Study says nose can detect a trillion odors
The human nose may be able to detect more than 1 trillion different odors, according to a study published in the journal Science.
The findings vary drastically from those of previous studies that contended that humans were able to detect approximately 10,000 odors. The new research demonstrates that humans’ sense of smell may have a much broader range than any other sense.
For the study, scientists from Rockefeller University in New York used 128 odor molecules—such as spearmint, orange and anise—to create various mixtures containing different proportions of 10, 20 or 30 molecules. The researchers recruited volunteers and gave each of them three vials of the odor mixtures. Two vials were identical, and the volunteers were asked to identify which vial was different.
The results showed that even when vials shared as much as 51 percent of the same odors, most volunteers were able to distinguish between the mixtures. On average, the volunteers were unable to distinguish between mixtures when the shared proportion was more than 51 percent. After further data analysis, the researchers estimated that the total number of distinguishable odor mixtures was approximately 1 trillion. The researchers concluded that the actual number of distinguishable odors may be more than 1 trillion, since the real world offers many more odor mixtures than did the vials in the laboratory.