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Establishment and generalization of aversion effects to alcoholic beverages in rats
Brhm. Prmed
Res. Thrr. Vol. 23. No. 3. pp. X.5-262. in Great Bntain. All rights reserved
1985 Copyrlpht
ESTABLISHMENT AND GENERALIZATION AVERSION EFFECTS TO ALCOHOLIC BEVERAGES IN RATS*
0005-7967185 53.00 + 0.00 ((_ 1985 Pergamon Press Lrd
OF
JOSEPH J. FRANCHINA, DAVID W. GILLEY, JAMES NESS and MICHAEL DODD Department of Psychology. Virginia Polytechnic Institute and State University. Blacksburg,
VA 24061.
U.S.A.
(Received 26 July 1984) Summary-Two experiments investigated whether the establishment of aversion to alcoholic beverages resulted from aversion conditioning to the taste/flavor characteristics of ethanol or to the specific characteristics of particular beverage(s) (i.e. ethanol + congeners). In Experiment 1 rats (n = 72) received a pairing of whiskey, bourbon, rum or ethanol. each at a 5y0 ethanol concentration, with an injection of 0.15 M LiCI. Relative to toxin and to beverage control groups, aversion effects to whiskey and bourbon were greater than those to ethanol. aversion effects to rum being intermediate. In Experiment 2 rats (n = 162) received whiskey, rum or ethanol paired with an LiCl injection and were tested for aversion to the conditioning beverage and to each of the other beverages. Relative to controls, aversion effects were generally greater to the conditioning beverage than to the generalization test beverages. Generalization depended upon which alcoholic beverage was the conditioning beverage and which. the generalization test beverage. Specifically, conditioning to whiskey yielded a reliable generalization gradient: greater aversion effects to whiskey, than to rum, than to ethanol. Conditioning to rum yielded similar aversion effects to whiskey and ethanol. Conditioning to ethanol produced comparable aversion to ethanol and whiskey and reliably less to rum.
INTRODUCTION
Chemical aversion therapy (CAT) for alcoholism is similar to flavor aversion learning (FAL) in terms of operational procedures and anticipated behavioral outcomes (i.e. decreased ingestion). Consequently, experimental studies of FAL have provided empirical evidence, a theoretical framework and an heuristic animal model for understanding CAT effects (Revusky, 1973: Davidson, 1974; Elkins. 1975; Revusky and Taukulis, 1975; Baker and Cannon, 1978; Pohl, Revusky and Mellor, 1980; Cannon and Baker, 1981). Evidence from FAL research has shown that aversion conditioning is related to flavor stimulus characteristics such as taste quality, intensity, complexity and palatability (Logue, 1979). However, mo?t studies have used nonalcoholic substances such as saccharin, saline, coffee, sucrose, vinegar or vanilla, as conditioning stimuli. Alcoholic beverages, loosely categorized as beers, wines and distilled spirits, are comprised of ethyl alcohol and congeners such as fructose, glucose, ketone, salts, minerals, acids and members of the vitamin B group (Leake and Silverman, 1971). Together, these combinations of ingredients are presumably responsible for an alcoholic beverage’s taste and odor characteristics, physiological effects. rate of absorption and, perhaps, conditionability under FAL procedures. Recent data has provided objective evidence of aversion effects to alcoholic beverages following emetic therapy in humans (Boland, Mellor and Revusky, 1978; Baker and Cannon, 1979; Cannon and Baker, 1981; Cannon. Baker and Wehl, 1981). However, Baker and Cannon (1979) pointed out that it is uncertain whether aversion was established to the taste/flavor characteristics of ethanol in the alcoholic beverage(s) or to the characteristics of the particular beverage(s) (i.e. ethanol + congeners). For example, Baker and Cannon (1979) and Cannon and Baker (198 1) used beer, wine and distilled spirits as the conditioning flavors. Since these beverages differed in ethanol concentration and congener characteristics, aversion conditioning may have occurred either to the ethanol stimulus or to the combination of ethanol and congeners which make up a particular beverage(s).
*These data
were presented
at the Meer. q/
the Sourheasrern Pswhological Associarion. New Orleans.
La.. March
1984.
256
JOSEPHJ. FRANCHINA et al.
An understanding of how the flavor characteristics of alcoholic beverages affect the establishment of aversion could contribute to the effective application of CAT. Further. if aversion is established to the flavor characteristics of particular beverages then differences in conditioning might affect the extent to which aversion effects generalized between beverages. Generalization. in turn, could influence the degree to which abstinence from alcohol occurred following the conclusion of CAT. Quinn and Henbest (1967) reported evidence of a partial failure of generalization of aversion effects. Ss which received CAT for their preferred drink. whiskey. avoided that substance. subsequently, but showed an increase in intake for other alcoholic beverages such as rum. gin. table wine and beer/stout. These data suggest that the aversion was conditioned to specific beverage cues. On the other hand, if aversion is established to the ethanol stimulus, apart from the other characteristics of a particular alcoholic beverage, then generalization of aversion might be promoted on the basis of the presence of ethanol, at least within the same category of beverages (e.g. distilled spirits). This paper reports two experiments on the establishment and generalization of aversion effects to alcoholic beverages in rats. The beverages were distilled spirits so that the beverage category was held constant for assessment of conditioning and generalization effects. Experiment I studied the establishment of aversion to whiskey, rum, bourbon and ethanol. each at a 5”, ethanol concentration. Experiment 2 studied the acquisition and generalization of aversion with whiskey. rum or ethanol orthogonally combined as conditioning and test beverages. METHOD Subjects The Ss were experimentally-naive, male, albino rats, Sprague-Dawley descendants (Rrzttrr.s nouegicus), who were born and reared in the colony maintained by the Department of Psychology at Virginia Polytechnic Institute and State University. The rats were 67-75 days of age at the start of each experiment. In each experiment each rat was housed in a single-hanging cage in a room 2.0 x 2.0 x 3.0 m. Room temperature was 24 + 1°C. Illumination was 240 lx on a light-dark cycle of 14 hr-10 hr; light onset was at 0800 hr daily. Procedure Each experiment consisted of 4 days of habituation to a regimen of fluid deprivation (Days l-4). 1 injection (training) day (Day 5), 1 day for recovery from the injection (Day 6) and 5 days of testing (Days 7-l 1). On Days l-4 each rat received 10 min access to distilled water (DW) in the home cage at 0830 and 1530 hr. On Day 5 food was removed from the home cage at 0800 hr. At 0830 hr each rat received 2 min access to distilled water or to an alcoholic beverage. Within 5 min, each rat received an intraperitoneal (i.p.) injection of 0.9% (isotonic) saline (NaCl) or 0.15 M lithium chloride (LiCl) at 2% body wt. After the injection the rat was returned to the home cage. At 1500 hr food was returned to the cage; at 1530 hr each rat received 10 min access to DW. On Day 6 all rats received 10 min access to DW at 0830 and at 1530 hr. These access periods were used to assess the effects of the LiCl injection (Day 5) on ingestion per se. There were no group differences in DW intake observed on Day 6. Aversion effects were measured daily on Days 7-l 1, one test trial per day. On each day food was removed from the rat’s cage at approx. 0800 hr. For a test trial each rat then received 10 min access to a single bottle which contained an alcoholic beverage. The amount drunk was measured by the difference (to the nearest 100mg) between pretest and posttest bottle weights. Food was returned to the rat’s home cage within 10 min after a test trial. For hydration purposes DW access occurred at 1530 hr daily. Experiment 1. Seventy-two male rats, 291-340 g each, were randomly and equally assigned to a 4 x 3 design (n = 6). This design orthogonally combined four beverage (Bev) conditions (whiskey. rum, bourbon and ethanol) with three injection procedures (Bev-LiC1, Bev-NaCl. DW-LiCl). The DW-LiCI group was used to evaluate the possible influence of the ingestion-toxin contingency on subsequent intake in testing. In testing, Bev-LiCl and Bev-NaCl groups received access to the alcoholic beverage which they had received on the injection day. The DW-LiCl groups received testing with either whiskey, bourbon, rum or ethanol (n = 6). Their intakes were compared with those of comparable Bev-LiC1 and Bev-NaCl groups.
