Congruent sound can modulate odor pleasantness.

This study aimed to determine 1) whether certain background sounds can be matched with specific odors and 2) whether the background sounds can increase pleasantness for their congruent odors. In Experiment 1, congruent sounds increased odor pleasantness, but not odor intensity, significantly more than incongruent sounds. Experiment 2 demonstrated that certain background sounds can be paired with specific odors. For example, cinnamon, clove, and orange odors were rated significantly more congruent with a Christmas carol compared with the sound of brushing teeth and/or the beach sound. The congruent sounds increased odor pleasantness significantly more than incongruent sounds. Similarly, the congruent sound-induced odor pleasantness was observed in Experiment 3. As participants judged the pair of odor and sound to be more congruent, they rated the odor significantly more pleasant. Congruent sound assisted participants in identifying and in being familiar with the odor, thereby leading to an increase in odor pleasantness. However, the congruent sound-induced odor pleasantness was not obtained in all odors. In conclusion, this study provides new empirical evidence that pleasantness ratings for odors can increase in the presence of their congruent sounds.