Ontogenesis of learning: IV. Dissociation of memory and perceptual-altering processes mediating taste neophobia in...

The rat's neophobic response to tastes can be conceptualized as depending on two processes: memory processes that store a representation of an experienced taste so that it can be recognized as familiar on subsequent encounters, and perceptual-altering processes that respond differentially to novel versus familiar tastes. We investigated the ontogeny of these processes by studying the preweanling rat's behavioral reaction to a 10% sucrose solution. Experiments I and II suggest that the memory processes mature earlier (by 7-8 days of age) than the perceptual-altering processes (about 11 days of age). Experiment III suggests that pups do not acquire an aversion to sucrose paired with illness until they are 12-days-old, implying a close correspondence between the maturation of processes mediating neophobia and taste aversion learning. These findings are consistent with our previous work (Vogt & Rudy, 1984), and our view that ontogenetic dissociations in taste-guided behavior reflect caudal-to-rostral maturation in the ascending gustatory system.