First of all, the fact that even water tastes sweeter when people think about love reveals that the emotion isn't acting on the taste receptors on the tongue, making them more sensitive to sugar. There's no sugar in the water, after all.

he finding is important for two reasons, Chan said. First of all, the fact that even water tastes sweeter when people think about love reveals that the emotion isn't acting on the taste receptors on the tongue, making them more sensitive to sugar. There's no sugar in the water, after all. Instead, the effect must arise from the brain's processing of the taste information.

Second, the lack of an effect caused by jealousy reveals language alone doesn't influences the senses — metaphors have to go deeper. Chan and his colleagues suspect that embodied metaphors develop only after a lot of experience. The linkage of love with the physical experience of sweetness may go back to infancy, he said. Babies start their lives drinking breast milk or formula, both of which are sweet, and may learn to associate that taste with their mother's love.

Similarly, a parent's physical warmth might be linked with closeness and acceptance, and being alone might be linked with feeling cold from an early age, Chan said. Even heaviness and importance have a physical linkage. Important books like dictionaries tend to be large and heavy, while fluffy reading usually comes in the form of lightweight paperbacks. 

Editor's note: This article was updated on Jan. 23 to correct the Mandarin spelling and translation of the phrase "chi cu."