British psychologists have found that putrescine - one of the main components of the smell of death - triggers an unconscious defense reaction in a person, forcing his body to prepare for flight or fight for his life, according to an article published in the journal Frontiers in Psychology.
Since ancient times, people began to distinguish among the smells a special sweetish "scent of death" hovering around the corpses of living beings.
At the beginning of the 20th century, scientists found out that the two main components of the "cadaveric smell" were two nitrogen-containing substances - cadaverine and putrescine, the molecules of which appear inside the corpse during its decomposition.
These scents, as shown by a study by American biologists in 2013, were so important to our distant ancestors that their nervous system contained a special olfactory receptor designed exclusively for recognizing cadaverine. Apparently, this ability helped them avoid those parts of their habitat, the waters or soils of which were contaminated with the decomposition products of corpses.
Arnaud Wisman of the University of Kent (UK) and his colleague Ilan Shrira of the Arkansas Tech Russellville (USA) found that a person apparently retained this ability by observing how people consciously and unconsciously react to the scent of putrescine.
Gathering a group of a dozen volunteers, scientists invited them to smell putrescine, explaining what it is, or "perfume" based on it, and observed how their reaction speed, adrenaline level, thinking speed and aggressiveness towards strangers changed.
All these factors, as scientists explain, are associated with the so-called "fight or flight" response - a special state of the body, into which it is mobilized in order to avoid or reflect the threat to its existence.
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As the experiments of Wismann and Srira have shown, inhaling the scent of putrescine triggers this reaction even when a person has no idea that he is dealing with a cadaveric odor. Even a small amount of this substance made a person more alert to danger and more aggressive towards others, and also improved his ability to seek a way out of life-threatening situations.
Such a reaction to the smell of death suggests that many other chemicals found in nature can quite strongly affect human behavior. Wisman and Srira plan to find them in their next works.
