Pavlovian conditioning with ingested saline solution as the US

Experience with 2% saline as the sole available fluid for drinking produced a decrement in preference for .9% saline in a two-bottle test with water as the alternative. This outcome was interpreted as a consequence of Pavlovian conditioning, with the taste of salt acting as the conditioned stimulus and postingestive consequences of saline ingestion acting as the unconditioned stimulus. An overshadowing group experienced salt mixed with vanilla as its sole fluid during the conditioning phase. This group showed an attenuated saline aversion relative to a group that drank 2% saline solution during the conditioning phase. In addition, a vanilla aversion developed in the former group. In the second experiment, conditioning of the aversion to the taste of vanilla mixed with 2% saline was attenuated by preexposing the vanilla. The results support a Pavlovian analysis of the modification of salt preference through experience with the postingestive consequences of saline ingestion.