Conditioned taste aversions: generalization to taste mixtures.

Rats were trained to take their daily water ration within a 30-min session, during which the number of licks per 10-sec presentation of a drinking tube could be recorded. During one of these sessions, one of three stimuli (sucrose, NaCl or HCl) was presented, followed by the administration of cyclophosphamide to produce a conditioned taste aversion. When tested with mixtures of the conditioned stimulus (CS) with the other two stimuli and also with quinine hydrochloride, the animals avoided mixtures containing the CS in proportion to its concentration in the mixture. Although the natural preferences and aversions for these stimuli interacted somewhat with the learned taste aversions, rats responded to the presence of a CS in a mixture and did not generalize to other stimuli not containing the CS. Thus, the generalization of conditioned taste aversions provides a good measure of the behavioral similarities among gustatory stimuli.