The “Old Person Smell” – a term most have heard and some might even have associated with aging – is a scientifically acknowledged phenomenon. It’s not merely a product of myth or derogatory stereotype, but a real, tangible experience whose mechanism is an interesting subject of research in the scientific community. In Japan, this distinct smell is referred to as kareishu1.
Our understanding of this ‘smell of aging’ deepens with a groundbreaking study2 that provided evidence supporting the notion that humans, much like other animals, can distinguish age based solely on body odor.
Unveiling the Odor of Aging: A Fascinating Experiment
To explore this fascinating aspect of human sensory perception, a study designed an intriguing experiment. They enlisted volunteers from different age groups and had them sleep in T-shirts with underarm pads for five consecutive nights. The objective? To collect the body odors emanating from each individual.
The pads soaked in sweat were cut and placed into separate jars. Then came the most exciting part – a group of lucky volunteers, aged between 20 and 30 years old, were asked to rate the ‘pleasantness’ of the odors and estimate the donor’s age.
The results of this experiment suggested that humans can discriminate age based on body odor. The unique smell linked to older individuals, often termed “old person smell” or “nursing home smell,” seemed to be a cross-cultural phenomenon, universally recognized irrespective of geographical or racial differences.
The Perception of ‘Old Person Smell’: Not Necessarily Unpleasant
Contrary to the popular notion that associates this unique odor with disagreeability, the younger volunteers found the underarm odor of the elderly to be rather neutral and not particularly unpleasant. This revelation, stated by the senior author of the study, Johan Lundström, a sensory neuroscientist, was surprising.
Lundström further mentioned that the odor emitted from other parts of the body, such as the skin or breath, might exhibit different qualities. It implies that a comprehensive understanding of ‘old person smell’ might involve more than just underarm odors.
The Biological Components behind the ‘Old Person Smell’
A separate study3 identified the odor-producing compound, 2-Nonenal, described as “an unsaturated aldehyde with an unpleasant greasy and grassy odor,” and specific skin lipids that tend to increase with age. The presence of these elements hints at their possible role in generating the distinct old age smell…
The Purpose of the ‘Old Person Smell’: An Evolutionary Perspective
Lundström’s team tentatively suggested a potential evolutionary purpose for this phenomenon. Like other animals, humans can extract signals from body odors, allowing us to identify biological age, avoid sick individuals, pick a suitable partner, and distinguish kin from non-kin. This ability could enhance our chances of survival and reproductive success, as demonstrated by certain insects where older males are preferred over younger ones, signaling their adaptive qualities that have enabled them to survive to old age.
Closing Remarks: The Quest for Knowledge Continues
While these findings significantly improve our understanding of the ‘old person smell,’ more studies are necessary to pinpoint the exact cause of this smell and identify the advantages it might offer humans.
These studies highlight the intricate and sophisticated ways in which our bodies function, and how our sensory perceptions can glean meaningful information about our surroundings and peers. The more we delve into the realm of these seemingly minor details, the closer we come to comprehending the complex symphony of life and human existence.
