Families often engage in conversations about a beloved family member who has passed away. They frequently share anecdotes about the individual’s actions before their passing, such as bidding farewell, resolving challenging relationships, or even bequeathing cherished possessions. This sometimes gives the impression that they possessed prior knowledge unknown to others.
However, interpretations on this matter can vary. Some attribute it to mere chance, while others firmly believe that individuals have an awareness of their impending demise. It is natural to seek understanding regarding the passing of a loved one or envision their final moments. Scientists have observed that a person’s body begins to deteriorate immediately after death.
One example is the emission of putrescine, a foul-smelling substance associated with decay, which can be detrimental to health. Research has revealed that people unconsciously register the presence of this unpleasant odor. What is intriguing is that the scent of putrescine triggers immediate reactions, both conscious and subconscious.
In the animal kingdom, scents play a crucial role in conveying information. Animals can detect and respond to each other’s scents, which can influence their behavior. Similarly, humans possess an innate ability to detect danger, whether it stems from a predator or a more dominant member of their group.
A study conducted by Arnaud Wisman from 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, suggests that humans and animals share similarities in their responses to chemical odors.
All species rely on their ability to detect chemical odors for survival. In the case of humans, they can sense when they are in danger of dying. When a body undergoes decomposition, it emits a chemical called putrescine, which serves as a warning signal. When people encounter this scent, they respond consciously and subconsciously.
To investigate these reactions, researchers conducted four different tests using putrescine, ammonia, and water. In one experiment, they placed putrescine in a specific location, and upon detecting it, people promptly left the area. This response mirrors the “fight-or-flight” reaction seen in dangerous situations. Just like animals that either confront or flee from threats, humans tend to act in a similar manner, as indicated by the study.
Sweat is another odor that triggers responses in people. Separate studies have shown that when individuals’ sweat, collected when they were frightened, was exposed to others for smelling, it induced an unconscious startle response.
Wisman and Shira state, “We don’t know why we like (or dislike) someone’s smell, and we usually don’t know how scent affects our feelings, preferences, and attitudes.” Other leading researchers add, “It’s challenging to identify a smell that would be considered frightening.” Nevertheless, individuals tend to exhibit heightened awareness and caution when encountering such scents.
In the face of danger, people’s natural response is often to avoid confrontations. They opt to steer clear of conflicts, whether verbal or physical, and generally prefer to maintain distance from one another until circumstances force them into action.
Although putrescine and sex pheromones may evoke different responses, both are linked to the sense of smell. Sex pheromones are chemical signals emitted by the body to attract potential mates, while putrescine serves as a sign of distress or danger. As the researchers note, “Putrescine conveys a different message compared to pheromones,” and “People’s reactions to putrescine (avoidance and hostility) seem to be the opposite of how they react to many sexual pheromones.”
During the study, participants were unaware that the odor was causing their discomfort. Wisman and Shira acknowledge that most individuals do not recognize putrescine or associate it with death or fear.