According to recent research, the human nose possesses a remarkable ability to detect various odors and react to them, even if they cannot be precisely identified. One such odor is putrescine, a chemical released by the body during the breakdown of certain substances, often associated with harmful behavior during an animal’s development. Scientists believe that the ability to sense and respond to putrescine traces back at least 420 million years.
Animals are believed to sense danger when detecting putrescine, and their reactions typically fall into two categories: either a predator is nearby, or their life is at risk, prompting them to instinctively flee.
To explore whether human reactions mirror those of animals, researchers conducted four experiments involving human subjects exposed to solutions of putrescine, water, and ammonia.
- Vigilance: In the first experiment, subjects were exposed to putrescine odor, and their vigilance was tested during the exposure. Results indicated that participants exposed to the scent of putrescine exhibited significantly higher alertness compared to those exposed to ammonia or water scents.
- Evasion Tactics: The second experiment involved unsuspecting subjects rating the strength, aversion, and familiarity of various odors while being monitored for their response. People who smelled putrescine tended to move away from the source more rapidly, suggesting that the odor strongly motivates individuals to flee.
- Word Associations: In a subsequent experiment, participants were exposed to the odor of putrescine and then asked to complete word stems. The results showed that the scent of putrescine triggered the group to choose word stems primarily related to escape and other protective behaviors. The use of such word stems intensified the aversion to the smell.
- Insecurity and Hostility: In the final experiment, subjects were exposed to a faint putrescine odor that was too weak to be consciously smelled. Despite this, participants displayed hostility and defensiveness when given a text to read and evaluate the author. This suggested that even unconscious exposure to putrescine led to protective behavior.
These experiments provide valuable insights into how humans react to certain odors, particularly putrescine, and how their behavior parallels that of animals in potentially dangerous situations. The findings highlight the significant impact odors can have on human behavior and instinctive responses to potential threats.