Scientists from the Weizmann Institute of Science and the University of California, Berkeley, discovered that it is possible to predict the pleasantness of a smell based on the molecular structure of the substance that creates the smell
What makes one smell pleasant and another smell "repulsive"? Is the chemical and physical structure of a molecule related in one way or another to the sense of smell it evokes when it binds to the receptors in our nose? Scientists from the Weizmann Institute of Science and the University of California at Berkeley discovered that such a relationship does exist, and that it is possible to predict the pleasantness of a smell based on the molecular structure of the substance that creates the smell.
In the fields of vision and hearing there is a known connection between the physical properties of the stimuli and the way in which the information is received and processed in the brain. The perception of color is dictated by the wavelength of the electromagnetic radiation, and the perception of sound is determined by the frequency of the sound waves. But in the field of smell, no orderly physical connection between the factors of smell and the way we perceive or feel it was known until now. The research by Prof. Noam Sobel from the Department of Neurobiology at the Weizmann Institute of Science and his research partners, which was recently published in the scientific journal Journal of Neuroscience, is an important first step in understanding these laws.
To identify the principle according to which our perception of smell is organized and classified, the researchers used a database that includes 160 odorants rated by 150 experts (smell and perfume researchers), according to 146 characteristics ("sweet", "smoky", "musty", etc.) . This data was analyzed using statistical software that produces an axis that describes the factor responsible for most of the variation in the way different people perceive smells. The researchers discovered that the axis created in this way actually describes the degree of pleasantness evoked by the smells - the axis ranges between adjectives such as "sweet" and "floral" on one side, and "musty" and "disgusting" on the other. The researchers also discovered that this axis coincides with the axis created by analyzing the difference between the physical and chemical properties of those substances. That is, the results allow the researchers to create a model that predicts the degree of pleasantness that any smell will evoke, according to the data of its chemical-physical structure.
To test the validity of the model, the researchers predicted the pleasantness of about 50 substances that they had never smelled, and checked how different groups of subjects rated their pleasantness. The results obtained using the model coincided to a very large extent with those obtained in the experiments, that is, the researchers were able to predict well the degree of pleasantness of unfamiliar smells. It is interesting to note that, contrary to the accepted approach, which sees the perception of smell as a subjective and culture-dependent matter, the pleasantness ratings obtained by American, Jewish-Israeli, and Arab-Muslim subjects from Israel corresponded to the prediction to a similar extent. Prof. Sobel: "These findings show that the way we perceive smells is innate, at least in part, and well encoded in brain activity. Admittedly, there is a certain flexibility in the perception of smell, and the degree of pleasantness may vary according to life experience. But a large part of the feeling of pleasantness reflects a real order that exists in the physical world. This discovery allows us to predict perceptual aspects of new fragrances."
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Kobi, your theory falls in the case of the flies and the dung beetle...
Kobi, without humans it is impossible to define a bad or good smell.
Our brain categorizes it as good or bad to protect us but it is equally possible that if garbage was a positive thing we would find its smell attractive. Besides, there are quite a few healthy products that smell very bad and unhealthy products that smell good. It is dangerous, for example, to smell a deodorant spray for too long because it pollutes the circulatory system and yet our brains have not yet had time to develop and classify the smells of sprays and other relatively modern products as dangerous.
It seems as if the olfactory property of a molecule was determined in the knowledge that some day life would appear that could interpret it. Nature made sure that garbage and other dangerous things spread molecules in the air that will be interpreted as a bad smell and this in order to protect us from infections.
About five years ago they showed on a TV show...a man who found the smell receptors in the nose! From the program it can be understood that the matter has been resolved and it was probably a long search on which several groups of researchers worked for years!
In the same program (about 5 years ago), there was already talk about an electronic nose that would be connected to a computer and transmit the smell on the network!! And also about a scent distributor that will convert the bits into a scent, of course this refers first of all to the food! But the truth is it is possible and these are my additions because it is possible that they were talking mainly about electronic noses for chemical plants and all kinds of environmental quality mobiles, etc.. I would also add to this a private smelling "pea" like headphones that replace speakers and only the person who puts them on can hear that way the private smell will be mounted on the nose and thus the smell will not Will fill the whole room!! Let's hope they don't try to commit the perfect crime of spreading killer smells ..see how my head works?? I immediately recognize negative points, that's how I'm built!! In this case it's for the better!
From all of this story I understand that the aforementioned study talks about deepening the understanding of the smell spectrum, it's just a shame that they don't mention the fact that the problem of the presence of the smell receptors was solved... it would have added to the understanding of the article and given a clearer picture of the situation!