The impact of wine tasters’ expectations on wine quality ratings and willingness-to-pay

Is it possible to exploit cognitive biases so that a non-professional taster prefers one wine to several other absolutely identical wines? To address this question, three complementary experiments were carried out. Each time, five wines were tasted blind in a tasting laboratory by 24 to 34 tasters. Converging evidence from the experiments shows that participants were not capable of identifying that some of the wines they were tasting were absolutely identical. Moreover, the results show that by providing information about the wines’ ratings, prices, or reputation, tasters’ expectations can be modified, and, as a result, their evaluations of the wines can be altered. Specifically, we show that it is possible to modify the ranking between different wines and to get tasters to prefer a wine over other absolutely identical wines. Finally, a surprising finding was that experienced tasters express stronger opinions and adapt their evaluations more strongly after being given manipulative information on the wines they taste.