In five experiments, rats' preference for a flavor was greater if the flavor had previously been consumed under low rather than high deprivation. This preference was conditioned in as few as three flavor-deprivation pairings (Experiment 1), and persisted through 28 test days, half under each deprivation level (Experiment 2). Rats never preferred the flavor associated with high deprivation even when calories were increased by giving 40 ml of 8% sucrose or when caloric density was increased to the equivalent of 20% sucrose. The preference for the lowdeprivation flavor was greater when saccharin solutions were used rather than sucrose solutions, but the preference did emerge when sucrose solutions were used as testing proceeded and when a lower concentration of sucrose was used. We suggest that these preferences may be a result of flavor-taste associations rather than associations between flavors and postingestive consequences, and that the taste of the solutions under low deprivation is preferred to the taste under high deprivation.We recently found that rats' preference for a flavor was greater if they had previously consumed it under low rather than high hunger when flavors were given separately from the daily feeding (Capaldi & Myers, 1982). Given the widespread assumption that the incentive value of food increases with increased hunger (e.g., Kurtz & Jarka, Revusky, 1967), this finding is surprising. Our aim in the first two of the present experiments was to establish the reliability of this effect and the range of conditions under which it occurs. Experiment 1 looked for the effect with minimal training, and Experiment 2 measured the persistence of the effect. EXPERIMENT 1Experiment 1 used 6 training days. In all our previous experiments, we have used 20 training days. However, taste aversions based on illness can be conditioned rapidly (Logue, 1979), so it was of interest to determine if taste preferences! based on hunger level were also learned rapidly. MetbodSubjects. The subjects were 24 male albino rats, 174 days old at the beginning of the experiment. They were 78 days old on arrival from the Holtzman Co., Madison, Wisconsin, and had been employed in a straight alley instrumental learning experiment in which they had received 14 g of food per day for 69 days. New groups were formed by evenly redistributing the rats from the old groups.Reprints can be obtained from Elizabeth D. Capaldi, Department of Psychological Sciences, Purdue University, West Lafayette, Indiana 47907. 107Materials. Flavored solutions were presented in 50-ml Nalgene centrifuge tubes with rubber stoppers and metal spouts. Flavor cues consisted of 111fo cinnamon (211fo imitation cinnamon flavoring mixed with 100llfo ethanol) or 111fo wintergreen (211fo imitation wintergreen flavoring mixed with IOOllfo ethanol) dissolved in a saccharin solution with water (.15I1fo saccharin) or a sucrosewater solution (811fo sucrose).Procedure. All training and testing occurred in the rats' home cages. Ad-lib water was available throughout the experime...

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In four experiments we showed that rats prefer a flavor associated with a delayed edible consequence if the delayed consequence contains calories; the greater the number of calories, the greater the preference. We obtained conditioned preferences with delayed consequences of dextrose plus quinine, 8% polycose, 8% sucrose, 10 g of high fat mash, and 14 g of lab chow. No conditioned preferences were obtained with delayed consequences of saccharin, 10 g of low fat mash, 1% polycose, or 1% sucrose. Thus, it seems that flavor preferences based on delayed caloric consequences occur only if there are appreciable calories in the consequence.

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In four experiments, rats' preferences for flavors consumed under high deprivation versus low deprivation were measured. In Experiment 1, rats preferred flavors received in unsweetened food under high deprivation to flavors received in unsweetened food under low deprivation. This preference did not vary with amount offood used to deliver the flavors (l-g vs, 16-g wet mash). Sweetening the food (0.10% saccharin) eliminated this preference when 16 g of mash was received, but not when 1 g of mash was received (Experiments 2 and 3). Sweetening the mash even more (0.15% saccharin) eliminated the preference when 1 g of mash was received, as well as when 20 g of mash was received. We suggested that the reinforcing value of sweetness is reduced by increasing deprivation level.The reward value of food should increase with increasing food deprivation, according to many theorists. Bolles (1972), for example, suggested that deprivation is one way to increase the reward value of a goal. Food deprivation, accordingly, should enhance the reward value of food.We were interested here in whether or not deprivation enhances the reinforcing effect of food. That is, we were interested in whether or not deprivation enhances the learning produced by food. To answer this question, two different flavors were associated with the same food under two different deprivation levels. Subsequently, preference between the flavors was measured under common deprivation levels. Revusky (1967) reported the first study measuring the effects of deprivation on conditioning (learning) of food preferences. He gave rats grape juice or milk before or after a meal (thus, high deprivation was before feeding, low deprivation following feeding). Later, rats' preference for the flavor given before feeding (under high deprivation) was increased relative to the flavor given after feeding (under low deprivation).When flavors are given before and after feeding, factors other than level of food deprivation can affect conditioned preferences. The flavor given before feeding can be associated with the subsequent large feeding; the flavor given after feeding can be associated with effects of having just completed a meal. In a series of experiments, Capaldi and Myers (1982) and Capaldi, Myers, Campbell, and Sheffer (1983) gave flavors either separately from feeding or before and after feeding. In these studies, This research was supported in pan by Grant MH 39453 to the first author from the National Institute of Mental Health. Requests for reprints should be sent to Elizabeth D. Capaldi, Department of Psychology, University of Florida, Gainesville, FL 32611-2065. saccharin or sucrose solutions were used to deliver the flavors. Rats preferred the flavor received under low deprivation to that received under high deprivation when flavors were given separately from feeding. When flavors were given immediately preceding and following a meal, rats preferred the flavor given under high deprivation (before feeding). Capaldi and Myers (1982) suggested that there might be som...