Reference: Davis, L. A., & Running, C. A. (2023). Good is sweet and bad is bitter: Conflation of affective value of aromas with taste qualities in untrained participants. Journal of Sensory Studies, e12820.
When we eat food, our perception of its taste is influenced by both our sense of taste and smell. It can be difficult to parse the influence of taste and the influence of smell on what we are tasting at the moment. To participants without formal taste training, it can be particularly hard to describe food. Part of the reason for this may be because they may lack the appropriate terminology or because many variables may make some tastes hard to distinguish by the average person. To complicate matters, the average, untrained taster might use “bitter” to describe foods they find bad and “sweet” to describe foods they find good. Two studies were conducted to test the hypothesis that one’s perceptions of whether or not something tastes good may be influenced by whether they think it is sweet or bitter.
Good and Bad Beans at the State Fair
The first experiment was conducted on 69 volunteers at the Indiana State Fair. The volunteers were presented with the test as a game in which they were given two identically tasting jelly beans with different aromas. One bean had a pleasant aroma, such as lime or coconut. The other bean had an unpleasant aroma, such as lawn clippings or spoiled milk. The researchers never said that one bean was good and one bean was bad, but they waited until the participants reported that as the result. Participants would pick a bean, taste it, and then rate the bitterness, sweetness, and whether they liked or disliked the jelly bean.
The results of the first experiment confirmed that there was indeed a bias on both the liking scale and the bitterness vs. sweetness scale. The taste of the good (pleasant) beans was overall rated as more intense than the taste of the bad (unpleasant) beans.
Testing Good and Bad Beans in the Lab
In the second experiment, there were four beans (i.e., two green and two white; one with a more pleasant taste, one with an unpleasant taste).
The Good and Bad Beans Used in Experiment 2
| Bean Color | Good Bean Flavor | Bad Bean Flavor |
| Green | Lime | Lawn Clippings |
| White | Coconut | Spoiled milk |
Participants – who were recruited as part of a lab procedure – were instructed to hold their noses and taste one of each color, then to rate the bean as bitter or sweet. Then, participants ate the jelly beans as they normally would (i.e., un-pinching their noses) and were asked if they thought the jelly bean was good or bad. Afterward, they were instructed to spit it out. Participants reported liking the sweet beans better than the bitter ones and rated bitterness as more intense when they unplugged their noses than when they plugged their noses.
Just as the researchers anticipated, untrained participants conflated whether or not they found the beans to be good or bad with whether they perceived the beans to be bitter or sweet. Bitterness was rated higher for bad-smelling beans than good-smelling beans, which suggests that participants who eat the bad beans assume that they are bitter because of their smell. Similarly, higher sweetness intensity ratings for good-smelling beans may mean that participants rated beans that they thought were good as sweet specifically because they thought the beans were good.
In the second experiment, the participants only rated bitterness higher when they were allowed to smell, but not when they had to plug their noses. In other words, participants were being misled by their sense of smell to infer bitter tastes. There was no difference in how they rated sweetness whether their nose was plugged or unplugged.
Humans prefer sweetness because it indicates the presence of nutrients that could give us energy, whereas bitterness may indicate poison. In previous studies, the presence of odor had been found to enhance sweetness, especially if it is congruent with the taste (Bingham, Birch, de Graaf, Behan, & Perring, 1990; Clark & Lawless,1994; Prescott,1999; Schifferstein & Verlegh,1996; Stevenson et al., 1999). Meanwhile, if taste and odor are incongruent (as was the case for the “bad beans”), it does not enhance the taste, nor does it minimize the taste.
In the first experiment, the questionnaire did not ask for the difference between taste and odor explicitly. In the second experiment, the fact that participants were asked to plug their nose, taste the bean, and then unplug their nose and taste the bean implies a difference between taste and odor. As a result, participants might have thought about their answers more thoroughly. In that sense, participants in the second experiment were trained but participants in the first experiment were not. Thus, although this study did not compare untrained participants to a group of individuals who had been trained to detect different tastes well, the second experiment offers a degree of training by providing participants with practice. Still, it would be interesting to see how trained participants compared to untrained participants in both experiments.
Another factor that may have influenced results is a unique characteristic of jelly beans that may make them difficult to smell. Jelly beans are harder to smell than some foods due to their waxy outer coating. There was a difference in the olfactory perceptions of participants who plugged their noses versus those who did not, but it is difficult to generalize these findings to other foods that are easier to smell. Future studies may consider using a different type of food with a stronger smell. Finally, many participants have likely tasted jelly beans before and have a preconceived notion of what they taste like, as well as a familiarity with the sweet taste in general. Therefore, the results may be hard to generalize to food as a whole.
This research raises more questions about how and if participants respond similarly to different foods and whether or not their sense of smell clouds their judgment of flavor and opens the door for more research about a variety of foods and their impact on our taste buds.
Additional References:
Bingham, A. F., Birch, G. G., de Graaf, C., Behan, J. M., & Perring, K. D. (1990). Sensory studies with sucrose-maltol mixtures. Chemical Senses, 15(4), 447–456. https://doi.org/10.1093/chemse/15.4.447
Clark, C. C., & Lawless, H. T. (1994). Limiting response alternatives in time-intensity scaling: An examination of the halo-dumping effect. Chemical Senses, 19(6), 583–594. https://doi.org/10.1093/chemse/19.6.583
Prescott, J. (1999). Flavour as a psychological construct: Implications for perceiving and measuring the sensory qualities of foods. Food Quality and Preference, 10(4), 349–356. https://doi.org/10.1016/S0950-3293(98)00048-2
Schifferstein, H. N. J., & Verlegh, P. W. J. (1996). The role of congruency and pleasantness in odor-induced taste enhancement. Acta Psychologica, 94(1), 87–105. https://doi.org/10.1016/0001-6918(95)00040-2
Stevenson, R. J., Prescott, J., & Boakes, R. A. (1999). Confusing tastes and smells: How odours can influence the perception of sweet and sour tastes. Chemical Senses, 24(6), 627–635. https://doi.org/10.1093/chemse/24.6.627
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