The issue of whether animals can actually respond to the smell of fear that humans emit remains debatable even if several studies have already been conducted.

A study published by PLOS One suggests that dogs in particular, react to human body postures and the chemicals emitted by humans when facing psychologically stressful conditions.

The research report published by the PLOS One science journal, revealed that dogs can detect whether humans are experiencing either typical or psychological stress based on odors emitted by the human body. A baseline human odor discriminates between the chemosignals produced by psychological stresses, which cause the body to emit different body odors called chemosignals.

According to the report, chemosignals had evolved as means of communications among like-species. Canine species for one, have developed a sense of smell to convey critical information. Such abilities enable dogs to communicate to familial members important information such as raising awareness about the presence of potential predators, conveying food locations and in recognizing conspecific species to interact with for reproduction purposes.

Overview of How the PLOS One-Published Report Conducted the Study

The PLO-published study conducted tests to which the results suggested that canines have the ability to recognize humans going through psychological stress; distinguishing the chemosignals as different from those emitted by humans experiencing baseline stress.

The chemosignals of combined breath and sweat samples were collected from participants in baseline phases and from those undergoing stressful conditions. such as taking mental arithmetic tests.

After which, the study results were validated using physiological measures recorded by a Biopac MP150 system. The latter is an Electrocardiograph (ECG) device that can measure changes in three psychological modules taken under controlled conditions, namely: the heart rate, the variability of the heart rate in synchrony with respiration and impedance cardiography.