Variety in the flavor of food enhances eating in the rat: a controlled demonstration.

The effect of variety in the flavor of food on rats' consumption of a meal was examined in two experiments in which the confounding factors of diet composition and palatability could be ruled out. Experiment 1 showed that rats ate more of a four-course meal when each course was flavored differently than when each course was flavored the same; furthermore, this "variety effect" did not appear to depend upon the rats' prior experience with the flavors. Experiment 2 replicated and extended these findings by showing that the enhancement of eating by variety did not depend critically upon the rat's level of food motivation. The results were discussed in terms of their implications for the etiology and control of obesity, as well as for theories of satiety. It was suggested that the "variety effect" may represent an adaptive mechanism in the control of feeding.