Alcohol
aversion
in rats
257
The concentration of ethanol in each alcoholic beverage* was 5% (w/v). Solutions were made by mixing commercial alcoholic beverages (80 proof each) or pure grade (95%) ethyl alcohol with DW. Solutions were mixed not less than 18 hr prior to use. Experiment 2. This experiment used 162 male rats. The rats were matched on body weights across treatment conditions on the day before injection. Mean body weight was 316 g @EM = 1.02). Following matching the rats were randomly assigned to training conditions in which an alcoholic beverage (whiskey, rum or ethanol) or DW was paired with an LiCl injection. After the recovery day (Day 6) the rats were tested for aversion to the alcohol conditioning beverage or to each of the other two alcohol beverages. Procedures for injection, the recovery day and test trials were exactly as described for Experiment 1. The data for each experiment was initially evaluated with analysis of variance (ANOVA) and, subsequently, with t-tests and Duncan’s multiple range tests (DMRT) as appropriate. For all analyses a-level was 0.05. RESULTS Experiment
1
On the training (injection) day mean intakes (g) of whiskey, bourbon, rum, ethanol and distilled water, were 2.3, 1.4, 2.9, 3.2 and 4.7, respectively. Intakes of the alcoholic beverages were highly similar to each other (F < 1) and were lower than that for distilled water. Figure 1 shows mean intakes for groups which were conditioned and tested, respectively, with whiskey, rum, bourbon or ethanol. In each panel intake of the Bev-LiCl group was lower than those of control groups. Control groups’ intakes were highly similar to each other. An ANOVA over all the data for each beverage yielded a reliable effect for groups: whiskey (F = 42.18), rum (F = 9.66), bourbon (F = 19.15) and ethanol (F = 5.15). Degrees of freedom were 2 and 15 in each ANOVA. Each Bev-LiCl group differed reliably from its Bev-NaCl and DW-LiCl control group (F’s < 0.01). Intakes of the control groups were generally similar to each other across alcoholic beverages. In order to compare aversion effects between alcoholic beverages the intake of each rat in a Bev-LiCl group (e.g. whiskey-LiCl) was divided on each test trial by the mean intake of the Bev-NaCl control group; the quotient was then multiplied by 100. The resultant index was a percent intake score. The higher the percentage was; the closer the intake of the Bev-LiCl group was to that of saline-injected controls and the weaker the aversion effect was. It should be noted that the percent index essentially eliminated the possibility that differences in intake among alcoholic beverages would be attributable to the potability of the beverages themselves. A percentage transformation was also obtained for the data of rats in the DW-LiCl groups (i.e. DW-LiCliBev-NaCl, the quotient, x 100). Table 1 presents mean percent intake for Bev-LiCl and DW-LiCl groups which were tested with whiskey. rum, bourbon or ethanol on Test Trials l-5. An ANOVA over all the data of Table 1 revealed reliable evidence of alcohol aversion effects for each beverage (P < 0.001). The magnitude of aversion was highly similar across beverages on Trials 1 and 2. However, over Trials 3-5 aversion effects were more persistent for whiskey and bourbon than for ethanol, with aversion effects to rum being intermediate. Results of an ANOVA of these data revealed a reliable effect of training condition for whiskey and for bourbon [F(l/lO) = 116.79 and 26.23, P < O.OOl] and a reliable training condition x test trials interaction for rum and ethanol [F(4/41) = 3.27 and 10.64, P < 0.01 and P < 0.0001, respectively]. It should be noted that the differences among the beverages in testing were due to differences among Bev-LiCl groups [F(3/20) = 3.14. P < 0.051 and not to differences among DW-LiCl groups [F(3/20) = 1.64, P > 0.201. Esperiment
2
On the training (injection) day mean intakes of whiskey, rum, ethanol and distilled water were 2.6, 3.1. 3.3 and 5.1, respectively. Intakes of the alcoholic beverages were highly similar to each other (F < 1) and less than that of distilled water. *Brand
names
of whiskey.
rum
and
bourbon
are available
on request
JOSEPH J. FRANCHINA rf al. RUM
ETOH
BOUR r
I
I
/
1
I
/
2
3
4
5
I
I
I
I
2
3
I
t
4
5
I
I
I
2
3
B
4
11
1
5
2
4
3
5
TEST TRIALS Fig.
1.
Mean intakes (g) of whiskey, rum, bourbon
on the test beverage
and ethanol on Test Trials 1-j for groups conditioned and them respective beverage and toxin control groups (Bev-Na and
(Bev-LiCl)
DW-LiCI.
respectively).
Tables 2-4 present mean intakes of whiskey, rum and ethanol on Test Trials l-5 for groups which received either whiskey (Table 2), rum (Table 3) or ethanol (Table 4) as the conditioning beverage and a DW-LiCI pairing as the control procedure. In each table comparison between the conditioning group and the DW control group reveals that aversion effects were generally larger
Table I. Mean percent make of wtuskey. bourbon. rum and ethanol on Test Trials l-5 for each Bev (CStLiCI and DW-LKI traming group
Table 2. Mean Intakes (8) of whlske) ethanol
(CS), rum or on Test Trials l-5 for group5 administered a .oa~mn . of whisker or DW wtth LICI
Test Trial No
Test Trial No.
