Your Sense of Smell May Be Quicker Than You Think

October 15, 2024
Ernie Mundell HealthDay Reporter

People sense millisecond shifts in odor as quickly as they might spot a change in color, new research shows.

The study discounts the notion that smell is a "slower" sense than sight or hearing, scientists say.

"A sniff of odors is not a long exposure shot of the chemical environment that averages out" over time, explained study lead author Dr. Zhou Wen, at the Institute of Psychology of the Chinese Academy of Sciences.

Instead, smell can spot fluctuations in odors with a "sensitivity on par with that for color perception" in vision, she said in an academy news release.

Zhou's team published its findings Oct. 14 in the journal Nature Human Behaviour.

Human's sense of smell is nowhere near that of many animals, such as dogs. But it may not be as sluggish as most people think, the new study found.

In their experiments, the Chinese team constructed a special sniff-triggered device that organized the emissions of odors with a precision of 18 milliseconds.

Using the device, they had it produce two odors one after the other, separated by milliseconds, switching which odor came first.

They then had 229 people sniff the odors to see if they could sense any differences.

According to the academy news release, "participants could tell the difference when the delay between the compounds was just 60 milliseconds -- about a third of the time it takes to blink."

That's roughly equal to the time it takes the human visual sense to distinguish the order of green and red lights blinking, Zhou's team noted.

In an accompanying journal editorial, Dr. Dmitry Rinberg, a professor of neuroscience and physiology at NYU Langone Health in New York City, described the new findings as akin to how people hear music.

“The timing of individual notes in music is essential for conveying meaning and beauty in a melody, and the human ear is very sensitive to this. However, temporal sensitivity is not limited to hearing: our sense of smell can also perceive small temporal changes in odour presentations,” he wrote. “Similar to how timing affects the perception of notes in a melody, the timing of individual components in a complex odour mixture that reaches the nose may be crucial for our perception of the olfactory world.”

Rinberg believes it's time the human sense of smell was taken more seriously by science.

“The study of human olfaction has historically lagged that of vision and hearing, because as humans we think of ourselves as visual creatures that largely use speech to communicate,” he said.

Her team's findings aren't just a scientific curiosity, Zhou told CNN.

“Our apparatus could be used for therapeutic purposes, such as olfactory training for patients with olfactory loss,” she said. “More broadly, our findings could guide the design and development of electronic noses and olfactory virtual reality systems, which could have significant clinical benefits.”

More information

Find out more about how your sense of smell works at the Cleveland Clinic.

SOURCES: Nature Human Behavior, Chinese Academy of Sciences, news release, Oct. 14, 2024; CNN

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