Bitter mouth-rinse affects emotions

The sense of taste enables evaluation of food and is an important regulator of food consumption. In general, sweet is an attractive taste modality that leads to ingestion of nutritive food, while sour and bitter are aversive taste modalities that lead to avoidance of spoiled and toxic food. Recent studies suggest inter-connections between taste, emotion and cognition. Here we test the potential effects of two prototypical taste modalities, bitter and sweet, on emotions and on generalized avoidance behaviors, such as risk aversion and mistrust. Three experiments included over 250 participants who tasted, without swallowing, one of the following stimuli: water control, quinine solution, sucrose solution, quinine-sucrose mixture solution, or propylthiouracil (PROP) solution. The participants had to identify the taste, rank its intensity, perform seemingly unrelated behavioral tasks, and fill a PANAS mood questionnaire. Our results indicate that oral exposure to bitter compounds negatively correlates with mood scores; that the effect depends on perceiving the solution as bitter; that bitter mouth rinse can lower PANAS mood score and that there is a potential asymmetry in the effects of bitter and sweet taste modalities on mood.