Tralnlng
I
condition
3
2
4
Traimng condition
5
I
Test = whiskq
Whi(CStLiC1 DW-LICI
22.5 70.3
12.0 76.2
Bour(CSkLiC1 DW-LiCI
21.0 440
13.1 97.8
Rum(CSkLiCI DW-LICI
16.2 76.8
22.0 97.8
Etoh(CSELiC1 DW-LICI
20.1 104.5
30.1 108.7
31.3 970
51.7 101.8
2 3 Trsr= n,hrskq
9.4 13.6
Whi-LiCI DW-LiCI
1.7 7.0
3.0 12.7
35.6 80.7
70.4 104.4
Wttl -LKI DW-LiCI
2.x 7.8
5.0 13.9
Tar = rum 1I.1 8.1 14.5 12.2
13.1 14.4
53.8 94.4
103.5 108
Whi-LiCl DW-LiCI
2.4 97
I-at = erlmnol 13.5 9.0 13.0 15.6 14.0 12.9
13.9 13.j
Tesr = rum
39.0 88.4
5
80.3 107.0
Test = bourbon
21.0 90.8
1 (CS) 4.9 13.7
4.9 11.3
Test = ethanol
59.9 95.7
82.6 98.4
118.9 124.1
Table 3. Mean intakes (g) of rum (CS). whiskey ethanol on Test Trials l-5 for groups admmistered paumg of rum or DW wth IXI Test Trial Training con&Ion
I
2
3
or a
Table 4. Mean mtakes (g) of ethanol (CS) whiskey or rum on Test Trials l-5 for groups admmistered a paring of ethanol or DW wth LICI Test Tnal
No. 4
5
Trammg condltlon
I
2
3
No. J
5
(CS)
9.4 IS.0
EtohmLKl DW-LICI
2.0 9.5
Tar = rrlrunoi 2.3 46 12.3 12.7
x.3 14.0
12.1 14.7
2.3 6.2
Test = n,hrskm 8.2 5.3 69 130 I?.‘) 12.6
12.1 12.5
TV>1= rum 12.6 96 13.6 I39 9x
12.3 13.0
Rum-LlCl DW-LICI
I.9 92
Test = rum (CS) 3.2 5.6 2.0 12.9 14.1 14.1
Rum-L&Z1 DW-LKl
2.6 6.4
7Ls1 = whrska 10.6 6.7 10.3 13.0 12.8 12.9
12.3 13.1
EtohmLKl DW-LiCI
Rum-LKI DW-LICI
2.2 8.8
Tm = erhunol I3 0 62 10.6 I4 3 13.5 13.3
12.4 14.1
Etoh-LiCI DW-LiCI
Alcohol
aversion
259
in rats
to the conditioning beverage (CS) than to either of the two generalization test beverages. An ANOVA of the data for conditioning to whiskey (Table 2) and for conditioning to rum (Table 3) yielded reliable effects (P < 0.05) for training condition, test beverage and training condition x test beverage. An ANOVA of the data for conditioning to ethanol (Table 4) yielded reliable effects (P < 0.05) for training condition and the training condition x test beverage interaction. Tables 2-4 also show that aversion effects to the generalization test beverages occurred mainly on Trials 1 and 2 and tended to dissipate thereafter, as compared to the more enduring aversion to the CS. An ANOVA of the data for conditioning to whiskey (Table 2) or to ethanol (Table 4) yielded a reliable training condition x test trials interaction in each case (P < 0.03 and P < 0.04, respectively). An ANOVA of the data for conditioning to rum (Table 3) revealed reliable interactions of training condition x test trials and test beverage x test trials (P < 0.001 and P < 0.02, respectively). Together, the results of these analyses and the data of Tables 2-4 provided reliable evidence for stimulus generalization decrement effects following conditioning for each beverage. When the test beverage was different from the conditioning beverage, intake of the former was generally higher than that for the latter. This effect was especially notable for the Bev-LiCl groups as compared to DW-LiCl groups in each table. In order to evaluate the generalization of aversion effects across CS and test beverages the data of Tables 2-4 were converted into percent intake scores. Specifically, the intake of each rat in a beverage conditioning group was divided by the mean intake of the comparable DW-LiCl group on each test trial for each of the test beverages, whiskey, rum and ethanol. The lower the percentage score is, the greater the difference in intake between conditioning and control (DW) groups and. thus, the stronger the aversion. A percentage score of 100 would indicate no evidence for aversion. Figure 2 presents the percentage intake data. An ANOVA over all the data of Fig. 2 yielded a reliable effect for test beverage, conditioning beverage x test beverage and conditioning beverage x test beverage x test trials [F(2/72, 4/72 and 16/128) = 3.69, 12:63 and 3.79, P < 0.03, P < 0.0002 and P < 0.0001, respectively]. Simple effects analyses together with the results of Fig. 2, yielded the following conclusions. On Test Trial 1 aversion effects to the CS and the generalized test beverages were similar to each other. Evidence for differences in the generalization of aversion effects appeared over test trials, beginning with Trial 2. Specifically, aversion conditioning to whiskey yielded generalized aversion effects to rum and to ethanol. However. each of the latter showed smaller aversion effects than that for the CS (Ps < 0.01). The aversion effect to rum was reliably greater than that to ethanol: test beverage and test beverage x test trials. F( l/ 16 and 4164) = 4.60 and 4.07, P < 0.05 and P < 0.005, respectively. Aversion conditioning to rum
CS=WHISKEY
CS=RUM
CS=ETOH
I
1
I
I
1
I
2
3
4
5
I
2
3
1
j
4
5
TEST TRIALS Fig. 2. Mean percent intake on Test Trials l-5 for groups conditioned (CS) on whiskey. rum or ethanol and then tested (‘TS) on the conditioning beverage or on either of the other two beverages.
260
JOSEPHJ. FRANCHINA et (11.
yielded aversion effects to whiskey and to ethanol, which were less than that to the CS (P < 0.002) but highly similar to each other (F < 1). Aversion conditioning to ethanol yielded aversion effects to whiskey which were similar to that for the ethanol conditioning beverage (F < 1) but which were reliably greater than those to rum: test beverage x test trials [F(4/64) = 3.74. P < O.Ol]. Conversely, the generalization of aversion effects to whiskey was greater following conditioning with ethanol than with rum (P < 0.05). But generalization of aversion to rum or to ethanol was nondifferentiable whether the CS was whiskey or ethanol for rum or whiskey or rum for ethanol (F < 1). DISCUSSION The effective use of CAT as a treatment for alcoholism may depend, in part, upon the associability between the characteristics of alcoholic beverages and toxicosis. These characteristics may regulate the magnitude of the originally-established aversion and the generalization of tlzat aversion to other alcoholic beverages. If conditioning occurs to the specific characteristics of an alcoholic beverage then, abstinence may occur toward that beverage. But intakes of other distinguishable alcoholic beverages may not be altered or may even increase. For example. Quinn and Henbest (1967) reported data which are consistent with a view of beverage specificity in alcohol aversion conditioning. The 10 alcoholic Ss in their experiment acquired an aversion to the CS. whiskey, and abstained from that beverage for intervals from 11 days to 17 yrs; 8 of the 10 Ss abstained for over 1 yr. However, 7 of the 10 Ss increased their intakes of other alcoholic beverages such as beer/stout, table wine, rum and gin. These data suggest a failure of generalization of aversion effects across alcoholic beverages. The results of Experiments 1 and 2 suggest that aversion effects were more strongly established to the characteristics of the particular alcoholic beverage(s) (i.e. ethanol + congeners) than to the characteristic(s) of ethanol. In Experiment 1 aversion effects were stronger (more perisistent) to whiskey and bourbon CSs than to ethanol, although all CSs contained 59,; ethyl alcohol. Experiment 2 provided reliable evidence for stimulus generalization effects, In this experiment the display of generalized aversion depended upon which beverage was the CS and which, the test stimulus. Since all beverages contained 5% ethanol Experiment 2 results suggested that specific beverage characteristics exerted a potent influence on the maintenance of the conditioned aversion. The present evidence for beverage/flavor specificity in alcohol aversion should not come as a surprise, considering Jounela-Eriksson’s (1979) data on human judgmental responses to the flavor of alcoholic beverages and data on FAL in rats (e.g. Braveman and Jarvis, 1978). Jounela-Eriksson (1979) reported reliable differences in human judgmental responding, based on the purity and taste of vodka and flavored distilled spirits and on the aroma and taste of red wines. Nachman (1963. 