People Can Smell Almost as Well as Dogs
Much of the gap comes down to sniffing, and Huberman says practice helps because smell cells turn over and retune with use.
Andrew Huberman · Your Top Health Questions AnsweredPeople can smell almost as well as dogs. Neuroscientist Andrew Huberman, describing research by olfaction researcher Noam Sobel, said the difference "has much more to do with the amount of sniffing that they do per unit time than the olfactory system itself," though dogs also have more smell neurons.
His advice for sharper smelling was to test yourself on smells. He suggested setting out distinct odors such as lemon, rose, and chocolate, then taking more deep, long sniffs than feels necessary, with eyes closed in a quiet place and full attention on the odor.
His explanation, citing Sobel's work, was that smell neurons are unusual. Unlike most brain neurons, they turn over throughout life, and how they become attuned to specific odors depends on activity, which sniffing an odor provides.
Dogs get extra help from J-shaped nostrils that keep odor circulating, so one breath carries many sniffs. They also presumably compare input from two nostrils to track odor plumes, and when fixated on a smell they seem almost deaf to sounds and blind to what is around.
Questions people ask
How often do smell-training studies have people practice?
Smell-training studies often have people sniff three or four distinct scents for about 20 to 30 seconds each, with brief rests in between. Sessions usually last a few minutes and are repeated daily for weeks or months.
If someone loses the sense of smell, can sniff training help bring it back?
Often, yes, especially after colds, flu, and COVID. Smell nerves turn over throughout life, which makes recovery possible, and ear, nose, and throat doctors often recommend structured sniffing to support it. Recovery tends to be better when training starts soon after the loss.
Do dogs really smell in stereo?
Dogs compare input from the left and right nostrils to judge where an odor is coming from, much as people use two ears to locate sound. Their nostril shape helps hold odor in place while they sample it repeatedly.