Learned taste avoidance (LTA) was studied by allowing rats to drink a novel sweet solution followed by induction of gastric malaise (training). When the solution was presented again (test), normal rats reduced their consumption. Ultrasonic vocalizations indicated that the rats experienced positive affect during training which shifted to negative affect during the test. Basolateral amygdala lesions eliminated the LTA and the negative affective shift when the rats were 23 hr water deprived during both training and test suggesting amygdala-based Pavlovian conditioning, but only attenuated the LTA and eliminated the aversive shift when the rats were 3 hr deprived on the test, suggesting instrumental learning. When rats were 3 h deprived during training the lesions had no effect on either the LTA or the negative affective shift, suggesting an amygdala-independent form of LTA based on latent learning.