New research reveals that our sense of smell is far more rapid than previously believed, detecting changes in scent in as little as 60 milliseconds — faster than the blink of an eye.
Assumed Scent Was Slow
Scientists from the Chinese Academy of Sciences published their findings in Nature Human Behaviour, showing that our noses can identify subtle chemical shifts within a single breath.
When we inhale, airborne chemicals enter our noses and activate receptors that allow us to recognize scents. These odor molecules are then expelled as we exhale.
Traditionally, the duration of a breath (about three to five seconds) led to assumptions that scent detection was a relatively slow process, according to WP.
Even Charles Darwin once dismissed the human sense of smell as “remarkably unimportant.” Yet, these new findings indicate that we’re more perceptive of scents than once thought.
Distinguish Scents With Only 60-Millisecond Delay
Our noses are constantly bombarded with an array of odor molecules, each representing a complex mixture.
For example, the scent of coffee is the result of hundreds of chemical components, none of which smell like coffee on their own.
Olfactory receptors, located in the cell membranes of sensory neurons, respond to these diverse molecules by creating unique activation patterns that our brains use to recognize specific smells.
In the study, Dr. Zhou Wen and her team used a special apparatus with two tubes of different lengths connected to separate scent containers.
By varying the tube lengths, the researchers could release different scents in rapid succession, with intervals as precise as 18 milliseconds.
Participants were exposed to two distinct scents, such as apple and floral, and asked to detect if the order of smells changed between tests.
Remarkably, 63% of participants could correctly identify whether the order was altered, even with an interval as short as 120 milliseconds.
The most sensitive participants could distinguish the order of two scents with just a 60-millisecond delay, showcasing how swiftly our sense of smell operates.
Further testing indicated that scent intensity, pleasantness, sharpness, or the number of odor molecules did not affect this ability.
While participants often noted when the scent changed, they found it challenging to identify which smell came first. Their overall perception of the mixed scents was influenced by whichever scent they detected first, suggesting that the order in which we sense smells plays a role in how we perceive them.
