人类具有辨别一万亿种气味的能力.docxVIP

In a world perfumed by freshly popped popcorn and exhaust fumes, where sea breezes can mingle with the scents of sweet flowers or wet paint, new research shows that humans are capable of discriminating at least one trillion different odors. Howard Hughes Medical Institute (HHMI) scientists determined that our sense of smell is prepared to recognize this vast olfactory（嗅觉的） palette（调色板） after testing individuals ability to recognize differences between complex odors mixed in the laboratory. It has been said for decades that humans are capable of discriminating between 10,000 different odors. The number is cited in scientific literature and appears in popular magazines. Its the generally accepted number, says HHMI investigator Leslie Vosshall, who studies olfaction at the Rockefeller University. Our analysis shows that the human capacity for discriminating smells is much larger than anyone anticipated.Vosshall and her colleagues published their findings March 21, 2014, in the journal Science. I hope our paper will overturn this terrible reputation that humans have for not being good smellers, she says.Vosshall had long been bothered by the idea that humans were limited to smelling 10,000 odors -- an estimate that was made in the 1920s, and not backed by any data. Objectively, everybody should have known that that 10,000 number had to be wrong, she says. For one thing, it didnt make sense that humans should sense far fewer smells than colors. In the human eye, Vosshall explains, three light receptors work together to see up to 10 million colors. In contrast, the typical persons nose has 400 olfactory receptors.But no one had tested humans olfactory capacity. We know exactly the range of sound frequencies that people can hear, not because someone made it up, but because it was tested. We didnt just make up the fact that humans cant see infrared or ultraviolet light. Somebody took the time to test it, Vosshall says. For smell, nobody ever took the time to test.Vosshall a