The human nose: an unsuspected power to decode scents 👃

Beyond its apparent modesty, the human nose conceals astonishing abilities to detect the subtleties of odors. Contrary to what was previously thought, our sense of smell reacts with a speed comparable to that of vision and hearing.

In a study published in Nature Human Behaviour, researchers used an innovative device to test the olfactory perception in 229 adults. By exposing them to mixtures of odors with precise delays, they demonstrated that participants could distinguish variations in just a few dozen milliseconds. This result challenges our understanding of the speed of our sense of smell, suggesting a temporal code for odor identification, similar to how we perceive colors.


Through a series of carefully orchestrated experiments, the researchers developed an innovative device capable of presenting odor mixtures with extreme precision, with delays as short as 18 milliseconds. This technology allowed for rigorous control over the precise moment each odor was released into the air, ensuring that participants inhaled the scents in a specific order. Thanks to this device, it became possible to observe how individuals could distinguish not only the odors themselves but also the order in which they were presented.

Even when the time differences between the two scents were minimal, the participants demonstrated an impressive ability to correctly identify which fragrance was perceived first. In fact, while previous research suggested that the time required to perceive two odors was about 1200 milliseconds, the tests conducted in this experiment revealed that the human nose could distinguish between two different scents with a latency of just 60 milliseconds between them.

This precision revealed an unexpected olfactory sensitivity, highlighting the efficiency with which the human nose can analyze and interpret complex chemical signals in a very short time.

The implications of these discoveries go far beyond the realm of science. They could profoundly impact sectors such as the food industry, perfumery, and even medicine, offering new perspectives for the development of advanced olfactory technologies.

Researchers are also considering potential applications in olfactory rehabilitation for people with anosmia (the loss of the sense of smell) and in the design of sensory virtual reality systems.

What is olfactory perception?

Olfactory perception is the brain's ability to interpret odor molecules captured by the nose. When a person inhales, olfactory receptors located inside the nasal cavity detect the chemical compounds present in the air. These signals are then sent to the brain, which translates them into odor sensations.

The brain uses a "temporal coding" mechanism to identify odors. Each odor corresponds to a particular combination of molecules captured by different receptors. This temporal coding allows the brain to quickly differentiate between nearby smells, even when they are perceived just a few milliseconds apart.