n c l u d i n g those f o r which timing would serve no u s e f u l purpose, e.g. VI and r a t i o shedules. Segal and Holloway's experiment confounded food d e l i v e r y w i t h s u c c e s s f u l t i m i n g . These authors' assumption regarding the n e c e s s i t y of d r i n k i n g to time IRTs i s underminded by the observation that d r i n k i n g only followed food p e l l e t d e l i v e r y . A rousal Hypothesis Wayner (1974) has suggested that the d e l i v e r y of a food p e l l e t to a hungry r a t i s an arousing event. On an i n t e r m i t t e n t schedule, food reinforcement i s an unconditioned stimulus which e l i c i t s a s t a t e of excitement or a r o u s a l . Once aroused, the animal w i l l engage i n some a c t i v i t y w i t h a higher than normal frequency. Wayner views t h i s s t a t e of a r o u s a l as being n o n s p e c i f i c ; the animal w i l l engage i n whatever motor a c t i v i t y h i s environment w i l l support. According to t h i s conten-t i o n , one would p r e d i c t that p o s t - p e l l e t motor a c t i v i t i e s are i n t e r -changeable. For example, a r a t could e q u a l l y be expected to engage i n d r i n k i n g , wheel running, a t t a c k , e t c . The l i t e r a t u r e does appear to support t h i s p r e d i c t i o n ( F a l k , 1972) . 13. "Stimulus-bound" behaviours have been shown to bear some s i m i l a r i t y to p o s t - p e l l e t behaviours. When e l e c t r i c a l s t i m u l a t i o n i s s d e l i v e r e d to the l a t e r a l hypothalamus, r a t s w i l l engage i n a v a r i e t y of motor behaviours i n c l u d i n g e a t i n g , d r i n k i n g , s n i f f i n g , and grooming f o r the d u r a t i o n of. the s t i m u l a t i o n . Which behaviour the animal emits i s dep-endent upon s t i m u l i a v a i l a b l e i n the environment ( V a l e n s t e i n , Cox and Kakolewski, 1970) . These i n v e s t i g a t o r s suggest that stimulus-bound behaviour occurs due to the a r o u s a l produced by hypothalamic s t i m u l a t i o n . Post-Reinforcement P e r i o d Aversiveness Schedule-induced p o l y d i p s i a occurs immediately f o l l o w i n g food p e l l e t i n g e s t i o n , during the post-reinforcement p e r i o d . I t i s w e l l known that periods of low p r o b a b i l i t y of reinforcement, which occur immediately post-reinforcement on p e r i o d i c schedules, are a v e r s i v e . During the post-reinforcement p e r i o d pigeons w i l l respond to terminate a stimulus a s s o c i a t e d w i t h a high response requirement FR schedule ( A z r i n , 1961). As w e l l as escape, a t t a c k behaviour can be generated' by these c o n d i t i o n s . F ollowing reinforcement on a FR 50 schedule, when the next reinforc.er i s not immediately a v a i l a b l e , a pigeon w i l l a t t a c k a r e s t r a i n e d pigeon (Gentry, 1968). This phenomenon i s not r e s t r i c t e d to high r a t i o requirements. A z r i n , Hutchinson, and Hake (1966) were able to demonstrate a t t a c k i n a pigeon when EXT was introduced f o l l o w i n g a p e r i o d of CRF. This a t t a c k was only observed f o l l o w i n g food con-sumption. A b r i e f feeder f l a s h was i n s u f f i c i e n t f o r the e l i c i t a t i o n 14. of a t t a c k . Attack has a l s o been produced with v a r i o u s FT schedules i n which food was presented non-contingently ( F l o r y , 1969) . Schedule-induced p o l y d i p s i a and e x t i n c t i o n - i n d u c e d a t t a c k share at l e a s t one common c h a r a c t e r i s t i c . F l o r y (1969) found that a pigeon's a t t a c k i n g of a nearby r e s t r a i n e d pigeon f o l l o w i n g food d e l i v e r y v a r i e d according to the food reinforcement schedule i n e f f e c t . In a s e r i e s of FT schedules, a t t a c k frequency,increased as the schedule d u r a t i o n increased to about FT 60-sec or FT 120-sec, and then decreased as the schedule length continued to i n c r e a s e . This b i t o n i c f u n c t i o n i s s i m i l a r to that observed by F a l k (1966b) , where SIP increased as FT schedules were extended to about 180 sec. A study by Deaux and Kakolewski (1970) provides p h y s i o l o g i c a l evidence to support the n o t i o n that emotionality, which i s i n t u i t i v e l y i m p l i c a t e d i n attack, might al s o play a r o l e i n e l i c i t i n g SIP. Rats i n t h i s study which were stre s s e d by handling or r o t a t i o n showed an increase i n d r i n k i n g con-current w i t h a decrease i n e a t i n g . Stress induced a r a p i d increase i n serum o s m o l a l i t y , which might e x p l a i n the emergence of d r i n k i n g . The aversiveness of the post-reinforcement p e r i o d may a l s o produce an increase i n o s m o l a l i t y , which can be returned to normal by the i n i t i a t i o n of d r i n k i n g . Amphetamine and p e n t o b a r b i t a l are commonly thought to increase and decrease e m o t i o n a l i t y , r e s p e c t i v e l y . F a l k (1964) and Segal, Oden and Deadwyler (1965c), however, have found r a t h e r p a r a d o x i c a l e f f e c t s 15. of these drugs on SIP. Amphetamine, which according to the e m o t i o n a l i t y hypothesis would be expected to increase SIP, i n f a c t does the opposite. The e f f e c t of t h i s drug i s d i f f i c u l t to evaluate, however, because i t a l s o decreases home cage water consumption and normal food d e p r i v a t i o n d r i n k i n g ( F a l k , 1964). P e n t o b a r b i t a l , which i s assumed to decrease e m o t i o n a l i t y , and thus would be expected to decrease SIP, does so by shortening d r i n k d u r a t i o n s . D r i n k i n g s t i l l occurs f o l l o w i n g the i n g e s t i o n of each food p e l l e t . These f i n d i n g s cannot be considered to support an e m o t i o n a l i t y i n t e r p r e t a t i o n of SIP. To use an i l l - d e f i n e d concept such as e m o t i o n a l i t y as an explanation of the SIP phenomenon creates more problems than i t s o l v e s . I t might be more i n s t r u c t i v e to look at phenomena which share p r o p e r t i e s of SIP and post-reinforcement aversiveness. A d j u n c t i v e Behaviour During the post-reinforcement p e r i o d , animals have been shown to engage i n a v a r i e t y of behaviours. Post-reinforcement d r i n k i n g , escape, and a t t a c k have been discussed. S e v e r a l other behaviours a l s o occur during the post-reinforcement p e r i o d on i n t e r m i t t e n t schedules. I f the water spout i s replaced by a d r i n k i n g tube which emits a steady stream of a i r , or a small b u r s t of n i t r o g e n contingent on a l i c k at the tube, the post-reinforcement p e r i o d w i l l be f i l l e d w i t h bouts of l i c k i n g a t the tube (Mendelson and C h i l l a g , 1970; Taylor and L e s t e r , 1969). L i c k i n g i n both these cases resembles SIP water l i c k i n g , except that 16. i t occurs f o r a much longer d u r a t i o n , o f t e n f i l l i n g the e n t i r e IRT. This i s p o s s i b l y due to an apparent l a c k of s a t i a t i o n . Rats r e i n f o r c e d w i t h food on a VI 1-min schedule f o r bar pr e s s i n g e x h i b i t e d much more wheel-running than during CRF or EXT co n d i t i o n s ( L e v i t s k y and C o l l i e r , 1968) . V i l l a r r e a l (1967) found that rhesus monkeys during a FT 15-min schedule of- food reinforcement would chew on wood shavings, which l i n e d the bottom of the chamber, f o l l o w i n g the i n g e s t i o n of the p e l l e t . He c a l l e d t h i s behaviour "schedule-induced p i c a " . These animals would manipulate, chew, and st o r e the wood shavings i n t h e i r cheeks as w e l l as i n g e s t them. This a c t i v i t y resembled SIP i n that i t r a p i d l y d e c l i n e d at shorter IRTs and disappeared during EXT. Some of these schedule-induced a c t i v i t i e s apparently compete or i n t e r f e r e w i t h SIP. Freed and Hymowitz (1969) n o t i c e d that r a t s ' SIP d r i n k i n g became d i s r u p t e d when the animals s t a r t e d chewing on the c e l l u l o s e m a t e r i a l l i n i n g the bottom t r a y . When t h i s e a s i l y manipulable m a t e r i a l was removed, SIP was immediately r e - e s t a b l i s h e d . V i l l a r r e a l (19.67) found that h i s rhesus monkeys e i t h e r p r e f e r r e d to d r i n k during the post-reinforcement p e r i o d , or a l t e r n a t e d between d r i n k i n g and chewing wood shavings. Segal (1969) reported s i m i l a r r e s u l t s w i t h r a t s . When both a d r i n k i n g tube and a wheel were a v a i l a b l e , post-reinforcement d r i n k i n g was the most frequent response. When the water spout was removed, wheel running increased i n frequency. I t appears from these s t u d i e s that a number of other behaviours 17. may be s u b s t i t u t e d f o r SIP. These a c t i v i t i e s share s i m i l a r temporal p a t t e r n s , and may be considered excessive when compared to b a s e l i n e . r a t e s . The s i m i l a r i t i e s shared by these post-reinforcement behaviours have given r i s e to the c u r r e n t l y most prevalent conception of SIP. As a l l of these behaviours can be construed as adjuncts to the reinforcement schedule, they can be considered to belong to a c l a s s c a l l e d a d j u n c