1970), Nowlis ( 1974), Braveman and Jarvis ( 1978) and Nowlis, Frank and Pfaffman (1980) reported that conditioning and/or generalization of aversion occurred to specific flavor characteristics. such as quality, concentration and temperature. The differences in aversion effects among whiskey, bourbon, rum and ethanol CSs (Experiment 1) may be described in terms of compound/complex flavor conditioning (Rescorla and Wagner, 1972). The combination of 5% ethanol + congeners which make up whiskey, bourbon and rum may constitute these beverages as compound/complex CSs with gustatory and olfactory characteristics. Because of the greater number of stimulus elements for conditioning, associative strength to a compound/complex stimulus is typically greater than that to the individual elements (e.g. Holland and Forbes, 1980). Thus, aversion effects were greater to whiskey, bourbon and rum than to ethanol. Greater aversion occurred to whiskey and bourbon than to rum perhaps because of differences in olfactory cues. Whiskey and bourbon contain high levels of fuse1 alcohol and fatty acid esters which determine the aromatic characteristics of an alcoholic beverage (Lehtonen and Suomalainen, 1979). The amount of fuse1 alcohol in whiskeys (including, bourbon) is ten times that in rum (Jounela-Eriksson, 1979). Thus, differences in aversion effects between whiskey/bourbon and rum may be related to differences in odor stimuli between the beverages. In Experiment 2 generalization of aversion effects presumably reflected the commonality of tlavor characteristics between CS and test stimuli. However, because compound/complex and elemental stimuli were presented in conditioning and testing, generalization effects may have depended upon the presence of distinctive as well as shared characteristics. Accordingly, conditioning with whiskey
Alcohol aversion in rats
261
yielded a gradient of generalization of aversion to rum and ethanol presumably because whiskey and rum shared more characteristics (e.g. numbers of fatty acid esters) than did whiskey and ethanol. Conditioning to rum yielded similar levels of aversion to whiskey and to ethanol. Perhaps, rum shared characteristics with whiskey and with ethanol separately without necessarily implicating a commonality between whiskey and ethanol. Or perhaps, the common presence of ethyl alcohol in whiskey and ethanol permitted comparable generalization of aversion to each of them following conditioning with rum. The present data do not permit a choice betwezn these alternatives. Finally, conditioning to ethanol yielded similar levels of aversion to ethanol and to whiskey. Since conditioning with whiskey yielded reliable evidence of stimulus generalization decrement in testing with ethanol these results, taken together, yield evidence of asymmetrical generalization effects between whiskey and ethanol. Asymmetrical generalization between flavors has been reported previously in aversion learning (e.g. Nowlis et al., 1980; Parker and Revusky, 1982). Although there are several explanations of this effect, the present results may be related to the use of compound/complex and elemental stimuli in conditioning and testing (Rescorla and Wagner, 1972). Specifically, a compound stimulus is comprised of a variety of elemental stimuli. Following conditioning to an individual element, generalization of aversion may be highly likely to occur in testing with the compound because the compound includes the original CS, the individual element. Conversely, after conditioning with the compound, aversion may be unlikely to generalize to testing with the individual element because that test stimulus may preclude the other elements of the compound and, thus, inadequately represent the original CS. The present analysis of aversion conditioning to alcoholic beverages proposes that they be viewed as compound/complex stimuli. If this supposition is reasonable, then the advancement of information about effective CAT might better be accomplished by studies of compound FAL (e.g. Holland and Forbes, 1980) within a theoretical context such as the Rescorla-Wagner (1972) model. A tentative conclusion of the present report is that the characteristic(s) of ethanol in alcoholic beverages influence(s) aversion effects much less than do the taste/flavor characteristics of particular beverages. If so, two suggestions might be offered. In CAT the taste and aromatic characteristics of the particular beverage(s) should be strongly emphasized to the patient, perhaps by verbal priming procedures. Secondly, perhaps CAT might employ ethanol-free beverages which simulate the taste and aromatic characteristics of the alcoholic beverage. The advantages of this strategy would be that larger CS doses and more frequent CS presentations could be used in CAT without risking the pharmacological side effects of ethanol. REFERENCES Baker T. B. and Cannon D. S. (1979) Taste aversion therapy with alcoholics: techniques and evidence of conditioned response. Behar. Res. Ther. 17, 229-242. Boland F. J.. Mellor C. S. and Revusky S. (1978) Chemical aversion treatment of alcoholism: lithium as the aversive agent. Behar. Res. Ther. 16, 401409.
Braveman N. S. and Jarvis P. S. (1978) Independence of neophobia and taste aversion learning. Anim. Learn. Behac. 6, 406-412.
Cannon D. S. and Baker T. B. (1981) Emetic and electric shock alcohol aversion therapy: assessment of conditioning. J. consult. clin. Psychol. 49, 20-33.
Cannon D. S.. Baker T. S. and Wehl C. K. (1981) Emetic and electric shock alcohol aversion therapy: six- and twelve-month follow-up. J. consult. clin. Psvchol. 49, 360-368. Davidson W. S. II (I 974) Studies of aversive conditioning for alcoholics: a critical review of theory and research methodology. Psychol. Bull. 81, 571-581. Elkms R S. (1975) Aversion therapy for alcoholism: chemical. electrical or verbal imagery? Inc. J. Addict. 10, 157-209. Holland P. C. and Forbes D. T. (1980) Effects of compound or element preexposure on compound flavor aversion conditioning. Anim. Learn. Behar. 8, 199-203. Jounela-Eriksson J. (1981) Panel experience and responses to the flavor of alcoholic beverages. In Criteria for Food .4ccepplance: HON. Marl Chooses Whar He ESS (Edited by Solms J. and Hall R. L.). Forster, Zurich. Leake C. D. and Silverman M. (1971) The chemistry of alcoholic beverages. In The Biology of Alcoholism: Biochemisfr_v, Vol. 1 (Edited by Kissin B. and Begleiter H.). Plenum Press, New York. Lehtonen M. and Suomalainen H. (1979) The analytic profile of some whiskey brands. Process. Biochem. 14, 5-9. Logue A. W. (I 979) Taste aversion and rhe generality of the laws of learning. Psychol. Bull. 86, 276-296. Nachman M. (1963) Learned aversion to the taste of lithium chloride and generalization to other salts. J. romp. phvsiol. P.~>~c-hOl. 56, 343-349.
Nachman
M. (1970) Learned taste and temperature
aversions due to lithium chloride sickness after temporal delays.
J. camp. ph,vsiol. Psvchol. 73, 22-30. Nowlls G. H. (I 974) Conditioned stimulus intensity and acquired alimentary aversions in the rat. J. camp. physiol. Psvchol. 86, 1173-1184.
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Nowlis G. H.. Frank M. and Pfaffman C. (1980) Specificity of acquired aversions to taste qualittes m hamsters and rats. J. camp. physiol. Psychoi. 94, 932-942. Parker L. A. and Revusky S. (1982) Generalized conditioned flavor aversions: effects of toxicosis training with one Havor on the preference for different novel flavors. Anim. Learn. Behac. 10, 505-510. Pohl R. W., Revusky S. and Mellor C. S. (1980) Drugs employed in the treatment of alcohohsm: rat data suggest they are unnecessanly severe. Behm. Res. Ther. 18, 71-78. Quinn J. T. and Henbest R. (1967) Partial failure of generalization in alcoholics following aversion therapy. Q. JI Srutl. Alcohol 28, 70-75. Rescorla R. A. and Wagner A. R. (1972) A theory of Pavlovian conditioning. Variations in the effectiveness of reinforcement and nonreinforcement. In Classical Conditioning II: Current Research und Theor? (Edited by Black A. H. and Prokasky W. F.). Appleton-Century-Crofts. New York. Revusky S. (1973) Some laboratory paradigms for the chemical aversion treatment of alcoholism. J. Behar. Ther. e.rp. Psychiat. 4, 15-17. Revusky S. and Taukulis H. K. (1975) Effects of alcohol and lithium habituation on the development of alcohol averston through contingent lithium injection. Behav. Res. Ther. 13, 163-166.
