EARLY EXPERIENCE WITH SOUR AND BITTER SOLUTIONS INCREASES SUBSEQUENT INGESTION

Rats exposed to quinine or citric acid solutions during nursing, during the early postweaning period, or during both nursing and early postweaning showed a modification in their voluntary ingestion of these substances. With quinine, the most effective period of exposure was after weaning. Rats exposed to quinine during the post weaning period or in adulthood showed increased quinine ingestion. Rats exposed to quinine during nursing, however, did not show increased quinine ingestion even if additional exposure to quinine was given postweaning. In contrast, rats exposed to citric acid while nursing showed an increased voluntary ingestion of citric acid compared to animals exposed to citric acid either after weaning or not exposed to citric acid at all. Both sour and bitter tastes are commonly thought to be innately aversive substances; however, with appropriate developmental experience, an animal's response to bitter and sour substances can be modified. The alteration of expected taste preferences or aversions through experience may be seen as one mechanism accounting for certain human food preferences. © 1979.