People with psychopathic tendencies seem to have a poor sense of smell, which points to inefficient processing in the brain’s front part, says a study. Psychopathy covers a severe personality disorder characterized by callousness, manipulation, sensation-seeking and anti-social behaviours, traits which may also be found in otherwise healthy and functional people. Studies have shown that such people 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, the journal Chemosensory Perception reported.
Conversely, a dysfunction in these brain areas is linked to an impaired sense of smell, according to Mehmet Mahmut and Richard Stevenson, from Macquarie University, Australia. Mahmut and Stevenson looked at whether a poor sense of smell was linked to higher levels of psychopathic tendencies, among 79 non-criminal adults living in the community, according to a Macquarie statement. They 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.
They also noted how much or how little they emphasized with other people’s feelings. 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, even though they knew they were smelling something. Mahmut and Stevenson concluded: “Our findings provide support for the premise that deficits in the front part of the brain may be a characteristic of non-criminal psychopaths.”
“Olfactory measures represent a potentially interesting marker for psychopathic traits, because performance expectancies are unclear in odour tests and may therefore be less susceptible to attempts to fake good or bad responses,” they added.