Res. Thrr. Vol. 23. No. 3. pp. X.5-262. in Great Bntain. All rights reserved
1985 Copyrlpht
ESTABLISHMENT AND GENERALIZATION AVERSION EFFECTS TO ALCOHOLIC BEVERAGES IN RATS*
0005-7967185 53.00 + 0.00 ((_ 1985 Pergamon Press Lrd
OF
JOSEPH J. FRANCHINA, DAVID W. GILLEY, JAMES NESS and MICHAEL DODD Department of Psychology. Virginia Polytechnic Institute and State University. Blacksburg,
VA 24061.
U.S.A.
(Received 26 July 1984) Summary-Two experiments investigated whether the establishment of aversion to alcoholic beverages resulted from aversion conditioning to the taste/flavor characteristics of ethanol or to the specific characteristics of particular beverage(s) (i.e. ethanol + congeners). In Experiment 1 rats (n = 72) received a pairing of whiskey, bourbon, rum or ethanol. each at a 5y0 ethanol concentration, with an injection of 0.15 M LiCI. Relative to toxin and to beverage control groups, aversion effects to whiskey and bourbon were greater than those to ethanol. aversion effects to rum being intermediate. In Experiment 2 rats (n = 162) received whiskey, rum or ethanol paired with an LiCl injection and were tested for aversion to the conditioning beverage and to each of the other beverages. Relative to controls, aversion effects were generally greater to the conditioning beverage than to the generalization test beverages. Generalization depended upon which alcoholic beverage was the conditioning beverage and which. the generalization test beverage. Specifically, conditioning to whiskey yielded a reliable generalization gradient: greater aversion effects to whiskey, than to rum, than to ethanol. Conditioning to rum yielded similar aversion effects to whiskey and ethanol. Conditioning to ethanol produced comparable aversion to ethanol and whiskey and reliably less to rum.
INTRODUCTION
Chemical aversion therapy (CAT) for alcoholism is similar to flavor aversion learning (FAL) in terms of operational procedures and anticipated behavioral outcomes (i.e. decreased ingestion). Consequently, experimental studies of FAL have provided empirical evidence, a theoretical framework and an heuristic animal model for understanding CAT effects (Revusky, 1973: Davidson, 1974; Elkins. 1975; Revusky and Taukulis, 1975; Baker and Cannon, 1978; Pohl, Revusky and Mellor, 1980; Cannon and Baker, 1981). Evidence from FAL research has shown that aversion conditioning is related to flavor stimulus characteristics such as taste quality, intensity, complexity and palatability (Logue, 1979). However, mo?t studies have used nonalcoholic substances such as saccharin, saline, coffee, sucrose, vinegar or vanilla, as conditioning stimuli. Alcoholic beverages, loosely categorized as beers, wines and distilled spirits, are comprised of ethyl alcohol and congeners such as fructose, glucose, ketone, salts, minerals, acids and members of the vitamin B group (Leake and Silverman, 1971). Together, these combinations of ingredients are presumably responsible for an alcoholic beverage’s taste and odor characteristics, physiological effects. rate of absorption and, perhaps, conditionability under FAL procedures. Recent data has provided objective evidence of aversion effects to alcoholic beverages following emetic therapy in humans (Boland, Mellor and Revusky, 1978; Baker and Cannon, 1979; Cannon and Baker, 1981; Cannon. Baker and Wehl, 1981). However, Baker and Cannon (1979) pointed out that it is uncertain whether aversion was established to the taste/flavor characteristics of ethanol in the alcoholic beverage(s) or to the characteristics of the particular beverage(s) (i.e. ethanol + congeners). For example, Baker and Cannon (1979) and Cannon and Baker (198 1) used beer, wine and distilled spirits as the conditioning flavors. Since these beverages differed in ethanol concentration and congener characteristics, aversion conditioning may have occurred either to the ethanol stimulus or to the combination of ethanol and congeners which make up a particular beverage(s).
*These data
were presented
at the Meer. q/
the Sourheasrern Pswhological Associarion. New Orleans.
La.. March
1984.
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JOSEPHJ. FRANCHINA et al.
An understanding of how the flavor characteristics of alcoholic beverages affect the establishment of aversion could contribute to the effective application of CAT. Further. if aversion is established to the flavor characteristics of particular beverages then differences in conditioning might affect the extent to which aversion effects generalized between beverages. Generalization. in turn, could influence the degree to which abstinence from alcohol occurred following the conclusion of CAT. Quinn and Henbest (1967) reported evidence of a partial failure of generalization of aversion effects. Ss which received CAT for their preferred drink. whiskey. avoided that substance. subsequently, but showed an increase in intake for other alcoholic beverages such as rum. gin. table wine and beer/stout. These data suggest that the aversion was conditioned to specific beverage cues. On the other hand, if aversion is established to the ethanol stimulus, apart from the other characteristics of a particular alcoholic beverage, then generalization of aversion might be promoted on the basis of the presence of ethanol, at least within the same category of beverages (e.g. distilled spirits). This paper reports two experiments on the establishment and generalization of aversion effects to alcoholic beverages in rats. The beverages were distilled spirits so that the beverage category was held constant for assessment of conditioning and generalization effects. Experiment I studied the establishment of aversion to whiskey, rum, bourbon and ethanol. each at a 5”, ethanol concentration. Experiment 2 studied the acquisition and generalization of aversion with whiskey. rum or ethanol orthogonally combined as conditioning and test beverages. METHOD Subjects The Ss were experimentally-naive, male, albino rats, Sprague-Dawley descendants (Rrzttrr.s nouegicus), who were born and reared in the colony maintained by the Department of Psychology at Virginia Polytechnic Institute and State University. The rats were 67-75 days of age at the start of each experiment. In each experiment each rat was housed in a single-hanging cage in a room 2.0 x 2.0 x 3.0 m. Room temperature was 24 + 1°C. Illumination was 240 lx on a light-dark cycle of 14 hr-10 hr; light onset was at 0800 hr daily. Procedure Each experiment consisted of 4 days of habituation to a regimen of fluid deprivation (Days l-4). 1 injection (training) day (Day 5), 1 day for recovery from the injection (Day 6) and 5 days of testing (Days 7-l 1). On Days l-4 each rat received 10 min access to distilled water (DW) in the home cage at 0830 and 1530 hr. On Day 5 food was removed from the home cage at 0800 hr. At 0830 hr each rat received 2 min access to distilled water or to an alcoholic beverage. Within 5 min, each rat received an intraperitoneal (i.p.) injection of 0.9% (isotonic) saline (NaCl) or 0.15 M lithium chloride (LiCl) at 2% body wt. After the injection the rat was returned to the home cage. At 1500 hr food was returned to the cage; at 1530 hr each rat received 10 min access to DW. On Day 6 all rats received 10 min access to DW at 0830 and at 1530 hr. These access periods were used to assess the effects of the LiCl injection (Day 5) on ingestion per se. There were no group differences in DW intake observed on Day 6. Aversion effects were measured daily on Days 7-l 1, one test trial per day. On each day food was removed from the rat’s cage at approx. 0800 hr. For a test trial each rat then received 10 min access to a single bottle which contained an alcoholic beverage. The amount drunk was measured by the difference (to the nearest 100mg) between pretest and posttest bottle weights. Food was returned to the rat’s home cage within 10 min after a test trial. For hydration purposes DW access occurred at 1530 hr daily. Experiment 1. Seventy-two male rats, 291-340 g each, were randomly and equally assigned to a 4 x 3 design (n = 6). This design orthogonally combined four beverage (Bev) conditions (whiskey. rum, bourbon and ethanol) with three injection procedures (Bev-LiC1, Bev-NaCl. DW-LiCl). The DW-LiCI group was used to evaluate the possible influence of the ingestion-toxin contingency on subsequent intake in testing. In testing, Bev-LiCl and Bev-NaCl groups received access to the alcoholic beverage which they had received on the injection day. The DW-LiCl groups received testing with either whiskey, bourbon, rum or ethanol (n = 6). Their intakes were compared with those of comparable Bev-LiC1 and Bev-NaCl groups.
