Scientists at Israel’s Weizmann Institute have “trained” an electronic system to be able to predict the pleasantness of novel odors, just like a human would perceive them – turning the popular notion that smell is completely personal and culture-specific on its head.
In research published in PLoS Computational Biology, the scientists argue that the perception of an odor’s pleasantness is innately hard-wired to its molecular structure, and it is only within specific contexts that personal or cultural differences are made apparent.
In practical terms, their conclusions might drastically affect fast odor screening in the perfume industry and develop the sense technology of transmitting scent digitally. The scientists’ findings may even allow for the digital transmission of smell to scent-enable movies, games and music.
Electronic noses have been around for a decade, but their sensors are based on an “odor fingerprint” that characterizes a specific odor, precluding them from identifying a novel odor not in the database. The Weizmann invention overcomes this limit.
The team of Weizmann scientists trained the “e nose” to predict whether an odor would be perceived as pleasant or unpleasant by comparing odor preferences among native Israelis. The scientists used the results to check out the preferences of a completely different group of native Israelis and found that the ratings were very similar.
They made sure that the smell preferences were not a cultural phenomena by studying how Ethiopian immigrants reacted to smells.
The results showed that the e nose’s ability to predict the pleasantness of novel odors against the native Ethiopians’ ratings was just as good, even though it was “tuned” to the pleasantness of odors as perceived by native Israelis. In other words, even though different odors have different meanings across cultures, the e nose performed equally well across these populations.
“Being able to predict whether a person who we never tested before would like a specific odorant, no matter their cultural background, provides evidence that odor pleasantness is a fundamental biological property," according to Prof. Noam Sobel, whose then-graduate student Dr. Rafi Haddad led the research.
“Many may wonder how the French can like the smell of their cheese, when most find the smell quite repulsive,” he said. “We believe that it is not that the French think the smell is pleasant per se; they merely think it is a sign of good cheese. However, if the smell was presented out of context in a jar, then the French would probably rate the odor just as unpleasant as anyone else would.”