Psychopaths are unable to show empathy toward others because their brains aren't wired to do so, according to a new study in JAMA Psychiatry.
Researchers from the University of Chicago used brain imaging technology to find that psychopaths have less activation in certain parts of the brain and high activation in other parts of the brain, compared with people who are not psychopaths, in response to scenarios of people being purposely hurt.
Scientific American provides a good definition of a psychopath:
Superficially charming, psychopaths tend to make a good first impression on others and often strike observers as remarkably normal. Yet they are self-centered, dishonest and undependable, and at times they engage in irresponsible behavior for no apparent reason other than the sheer fun of it. Largely devoid of guilt, empathy and love, they have casual and callous interpersonal and romantic relationships.
In the new study, researchers conducted functional MRI brain imaging on 80 prisoners ages 18 to 50, all of whom had tests done to measure their levels of psychopathy. Then, they posed some scenarios of someone being hurt purposely, as well as had them watch videos of pained facial expressions.
Researchers found that those who scored higher on the psychopathy test experienced less activation in the amygdala, ventromedial prefrontal cortex, lateral orbitofrontal cortex, and periaqueductal gray brain regions, compared with those who scored lower on the test. Those who scored higher on the psychopathy test had more activation of the striatum and insula brain regions -- the insula brain region is known to play a role in emotion, researchers noted.
"This is the first time that neural processes associated with empathic processing have been directly examined in individuals with psychopathy, especially in response to the perception of other people in pain or distress," study researcher Jean Decety, a professor of psychiatry and psychology at the University of Chicago, said in a statement.
In the past, British researchers found that psychopaths actually have differences in their brain structure, compared with people who aren't psychopaths. A study published last year in the journal Archives of General Psychiatry and conducted on violent criminals in Britain showed that psychopaths have less gray matter in the anterior rostral prefrontal cortex brain region, Reuters reported.