Alcohol
aversion
in rats
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The concentration of ethanol in each alcoholic beverage* was 5% (w/v). Solutions were made by mixing commercial alcoholic beverages (80 proof each) or pure grade (95%) ethyl alcohol with DW. Solutions were mixed not less than 18 hr prior to use. Experiment 2. This experiment used 162 male rats. The rats were matched on body weights across treatment conditions on the day before injection. Mean body weight was 316 g @EM = 1.02). Following matching the rats were randomly assigned to training conditions in which an alcoholic beverage (whiskey, rum or ethanol) or DW was paired with an LiCl injection. After the recovery day (Day 6) the rats were tested for aversion to the alcohol conditioning beverage or to each of the other two alcohol beverages. Procedures for injection, the recovery day and test trials were exactly as described for Experiment 1. The data for each experiment was initially evaluated with analysis of variance (ANOVA) and, subsequently, with t-tests and Duncan’s multiple range tests (DMRT) as appropriate. For all analyses a-level was 0.05. RESULTS Experiment
1
On the training (injection) day mean intakes (g) of whiskey, bourbon, rum, ethanol and distilled water, were 2.3, 1.4, 2.9, 3.2 and 4.7, respectively. Intakes of the alcoholic beverages were highly similar to each other (F < 1) and were lower than that for distilled water. Figure 1 shows mean intakes for groups which were conditioned and tested, respectively, with whiskey, rum, bourbon or ethanol. In each panel intake of the Bev-LiCl group was lower than those of control groups. Control groups’ intakes were highly similar to each other. An ANOVA over all the data for each beverage yielded a reliable effect for groups: whiskey (F = 42.18), rum (F = 9.66), bourbon (F = 19.15) and ethanol (F = 5.15). Degrees of freedom were 2 and 15 in each ANOVA. Each Bev-LiCl group differed reliably from its Bev-NaCl and DW-LiCl control group (F’s < 0.01). Intakes of the control groups were generally similar to each other across alcoholic beverages. In order to compare aversion effects between alcoholic beverages the intake of each rat in a Bev-LiCl group (e.g. whiskey-LiCl) was divided on each test trial by the mean intake of the Bev-NaCl control group; the quotient was then multiplied by 100. The resultant index was a percent intake score. The higher the percentage was; the closer the intake of the Bev-LiCl group was to that of saline-injected controls and the weaker the aversion effect was. It should be noted that the percent index essentially eliminated the possibility that differences in intake among alcoholic beverages would be attributable to the potability of the beverages themselves. A percentage transformation was also obtained for the data of rats in the DW-LiCl groups (i.e. DW-LiCliBev-NaCl, the quotient, x 100). Table 1 presents mean percent intake for Bev-LiCl and DW-LiCl groups which were tested with whiskey. rum, bourbon or ethanol on Test Trials l-5. An ANOVA over all the data of Table 1 revealed reliable evidence of alcohol aversion effects for each beverage (P < 0.001). The magnitude of aversion was highly similar across beverages on Trials 1 and 2. However, over Trials 3-5 aversion effects were more persistent for whiskey and bourbon than for ethanol, with aversion effects to rum being intermediate. Results of an ANOVA of these data revealed a reliable effect of training condition for whiskey and for bourbon [F(l/lO) = 116.79 and 26.23, P < O.OOl] and a reliable training condition x test trials interaction for rum and ethanol [F(4/41) = 3.27 and 10.64, P < 0.01 and P < 0.0001, respectively]. It should be noted that the differences among the beverages in testing were due to differences among Bev-LiCl groups [F(3/20) = 3.14. P < 0.051 and not to differences among DW-LiCl groups [F(3/20) = 1.64, P > 0.201. Esperiment
2
On the training (injection) day mean intakes of whiskey, rum, ethanol and distilled water were 2.6, 3.1. 3.3 and 5.1, respectively. Intakes of the alcoholic beverages were highly similar to each other (F < 1) and less than that of distilled water. *Brand
names
of whiskey.
rum
and
bourbon
are available
on request
JOSEPH J. FRANCHINA rf al. RUM
ETOH
BOUR r
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/
2
3
4
5
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2
3
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t
4
5
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B
4
11
1
5
2
4
3
5
TEST TRIALS Fig.
1.
Mean intakes (g) of whiskey, rum, bourbon
on the test beverage
and ethanol on Test Trials 1-j for groups conditioned and them respective beverage and toxin control groups (Bev-Na and
(Bev-LiCl)
DW-LiCI.
respectively).
Tables 2-4 present mean intakes of whiskey, rum and ethanol on Test Trials l-5 for groups which received either whiskey (Table 2), rum (Table 3) or ethanol (Table 4) as the conditioning beverage and a DW-LiCI pairing as the control procedure. In each table comparison between the conditioning group and the DW control group reveals that aversion effects were generally larger
Table I. Mean percent make of wtuskey. bourbon. rum and ethanol on Test Trials l-5 for each Bev (CStLiCI and DW-LKI traming group
Table 2. Mean Intakes (8) of whlske) ethanol
(CS), rum or on Test Trials l-5 for group5 administered a .oa~mn . of whisker or DW wtth LICI
Test Trial No
Test Trial No.