t i v e behaviour ( F a l k , 1969, 1971, 1972). F a l k makes a compelling argument f o r the u t i l i t y of regarding SIP as an a d j u n c t i v e behaviour. There are indeed many correspondences among these post-reinforcement, or schedule-induced, behaviours. For example, a l l these a c t i v i t i e s occur during the p e r i o d immediately p o s t - p e l l e t , when, w i t h the exception of CRF, p r o b a b i l i t y of reinforcement i s lowest. I t must be noted that SIP and other a d j u n c t i v e behaviours, do not occur during CRF. As F a l k p o i n t s out, SIP i s c o n t r o l l e d e i t h e r by the recency of p e l l e t d e l i v e r y , or the p e r i o d of lowest p r o b a b i l i t y of reinforcement, or both. There i s c u r r e n t l y i n s u f f i c i e n t evidence to make a d e f i n i t i v e statement regarding t h i s d i s t i n c t i o n . According to F a l k , " . . . a d j u n c t i v e behaviour i s behaviour maintained at high p r o b a b i l i t y by s t i m u l i whose r e i n f o r c i n g p r o p e r t i e s i n the s i t u a t i o n are derived p r i m a r i l y as a f u n c t i o n of schedule parameters governing the a v a i l a b i l i t y of another c l a s s of r e i n f o r c e r s . " ( F a l k , 1972, p. 172). Water thus gains i t s a b i l i t y to r e i n f o r c e d r i n k i n g by v i r t u e of the c o n c u r r e n t l y a v a i l a b l e food reinforcement schedule. 18. F a l k suggests that a behaviour which has been c l a s s i f i e d as a d j u n c t i v e must d i s p l a y c e r t a i n c h a r a c t e r i s t i c s . The frequency of the response which occurs during the IRT must increase to an excessive l e v e l , at which i t remains s t a b l e , during repeated p r e s e n t a t i o n of the r e i n f o r c i n g s t i m u l u s . This stimulus must not act as a conditioned or unconditioned stimulus which e l i c i t s the response, nor must i t r e i n f o r c e that response. The s t r e n g t h of the behaviour should be a b i t o n i c f u n c t i o n of the r a t e of p r e s e n t a t i o n of the r e i n f o r c i n g s t i m u l u s . F i n a l l y , the behaviour should occur w i t h highest p r o b a b i l i t y immediately f o l l o w i n g p r e s e n t a t i o n of the r e i n f o r c i n g s t i m u l u s . With respect to SIP, p o s t - p e l l e t d r i n k i n g increases at a steady r a t e to a s t a b l e asymptotic l e v e l . . This d r i n k i n g i s not under d i r e c t c o n t r o l of the contingencies maintaining bar pr e s s i n g f o r food, but ra t h e r i s i n d i r e c t l y c o n t r o l l e d by the v a r i a b l e s a s s o c i a t e d w i t h bar pr e s s i n g and i n g e s t i o n of food. F a l k r e l i e d h e a v i l y on the e t h o l o g i c a l a n a l y s i s of displacement behaviour (Tinbergen, 1952) i n the fo r m u l a t i o n of h i s d e f i n i t i o n . Displacement a c t i v i t y occurs when an ongoing s p e c i e s - s p e c i f i c , g o a l -d i r e c t e d behaviour p a t t e r n i s i n t e r r u p t e d . For example, black-headed g u l l s have been observed to s t a r t nest b u i l d i n g when t h e i r brooding behaviour i s i n t e r r u p t e d (Moynihan, 1953). I n t e r r u p t i n g , or thwarting,-an ongoing g o a l - d i r e c t e d behaviour p a t t e r n occurs when the s t i m u l i necessary to maintain that behaviour are removed. In the SIP s i t u a t i o n , 19. r a t s engaged i n a high r a t e of consummatory (eating) behaviour are thwarted i n t h i s a c t i v i t y due to the i n t e r m i t t e n c y of the reinforcement schedule. Their consummatory behaviour thus becomes d i s p l a c e d . ; D r i n k i n g serves as a convenient displacement because i t contains some of the elements of e a t i n g . Bar p r e s s i n g f o r food, one of the elements of consummatory behaviour, engages the animal i n a high r a t e of motor behaviour. When t h i s behaviour i s i n t e r r u p t e d , the animal's motor behaviour might be d i s p l a c e d to wheel running, or any other conveniently a v a i l a b l e a c t i v i t y i n v o l v i n g elements of motor or consummatory behaviour. The " e x p l a n a t i o n " of SIP as an a d j u n c t i v e behaviour i s c u r r e n t l y the most popular hypothesis. Purpose of Present Research I f SIP i s an a d j u n c t i v e behaviour, i t must meet a l l of the c o n d i t i o n s which F a l k considers c h a r a c t e r i s t i c of a d j u n c t i v e behaviour. I n t e r c h a n g e a b i l i t y of both a d j u n c t i v e behaviours and r e i n f o r c i n g s t i m u l i seems to be an i n t e g r a l part of the a d j u n c t i v e hypothesis. The hypothesis would presumably p r e d i c t that any r e i n f o r c i n g stimulus which maintains a high frequency of consummatory, or g o a l - d i r e c t e d , operant behaviour would, once removed, r e s u l t i n the production of a d j u n c t i v e behaviour. Past research has y i e l d e d both successes and f a i l u r e s i n demonstrating SIP w i t h d i f f e r e n t substances s e r v i n g as reinforcement. Falk (1969) suggests that these d i s c r e p a n c i e s have occurred because of a f a i l u r e to observe a l l the c r i t e r i a necessary to produce a d j u n c t i v e behaviour. For example, the IRT must be s u f f i c i e n t l y l o n g , the substance 20. must be s u f f i c i e n t l y r e i n f o r c i n g , the animal must be h i g h l y motivated, and so on. The present study employed e l e c t r i c a l s t i m u l a t i o n of the b r a i n (ESB) as the r e i n f o r c i n g s t i m u l u s . I f SIP can be c l a s s i f i e d as an a d j u n c t i v e behaviour according to F a l k ' s c r i t e r i a , i t should occur f o l l o w i n g i n t e r m i t t e n t p r e s e n t a t i o n of ESB. E l e c t r i c a l s t i m u l a t i o n of the b r a i n has been shown to maintain a high r a t e of operant behaviour (Olds and M i l n e r , 1954) and w i l l r e l i a b l y maintain scheduled responding ( P l i s k o f f , Wright, and Kawkins, 1965). In a d d i t i o n , Hoebel (1968) has shown that such p o s t i n g e s t i o n a l events as g a s t r i c d i s t e n t i o n , increased blood-sugar l e v e l , and c e l l u l a r o s m o l a l i t y , both when they occur normally and when they are experimentally induced, i n t e r a c t w i t h r a t e s of l a t e r a l hypothalamic s e l f - s t i m u l a t i o n . Hoebel has demonstrated s t r i k i n g correspondences between l a t e r a l hypothalamic a c t i v i t y and feeding. F u r t h e r , V a l e n s t e i n _et a l . (1970) have r e l i a b l y demonstrated that ESB d e l i v e r e d independent of the.animal's behaviour w i l l produce a v a r i e t y of consummatory behaviours, when the app r o p r i a t e s t i m u l i are present. GENERAL METHOD Subj ects Two Wistar a l b i n o r a t s (SI and S2) obtained from Woodlyn Breeding L a b o r a t o r i e s , Guelph, Ontario, and nine b l a c k hooded r a t s 21. (S3 through S l l ) obtained from Canadian Breeding L a b o r a t o r i e s , La P r a i r i e , Quebec, served as s u b j e c t s . A l l animals were males weighing between 300 and 350 g at time of surgery. Surgery and H i s t o l o g y The animals were anesthetized w i t h sodium p e n t o b a r b i t a l (Nembutal, 50 mg/kg) i n j e c t e d i n t r a p e r i t o n e a l l y . Each animal was c h r o n i c a l l y implanted w i t h a P l a s t i c Products b i p o l a r s t i m u l a t i n g 0.25 mm e l e c t r o d e aimed at .the medial f o r e b r a i n bundle at the l a t e r a l hypothalamus. The coordinates f o r i m p l a n t a t i o n were 2 mm p o s t e r i o r to Bregma, 1.8 mm l a t e r a l to the s a g i t t a l suture, and 8.6 mm v e n t r a l to the dura. E l e c t r o d e s were held i n place w i t h a c r y l i c cemented to machine screws imbedded i n the s k u l l . The el e c t r o d e s protruded from the a c r y l i c s u f f i c i e n t l y to allow p o s i t i v e connection to a P l a s t i c Products l e a d . F o l l o w i n g surgery a l l animals were i n j e c t e d i n t r a m u s c u l a r l y w i t h 0.2 ml p e n i c i l l i n , and allowed at l e a s t one week to recover p r i o r to experimentation. F o l l o w i n g t e r m i n a t i o n of the experiment, animals were s a c r i f i c e d by means of carbon d i o x i d e . Their b r a i n s were f i x e d i n formal s a l i n e , and then f r o z e n . Forty-u_ t h i c k s e c t i o n s were cut and s t a i n e d w i t h t h i o n i n . H i s t o l o g i c a l i n s p e c t i o n v e r i f i e d that the el e c t r o d e s had been implanted throughout the medial f o r e b r a i n bundle i n 10 of the animals. Rat S3's electrode was located in a more posterior section within the substantia nigra. Fig. 1 illustrates these placements according to the stereotaxic coordinate system used by Pellegrino and Cushman (1967). Apparatus Two experimental chambers were used in these experiments. Chamber 1 was constructed 3 sides of metal and one of plexiglass and measured 25 cm x 25 cm x 38 cm high. A Scientific Prototype lever was centrally mounted on one metal wall, 6 cm from the.grid floor. A ball-type drinking spout protruded 1 cm through a 1.5 cm diameter hole to the l e f t of the lever, 3 cm from the floor. A food cup connected to a food dispenser was mounted to food dispenser was mounted to the right of the lever, 3 cm from the grid floor. This apparatus was enclosed within a ventilated, lighted, sound-attenuating chamber. A 21 cm x 27 cm x 40 cm high plywood chamber served as Chamber 2. A lever, food cup, and drinking spout were similarly mounted on one wall of this chamber. An additional hole through which a second drinking spout could protrude was made between the f i r s t hole and the wall. This hole was covered when not in use. Chamber 2 was also enclosed within a ventilated sound-attenuating box, and illuminated. El e c t r i c a l stimulation of the brain was delivered from a 60 Hz sine wave stimulator. A commutator which connected the leads from the power source to the stimulating electrodes allowed the animals unrestrained movement within the experimental space. Experimental 23. Figure 1:. Electode sites of. animals SI through S l l . Drawings were taken from Pellegrino and Cushman (1967). 