It is inherent in human nature to contemplate the concept of death, and our perception of death often intertwines with images of deceased animals, humans, birds, or flies. Have you ever considered the common thread connecting them? It’s the sense of smell.
Recent studies indicate that the human nose can detect a diverse array of odors, some of which cannot be neatly categorized but still elicit a reaction. One such scent is produced by a chemical called putrescine, a byproduct of decaying bodies. Interestingly, the distinct odor is believed to be a result of animals developing a fear of death, known as necrophobic behavior, over the course of evolutionary history, dating back at least 420 million years.
Animals are thought to respond to the smell of putrescine in two distinct ways: as a sign that a predator is nearby or as an indication that they are in mortal danger, prompting an instinctual urge to escape.
To validate the similarity of human reactions to those of animals, scientists conducted four experiments using a combination of putrescine, water, and ammonia.
- Vigilance Experiment:
Participants exposed to the scent of putrescine exhibited heightened vigilance compared to those exposed to ammonia and water, demonstrating a shared reaction with animals. - Escape Behavior Test:
A group of unsuspecting individuals rated the intensity, repugnance, and familiarity of various smells and were observed for how quickly they moved away from an 80-meter distance. Those exposed to putrescine tended to distance themselves more rapidly, affirming the scent’s potent motivation to escape. - Word Stem-Completion Task:
Following exposure to putrescine, participants engaged in a word stem-completion task. The results revealed a correlation between the scent and words related to escape, highlighting the subconscious impact of the odor on cognitive associations. - Defensiveness and Hostility Experiment:
Participants exposed unknowingly to a subtle putrescine scent displayed defensiveness and hostility when evaluating an author in a reading task. This suggested that non-conscious exposure to the smell triggered defensive behavior.
In summary, these experiments shed light on the profound influence of the scent of putrescine on human behavior, drawing intriguing parallels with the instinctive responses observed in the animal kingdom.
