Whether you like one scent or another can be highly subjective. Traditionally it has been thought that people respond to this question motivated by their culture, that is, it is something that they culturally learn. This type of smell is unpleasant and this other is pleasant because that is how it is culturally accepted. However, a study published in the journal Current Biology shows that the odors we like or dislike are mainly determined by the structure of the particular odor molecule.
“We wanted to examine whether people all over the world have the same olfactory perception and like the same types of smell, or if this is something culturally learned,” says Artin Arshamian, a researcher at the Karolinska Institutet’s Department of Clinical Neuroscience who has participated in the investigation. “Traditionally it has been seen as something cultural, but we can show that culture has very little to do with it.”
The present study demonstrates that the structure of the odor molecule determines whether an odor is considered pleasant or not. The researchers found that certain smells were liked more than others , regardless of the culture of the participants.
“Cultures around the world classify different odors similarly, regardless of where they come from, but there is a personal, not a cultural, component to odor preferences,” says Dr. Arshamian.
The experiment has the participation of researchers belonging to institutions around the world such as the Karolinska Institutet (Sweden), the University of Oxford (United Kingdom), the Universidad San Francisco de Quito (Ecuador), the University of Melbourne (Australia) and the National Autonomous University of Mexico. Many of these scientists are field workers working with indigenous populations.
For the investigation, the researchers selected nine communities representing different lifestyles : four hunter-gatherer groups and five groups with different forms of agriculture and fishing. Some of these groups have very little contact with Western food products or household items.
“Because these groups live in such disparate odor environments, such as the jungle, the coast, the mountains and the city, we pick up many different types of ‘smell experiences,'” says Dr. Arshamian.
A total of 235 people participated in the study, who were asked to rate odors on a scale from pleasant to unpleasant. The results show changes between individuals within each group, but also an agreement on which odors are pleasant and unpleasant. The researchers show that the variation is largely explained by molecular structure (41%) and personal preference (54%).
“Personal preference may be due to learning, but it could also be a result of our genetic makeup,” says Dr. Arshamian.
Vanilla is the smell that I like the most
Among the odors that participants were asked to classify as pleasant or unpleasant was vanilla, which smelled the best, followed by ethyl butyrate, which smells like peaches. The smell that most participants found least pleasant was that of isovaleric acid, which is found in many foods, such as cheese, soy milk, and apple juice, but also in foot sweat.
According to Dr. Arshamian, one possible reason why people consider some odors more pleasant than others, regardless of culture, is that such odors increased the chances of survival during human evolution .
“We now know that there is a universal perception of odors that is governed by molecular structure and that explains why we like or dislike a certain smell,” continues Dr. Arshamian. “The next step is to study why this is so, linking this knowledge to what happens in the brain when we smell a particular odour.”
Arshamian et al. 2022. The perception of odor pleasantness is shared across cultures. Current Biology. DOI:https://doi.org/10.1016/j.cub.2022.02.062