When someone asks me what flavor slushie I want, I don’t say “cherry,” I say “red.” That flavor is called “red.” “Blue” is another flavor a slushie might have. Similarly, a cherry smell—especially the chemically cherry smell of a red slushie—is a red smell.
That one’s easy, since cherries are red. It doesn’t take a wild leap to make that association. But what color is the smell of, say, soap?
A new study published in PLOS One finds that some people say white, some say yellow, some say blue. A group of international researchers had people from different cultures smell 14 scents and choose from 36 colors the one that they associated most with the odor.
This isn’t a study about synesthesia—the neurological phenomenon that causes some people to mix their senses, associating colors with certain letters, or sounds, or smells. It just aimed to find commonalities in how we think about smell, visually. Some of the study’s participants were Dutch, some were Chinese residing in the Netherlands, some German, some American, some Malay, and some Chinese residing in Malaysia.
Some associations were stronger across cultures—fruity smells usually went with pinks and reds, vegetable smell was often seen as green, and a “musty” odor was typically linked with browns and oranges. Others were harder to nail down—as shown in the chart below, “plastic” smell led to a wide range of color choices.
The chart also shows what smells each culture finds similar. For example, in the U.S., fruity, candy, and flower smells were all pinks and reds. Differences between cultures could be “due to patterns in dietary habits, the role of fragrance in each society, or other social factors,” the study reads.
Even for non-synesthetes, our senses relate to and support each other in interesting ways. In the introduction to the study, the researchers sum it up well: “Would a rose smell as sweet if it were blue? Perhaps not.”