© QMI Agency/HandoutComposite photo of Canadian criminal psychopaths (L to R): Michelle Erstikaitis; Paul Bernardo; Col. Russ Williams.
Researchers from universities in Ontario, Alberta and Saskatchewan studied 289 murderers, rapists and other violent offenders, and concluded "psychopaths are executing a well-functioning, if unscrupulous strategy."
Psychopaths, with their trademark ruthless, risk-taking and often violent behaviour, "may have evolved to exploit others."
The theory rests in part on the victims of psychopaths.
Mental disorders "disrupt" the mechanism that stops people from hurting their families. But the violent offenders researchers spoke to, who were diagnosed as psychopaths, tended not to hurt family members.
"On average, psychopathy is associated with less harm to genetic relatives - that's exactly what you'd expect of healthy people," lead author Daniel Krupp, of Queen's University, told QMI Agency.
They are preserving their genetic material, he said.
But if being a psychopath is beneficial, why wouldn't everyone evolve that way?
Researchers call it "frequency dependent selection."
If most of society is one way - generally co-operative and trusting - there is a niche for a few people to take advantage, Krupp explained.
"It's a sort of balance between the population being exploitable enough for a handful of people to invade ... but if there's too many of them, then selection favours being skeptical of those people," Krupp said.
Meanwhile, the psychopaths among us are difficult to detect because they don't show any of the signs doctors expect to see in mentally disordered people, such as neurological or developmental problems, lower intelligence and difficulty interacting with others.
They may be selfish, antisocial and violent, but they are not dysfunctional, according to Krupp.
"Psychopaths know full well the consequence of their behaviour," he said.
The study appears in the latest issue of the journal Frontiers in Psychology.
But we needn't be picky. These people are just psychologists.
I don't know why psychologists would be qualified to speak about the evolution of character traits. Is that even proven?
Of course it is sensible to see psychopathy as an adaptive behavior.
But I don't believe that. I believe it's a commanded behavior. They've received a command to shut down what many call empathy, and if they obey that command, psychopathy results.
But I bet the psychiatrists will fight this conclusion. They want those guys in their mental institutions so they can release them back into society as "cured!"