In the present study, we observed age-related differences in terms of baseline preference for the tactile cue employed as CS2. Specifically, UP adolescents exhibited less preference for the sandpaper-lined floor than their adult counterparts. This differential preference may reflect inherent age-related differences in predilection for rough textures. Stimuli of the same modality are organized on “natural preference scales” (Rakovee-Ratar & Weeler, 1997) and such preferences are known to change across ontogeny. At any rate, it should be noted that, in the present work, the claim for ethanol-mediated conditioned responses at each age is made by contrasting animals exposed to ethanol-CS pairings (Paired groups) against groups in which the CS had relatively little contingency with ethanol’s postabsorptive effects (i.e., Unpaired animals). In other words, differential sandpaper baseline preference across age should not obscure the fact that a single pairing between the latter cue and an ethanol-related flavor significantly affected tactile preferences in adolescent but not in adult subjects.