Tralnlng
I
condition
3
2
4
Traimng condition
5
I
Test = whiskq
Whi(CStLiC1 DW-LICI
22.5 70.3
12.0 76.2
Bour(CSkLiC1 DW-LiCI
21.0 440
13.1 97.8
Rum(CSkLiCI DW-LICI
16.2 76.8
22.0 97.8
Etoh(CSELiC1 DW-LICI
20.1 104.5
30.1 108.7
31.3 970
51.7 101.8
2 3 Trsr= n,hrskq
9.4 13.6
Whi-LiCI DW-LiCI
1.7 7.0
3.0 12.7
35.6 80.7
70.4 104.4
Wttl -LKI DW-LiCI
2.x 7.8
5.0 13.9
Tar = rum 1I.1 8.1 14.5 12.2
13.1 14.4
53.8 94.4
103.5 108
Whi-LiCl DW-LiCI
2.4 97
I-at = erlmnol 13.5 9.0 13.0 15.6 14.0 12.9
13.9 13.j
Tesr = rum
39.0 88.4
5
80.3 107.0
Test = bourbon
21.0 90.8
1 (CS) 4.9 13.7
4.9 11.3
Test = ethanol
59.9 95.7
82.6 98.4
118.9 124.1
Table 3. Mean intakes (g) of rum (CS). whiskey ethanol on Test Trials l-5 for groups admmistered paumg of rum or DW wth IXI Test Trial Training con&Ion
I
2
3
or a
Table 4. Mean mtakes (g) of ethanol (CS) whiskey or rum on Test Trials l-5 for groups admmistered a paring of ethanol or DW wth LICI Test Tnal
No. 4
5
Trammg condltlon
I
2
3
No. J
5
(CS)
9.4 IS.0
EtohmLKl DW-LICI
2.0 9.5
Tar = rrlrunoi 2.3 46 12.3 12.7
x.3 14.0
12.1 14.7
2.3 6.2
Test = n,hrskm 8.2 5.3 69 130 I?.‘) 12.6
12.1 12.5
TV>1= rum 12.6 96 13.6 I39 9x
12.3 13.0
Rum-LlCl DW-LICI
I.9 92
Test = rum (CS) 3.2 5.6 2.0 12.9 14.1 14.1
Rum-L&Z1 DW-LKl
2.6 6.4
7Ls1 = whrska 10.6 6.7 10.3 13.0 12.8 12.9
12.3 13.1
EtohmLKl DW-LiCI
Rum-LKI DW-LICI
2.2 8.8
Tm = erhunol I3 0 62 10.6 I4 3 13.5 13.3
12.4 14.1
Etoh-LiCI DW-LiCI
Alcohol
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in rats
to the conditioning beverage (CS) than to either of the two generalization test beverages. An ANOVA of the data for conditioning to whiskey (Table 2) and for conditioning to rum (Table 3) yielded reliable effects (P < 0.05) for training condition, test beverage and training condition x test beverage. An ANOVA of the data for conditioning to ethanol (Table 4) yielded reliable effects (P < 0.05) for training condition and the training condition x test beverage interaction. Tables 2-4 also show that aversion effects to the generalization test beverages occurred mainly on Trials 1 and 2 and tended to dissipate thereafter, as compared to the more enduring aversion to the CS. An ANOVA of the data for conditioning to whiskey (Table 2) or to ethanol (Table 4) yielded a reliable training condition x test trials interaction in each case (P < 0.03 and P < 0.04, respectively). An ANOVA of the data for conditioning to rum (Table 3) revealed reliable interactions of training condition x test trials and test beverage x test trials (P < 0.001 and P < 0.02, respectively). Together, the results of these analyses and the data of Tables 2-4 provided reliable evidence for stimulus generalization decrement effects following conditioning for each beverage. When the test beverage was different from the conditioning beverage, intake of the former was generally higher than that for the latter. This effect was especially notable for the Bev-LiCl groups as compared to DW-LiCl groups in each table. In order to evaluate the generalization of aversion effects across CS and test beverages the data of Tables 2-4 were converted into percent intake scores. Specifically, the intake of each rat in a beverage conditioning group was divided by the mean intake of the comparable DW-LiCl group on each test trial for each of the test beverages, whiskey, rum and ethanol. The lower the percentage score is, the greater the difference in intake between conditioning and control (DW) groups and. thus, the stronger the aversion. A percentage score of 100 would indicate no evidence for aversion. Figure 2 presents the percentage intake data. An ANOVA over all the data of Fig. 2 yielded a reliable effect for test beverage, conditioning beverage x test beverage and conditioning beverage x test beverage x test trials [F(2/72, 4/72 and 16/128) = 3.69, 12:63 and 3.79, P < 0.03, P < 0.0002 and P < 0.0001, respectively]. Simple effects analyses together with the results of Fig. 2, yielded the following conclusions. On Test Trial 1 aversion effects to the CS and the generalized test beverages were similar to each other. Evidence for differences in the generalization of aversion effects appeared over test trials, beginning with Trial 2. Specifically, aversion conditioning to whiskey yielded generalized aversion effects to rum and to ethanol. However. each of the latter showed smaller aversion effects than that for the CS (Ps < 0.01). The aversion effect to rum was reliably greater than that to ethanol: test beverage and test beverage x test trials. F( l/ 16 and 4164) = 4.60 and 4.07, P < 0.05 and P < 0.005, respectively. Aversion conditioning to rum
CS=WHISKEY
CS=RUM
CS=ETOH
I
1
I
I
1
I
2
3
4
5
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2
3
1
j
4
5
TEST TRIALS Fig. 2. Mean percent intake on Test Trials l-5 for groups conditioned (CS) on whiskey. rum or ethanol and then tested (‘TS) on the conditioning beverage or on either of the other two beverages.
260
JOSEPHJ. FRANCHINA et (11.
yielded aversion effects to whiskey and to ethanol, which were less than that to the CS (P < 0.002) but highly similar to each other (F < 1). Aversion conditioning to ethanol yielded aversion effects to whiskey which were similar to that for the ethanol conditioning beverage (F < 1) but which were reliably greater than those to rum: test beverage x test trials [F(4/64) = 3.74. P < O.Ol]. Conversely, the generalization of aversion effects to whiskey was greater following conditioning with ethanol than with rum (P < 0.05). But generalization of aversion to rum or to ethanol was nondifferentiable whether the CS was whiskey or ethanol for rum or whiskey or rum for ethanol (F < 1). DISCUSSION The effective use of CAT as a treatment for alcoholism may depend, in part, upon the associability between the characteristics of alcoholic beverages and toxicosis. These characteristics may regulate the magnitude of the originally-established aversion and the generalization of tlzat aversion to other alcoholic beverages. If conditioning occurs to the specific characteristics of an alcoholic beverage then, abstinence may occur toward that beverage. But intakes of other distinguishable alcoholic beverages may not be altered or may even increase. For example. Quinn and Henbest (1967) reported data which are consistent with a view of beverage specificity in alcohol aversion conditioning. The 10 alcoholic Ss in their experiment acquired an aversion to the CS. whiskey, and abstained from that beverage for intervals from 11 days to 17 yrs; 8 of the 10 Ss abstained for over 1 yr. However, 7 of the 10 Ss increased their intakes of other alcoholic beverages such as beer/stout, table wine, rum and gin. These data suggest a failure of generalization of aversion effects across alcoholic beverages. The results of Experiments 1 and 2 suggest that aversion effects were more strongly established to the characteristics of the particular alcoholic beverage(s) (i.e. ethanol + congeners) than to the characteristic(s) of ethanol. In Experiment 1 aversion effects were stronger (more perisistent) to whiskey and bourbon CSs than to ethanol, although all CSs contained 59,; ethyl alcohol. Experiment 2 provided reliable evidence for stimulus generalization effects, In this experiment the display of generalized aversion depended upon which beverage was the CS and which, the test stimulus. Since all beverages contained 5% ethanol Experiment 2 results suggested that specific beverage characteristics exerted a potent influence on the maintenance of the conditioned aversion. The present evidence for beverage/flavor specificity in alcohol aversion should not come as a surprise, considering Jounela-Eriksson’s (1979) data on human judgmental responses to the flavor of alcoholic beverages and data on FAL in rats (e.g. Braveman and Jarvis, 1978). Jounela-Eriksson (1979) reported reliable differences in human judgmental responding, based on the purity and taste of vodka and flavored distilled spirits and on the aroma and taste of red wines. Nachman (1963. 