24. c o n d i t i o n s were programmed and data c o l l e c t e d by BRS/LVE s o l i d s t a t e and electromechanical c i r c u i t s . Procedure F o l l o w i n g food d e p r i v a t i o n to 80% of t h e i r f r e e - f e e d i n g weight, a l l animals were screened f o r s e l f - s t i m u l a t i o n . Only those animals that r e l i a b l y bar pressed f o r ESB reinforcement were employed i n these experiments. Current l e v e l s were set at 10 uA above the l e v e l which would maintain responding on a CRF schedule. This l e v e l was maintained f o r the d u r a t i o n of the experiment. During i n i t i a l bar press t r a i n i n g , ESB was d e l i v e r e d f o r 0.25 sec contingent on each response. Once bar pr e s s i n g was r e l i a b l y e s t a b l i s h e d , ESB reinforcement i n Chamber 1 c o n s i s t e d of f i v e e q u a l l y spaced pulses each of 0.25 sec d u r a t i o n , covering a t o t a l p e riod of 2.5 sec. Animals t e s t e d i n Chamber 2 r e c e i v e d 2.5 sec continuous current at scheduled reinforcement p e r i o d s . Except as noted reinforcement was always contingent upon a bar press response. I n i t i a l l y each response produced one ESB reinforcement. Over the f i r s t two or three sessions the schedule parameters were changed g r a d u a l l y u n t i l ESB reinforcement was d e l i v e r e d according to the appropriate i n t e r m i t t e n t schedule. F o l l o w i n g bar press t r a i n i n g f o r ESB reinforcement, a l l animals were t r a i n e d to bar press f o r 45 mg Noyes food p e l l e t s . T r a i n i n g proceeded i n a s i m i l a r manner as w i t h ESB reinforcement. A l l experimental s e s s i o n s , except f o r designated exceptions, 25. were of 90 min duration. Animals received sessions an average of s i x days per week, at about the same time each day. Each animal was fed Purina rat chow following each experimental session so as to maintain the r a t at 80% weight. Water was continuously available i n the home cage. Home cage water consumption was monitored on a d a i l y basis. EXPERIMENT 1 Schedule-induced polydipsia has been reported to have occurred during ESB reinforcement schedules (Atrens, 1973; Wayner, Greenberg, Fraley, and Fisher, 1973). " Atrens observed post-ESB drinking i n two rats , and consumption of wet mash i n three others. The SIP, however, ceased after several sessions. Wayner et^ ^ 1. were able to maintain SIP, though at a greatly reduced rate, i n one of four rats switched to ESB following food reinforcement. These results were not replicated by Cohen and Mendelson (1974), who observed rats to drink excessively following food, but not ESB, reinforcement on several simultaneous VI schedules. In this experiment, rats had the opportunity to work for both food and ESB reinforcers, delivered according to various VI schedules. Although animals received both food and ESB within each session, drinking occurred only following food reinforcement. The Cohen and Mendelson experiment compared SIP following food and ESB on a within-subject basis. I t i s possible, however, that rats did not drink following ESB reinforcement because of the large volume consumed i n association with food. Although these animals did 26. not d r i n k immediately post-ESB, they d i d engage i n d r i n k i n g during each s e s s i o n . The present experiment sought to determine whether r a t s d r i n k during sessions of ESB reinforcement i n the absence of food. Both food and ESB served as r e i n f o r c e r s i n successive b l o c k s of s e s s i o n s , i n order to compare t h e i r e f f e c t s on SIP w i t h i n each animal. Reinforcement schedules other than those used by Cohen and Mendelson, which a l s o have been shown to produce a high degree of SIP ( c f . F a l k , 1969), were employed. Method Subjects and Apparatus Rats SI through S8 were t e s t e d i n Chamber 1. Procedure The procedure i s summarized i n Table 1. Conditions are l i s t e d i n the sequence i n which they occurred. Values of the schedule of r e i n -forcement are given i n sec. For example, DRL 20 i n d i c a t e s that a response was r e i n f o r c e d only i f i t occurred at l e a s t 20 sec f o l l o w i n g the previous response. On FI schedules the f i r s t response to occur f o l l o w i n g the r e q u i r e d i n t e r v a l produced reinforcement, e.g. FI 90 means that the f i r s t response to occur 90 sec f o l l o w i n g the previous reinforcement was r e i n f o r c e d . On VI schedules responses produced reinforcement according to the average designated v a l u e , e.g. a VI 30 schedule provided, on the average, 2 reinforcements per min. 27. Throughout a l l segments of the experiment, bar press responses, number of reinforcements (food and ESB), and water consumed were recorded. Results and D i s c u s s i o n The f i n a l three columns of Table 1, "Responses", " R e i n f o r c e -ments", and "Water Consumed", summarize data from the l a s t f i v e sessions w i t h i n each c o n d i t i o n . Where only f i v e sessions occurred w i t h i n a c o n d i t i o n , data from a l l the sessions are i n c l u d e d . S i m i l a r l y , only data from the s i n g l e s e s s i o n are included when c o n d i t i o n s were a l t e r n a t e d d a i l y . Both ESB and food reinforcement r e l i a b l y maintained responding i n a l l animals throughout the experiment. Food reinforcement g e n e r a l l y maintained a higher response r a t e , but t h i s was not a c o n s i s t e n t trend w i t h each animal. When food p e l l e t s served as reinforcement, SIP t y p i c a l l y • o c c u r r e d . Only a minimal amount of d r i n k i n g occurred during sessions i n which ESB reinforcement was d e l i v e r e d . U s u a l l y there was no measurable water consumption during t h i s c o n d i t i o n . At most, 4 ml of water were consumed w i t h i n one ESB s e s s i o n , w h i l e water consumption approached and even exceeded 60 ml during 90 min food s e s s i o n s . F i g . 2 g r a p h i c a l l y i l l u s t r a t e s these l a r g e d i f f e r e n c e s of water consumption during food and ESB reinforcement c o n d i t i o n s . These data are from SI and correspond to the f i v e sessions of ESB and f i v e sessions of food reinforcement followed by d a i l y a l t e r n a t i o n of these c o n d i t i o n s , as depicted by Table 1. 28. TABLE 1 Summary of Procedure and Results - Experiment 1 Subject Schedule Reinforcer Number of Sessions Number of Responses Mean(Range) Number of Reinforcements Mean(Range) Volume of Water (ml) Mean(Range) SI DRL 20 VI 30 FI 80 FI 160 ESB . 15 453(438-471) 26(28-36) 0.0 Food 10 393(370-420) 142(126-157) 58.8(56-64) ESB 5 459(336-538) 54(41-66) 0.0 Food 5 404(i00-538) 120(100-139) 41.2(24-50) ESB 1 434 81 0.0 Food 1 363 150 46.0 ESB 1 352 90 0.0 Food 1 513 137 60.0 ESB 1 406 49 0.0 Food 1 555 140 62.0 ESB 10* 352(317-383) 74(55-89) 0.4(0-1) ESB 7 1714(1306-2342) 186(177-199) 0.0 Food 7 2240(1915-2575) 180 47.2(41-55) ESB 7 1653(1047-2752) 182(180-188) 0.2(0-1) ESB ; 5 1114(945-1398) 67(67-68) 0.0 Food ; 5 1340(1022-1683) 69(69-70) 37.3(35-39) ESB 5 1244(1100-1407) 69 0.0 ESB 5** 1321(1027-1433) 46 0.0 Food 5** 1965(1765-2227) 46(46-47) 24.9(21-31) S2 DRL 20 S3 VI 30 FI 80 FI 160 DRL 20 Food 15 480(465-510) 50(23-72) 10.5(6-17) ESB 10 629(571-696) 36(32-43) 0.0 Food 5 486(453-519) 36(26-41) 8.0(6-10) ESB 5 412(382-470) 56(33-71) 0.0 Food 1 435 62 11.5 ESB 1 345 87 0.0 Food 1 405 73 15.0 ESB 1 297 122 0.0 Food 1 423 97 13.0 ESB lv. 417 48 0.0 ESB 10* 194(147-254) 116(91-142) 0.7(0-2) ESB 7* 219(191-275) 124(110-138) 0.0 Food 7 2052(1789-2349) 180 22.6(20-25 ESB 7 1187(595-1814) 178(171-180) 0.2(0-1) ESB 5 1115(1019-1189) 69(68-69) 0.5(0-2) Food 5 1636(1414-1849) 70(69-70) 9.7(6-14) ESB 5 1362(1235-1509) 69 0.2(0-1) ESB 5** 1438(1303-1677) 46(46-47) 0.0. Food 5** 1994(1286-2328) 46 5.4(2-8) ESB 10 238(148-291) 129(102-145) 0.9(0-2) Food 10 290(211-326) 104(96-126) 11.1(5-16) S4 DRL 20 DRL 30 DRL 40 Food ESB Food ESB Food ESB 10 10 10 10 10 10 342(301-371) 330(283-352) 254(228-275) 230(208-253) 194(181-214) 194(163-243) 146(138-152) 94(84-121) 63(50-74) 67(61-75) 41(35-51) 47(25-62) 30.3(29-32) 1.9(1-3) 16.9(15-20) 0.6(0-1) 8.5(4-14) 0.1(0-1) Continued TABLE 1 - Continued Number of Number of Volume of Number of Responses Reinforcements Water (ml) Subject Schedule Reinforcer Sessions Mean(Range) Mean(Range) Mean(Range) S5 S6 S7 FI 30 ESB 10 916(749-1088) 175(166-193) 1.5(0-3) 90 Food 10 1684(1275-2185) 168(163-171) 24.0(20-29) FI ESB 10 698(577-804) 59(56-60) 0.7(0-2) FI 30 - Food 10 1420(1180-1871) 60(60-62) 6.4(5-8) ESB 10 1274(1061-1402) 173(171-174) 1.2(1-2) Food 10 2153(1982-2300) 174(160-180) 16.7(15-18) FI 30 Food 10 1078(950-1189) 181(178-185) 40.4(36-45) FI 90 ESB 10 714(581-862) 175(170-180) 2.5(0-4) Food 10 1614(1325-1845) 62(61-63) 29.0(28-30) 150 ESB 10 578(423-698) 60 1.8(0-3) FI Food 10 1600(1327-1799) 38(36-39) 22.3(19-26) ESB 10 601(514-668) 37(36-38) 2.6(1-4) FI 210 Food 10 1760(1591-1905) 27(26-27) 16.1(15-17) ESB 10 433(397-465) 25(24-26) 0.3(0-1) FI 30 ESB 10 512(436-560) 172(167-179) 0.0 Food 10 2315(1623-2693) 188(183-192) 32.4(30-34) FI 90 ESB 10 558(441-676) 64(63-65) 0.0 150 Food 10 2675(2512-2900) 64(62-68) 21.3(20-22) FI ESB 10 491(438-530) 37(35-39) 0.0 Food 10 2335(2186-2563) 38(36-39) 8.5(7-12) FI 30 ESB 10 1923(1747-2144) 184(158-193) 0.0 90 Food 10 1473(1193-1655) 184(182-186) 32.5(29-34) FI ESB 10 1473(1141-1665) 63(60-67) 0.0 150 Food . 