Australian scientists say that persons with psychopathic tendencies could be spotted through a smell test, correlated with a psychological questionnaire. The link doesn't lye in the actual odor emanated by a potentially psychopathic person, though, but rather in their sense of smell.
The study conducted by Mehmet Mahmut and Richard Stevenson, from Macquarie University, is based on findings which show that people with psychopathic traits have impaired functioning in the front part of the brain - responsible for planning, impulse control and acting in accordance with social norms. The same impaired functioning in the front part of the brain, however, has also been linked with an impaired sense of smell.
In order to test whether there's a correlation between the two, the scientists asked 79 non-criminal adults living in the community to participate as volunteers. The researchers measured their levels of psychopathic traits like callousness, manipulation, the urge to commit criminal acts, and leading an erratic lifestyle, as well as their olfactory ability. The researchers found that those individuals who scored highly on psychopathic traits were more likely to struggle to both identify smells and tell the difference between smells.
"Our findings provide support for the premise that deficits in the front part of the brain may be a characteristic of non-criminal psychopaths," the researchers, from Macquarie University, said in a statement. "Olfactory measures represent a potentially interesting marker for psychopathic traits, because performance expectancies are unclear in odor tests and may therefore be less susceptible to attempts to fake good or bad responses."
Also, previous research has found that criminals who are psychopaths also have differently structured brains from non-criminals and criminals who aren't psychopaths. Psychopath speech patterns may also provide a metric, as it was found to be different from non-psychopaths.
The Australian scientists' findings were published in the journal Chemosensory Perception.