The taste of a preferred food, pizza, was adulterated with quinine sulfate and the effects of taste experience on subsequent measures of palatability were measured. The measures of palatability were salivary responses to the thought and presentation of pizza. Additional measures were latency to start eating, amount eaten, meal duration, rate of eating and preference ratings of the pizza's taste, aroma and appearance. Thirty-six subjects received access to regular and/or adulterated pizza over two experimental sessions. The resulting groups of nine subjects each received either adulterated and adulterated, adulterated and regular, regular and regular, or regular and adulterated pizza over the two sessions. In a third session all subjects received regular pizza. In session two, groups which had received regular pizza in session one showed a reliably greater salivary response on the presentation trial than on the thought trial. Groups which had received adulterated pizza showed minimal differences in salivation between these trials. In session three, groups which had received regular pizza in session one yielded reliably greater salivation on the presentation trial than did groups which had received adulterated pizza in session one. Furthermore, nonshift groups, which had received the same pizza condition over sessions one and two, showed a greater difference between thought and presentation trial responses than did shift groups, which had received different pizza conditions over sessions one and two. An approach-avoidance conflict model of behavior was applied to the salivation data. Preference ratings of the pizza's taste, the amount eaten and the rate of eating data yielded reliably greater responses for groups which received regular pizza than for groups which received adulterated pizza in sessions one and two. Positive and negative contrast effects were also evidenced by these data. The meal duration and latency to start eating data yielded highly similar responses among groups over days. / M.S.