Humans can discriminate between 1 trillion smells
Summary
- Humans have an excellent sense of smell - we can detect differences between one trillion different odors.
Details
- Humans can outperform dogs with our sensitivity to odors
- we can discriminate more smells than we can see colors or sounds
- 3 percent of the human genome deals with olfactory receptor types.
References
- How to Taste Coffee - Develop Your Sensory Skills and Get the Most Out of Every Cup - Jessica Easto
- The Idiot Brain - Dean Burnett
Quotes
Mammals tend to have well-developed olfaction systems, particularly when it comes to discriminating different smells. We humans can discriminate—that is, detect differences between—at least one trillion odor stimuli. That means we can discriminate more odors than colors (2.3 to 7.5 million) and sound tones (340,000).3 People used to think that humans’ sense of smell was inferior to that of other mammals, such as dogs and mice, since we have relatively few olfactory receptors in comparison. New research has shown that we have quite an advanced olfaction system and outperform many mammals, including dogs, with our sensitivity to tested odor stimuli—which are called odorants—and are on par with or only slightly worse at discriminating tested odorants
Flash forward to 2014, when Caroline Bushdid and her team actually tested this claim, getting subjects to discriminate between chemical cocktails of very similar odours, something that should be practically impossible if our olfactory system is limited to 10,000 smells. Surprisingly, the subjects could do it quite easily. In the end, it was estimated that humans can actually smell in the region of 1 trillion odours. This sort of number is usually applied to astronomical distances, not something as humdrum as a human sense.
There are a lot of different smell receptors; a Nobel Prize-winning study by Richard Axel and Linda Buck in 1991 discovered that 3 per cent of the human genome codes for olfactory receptor types.