Human Sense of Smell Is Faster Than Previously Thought, New Study Suggests

A new study reveals that the human sense of smell is far more sensitive than previously thought, capable of distinguishing odors and their sequences within just 60 milliseconds. CNN reports: In a single sniff, the human sense of smell can distinguish odors within a fraction of a second, working at a level of sensitivity that is 'on par' with how our brains perceive color, 'refuting the widely held belief that olfaction is our slow sense,' a new study finds. Humans also can discern between various sequences of odors -- distinguishing a sequence of 'A' before 'B' from sequence 'B' before 'A' -- when the interval between odorant A and odorant B is merely 60 milliseconds, according to the study, published Monday in the journal Nature Human Behavior.

The new findings challenge previous research in which the timing it took to discriminate between odor sequences was around 1,200 milliseconds, Dr. Dmitry Rinberg, a professor in the Department of Neuroscience and Physiology at NYU Langone Health in New York, wrote in an editorial accompanying the study in Nature Human Behavior. '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 odor presentations,' he wrote. 'Similar to how timing affects the perception of notes in a melody, the timing of individual components in a complex odor mixture that reaches the nose may be crucial for our perception of the olfactory world.'

The ability to tell apart odors within a single sniff might be an important way in which animals detect both what a smell is and where it might be in space, said Dr. Sandeep Robert Datta, a professor in the Department of Neurobiology at Harvard Medical School, who was not involved in the new study. 'The demonstration that humans can tell apart smells as they change within a sniff is a powerful demonstration that timing is important for smell across species, and therefore is a general principle underlying olfactory function. In addition, this study sheds important light on the mysterious mechanisms that support human odor perception,' Datta wrote in an email. '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, adding that the new study helps 'fill a critical gap in our understanding of how we as humans smell.'

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