1970), Nowlis ( 1974), Braveman and Jarvis ( 1978) and Nowlis, Frank and Pfaffman (1980) reported that conditioning and/or generalization of aversion occurred to specific flavor characteristics. such as quality, concentration and temperature. The differences in aversion effects among whiskey, bourbon, rum and ethanol CSs (Experiment 1) may be described in terms of compound/complex flavor conditioning (Rescorla and Wagner, 1972). The combination of 5% ethanol + congeners which make up whiskey, bourbon and rum may constitute these beverages as compound/complex CSs with gustatory and olfactory characteristics. Because of the greater number of stimulus elements for conditioning, associative strength to a compound/complex stimulus is typically greater than that to the individual elements (e.g. Holland and Forbes, 1980). Thus, aversion effects were greater to whiskey, bourbon and rum than to ethanol. Greater aversion occurred to whiskey and bourbon than to rum perhaps because of differences in olfactory cues. Whiskey and bourbon contain high levels of fuse1 alcohol and fatty acid esters which determine the aromatic characteristics of an alcoholic beverage (Lehtonen and Suomalainen, 1979). The amount of fuse1 alcohol in whiskeys (including, bourbon) is ten times that in rum (Jounela-Eriksson, 1979). Thus, differences in aversion effects between whiskey/bourbon and rum may be related to differences in odor stimuli between the beverages. In Experiment 2 generalization of aversion effects presumably reflected the commonality of tlavor characteristics between CS and test stimuli. However, because compound/complex and elemental stimuli were presented in conditioning and testing, generalization effects may have depended upon the presence of distinctive as well as shared characteristics. Accordingly, conditioning with whiskey
Alcohol aversion in rats
261
yielded a gradient of generalization of aversion to rum and ethanol presumably because whiskey and rum shared more characteristics (e.g. numbers of fatty acid esters) than did whiskey and ethanol. Conditioning to rum yielded similar levels of aversion to whiskey and to ethanol. Perhaps, rum shared characteristics with whiskey and with ethanol separately without necessarily implicating a commonality between whiskey and ethanol. Or perhaps, the common presence of ethyl alcohol in whiskey and ethanol permitted comparable generalization of aversion to each of them following conditioning with rum. The present data do not permit a choice betwezn these alternatives. Finally, conditioning to ethanol yielded similar levels of aversion to ethanol and to whiskey. Since conditioning with whiskey yielded reliable evidence of stimulus generalization decrement in testing with ethanol these results, taken together, yield evidence of asymmetrical generalization effects between whiskey and ethanol. Asymmetrical generalization between flavors has been reported previously in aversion learning (e.g. Nowlis et al., 1980; Parker and Revusky, 1982). Although there are several explanations of this effect, the present results may be related to the use of compound/complex and elemental stimuli in conditioning and testing (Rescorla and Wagner, 1972). Specifically, a compound stimulus is comprised of a variety of elemental stimuli. Following conditioning to an individual element, generalization of aversion may be highly likely to occur in testing with the compound because the compound includes the original CS, the individual element. Conversely, after conditioning with the compound, aversion may be unlikely to generalize to testing with the individual element because that test stimulus may preclude the other elements of the compound and, thus, inadequately represent the original CS. The present analysis of aversion conditioning to alcoholic beverages proposes that they be viewed as compound/complex stimuli. If this supposition is reasonable, then the advancement of information about effective CAT might better be accomplished by studies of compound FAL (e.g. Holland and Forbes, 1980) within a theoretical context such as the Rescorla-Wagner (1972) model. A tentative conclusion of the present report is that the characteristic(s) of ethanol in alcoholic beverages influence(s) aversion effects much less than do the taste/flavor characteristics of particular beverages. If so, two suggestions might be offered. In CAT the taste and aromatic characteristics of the particular beverage(s) should be strongly emphasized to the patient, perhaps by verbal priming procedures. Secondly, perhaps CAT might employ ethanol-free beverages which simulate the taste and aromatic characteristics of the alcoholic beverage. The advantages of this strategy would be that larger CS doses and more frequent CS presentations could be used in CAT without risking the pharmacological side effects of ethanol. REFERENCES Baker T. B. and Cannon D. S. (1979) Taste aversion therapy with alcoholics: techniques and evidence of conditioned response. Behar. Res. Ther. 17, 229-242. Boland F. J.. Mellor C. S. and Revusky S. (1978) Chemical aversion treatment of alcoholism: lithium as the aversive agent. Behar. Res. Ther. 16, 401409.
Braveman N. S. and Jarvis P. S. (1978) Independence of neophobia and taste aversion learning. Anim. Learn. Behac. 6, 406-412.
Cannon D. S. and Baker T. B. (1981) Emetic and electric shock alcohol aversion therapy: assessment of conditioning. J. consult. clin. Psychol. 49, 20-33.
Cannon D. S.. Baker T. S. and Wehl C. K. (1981) Emetic and electric shock alcohol aversion therapy: six- and twelve-month follow-up. J. consult. clin. Psvchol. 49, 360-368. Davidson W. S. II (I 974) Studies of aversive conditioning for alcoholics: a critical review of theory and research methodology. Psychol. Bull. 81, 571-581. Elkms R S. (1975) Aversion therapy for alcoholism: chemical. electrical or verbal imagery? Inc. J. Addict. 10, 157-209. Holland P. C. and Forbes D. T. (1980) Effects of compound or element preexposure on compound flavor aversion conditioning. Anim. Learn. Behar. 8, 199-203. Jounela-Eriksson J. (1981) Panel experience and responses to the flavor of alcoholic beverages. In Criteria for Food .4ccepplance: HON. Marl Chooses Whar He ESS (Edited by Solms J. and Hall R. L.). Forster, Zurich. Leake C. D. and Silverman M. (1971) The chemistry of alcoholic beverages. In The Biology of Alcoholism: Biochemisfr_v, Vol. 1 (Edited by Kissin B. and Begleiter H.). Plenum Press, New York. Lehtonen M. and Suomalainen H. (1979) The analytic profile of some whiskey brands. Process. Biochem. 14, 5-9. Logue A. W. (I 979) Taste aversion and rhe generality of the laws of learning. Psychol. Bull. 86, 276-296. Nachman M. (1963) Learned aversion to the taste of lithium chloride and generalization to other salts. J. romp. phvsiol. P.~>~c-hOl. 56, 343-349.
Nachman
M. (1970) Learned taste and temperature
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Nowlis G. H.. Frank M. and Pfaffman C. (1980) Specificity of acquired aversions to taste qualittes m hamsters and rats. J. camp. physiol. Psychoi. 94, 932-942. Parker L. A. and Revusky S. (1982) Generalized conditioned flavor aversions: effects of toxicosis training with one Havor on the preference for different novel flavors. Anim. Learn. Behac. 10, 505-510. Pohl R. W., Revusky S. and Mellor C. S. (1980) Drugs employed in the treatment of alcohohsm: rat data suggest they are unnecessanly severe. Behm. Res. Ther. 18, 71-78. Quinn J. T. and Henbest R. (1967) Partial failure of generalization in alcoholics following aversion therapy. Q. JI Srutl. Alcohol 28, 70-75. Rescorla R. A. and Wagner A. R. (1972) A theory of Pavlovian conditioning. Variations in the effectiveness of reinforcement and nonreinforcement. In Classical Conditioning II: Current Research und Theor? (Edited by Black A. H. and Prokasky W. F.). Appleton-Century-Crofts. New York. Revusky S. (1973) Some laboratory paradigms for the chemical aversion treatment of alcoholism. J. Behar. Ther. e.rp. Psychiat. 4, 15-17. Revusky S. and Taukulis H. K. (1975) Effects of alcohol and lithium habituation on the development of alcohol averston through contingent lithium injection. Behav. Res. Ther. 13, 163-166.