Identifying humans by their sense of smell
Each individual human's sense of smell may be unique, with new research suggesting a person could even be identified by their "olfactory fingerprint".
The human nose has about six million smell receptors of around 400 types. How they are distributed varies from person to person according to research recently published by scientists from Israel's Weizmann Institute in the Proceedings of the National Academy of Sciences.
The research looked at how different – or similar – smells were to one another. In an experiment led by Lavi Secundo, volunteers were asked to rate 28 smells according to 54 descriptive words such as "lemony" or "masculine". These ratings then formed the basis of a mathematical formula that was used to determine how similar any two odours were to the human nose. The 28 odours made for 378 different pairs, each with a different level of similarity. Using this tool, the scientists determined that each person tested had a unique pattern – an olfactory fingerprint.
The next stage of the research will examine how this olfactory fingerprint ties in with an individual's immune system. The researchers believe the method could be used for the early detection of diseases such as Parkinson's and Alzheimer's and could also be used to help determine whether bone marrow or organ donors are a good match.