Non-fatal poisoning of rats has been known to produce an increased reluctance to ingest any novel tasting substance (neophobia). I have recently found that an abrupt shift to a less preferred reward also produces enhanced neophobia and that such a shift may facilitate learning to avoid flavors that are followed by poison. The goal of the present research will be twofold, first to explore the mechanism by which reward shifts facilitate poison avoidance learning, and second to examine the effects of neophobia produced by shifts in reward on investigatory behavior.