New Study Suggests Human Sense of Smell Is Faster Than Previously Believed

 New Study Suggests Human Sense of Smell Is Faster Than Previously Believed

Your Nose Might Be More Powerful Than You Realize.

A single sniff allows the human sense of smell to identify odors in just a fraction of a second, demonstrating a sensitivity that rivals our brain's perception of color. This challenges the common belief that our sense of smell is relatively slow, according to a new study.

Humans can differentiate between sequences of odors, recognizing whether “A” comes before “B” or vice versa, even when the gap between the two is just 60 milliseconds, according to a study published Monday in Nature Human Behaviour.

Dr. Wen Zhou, the study's lead author and a principal investigator at the Chinese Academy of Sciences in Beijing, expressed surprise at the findings. “Participants could distinguish between two odorants presented in one order and the reverse with a latency as short as 60 milliseconds,” he explained in an email. For context, an eye blink lasts about 180 milliseconds.

Zhou noted that this technology could have therapeutic applications, such as olfactory training for those with smell loss. "Our findings could also inform the design of electronic noses and olfactory virtual reality systems, which may offer significant clinical benefits."

The research team from the University of Chinese Academy of Sciences and Ohio State University created a sniff-triggered device featuring check valves and Teflon tubes, allowing for precise odor delivery within 18 milliseconds. They asked 229 adults in China to use the device and smell various odor mixtures, including apple, sweet floral, lemon, and onion scents, with carefully controlled latency between the two odors.

The researchers investigated whether participants could differentiate between two odors presented in one order versus the reverse at various latencies. They discovered that two odors became “perceptually discriminable” when presented just 60 milliseconds apart in a single sniff, according to Zhou.

However, the team noted they only tested four specific odorants and suggested that exploring a broader range could reveal whether human sensitivity varies with different odor dynamics or compounds. “This could enhance our understanding of the computational principles that shape our olfactory experience,” Zhou explained.

These new findings challenge earlier research, which suggested that distinguishing between odor sequences took around 1,200 milliseconds. In an accompanying editorial, Dr. Dmitry Rinberg, a professor at NYU Langone Health, emphasized that just as timing is crucial for conveying meaning in music, our sense of smell is also capable of detecting subtle temporal differences in odor presentations. “The timing of individual components in a complex odor mixture may be essential for our perception of the olfactory world,” he noted.

The ability to distinguish odors within a single sniff may play a crucial role in how animals identify smells and their spatial location, according to Dr. Sandeep Robert Datta, a professor of Neurobiology at Harvard Medical School, who was not involved in the study.

“This finding demonstrates that humans can differentiate smells as they evolve within a sniff, highlighting that timing is vital for olfactory perception across species. This principle is fundamental to understanding how smell functions,” Datta noted in an email.

He pointed out that research on human olfaction has historically lagged behind studies of vision and hearing, as we tend to see ourselves as primarily visual beings who communicate through speech. However, he emphasized that this new study helps “fill a critical gap in our understanding of how we perceive odors.”