By Will Dunham / Reuters / 22 Mar 2014
What does your nose know? A lot more than you might expect.
Scientists studying the breadth of people's sense of smell said on Thursday the human nose can discern far more than the 10,000 different odors long cited as the outer limit of our olfactory abilities.
They concluded that the human nose can differentiate an almost infinite number of smells - more than a trillion - based on their extrapolation of findings in laboratory experiments in which volunteers sniffed a large collection of odor mixtures.
"The single most important contribution of this research is that it revises this current idea that humans are terrible smellers," said Leslie Vosshall, who heads the Laboratory of Neurogenetics and Behavior at Rockefeller University in New York that conducted the study published in the journal Science.
"We're very good smellers," Vosshall added.
Just like with sights and sounds, people are accosted with a multitude of smells like perfume, body odor, rose blossom, beer, rotten egg, paint, cut grass, spoiled milk, fresh popcorn, dog breath, burning wood, ammonia, grilled meat, orange peel, pine, excrement, cinnamon, exhaust fumes, cookies and skunk spray.
Research has shown that people can distinguish several million different colors and about 340,000 audio tones, but the dimensions of the sense of smell had remained a mystery.
There has been a notion around since the 1920s that people could discern only about 10,000 odors, but that was based on faulty assumptions, these researchers said. They designed experiments to try to zero in on the actual number.
Their experiments involved 26 men and women of various racial and ethnic groups, ages 20 to 48. The volunteers were given three glass vials of scents at a time - two identical to one another and the third different - and were asked to identify the different one. Each did this with 264 different scents.