Latent inhibition in conditioned taste aversion: the roles of stimulus frequency and duration and the amount of fluid ingested during preexposure.

Two experiments examined the effects of total stimulus preexposure on latent inhibition (LI) in a conditioned taste aversion procedure with rats. Experiment 1 varied the frequency and duration of saccharin preexposures. LI was an increasing function of the product of frequency x duration. Experiment 2 kept saccharin exposure time constant but varied the amount of saccharin consumed by manipulating number of hours of fluid deprivation prior to exposure. Deprivation schedule conditions affected the amounts consumed which, in turn, modulated LI magnitude, at least with a 1-day acquisition-test interval, as in Experiment 1. The data clearly indicate that LI is a function of total amount of contact with the preexposed saccharin solution. In addition, half of the subjects in Experiment 2 were tested 21 days after the conditioning event. LI was not present in any group tested at this interval. These data were discussed in regard to the controversy regarding whether LI represents a failure to acquire the CS-US association or a failure to retrieve that association.