Body odour reveals a person's age
Old spice It's true: Old people smell. But not in an offensive way, according to a study that has found humans can identify another person's age group purely by getting a whiff of their body odour.
Although considered an offensive smell to be masked with deodorants and perfume, body odour is thought to send out an array of messages that people receive on an unconscious level.
"Signals in body odour can help us identify kin from non-kin, choose a suitable partner and also determine age," says Assistant Professor Johan Lundström, an experimental neuropsychologist at the Monell Chemical Sciences Centre in the United States, and senior author of the paper published today in PLoS One.
It is widely believed that body odour changes as people get older. Previous studies found that rats could identify different ages based on smell and researchers wanted to see if humans also have this ability.
In the study, scientists gathered data from three age groups - young (20 to 30 years), middle-age (45 to 55 years) and old-age (75 to 95 years). The participants slept in t-shirts with pads located under the armpits. After five nights the armpit pads were removed and placed in jars. Other participants were then asked to rate the scent and group the jars according to age.
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Researchers found that people were easily, and correctly, able to group the armpit pads according to age categories.
"These results indicate that we are much better at using our noses than we previously thought," says Lundström.
The team found that the old-age group had a characteristic odour which, contrary to common beliefs, was rated as less intense and more pleasant than the younger age groups.
The results also showed that in the young and middle-age groups, people were able to identify differences between genders. Overall, middle-aged men were reported to have the strongest and most unpleasant smell.
Associate Professor David O'Carroll, a neuroscientist from the University of Adelaide describes the findings as "very interesting."
"This study shows quite clearly that as we get older we smell better," he says.
Lundström explains that body odour is a complex chemical mixture with between 120 to 200 individual molecules.
He hopes that further research will be able to pinpoint which molecules are responsible for providing information about a person's age.
Lundström is also keen to discover what other messages are hidden in a person's scent and investigate how this impacts our behaviour in everyday life.