10 2000(1818-2116) 65(62-67) 23.3(20-25) FI ESB 10 1634(1419-1838) 37(36-38) 0.2(0-1) Food 10 1448(1377-1538) 37(36-38) 20.3(19-21) * 100% body weight ** 2 hr sessions 30. F O O D <y —' 1 1 1 i I I I I I 4 7 10 13 SESSIONS Figure 2: Water consumption of SI during sessions of ESB and food reinforcement. 31. C o CL £ D 05 C O O CD -t—< 50r 40 30 20 10 M L 6 7 8 Pre -Exp 6 7 8 E S B 6 7 8 6 7 8 6 7 8 120/hr 40/hr 24/hr Food Pel le ts Figure 3: Mean d a i l y water consumption of S6, S7, and S8 p r i o r to e x p e r i -mentation (Pre-Exp) and during sessions of ESB and food r e i n f o r c e -ment. The l a s t three groups of columns represent mean d a i l y water consumption during FI 30-sec, 90-sec, and 150-sec reinforcement schedules, r e s p e c t i v e l y . The shaded areas represent s e s s i o n water consumption. 32. Animals SI and S2 were run for several ESB sessions at 100% weight. Consistent with sessions at 80% weight, very l i t t l e drinking occurred. ' Figure 3 shows a comparison of drinking by three animals under several conditions. Total daily water consumption before experimentation differed l i t t l e from daily consumption when ESB reinforcement sessions occurred. This contrasts with total consumption on days in which food reinforcement sessions occurred. The differences within the last three groups of columns in Fig. 3 suggest that an inverse relationship exists between home cage consumption and experimental session consumption. This relationship has also been described by Falk (1969). Also, the differences of session consumption among these three groups of columns indicates that volume of water consumed may depend on number of pellets delivered. Most of the session water consumption occurred during FI 30-sec food sessions, which delivered 120 pellets per hour. Similarly, least session consumption occurred during delivery of 24 pellets per hour. Lotter, Woods, and Vasselli (1973) found that SIP water consumption and number of pellets delivered were highly correlated (r = 0.953), when data from a number of studies were analyzed. Table 2 shows individual subject Pearson correlation coefficients between the number of pellets delivered and volume of water consumed in the present experiment. These coefficients are based on the last five sessions within each condition. TABLE 2 Pearson correlation coefficients between number of pellets delivered and volume of water consumed, for each animal. Subject r SI 0.74 S2 0.92 S3 0.73 S4 0.96 S5 0.85 S6 0.92 S7 :. 0.91 S8 0.95 Water consumption during experimental sessions, then, is highly related to the number of pellets delivered to the animal. It is apparent from this experiment that SIP does not occur following ESB delivered at least with the present parameters. One might think that, once established, some degree of SIP would be maintained during the f i r s t session of ESB reinforcement after food reinforcement.. This did not happen. EXPERIMENT 2 The effects of p a l a t i b i l i t y on SIP have been well documented. Post-pellet drinking increases when the solutions consist of saccharin 34. and sucrose (Gilbert and Sherman, 1970), saccharin and glucose (Valenstein, Cox, and Kakolewski, 1967), saccharin and saline (Segal and Deadwyler, 1965b_) , saline and water (Strieker and Adair, 1966), and saccharin and water (Keehn, Colotla, and Beaton, 1970). As far as is known, none of these solutions previously has been made available to rats on a schedule of ESB reinforcement. Experiment 2 sought to determine whether rats would drink a solution more palatable than water following ESB reinforcement. For this purpose, the subjects were provided with simultaneous access to water and a water-saccharin solution both in the home cage and in the experimental chamber. Method Subjects and Apparatus Two naive animals, S10 and S l l were employed in this experi-ment. These animals were tested in Chamber 2. Two drinking spouts, one containing water and the other a 0.9% solution of sodium saccharin and water protruded through the two openings in Chamber 2. The l e f t -right position of the spouts was randomly alternated on a daily basis. Bar press responses, reinforcement delivery, and licks detected by a drinkometer circuit connected between the brass grid floor and the saccharin solution drinking spout were recorded by a Gerbrands cumulative recorder. The drinkometer circuit was electrically isolated from the ESB circ u i t by a series of relays. 35 Procedure Both animals were exposed to the sequence of c o n d i t i o n s depicted by Table 3. Rat S l l ' s e l e c t r o d e assembly became loose before a r e t u r n to the f i n a l ESB c o n d i t i o n could be made. A FI 90-sec schedule was i n e f f e c t throughout t h i s experiment. Food or ESB was d e l i v e r e d during each c o n d i t i o n according to the parameters described i n the General Method. During the EXT c o n d i t i o n reinforcement was w i t h h e l d . Both animals were provided w i t h f r e e access i n the home cage to one d r i n k i n g spout c o n t a i n i n g water and another c o n t a i n i n g a 0.9% sa c c h a r i n s o l u t i o n . D a i l y consumption from both spouts was recorded. Results and D i s c u s s i o n Data from the l a s t f i v e sessions w i t h i n each c o n d i t i o n are summarized i n Table 3. Rat S10 responded more f r e q u e n t l y f o r food, w h i l e S l l responded e q u a l l y o f t e n f o r both r e i n f o r c e r s . Very l i t t l e water was consumed by e i t h e r animal, both i n the home cage and during experimental s e s s i o n s . Both animals drank s a c c h a r i n s o l u t i o n during a l l c o n d i t i o n s . Least of the s o l u t i o n was consumed during EXT (S10). While both animals consumed a l a r g e amount of sa c c h a r i n s o l u t i o n during ESB , the food c o n d i t i o n engendered the great e s t consumption. The temporal d i s t r i b u t i o n of bar press responses, reinforcements, and l i c k s at the s a c c h a r i n spout i s i l l u s t r a t e d i n F i g . 4 . These cumulative recordings were taken from the f i r s t hour of r e p r e s e n t a t i v e sessions of S10. TABLE 3 Summary of Procedure and Results - Experiment 2 S10 S l l Relnforcer ESB Food EXT ESB ESB Food EXT Number of Sessions 10 10 10 10 10 10 10 Number of Responses  Mean(Range) 908(768-994) 1418(1295-1710) 46(35-69) 966(757-1207) 1721(1627-1888) 1619(1547-1965) 20(3-45) Number of Reinforcements  Mean(Range) 65(63-67) 63(63-64) 0 63(60-64) 64(62-66) 66(64-68) 0 Experimental Session Volume of Volume of Water (ml)  Mean(Range) 0.0 0.0 0.2(0-1) 0.2(0-1) 0.2(0-1) 0.0 0.2(0-1) Saccharin(ml)  Mean(Range) 19.9(16-27) 36.2(31-40) 6.0(5-7) 18.2(16-20) 20.0(9-28) 75.1(68-85) 26.4(24-31) Volume of Water(ml)  Mean(Range 5.8(1-10) 3.2(2-4) 1.8(1-2) 3.0(2-5) 2.4(1-4) 4.6(1-9) 2.2(2-3) Home Cage Volume of Saccharin(ml) Mean(Range) 102.6(81-123) 87.2(71-106) 86.0(73-98) 73.5(62-100) 190.2(182-215) 227.6(187-255) 218.2(150-261) ESB FOOD 9 0 s e c Figure 4: Cumulative recordings•of S10 during conditions of ESB and food reinforcement. Each bar press response stepped the pen upwards. The pen was reset at reinforcement delivery. Every eighth l i c k is represented by a downward , deflection of the pen. 38. Cursory i n s p e c t i o n of these data suggest that SIP was e s t a b l i s h e d w i t h ESB reinforcement. This c o n c l u s i o n would be wrong on two accounts. F i r s t , an examination of the top h a l f of F i g . 4 i n d i c a t e s that d r i n k i n g occurred i n t e r m i t t e n t l y throughout the IRT w i t h i n t h i s ESB s e s s i o n . This p a t t e r n d i f f e r s from that of normal SIP which occurs only w i t h i n the post-reinforcement i n t e r v a l . Second, home cage s a c c h a r i n consumption by S10 was i n the range of 80 to 150 ml per day. Rat S l l drank even more s a c c h a r i n i n the home cage. Table 3 shows that home cage saccharin'consumption f a r exceeded d r i n k i n g during experimental s e s s i o n s . While S10 drank more during ESB than during EXT, S l l d i d not. The lower h a l f of F i g . 