It is not uncommon to hear family members talk about a loved one who has passed away. One interesting and surprising anecdote often heard is a person’s behaviour prior to dying like; saying goodbye, getting closure on troubled relationships, and even giving away prized possessions. It seems they may know something before anyone else does.
Some may argue this is purely coincidence while others are confident people know when death is near. It is only natural to try to understand the death of someone we love or make sense of what happens in those final moments. Scientists know when someone dies, the body immediately begins to break down.
Putrescine, for example, is a foul and toxic scent; the result of decomposition. Researchers have come to realize humans subconsciously recognize this putrefying odour. Not only that, the scent, when released, causes an immediate response.
Animals have the ability to smell the scent of others, prompting them to react accordingly.
This is the equivalent to sensing danger whether from a predator or stronger and bigger animal from their pack.
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 in Arkansas' Tech University in Russellville, AK have discovered animals and humans might not be so different after all.
The ability to detect chemical scents is part of survival across the species. The threat of death is revealed through smell to humans.
Putrescine is a chemical compound released when a body decays.
It also has a secondary function as a warning signal. People have both a conscious and subconscious reaction when they are exposed to this scent.
There were four different experiments conducted using putrescine, ammonia, and water to study people's reaction.
One of the experiments included putrescine exposed at a site, people's immediate response was to move away from the area.
This is the same response around fight-or-flight reaction.
When animals feel they are in danger there are only two responses; fight off the threat or run away from it. The study revealed people react similarly.
There are other scents humans respond to as well like sweat.
Separate studies have shown that sweat taken from people in fearful situations and exposed for others to smell generated an automatic and startled reflex.
"We do not know why we like (or dislike) someone’s smell, and we’re usually not aware of how scent influences our emotions, preferences, and attitudes," explain Wisman and Shira.
"It is hard to think of a scent as frightening," comment the two leading researchers. These scents make people more aware and vigilant of their surroundings.
Humans' natural reaction to danger is not to face it and fight.
People tend to avoid any type of confrontation, whether its verbal or physical. For the most part, folks choose to distance themselves until fight is the only option left.
The responses may be different from each other but putrescine and sex pheromone are based on scent.
Sex pheromones are chemicals released by the body to attract a mate while putrescine works as a warning signal. "Putrescine signals a different type of message than pheromones, but people’s responses to putrescine (avoidance and hostility) do seem indeed to be the opposite of responses to many sexual pheromones," explain the research duo.
During the study, people were not aware they had a negative reaction to the scent.
"People are not familiar with putrsescine and do not consciously associate it with death or fear," admits Wisman and Shira.