Effects of Early Experience on Flavor Preference

Abstract

P. T. Young (1955) presented a study in support of his hedonic theory of motivation. He concluded that a definite preference for tap water over distilled water which was exhibited by a group of rats was determined by the fact that tap water is higher in sense appeal or positive affective arousal and this determined the choice. However, the present authors contend that a crucial variable was overlooked, viz., the effects of early experience. The present preliminary study was designed to determine the effects of early drinking experience on flavor preference. A group of freshly weaned rats, who had only experienced mother's milk prior to the experiment, was reared for 35 days, beginning at 22 days of age, on ad libitum diet of Purina rat chow and distilled water tainted with kerosene. A control group was reared in the same manner but had a choice of two drinking solutions: kerosene-tainted distilled water and Chicago tap water. At the end of Day 57, each S was housed individually in identical cage conditions containing two separate water fountains filled with kerosene-tainted distilled water and Chicago tap water, respectively. The bottle positions were reversed daily to minimize position preferences. The water consumption of each animal was recorded daily. When the individual consumption rate reached an asymptote and this persisted for three days, S was considered to have established a definite flavor preference. This preference criterion was reached in from 10 to 15 days. Six of the 12 experimental Ss reared on kerosene-tainted distilled water showed a marked preference for the kerosene water. The average consumption of these six Ss on the final test day was 72% kerosene water. The range of individual records was from 51% to 89%. The remaining seven Ss preferred the tap water, and their average consumprion on the final testing day was 85% with a range of from 66% to 94%. All control Ss who had a choice of kerosene water and tap water for the entire rearing exhibited on the average 71% tap water consumption on the final test day. These results suggest that, although tap water seems to be innately preferable, animals, e.g., 6 of 13 in the experimental group, can learn to shift their preferences to fluids which are biologically non-preferred. The present exploratory study did not determine the physiological mechanisms underlying such shifts in the development of flavor preference. Investigations of these mechanisms, e.g., the effects of oIfaction and gustation on flavor adaptation, are currently being conducted.