4 c l e a r l y shows both the t y p i c a l post-p e l l e t p a t t e r n of SIP and instances of d r i n k i n g at times other than during t h i s p e r i o d , during the food reinforcement c o n d i t i o n . This a d d i t i o n a l IRT d r i n k i n g lends support to the p o i n t made by Keehn, C o l o t l a , and Beaton (1970) regarding p a l a t a b i l i t y s t i m u l a t i n g d r i n k i n g i n a d d i t i o n to that which i s schedule induced. Despite the occurrence of some d r i n k i n g during ESB s e s s i o n s , these data must be construed as a f a i l u r e to demonstrate SIP w i t h s a c c h a r i n s o l u t i o n during a schedule of ESB reinforcement. 39. EXPERIMENT 3 Several reports have suggested that SIP drinking occurs after a stimulus which has been paired with food. Rosenblith (1970) found that rats slowly acquired SIP after conditioned reinforcement. In this study, every t h i r d FI terminated i n food p e l l e t delivery. A feeder c l i c k and l i g h t f l a s h , which accompanied food p e l l e t delivery on every t h i r d i n t e r v a l , terminated the other two FIs. A si m i l a r study by Porter and Kenshalo (1974) found drinking to occur i n rhesus monkeys following conditioned reinforcement. During EXT after a DRL 30-sec schedule, two of three rats drank more following a feeder c l i c k which occurred contingent upon a successfully spaced response than during similar periods i n the absence of a feeder c l i c k (Segal and Deadwyler, 1965a.) . However, a recent study f a i l e d to re p l i c a t e this phenomenon. A l l e n , Porter, and Arazie (1975) f a i l e d to observe drinking i n f i v e of s i x rats following a b r i e f l i g h t f l a s h and c l i c k which had been associated with p e l l e t delivery. Conditioned reinforcement procedures can be used to determine which aspect of food p e l l e t delivery i s important for the occurrence and maintenance of SIP. Food pe l l e t s act as reinforcers, often signal periods of lowered reinforcement p r o b a b i l i t y , e l i c i t various consumatory a c t i v i t i e s such as s n i f f i n g , chewing, and swallowing, and possess sensory q u a l i t i e s such as taste and texture. Conditioned reinforcers possess only these f i r s t two att r i b u t e s , thus allowing a comparison with the l a t t e r characteristics to be made. 4 0 . Experiment 3 was an attempt to produce SIP after ESB using the conditioned reinforcement procedure of pairing ESB with food reinforcement. Method Subjects and Apparatus Rats S4 and S6 of Experiment 1 served as subjects for the present experiment. They were tested i n Chamber 1. Procedure Both animals i n i t i a l l y received ten sessions of paired ESB and food reinforcement, followed by f i v e sessions of ESB reinforcement. During the f i r s t condition, a food p e l l e t and ESB of the parameters described i n the General Method were concurrently delivered contingent on the reinforced bar press. Since i t took a portion of a second for the animal to reach the p e l l e t , ESB onset actually preceded ingestion of the food p e l l e t . Both animals were f i n a l l y returned to the o r i g i n a l condition, S4 having f i r s t received an additional ten sessions of food reinforcement alone. A FI 90-sec schedule of reinforcement was i n effect throughout the experiment. Results and Discussion The data from the l a s t f i v e sessions of each condition are summarized i n Table 4. Food and ESB, as w e l l as food alone, r e l i a b l y TABLE 4 Summary of Procedure and Results - Experiment 3 Number of Subject Reinforcer Sessions Number of Responses Mean(Range) Number of Reinforcements Mean(Range) Number of Licks  Mean(Range) Volume of Water (ml) Mean(Range) S4 Food + ESB ESB Food Food + ESB 10 5 10 10 1060(889-1261) 650(519-777) 924(819-1052) 848(685-1049) 62(59-66) 57(54-60) 60(60-61) 60(58-63) 9102(8663-10465) 208(6-366) 6487(5491-7006) 6878(5940-7852) 18.9(16-20) 0.6(0-1) 13.5(12-15) 16.4(15-18) S6 Food + ESB ESB Food + ESB 10 5 5 1846(1521-2196) 60(60-61) 645(387-982) 59(58-60) 2098(1915-2294) 62(60-65) 7859(7620-8157) 69(15-174) 7066(6771-7803) 25.4(22-28) 0.5(0-1) 25.1(23-26) 42. S4 F O O D - + E S B E S B F O O D cc o o F O O D + E S B F O O D + E S B S 6 E S B F O O D + E S B 9 0 s e c Figure 5: Cumulative recordings of S4 and S6. See Figure 4 for additional' description. 43. produced excessive d r i n k i n g which was c o n s i s t e n t across s e s s i o n s . When food reinforcement was removed, d r i n k i n g was immediately and g r e a t l y reduced. This r e d u c t i o n was apparent i n both the volume of water consumed and i n the number of l i c k s . S l i g h t l y more water was consumed by one animal when ESB was p a i r e d w i t h food than when food alone was d e l i v e r e d . A cumulative record from a food and ESB s e s s i o n and an ESB alone s e s s i o n i s shown i n F i g . 5. These data were taken from the middle p o r t i o n of a s e s s i o n w i t h i n each c o n d i t i o n , and are r e p r e s e n t a t i v e . While the magnitude of responding g e n e r a l l y d i f f e r e d f o r the food and ESB and ESB alone c o n d i t i o n s , the response d i s t r i b u t i o n was s i m i l a r i n both cases to t y p i c a l FI performance. D r i n k i n g occurred almost e n t i r e l y during the per i o d immediately post-reinforcement, w i t h i n c o n d i t i o n s i n which food p e l l e t s were d e l i v e r e d . There was seldom any d r i n k i n g during the ESB c o n d i t i o n . These r e s u l t s agree w i t h those reported by A l l e n et a l . (1975). Should SIP simply be a f u n c t i o n of the r e i n f o r c i n g and d i s c r i m i n a t i v e p r o p e r t i e s of food reinforcement ( i . e . be schedule-induced) , i t should have occurred i n the present experiment as w e l l as i n the f i r s t two experiments. The r e s u l t s of these experiments suggest that food i s a necessary c o n d i t i o n f o r the occurrence of SIP. More s p e c i f i c a l l y , i t appears that some sensory-consumatory aspect of food i s important i n producing SIP. EXPERIMENT 4 Related to the phenomenon of post-reinforcement d r i n k i n g i s that of p o s t - p e l l e t a i r l i c k i n g ( F a l k , 1971). I t i s p o s s i b l e that SIP d r i n k i n g would occur f o l l o w i n g ESB reinforcement were i t not f o r the extreme h y d r a t i o n which occurs i n the absense of food consumption. The present experiment provided r a t s w i t h an opportunity to engage i n a post-reinforcement a c t i v i t y which circumvents t h i s problem. Rats have p r e v i o u s l y demonstrated both a i r - (Mendelson and C h i l l a g , 1970) and n i t r o g e n - l i c k i n g (Taylor and L e s t e r , 1969) f o l l o w i n g d e l i v e r y of food p e l l e t s . This a c t i v i t y occurred at a much higher r a t e than water d r i n k i n g , p o s s i b l y due to l a c k of s a t i a t i o n . Method Subj ects Three animals (S5, S6, S7) that had r e l i a b l y demonstrated food-associated SIP i n previous experiments, and one experimentally naive animal (S9) completed the experiment. Apparatus Chamber 2 served as the experimental space. The d r i n k i n g spout was connected to a r e g u l a t e d supply of compressed a i r . During experimental sessions a i r was c o n s t a n t l y d e l i v e r e d to the spout at a 2 pressure of approximately 1.03-2.07 N/cm . V 45. Procedure A FI 90-sec schedule was in effect for the duration of this experiment. Although three of the four subjects had previously acquired SIP, none of the animals air licked during the f i r s t few sessions with food reinforcement. Consequently the animals were water deprived for 23 hr prior to each session. Following three such sessions during which air licking occurred at a high rate, water was again made freely available in the home cage, and the regular experimental regime ensued. This procedure had to be repeated two or three times before a l l animals would reliably l i c k during the food condition. An additional four animals, some of which were employed in previous SIP experiments, failed to continue air licking after a return to free access to water and were excluded from the experiment. Table 5 summarizes the sequence of conditions of food and ESB alternation. As in the previous experiments, number of bar press responses, reinforcements, and licks at the drinking spout were recorded. Results and Discussion Data were collected from the last five sessions within each condition and summarized in Table 5. Air licking occurred at a high rate during food reinforcement sessions. Licking was almost completely eliminated during ESB reinforcement sessions. These results are consistent 46. TABLE 5 Summary of Procedure and Results - Experiment 4 Number of Number of Number of Number of Responses Reinforcements L i c k s Subject R e i n f o r c e r Sessions Mean(Range) Mean(Range) Mean(Range) 55 Food 10 ESB K) Food 5 56 Food 10 ESB 10 Food 5 57 Food 10 ESB 10 Food 5 S9 Food 10 ESB 10 Food 5 1100(813-1362) 60(59 1122(1078-1135) 62(62 1328(963-1789) 62(60 2179(1634-3078) 61(53 1182(1062-1308) 59(54 2644(2340-2935) 62(60 2257(1716-2710) 60(58 458(414-502) 60(60 1716(1619-1930) 61(60 1225(1167-1322) 63(60 516(466-614) 50(44 1265(1023-1469 61(53 62) 8374(4203-13013) 62) 9(1-14) 66) 5800(1972-8562) 67) 7289(3497-14623) 62) 2(0-6) 66) 6676(4062-13884) 60) 14228(12950-15510) 61) 10(4-16) 63) 10977(3102-15880) 65) 3489(2190-4804) 55) 79(6-341) 67) 6576(4005-8589) both w i t h i n each animal and across sessions w i t h i n each c o n d i t i o n . F i g . 