A new Australian study finds that people with psychopathic tendencies have an impaired sense of smell.
Psychopathy is a global description of a severe personality disorder characterized by antisocial behaviors. Behaviors such as callousness, manipulation, and sensation-seeking are often associated with the disorder although these traits may also be found in otherwise healthy and normal people.
Research studies have found that people with psychopathic traits have impaired functioning in the front part of the brain — the area largely responsible for functions such as planning, impulse control and acting in accordance with social norms.
Moreover, frontal brain dysfunction is linked to an impaired sense of smell.
In the new study, psychologists Drs. Mehmet Mahmut and Richard Stevenson investigated if a poor sense of smell was linked to higher levels of psychopathic tendencies, among 79 non-criminal adults living in an Australian community.
For the study, investigators assessed the participants’ olfactory ability as well as the sensitivity of their olfactory system. They also measured subjects’ levels of psychopathy, looking at four measures: manipulation; callousness; erratic lifestyles; and criminal tendencies.
Finally, they also noted how much or how little study participants emphasized with other people’s feelings.
During the course of the study, 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, even though they knew they were smelling something.
These results show that brain areas controlling olfactory processes are less efficient in individuals with psychopathic tendencies.
The authors believe that their findings confirm the premise that frontal brain deficits may contribute to behaviors displayed by non-criminal psychopaths.
The use of olfactory measures, which include a mixture of assessment protocols, could serve as a potential marker for psychopathic traits.
This marker will be helpful because performance expectancies are unclear in odor tests and may therefore be less susceptible to attempts to fake good or bad responses, say the authors.
The findings are published online in the journal Chemosensory Perception.