Flavor expectation: The effect of assuming homogeneity on drink perception

Here, we investigate whether the expectation that a drink tastes consistent across mouthfuls influences reported taste. A paradigm was developed to prompt the expectation that drink stimuli tasted identical to each other. Participants sipped two drinks and indicated whether they tasted the same. In some trials, the drinks appeared to be poured from the same jug, prompting the homogeneous taste expectation. These 'same-jug' drink pairs were reported more similar than 'different-jug' drink pairs, where the drinks were seen to be poured from different jugs, even when sweetness differed. This effect did not occur when the difference in sweetness between the drinks was too great. This suggests that expectancy effects act to smooth out variation in taste within a window of taste differences, until differences become perceptually noticeable. The expectation effect also dwindled over the course of the experiment, suggesting that expectations of similarity were updated with increasing experience of incongruous same-jug drinks. We conclude that flavor perception is best considered in terms of windows of flavor variation within which sensation changes to be more in line with expectations derived from past and current consumption experiences.