Human nose can detect 1 trillion odors

A new study published in the journal Science finds that the human sense of smell can detect more than 1 trillion odors, far exceeding the number previous studies have indicated. Humans can discriminate several million different colors and nearly half a million sounds or tones, so by showing we can discriminate over 1 trillion odors, the study places the human sense of smell in a different league altogether. The authors write that the study "demonstrates that the human olfactory system, with its hundreds of different olfactory receptors, far outperforms the other senses in the number of physically different stimuli it can discriminate." Study leader Dr. Andreas Keller, of the Laboratory of Neurogenetics and Behavior at Rockerfeller University in New York, NY, says even 1 trillion may be an underestimate: "The message here is that we have more sensitivity in our sense of smell than for which we give ourselves credit. We just don't pay attention to it and don't use it in everyday life," according to a news agency.