6 i l l u s t r a t e s r e p r e s e n t a t i v e r e s u l t s from two of the animals. Each cumulative recording from S9 was taken from the middle of the f i n a l day of each c o n d i t i o n . The top r e c o r d i n g f o r S7 was taken from the beginning of day nine. The ESB re c o r d i n g f o r S7 was made during the f i r s t day w i t h i n t h i s c o n d i t i o n , as was the t h i r d r e c o r d i n g , which i l l u s t r a t e s a r e t u r n to a i r l i c k i n g f o l l o w i n g reinstatement of the food reinforcement c o n d i t i o n . 47. S 7 F O O D E S B F O O D w DC O O E S B 9 0 s e c Figure 6: Cumulative recordings of S7 and S9. Additional description,is provided in Figure 4. 48. Close examination of these recordings reveals several interesting points. For example, S7, which showed the highest rate of licking, licked after most, but not a l l , pellets. This licking ' occurred for longer durations than SIP water licking and recurred throughout the IRT. The ESB record of this animal indicates no recorded licking. Returning to food reinforcement resulted in a gradual return to air licking which was maintained once reestablished. Rat S9's records, while indicative of the discrepancy of air licking between food and ESB conditions, i l l u s t r a t e the long latency of i n i t i a t i o n of air licking following pellet delivery. Usually several bar press responses interpolated between reinforcement and air licking. This pattern was generally consistent with the other animals. EXPERIMENT 5 The failure of the previous experiments to reliably demonstrate SIP or schedule-induced air licking following ESB reinforcement may be either directly or indirectly attributable to the chronically implanted stimulating electrodes. Falk (1964) has shown that small hypothalamic lesions have a marked attenuating effect on SIP. However, the within-subject comparisons of the present study preclude this possibility from preventing the establishment of ESB-associated SIP. Another possibility exists, however. Valenstein, Cox and Kakolewski (1970) found that rather long (10 sec or more) trains of hypothalamic stimulation, which produced various "stimulus-bound" behaviours r e s u l t e d i n a decrease i n normal d e p r i v a t i o n - e l i c i t e d food and water consumption f o l l o w i n g s t i m u l a t i o n . This suppressive e f f e c t was r e f e r r e d to as "post-stimulus i n h i b i t i o n " . I t i s u n l i k e l y that post-stimulus i n h i b i t i o n occurred i n animals i n the present experiments. The s t i m u l a t i o n d u r a t i o n was much s h o r t e r than that used by V a l e n s t e i n et a l . A l s o , the simultaneous p r e s e n t a t i o n of food and ESB i n Experiment 3 d i d not appear to attenuate post-reinforcement d r i n k i n g . I f anything, t h i s m a n i p u l a t i o n p o t e n t i a t e d SIP. Experiment 5 was' designed to f u r t h e r determine whether ESB acted i n any way to prevent the occurrence of SIP. D e p r i v a t i o n -produced d r i n k i n g served as the response measure. Method Subjects Rats S4, 5, 6, 7, 8, and 10 were water deprived f o r 22 hr preceding each experimental s e s s i o n . Rat S10 was a l s o deprived of s a c c h a r i n , normally a v a i l a b l e i n the home cage, f o r the same length of time. Apparatus Subjects were test e d i n Chamber 1 or 2 as i n d i c a t e d i n Table 6. The l e v e r was removed from both chambers. I t s space was covered by a metal p l a t e . TABLE 6 Summary of Procedure and Results - Experiment 5 Subject Chamber ESB Schedule Measure Volume No ESB/ESB Number of . Licks No ESB/ESB S4 1 FT 90 Water 10.3/12.5 2209/1889 S5 1 FT 30 Water 14.7/16.5 435/449 S6 1 FT 90 Water 14.0/16.5 1976/2354 S7 2 FT 90 A i r - 4611/4311 S8 2 FT 90 Water 15.0/14.3 2387/2534 S10 2 FT 90 Saccharin 16.8/16.8 1511/2658 Procedure Each animal was connected to the stimulator and put i n the experimental chamber for 15 min. During the f i r s t three daily sessions the animals received no ESB. Stimulation was noncontingently delivered during the next three sessions according to the schedule as described i n Table 6. Water, saccharin, or a i r was available during these s i x sessions. Volume, where appropriate, and number of l i c k s were measured. Results and Discussion Table 6 indicates the volume consumed and number of l i c k s of water, saccharin, and a i r , averaged across the f i r s t three (No ESB) and 51. FIGURE 7: Cumulative recordings of S4 and S6. Each l i c k stepped the recording pen upwards. Downward d e f l e c t i o n s of the pen represent ESB d e l i v e r y . 52. the l a s t three (ESB) sessions. I t i s apparent that stimulation produced only minor disruption of drinking. This i s true for a l l three of the measures employed. Fig. 7 further i l l u s t r a t e s this point. These' ; recordings are representative of 15 min periods of FT 90-sec ESB delivered to S4 and S6. These cumulative recordings provide examples of instances where stimulation was delivered at the beginning, the end, and the middle of a bout of l i c k i n g . Post-stimulus i n h i b i t i o n does not appear to be operating here. I t i s int e r e s t i n g to note the discrepancy between number of l i c k s and volume, both here and i n previous experiments. This may be due to i n s e n s i t i v i t y of the drinkometer device, or to the v a r i a b i l i t y inherent i n l i c k i n g . Volume, then, would serve as a more r e l i a b l e measure of drinking. GENERAL DISCUSSION These experiments have confirmed and extended a previous f a i l u r e to produce SIP with schedules of ESB reinforcement. Cohen and Mendelson (1974) found drinking to occur following food, but not ESB, reinforcement when these reinforcers were available on various VI schedules within the same session. The present study found si m i l a r results when food and ESB reinforcement were available during successive sessions, not simultaneously as i n the Cohen and Meldelson experiment. 53. The present study also employed d i f f e r e n t reinforcement schedules complementing Cohen and Mendelson's conclusion that SIP i s not simply schedule-induced. In the present attempt to produce SIP with ESB reinforcement, a v a r i e t y of schedules, including those which maximize p o s t - p e l l e t drinking, was used. The animals were also provided with a s o l u t i o n more palatable than water. E l e c t r i c a l stimulation of the b r a i n was paired with food p e l l e t d e l i v e r y . An opportunity to l i c k a i r , which precludes s a t i a t i o n and i s highly re l a t e d to SIP water drinking, was provided. None of these manipulations resulted i n the occurrence of schedule-induced l i c k i n g i n a s s o c i a t i o n with ESB reinforcement. F a i l u r e to observe SIP cannot be a t t r i b u t e d to post-ESB i n h i b i t i o n of drinking (Valenstein et a l . , 1970). This was c l e a r l y demonstrated i n Experiments 3 and 5. I t has also been suggested that the l o c a t i o n of the water spout r e l a t i v e to the food cup i s an important consideration (e.g. A l l e n , Porter, and Arazie, 1975). For example, the water spout i n the Porter and Kenshalo (1974) study, which reported SIP i n rhesus monkeys during conditioned reinforcement, was located d i r e c t l y above the food hopper. I t i s possible that animals pause to drink on the way back from the food cup to the l e v e r . However, rats i n the present study developed SIP following food reinforcement despite the water spout's inconvenient l o c a t i o n r e l a t i v e to the food cup. Further, the f a i l u r e to obtain SIP cannot be a t t r i b u t e d to the f a c t that ESB was not r e i n f o r c i n g 54. or intermittently presented. Nor does i t appear that ESB and food differed greatly in reinforcing value as both maintained an approximately equal rate of operant responding. It is also unlikely that SIP failed 1 to occur due to specificity of neural stimulation. As is indicated by Fig. 1, electrode placements were located generally throughout the medial forebrain bundle. Stimulation at a placement outside this area also failed to produce SIP. Since ESB and food share reinforcing and discriminative functions, i t appears that SIP is due to some other aspect of food reinforcers. The sensory-consummatory response differences are the most obvious. The present results f a i l to corroborate those reported by Atrens (1973) and Wayner et a l . (1973). These investigators, however, did not as has been claimed, unequivocably demonstrate SIP. Atrens reported drinking following ESB reinforcement delivered according to a FI 120-sec schedule in one animal and a VI 60-sec shedule in another. In both cases, however, drinking showed a marked decrement with repeated testing over days. Food deprivation and increasing and decreasing both the IRT and the number of ESB reinforcers per session failed to prevent this drinking from ceasing. Wayner et a l . observed post-ESB drinking to occur intermittently in one of four rats, at a magnitude well below that which occurred with food reinforcement. This rat drank more during ESB reinforcement sessions than during EXT. However, drinking during ESB sessions occurred in a few long bursts, atypical of the normal pattern 55. o f p o s t - p e l l e t S I P . T h e p r e s e n t f a i l u r e t o f i n d S I P w i t h ESB r e i n f o r c e m e n t s u g g e s t s t h a t s e v e r a l o f t h e m a j o r h y p o t h e s e s o f S I P a r e u n t e n a b l e . 