It’s a common occurrence to hear relatives reflect on the peculiar behaviors exhibited by someone shortly before their passing. These behaviors often include bidding farewells, resolving long-standing conflicts, and distributing cherished belongings, almost as if they sensed the end was approaching.
While some may dismiss these actions as mere coincidences, many believe that individuals can indeed sense their imminent demise. It’s a natural inclination to seek understanding or closure concerning the death of a loved one, as well as the events leading up to those final moments. Scientifically, it’s known that immediately after death, the process of bodily decomposition begins.
One of the first signs of decomposition is the emission of putrescine, a noxious and harmful odor. Studies have shown that humans can detect this scent, albeit subconsciously, which triggers an instinctual response.
Animals, too, are adept at detecting such scents, which prompts them to react appropriately, whether to avoid danger or to assess threats within their group.
Researchers Arnaud Wisman of the University of Kent’s School of Psychology in Canterbury, UK, and Ilan Shira from the Department of Behavioral Sciences at Arkansas’ Tech University in Russellville, AK, have found that the line between human and animal reactions to these scents is quite thin.
The detection of chemical odors is a critical survival mechanism across species. Humans, like animals, can perceive the threat of death through olfactory signals.
Putrescine, a chemical released during decomposition, also serves as an alarm signal, eliciting both conscious and subconscious reactions in humans.
In a series of four experiments involving putrescine, ammonia, and water, researchers observed human reactions. Notably, when putrescine was introduced at a location, the immediate human response was to withdraw from that area.
This reaction mirrors the fight-or-flight response observed in animals facing peril, where the options are to confront the threat or flee.
Humans also respond instinctively to other scents, such as sweat. Additional research has demonstrated that sweat from individuals in fearful situations, when presented to others, can induce an automatic and startled response.
Wisman and Shira explain, “The intricacies of why we are attracted or repelled by certain scents remain elusive, and we are often oblivious to the profound impact scents have on our emotions, preferences, and attitudes.”
They further note, “Considering a scent as frightening seems counterintuitive,” highlighting how certain odors heighten our awareness and alertness to our surroundings.
Typically, humans prefer to avoid confrontation, whether verbal or physical, opting to distance themselves unless confrontation is unavoidable.
The reactions elicited by putrescine and sex pheromones, although both scent-based, are fundamentally different. Sex pheromones are intended to attract mates, whereas putrescine acts as a cautionary signal. “The reactions to putrescine—avoidance and hostility—contrast starkly with the generally attractive nature of sexual pheromones,” the researchers clarify.
During their studies, participants were unaware of their adverse reactions to the scent.
“Most people are unfamiliar with putrescine and do not consciously link it to death or fear,” Wisman and Shira acknowledge, underscoring a significant aspect of human sensory perception and its subconscious influences.
