Smell of dead can threaten humans: study

The smell of dead organisms can trigger fight or flight in us, according to a new study which suggests humans, like other species, can perceive certain scents as threatening.
Dr Arnaud Wisman, from the University of Kent's School of Psychology, found that putrescine, the chemical produced by decaying tissue of dead organisms, can produce a fight-or-flight response in humans.
In four different experiments, people were exposed consciously and non-consciously to putrescine.
The results show that putrescine can serve as a (non-conscious) signal that initiates threat management responses.
The researchers found that even brief exposure to putrescine increases vigilance, followed by the readiness to either escape (flight), or engage in aggressive readiness (fight) when escape is not possible.

These are the first results to show that a scent emanating from a specific chemical compound (putrescine) can be processed as a threat signal.

So far, nearly all the evidence for threat chemosignals has come from those that are transmitted by body sweat.
The researchers also believe their study as being among the first to show that a specific chemical compound can cause overt behaviour change in humans.
One of the outcomes of isolating putrescine in threat management processes is that it may help in determining which sensory and brain pathways are involved in chemosensory threat detection and processing.
The research was published in the journal Frontiers in Psychology.