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 i s u n l i k e l y a n a d v e n t i t i o u s l y r e i n f o r c e d r e s p o n s e . B o t h f o o d a n d ESB p r e s u m a b l y h a v e t h e c a p a c i t y t o s u p e r s t i t i o u s l y r e i n f o r c e l i c k i n g . H o w e v e r , t h i s n e v e r o c c u r r e d , e v e n o n a s h o r t V I s c h e d u l e . N o r was a n y e v i d e n c e f o u n d t h a t t h e S I P o b s e r v e d w i t h f o o d r e i n f o r c e m e n t w a s d u e t o t h i s s o r t o f p r o c e s s . F u r t h e r , r a t s i n t h e p r e s e n t s t u d y w e r e n e v e r o b s e r v e d t o u s e l i c k i n g t o m e d i a t e DRL r e s p o n d i n g , d u r i n g f o o d o r ESB s e s s i o n s . P o s t - r e i n f o r c e m e n t a v e r s i v e n e s s , o r t h e a r o u s a l o r e m o t i o n a l i t y w h i c h h a s b e e n a s s u m e d t o o c c u r f o l l o w i n g r e m o v a l o f t h e r e i n f o r c i n g s t i m u l u s , s u r e l y m u s t b e a s s u m e d t o o c c u r f o l l o w i n g ESB a s w e l l a s f o o d . R a t s i n t h e p r e s e n t s t u d y n e v e r p l a c a t e d t h i s e m o t i o n a l i t y b y l i c k i n g , n o r w e r e t h e y a r o u s e d t o d r i n k d u r i n g t h e p o s t -ESB p e r i o d . The c u r r e n t l y m o s t p o p u l a r a c c o u n t o f S I P , w h i c h c o n s i d e r s i t t o b e a member o f a c l a s s c a l l e d a d j u n c t i v e b e h a v i o u r , c a n n o t b e s u p p o r t e d b y t h e s e d a t a . F a l k ( 1 9 7 1 , 1 9 7 2 ) c o n s i d e r s a d j u n c t i v e b e h a v i o u r t o b e p r o d u c e d b y t h e r e i n f o r c e m e n t s h e d u l e . The r e i n f o r c i n g s t i m u l u s , a s w e l l a s c o n s t i t u t i n g a n i m p o r t a n t c o m p o n e n t o f c o n s u m m a t o r y a c t i v i t y , a l s o s i g n a l s a n i n t e r r u p t i o n i n t h i s a c t i v i t y . T h e a n i m a l i s t h u s p r e d i s p o s e d t o " d i s p l a c e " h i s c o n s u m m a t o r y b e h a v i o u r . A c c o r d i n g t o F a l k , s u c h d i s p l a c e m e n t i s a d a p t i v e t o t h e a n i m a l s i n c e i t a l l o w s t h e o p p o r t u n i t y 56. to acquire other reinforcers from the environment when food is not available. This displacement process encompasses a number of possible ac t i v i t i e s , .one of which is drinking. The consistent failure to establish post-reinforcement water, saccharin, or air licking following ESB reinforcement strongly suggests that SIP is a function of other factors in addition to schedule variables. Thus, at present, there seems to be no obvious way to predict from the adjunctive concept whether the intermittent delivery of a reinforcer w i l l produce a schedule-induced response such as SIP drinking. Since at least certain adjunctive behaviours do not occur with a l l reinforcers, the adjunctive concept needs to be revised to regain predictive a b i l i t y . Otherwise, "adjunctive" w i l l simply be a label for the occurrence of certain post-reinforcement behaviours. A survey of the literature suggests that SIP occurs only during food deprivation, and only when small amounts of food of one sort or another are presented intermittently. Forty-five mg Noyes food pellets produce the largest degree of SIP, followed closely by small portions of liquid monkey diet. Other substances, such as sucrose and glucose pellets, liquid sucrose, and vegetable o i l produce l i t t l e or no SIP (Falk, 1969) . Stein (1964) f i r s t suggested that dry food acts as a stimulus to i n i t i a t e drinking. However, i t is unlikely that liquid monkey diet, one-third water by weight, produces a dry mouth. Sucrose and glucose pellets are both dry substances, yet neither produce SIP. Drinking following liquid food and Stein's notion may be reconciled since i t is possible that drinking occurs following liquid and dry foods for different reasons. Different liquids, for example, may leave aversive oral aftereffects which are attenuated by drinking. One aversive aftereffect of eating dry foods might be oral dryness. It is possible that different food substances, such as sucrose and glucose pellets, either do not produce oral dryness as presumably do Noyes rat pellets, or they leave more pleasant oral aftereffects. At present, however, l i t t l e is known of these p o s s i b i l i t i e s . Rats have most often served as subjects in SIP studies. It is known that rats normally drink 70% of their total daily water intake in close association with the ingestion of food (Fitzsimons and Le Magnen, 1969). Even when rats are prevented by rearing techniques from ingesting food and water in close temporal proximity, SIP occurs (Hymowitz and Koronakos, 1968). This would suggest a strong predis-position for rats to consume food and water together. Food is not the only cue to drinking (cf. Falk, 1961), but in "unnatural" experimental situations rats may rely heavily on this cue (cf. K i s s i l e f f , 1969; Ki s s i l e f f and Epstein, 1969). To add support to this contention, drinking has been shown to depend more upon the number of "bites" than on bite size (Lotter, Woods, and Vasselli, 1973; Reynierse, 1966). One bite consists of one uninterrupted bout of eating. Rats typically consume a small draught of water following each bite, which is usually larger than a 45 mg food pellet. When bite size and frequency are determined 58. experimentally by intermittently delivering food pellets, drinking changes accordingly. Keehn and Colotla (1971) found that drink durations were essentially the same when a series of 1, 3, 6, or 9 pellets were delivered one immediately after the other at the end of various fixed interval schedules. Rats in this study drank only following the last pellet in the series, and then only a normal SIP amount. The notion that volume of water consumed is related to number of bites, or meals, is strongly supported by the high positive correlations between volume consumed and number of 45 mg pellets delivered per session, reported by Lotter, Woods, and Vasselli (1973) and by the present study. There i s evidence to suggest that SIP occurs in response to food ingestion only in species with a predisposition to eat and drink in temporal proximity. Whalen (1975) failed to observe polydipsia in pigeons. These animals typically meet their daily water requirements in two or three large draughts. It seems reasonable to assume that pigeons would be less l i k e l y than rats to u t i l i z e food ingestion as a cue to i n i t i a t e drinking. Whalen's results are also inconsistent with a l l SIP theories except that of Stein. CONCLUSION The greater than normal post-reinforcement drinking that has been called schedule-induced polydipsia appears to occur in rats only when certain reinforcers such as Noyes food pellets are intermit-tently delivered. Rats appear to eat food in several bites or meals and to drink a certain amount after each bite. Osmotic cues have been suggested to play a role in the initation of drinking. If food is delivered periodically in quantities less than the normal bite size the rat s t i l l drinks after each bite. The results, i f a sufficient number of small bites occur, is a large, sometimes excessive, volume of water intake. No reference to superstitions, mediations, states of emotionality or arousal, post-reinforcement aversiveness, or adjunctive behaviour induced by reinforcement schedules appears necessary. 60. REFERENCES A l l e n , J.D., P o r t e r , J.H., and A r a z i e , R. Schedule-Induced D r i n k i n g as a Function of Percentage Reinforcement. J o u r n a l of the  Experimental A n a l y s i s of Behavior, 1975, 23, 223-232. Atrens, D.M. Schedule-Induced P o l y d i p s i a and Polyphagia i n Nondeprived Rats Reinforced by I n t r a c r a n i a l S t i m u l a t i o n . Learning  and M o t i v a t i o n , 1973, _4, 320-326. A z r i n , N.H. Time-Out from P o s i t i v e Reinforcement. Science, 1961, 133, 382-383. A z r i n , N.H., Hutchinson, R.R., and Hake, D.F. Extinction-Induced Aggression. J o u r n a l of the Experimental A n a l y s i s of  Behavior, 1966, 9_, 191-204. Burks, CD. Schedule-Induced P o l y d i p s i a : Are Response-Dependent Schedules a L i m i t i n g Condition? J o u r n a l of the Experimental  A n a l y s i s of Behavior, 1970, 13, 351-358. Cl a r k , F.C. Some Observations on the A d v e n t i t i o u s Reinforcement of D r i n k i n g Under Food Reinforcement. J o u r n a l of the  Experimental A n a l y s i s of Behavior, 1962, 5, 61-63. Cohen, I.L. and Mendelson, J . Schedule-Induced D r i n k i n g With Food, But Not ICS, Reinforcement. B e h a v i o r a l B i o l o g y , 1974, 12, 21-29. C o l l i e r , G. and K n a r r , F. Defense of Water Balance i n the Rat. J o u r n a l of Comparative and P h y s i o l o g i c a l Psychology, 1966, 61, 5-10. Deadwyler, S.A. and Segal, E.F. Determinants of P o l y d i p s i a : V I I . Removing the D r i n k i n g S o l u t i o n Midway Through DRL Sessions. Psychonomic Science, 1965, _3, 185-186. Deaux, E. and Kakolewski, J.W. Emotionally Induced Increases i n E f f e c t i v e Osmotic Pressure and Subsequent T h i r s t . Science, 1970, 169, 1226-1228. Falk,. J.L. Production of P o l y d i p s i a i n Normal Rats by an I n t e r m i t t e n t Food Schedule. Science, 1961, 133, 195-196. F a l k , J.L. Studies on Schedule-Induced P o l y d i p s i a . In M.J. Wayner (Ed.), T h i r s t : F i r s t I n t e r n a t i o n a l Symposium on T h i r s t  i n the Regulation of Body Water. New York: Pergamon Press, 1964. Falk, J.L. Falk, J.L. Falk, J.L. Falk, J.L. Falk, J.L. Falk, J.L. Falk, J.L. The Motivational Properties of Schedule-Induced Polydipsia. Journal of the Experimental Analysis of  Behavior, 1966, j>> 19-25. (a) Schedule-Induced Polydipsia as a Function of Fixed Interval Length. Journal of the Experimental Analysis of  Behavior, 1966, 9_, 37-39. (b) Analysis of Water and NaCl Solution Acceptance by Schedule-Induced Polydipsia. Journal of the Experimental Analysis  of Behavior, 1966, J , 111-118. (c) Control of Schedule-Induced Polydipsia: Type, Size, and Spacing of Meals. Journal of the Experimental Analysis  of Behavior, 1967, 10. 