WSJournal. Orange.. You Hungry. Psychology:

A small but tasty study bolsters the old saying that people eat with their eyes.

Researchers in Europe asked 57 participants to assess the taste of hot cocoa served in four different colored cups, all the same size: white, cream, orange and red. By a significant margin, volunteers preferred the taste of cocoa served in the orange cup and the cream cup over the other two colors, even though they were drinking the same beverage.

The results are consistent with earlier research that involved a variety of foods and demonstrated that colors influence the perception of taste. In an earlier paper, the same researchers showed that people liked strawberry mousse better, finding it sweeter and more intense, when it was served on a white plate rather than on a black one.

"The Influence of the Color of the Cup on Consumers' Perception of a Hot Beverage," Betina Piqueras-Fiszman and Charles Spence, Journal of Sensory Studies (August)