People all over the world have similar preferences for smells. Cultural differences play a smaller role than previously assumed, according to a new study by an international research team led by neuroscientist Artin Arshamian from the Karolinska Institute in Sweden in the journal Current Biology.
In this study, 235 people from nine different regions of the world had to rank ten smells according to their preferences. Among the test subjects were hunter-gatherer tribes from Mexico or Thailand, farmers from Ecuador, or city dwellers from Mexico and Thailand. When choosing the smells, the team referred to a 2016 study by researchers Andreas Keller and Leslie Vosshall, in which 476 different odor molecules were tested. The new data was also compared with the results from Keller and Vosshall.
The selected odorants included vanillin and the fruity-smelling butyric acid ethyl ester or linalool, which can be smelled in herbs such as basil or oregano. Ultimately, among the ten test samples, vanillin prevailed as the most pleasant smell in all of the population groups surveyed. The most unpleasant was the smell of isovaleric acid, which is responsible for the smell of foot sweat.
Some smells were probably evolutionarily decisive
The results show that while people’s odor preferences differ, there are no major differences between different cultures. Arshamian’s team puts the cultural influence on preference at just six percent. According to the group, 54 percent of the differences can be attributed to personal preferences and 41 percent have to do with the chemical structure of the scent molecule. “Traditionally, the perception of smell has always been considered a cultural phenomenon, but our results show that culture has very little to do with it,” says Arshamian.
The results of the olfactory study show serious differences, for example in comparison to the perception of the attractiveness of faces. According to earlier studies, cultural imprinting plays the dominant role. How pleasant or unpleasant we perceive smells is therefore less dependent on a person’s cultural background than the perception of whether we find a face attractive. “We now know that there is a universal sense of smell,” says Arshamian. This is strongly controlled by the molecular structure of the odorous substances. This explains why there are globally universal odor preferences.
The next step is now to find out what happens in the brain when smelling, says Arshamian. Some smells might be perceived as more pleasant because they were important for survival in human evolution. Already in early human history, smells were an indicator of whether food could still be eaten. If it smelled bad, there was a high probability that the planned meal was already spoiled and therefore dangerous.