199-206. Conditions Producing Psychogenic Polydipsia in Animals. Annals of the New York Academy of Sciences, 1969, 157, 569-593. The Nature and Determinants of Adjunctive Behavior. Physiology and Behavior, 1971, _6, 577-588. The Nature and Determinants of Adjunctive Behavior. In R.M. Gilbert and J.D. Keehn (Eds.) , Schedule Effects: Drugs, Drinking, and Aggression. Toronto: University ,of Toronto Press, 1972. Fitzsimons, T.J. and Le Magnen, J. Eating as a Regulatory Control of Drinking in the Rat. Journal of Comparative and  Physiological Psychology, 1969, 67_, 273-283. Flory, R.K. Attack Behavior as a Function of Minimum Inter-Food Interval. Journal of the Experimental Analysis of Behavior, 1969 , 12, 825-828. Freed, E.X. Schedule-Induced Polydipsia with Nutritive and Non-Nutritive Reinforcers. Psychonomic Science, 1971, 23, 367-368. Freed, E.X. and Hymowitz, N. A Fortuitous Observation Regarding "Psychogenic" Polydipsia. Psychological Reports, 1969, 24, 224-226. Gentry, W.D. Fixed-Ratio Schedule-Induced Aggression. Journal of the  Experimental Analysis of Behavior, 1968, ]_1, 813-817. Gilbert, R.M. and Sherman, I.P. Palatibility-Induced Polydipsia: Saccharin, Sucrose, and Water Intake in Rats, With and Without Food Deprivation. Psychological Reports, 1970, 27_, 319-325. Hoebel, B.G. In h i b i t i o n and D i s i n h i b i t i o n of Self-Stimulation and Feeding: Hypothalamic Control and Postingestional Factors. Journal of Comparative and Physiological Psychology," 1968, 66. 89-100. Keehn, J.D. and Colotla, V.A. Stimulus and Subject Control of Schedule-Induced Drinking. Journal of the Experimental  Analysis of Behavior, 1971, 16, 257-262. Keehn, J.D., Colotla, V.A., and Beaton, J.M. P a l a t i b i l i t y as a Factor i n the Duration and Pattern of Schedule-Induced Drinking. Psychological Record, 1970, 20, 433-442. K i s s i l e f f , H.R. Food-Associated Drinking i n the Rat. Journal of  Comparative and Physiological Psychology, 1969 , 67, 284-300. (a) K i s s i l e f f , H.R. Oropharyngeal Control of Prandial Drinking. Journal  of Comparative and Physiological Psychology, 1969, 67, . 309-319. (b) K i s s i l e f f , H.R. and Epstein, A.N. Exaggerated Prandial Drinking i n the "Recovered La t e r a l " Rat without Saliva. Journal of  Comparative and Physiological Psychology, 1969, 67_, 301-308. Kutscher, C.L., Stillman, R.D., and Weiss, I.P. Food-Deprivation Polydipsia i n Gerbils. Physiology and Behavior, 1968, 3_,' 667-671. Lepkovsky, S., Lyman, R., Fleming, D., Nagumo, M., and Dimick, M.M. Gastrointestinal Regulation of Water and i t s Effect on Food Intake. American Journal of Physiology, 1957, 188, 327-331. Levitsky, D. and C o l l i e r , G. Schedule-Induced Wheel Running. Physiology and Behavior, 1968, _3> 571-573. Lotter, E.C., Woods, S.C., and V a s s e l l i , J.R. Schedule-Induced Polydipsia: An A r t i f a c t . Journal of Comparative and  Physiological Psychology, 1973, 83, 478-484. Mendelson, J. and C h i l l a g , D. Schedule-Induced A i r Licking i n Rats. Physiology and Behavior, 1970, 5., 535-537. Mottin, J.L. Schedule-Induced Polydipsia: A P a r t i a l Reinforcement Effect. Psychonomic Science, 1969, 15_, 26. Moynihan, M. Some Displacement A c t i v i t i e s of the Black-Headed G u l l . Behaviour, 1953, J5, 58-80. 63. Olds, J . and M i l n e r , P. P o s t i v e Reinforcement Produced by E l e c t r i c a l S t i m u l a t i o n of Septal Area and Other Regions of Rat B r a i n . J o u r n a l of Comparative and P h y s i o l o g i c a l Psychology, 1954, 47, 419-427. ' , ' P e l l e g r i n o , L . J . and Cushman, A.J. A S t e r e o t a x i c A t l a s of the Rat B r a i n . New York: Appleton-Century-Crofts, 1967. P l i s k o f f , S.S., Wright, J.E., and Hawkins, T.D. B r a i n S t i m u l a t i o n as a R e i n f o r c e r : I n t e r m i t t e n t Schedules. J o u r n a l of the Experimental  A n a l y s i s of Behavior, 1965, 8_, 75-88. P o r t e r , J.H. and Kenshalo, D.R. Schedule-Induced D r i n k i n g F o l l o w i n g Omission of Reinforcement i n the Rhesus Monkey. Physiology  and Behavior, 1974, 12_, 1075-1077. R o s e n b l i t h , J.Z. P o l y d i p s i a Induced i n the Rat by a Second-Order Schedule. J o u r n a l of the Experimental A n a l y s i s of  Behavior, 1970, 14, 139-144. Schuster, C.R. and Woods, J.H. Schedule-Induced P o l y d i p s i a i n the Rhesus Monkey. P s y c h o l o g i c a l Reports, 1966, 19, 823-828. Segal, E.F. The Development of Water D r i n k i n g on a Dry-Food Free-Reinforcement Schedule. Psychonomic Science, 1965, 2^ , 29-30. Segal, E.F. The I n t e r a c t i o n of Psychogenic P o l y d i p s i a w i t h Wheel Running i n Rats. Psychonomic Science, 1969, _14_, 141-144. Segal, E.F. and Deadwyler, S.A. Determinants of P o l y d i p s i a i n Rats: I I . DRL-Extinction. Psychonomic Science, 1965, 2, 203-204. (a) Segal, E.F. and Deadwyler, S.A. Determinants of P o l y d i p s i a : VI. Taste of the D r i n k i n g S o l u t i o n on DRL. Psychonomic Science, 1965, 3, 101-102. (b) Segal, E.F. and Holloway, S.M. Timing Behavior i n Rats w i t h Water D r i n k i n g as a Mediator. Science, 1963,140. , 888-889. Segal, E.F. and Oden, D.L. Determinants of P o l y d i p s i a i n Rats: A Reply to S t e i n . I . Emptying the Water B o t t l e . Psychonomic  Science, 1965, 2, 201-202. Segal, E.F. and Oden, D.L. Schedule-Induced P o l y d i p s i a : E f f e c t s of P r o v i d i n g an A l t e r n a t e Reinforced Response and of Introdu c i n g a Lick-Contingent Delay i n Food D e l i v e r y . Psychonomic Science, 1969, 15, 153-154. 64. Segal, E.F., Oden, D.L. and Deadwyler, S.A. Determinants of Polydipsia: III. Withholding Food on a Free-Reinforcement Schedule. Psychonomic Science, 1965, _2, 205-206. (a) Segal, E.F., Oden, D.L., and Deadwyler, S.A. Determinants of Polydipsia: IV. Free-Reinforcement Schedules. Psychonomic Science, 1965, 3, 11-12. (b) Segal, E.F., Oden, D.L., and Deadwyler, S.A. Determinants of Polydipsia: V. Effect of Amphetamine and Pentobarbital. Psychonomic  Science, 1965, 3, 33-34. (c) Shanab , M.E. and Peterson, J.L. Polydipsia in the Pigeon, Psychonomic  Science, 1969, 15, 51-52. Skinner, B.F. "Superstition" in the Pigeon. Journal of Experimental  Psychology, 1948, 38, 168-172. Staddon, J.E.R. and Simmelhag, V.L. The "Superstition" Experiment: A Reexamination of i t s Implications for the Principles of Adaptive Behavior. Psychological Review, 1971, 7_8_, 3-43. Stein, L. Excessive Drinking in the Rat: Superstition or Thirst? Journal of Comparative and Physiological Psychology, 1964, 58, 237-242. Strieker, E.M. and Adair, E.R. Body Fluid Balance, Taste, and Post-Prandial Factors in Schedule-Induced Polydipsia. Journal  of Comparative and Physiological Psychology, 1966, 62_, 449-459. Taylor, D.B. and Lester, D. Schedule-Induced Nitrogen Drinking in the Rat. Psychonomic Science, 1969, L5, 17-18. Teitelbaum, P. and Epstein, A.N. The Lateral Hypothalamic Syndrome: Recoveryof Feeding and Drinking after Lateral Hypothalamic Lesions. Psychological Review, 1962, ji9_, 74-90. Tinbergen, N. "Derived" Activities: Their Causation, Biological Sig-nificance, Origin, and Emancipation During Evolution. Quarterly Review of Biology, 1952, 27_, 1-32. Valenstein, E.S., Cox, V.C., and Kakolewski, J.W. Polydipsia E l i c i t e d by the Synergistic Action of a Saccharin and a Glucose Solution. Science, 1967 , 157 , 552-554. Valenstein, E.S., Cox, V.C., and Kakolewski, J.W. Re-examination of the Role of the Hypothalamus in Motivation. Psychological Review, 1970, 77_, 16-31. Vance, W.B. Observations on the Role of Salivary Secretions in the Regulation of Food and Fluid Intake in the White Rat. Psychological Monographs, 1965, 79. V i l l a r r e a l , J.E. Schedule-Induced Pica. Paper read at Meeting of Eastern Psychological Association, Boston, April, 1967. Wayner, M.J. Specificity of Behavioral Regulation. Physiology and  Behavior, 1973, 10, 109-132. Wayner, M.J., Greenberg, I., Fraley, S., and Fisher, S. Effects of A 9 - Tetrahydrocannabinol and Ethyl Alcohol on Adjunctive Behavior and the Lateral Hypothalamus. Physiology and  Behavior, 1 9 7 3 , 1 0 , 109-132. Whalen, T.E. A Failure to Find Schedule-Induced Grit and Water Consumption in the Pigeon. Unpublished Master's Thesis, University of British Columbia, 1975. 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0093419/manifest

Comment

Related Items