A poor sense of smell may be a biomarker for psychopathic traits, in addition to reflecting a dysfunction of part of the brain, according to a newly-published study from a pair of Australian researchers.
“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," Mehmet Mahmut and Richard Stevenson of Australia’s Macquarie University concluded in their study, published yesterday in the journal Chemosensory Perception.
Mahmut and Stevenson studied answers supplied by 79 noncriminal adults. They completed the Self-Report Psychopathy scale, which measured manipulation, callousness, erratic lifestyles, and criminal tendencies, as well as their degree of empathy with the feelings of others. The 79 were also examined through a standardized measure of odor threshold, identification, and discrimination, the Sniffin’ Stick.
Results showed that individuals who scored highly on psychopathic traits most likely knew they were smelling something, but were likelier to struggle to both identify smells and distinguish between them.
The researchers concluded that brain areas in control of olfactory processes were less efficient in individuals with psychopathic tendencies compared with those without—even after controlling for gender, age, empathy, smoking status, and craniofacial surgery/injury.
“In particular, we suggest that this relates to processing within the orbitofrontal cortex,” which affects olfactory processing, as well as planning, impulse control, and acting in accordance with social norms, the researchers stated in the study.