In four experiments, food deprivation was varied during conditioning and testing of conditioning of flavor preferences by sweeteners. Conditioned preferences for a flavor associated with a more concentrated solution were enhanced by increased deprivation in training whether sucrose or saccharin was used when rats consumed solutions freely during training. When consumption of solutions was controlled and higher deprivation levels were used, preference for the higher concentration of sucrose was still enhanced by increased deprivation in training, but this did not occur with saccharin. We suggest that deprivation may enhance the reinforcing value ofsweetness only when calories increase along with sweetness. We also suggest that deprivation can enhance flavor preference learning by increasing consumption and thereby increasing exposure to ' the flavored solutions.

No abstract

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...

When a caloric substance is followed by a flavored substance, preference for the flavor that followed the calories can increase because of a flavor-nutrient association. We showed here that this effect is opposed by a fullness effect: consuming the caloric substance itself reduces consumption of the flavor that follows. Because consumption of this flavor was less than consumption of a flavor that was given alone, there was a reduced preference for the flavor that followed the calories-an effect opposing flavor-nutrient learning. The preference for the flavor that was given alone and consumed in greater amounts seems to be due to exposure per se and is not a result of contrast. When the amount of the flavor given alone was directly controlled so that it was one half the amount of the flavor that followed the calories, preference for the flavor following the calories was no higher than when consumption of the two flavors was equal. Thus, exposure can interfere with flavor-nutrient learning, but does not enhance it.Capaldi and Sheffer (1992) showed that a flavor of saccharin given after chocolate milk was later preferred to a flavor given alone. They suggested that the flavor given after the chocolate milk was associated with the postingestive effects (nutrients) of the chocolate milk, and was therefore later preferred on the basis of flavor-nutrient learning. Boakes and Lubart (1988) suggestedthis hypothesis to account for their finding that a flavor of saccharin given shortly after glucose was preferred to a flavor given alone. When flavored saccharin followsglucose, the flavor of saccharin is more closely associated in time with the postingestive effects of glucose than is the flavor of glucose itself. Consistent with this hypothesis, Boakes and Lubart (1988) showed that a flavor of saccharin given 60 min after glucose, long enough for the postingestive effects of glucose to have dissipated, was not preferred to a flavor given alone.In Experiment I, we were concerned with whether exposure to flavored saccharin or the nutrient prior to flavor-nutrient learning would interfere with that learning. Holder (1991) showed that a cue (taste or odor) that had been paired with sucrose was preferred to one that had been paired with saccharin. When a second cue was added that was associated with sucrose, the second cue was ignored in favor of the cue that was learned first-a blocking effect (Kamin, 1969). We hypothesized that as a result of preexposure to chocolate milk, rats would form an association between the taste of chocolate milk and the resulting calories, and that when saccharin followed chocolate milk in training, the saccharin cue would be ig-