Most people would associate psychopaths with cold-blooded murderers.
However, a new study claims that US presidents have displayed certain psychopathic traits, meaning that these leaders could be, in some sense, “successful psychopaths”.
Researchers from Emory University in Atlanta found a link between psychopathic boldness and US presidential success.
"Certain psychopathic traits may be like a double-edged sword," said psychologist and lead author Scott Lilienfeld.
"Fearless dominance, for example, may contribute to reckless criminality and violence, or to skillful leadership in the face of a crisis."
In fact, the researchers said, fearless dominance, linked to diminished social and physical apprehensiveness, appears to correlate with better-rated presidential performance for leadership, persuasiveness, crisis management and Congressional relations.
Theodore Roosevelt, in office between 1901 and 1909, ranked highest in fearless dominance, followed by John F Kennedy, Franklin D Roosevelt, Ronald Reagan, Rutherford Hayes, Zachary Taylor, Bill Clinton, Martin Van Buren, Andrew Jackson and George W Bush.
This conclusion was drawn from personality assessments of 42 presidents, up to George W Bush, compiled by Steven Rubenzer and Thomas Faschingbauer for their book Personality, Character and Leadership in the White House.
"The way many people think about mental illness is too cut-and-dried," Lilienfeld says. "Certainly, full-blown psychopathy is maladaptive and undesirable. But what makes the psychopathic personality so interesting is that it's not defined by a single trait, but a constellation of traits."
Was Franklin D Roosevelt (centre) a psychopath?
A clinical psychopath, the authors said, has many characteristics such as fearless social dominance, self-centered impulsivity, superficial charm, guiltlessness, callousness, dishonesty and immunity to anxiety.
All individuals may exhibit one of more of these traits to some degree.
"You can think of it like height and weight," Lilienfeld explained. "Everyone has some degree of both, and they're continuously distributed in the population."
The researchers also looked at presidential scores for self-centered impulsivity, which in contrast to boldness, was linked to some negative job performance indicators, including Congressional impeachment resolutions, tolerating unethical behaviour in subordinates and negative character.
Theodore Roosevelt, for instance, ranked the highest for fearless dominance, but lower than average for self-centered impulsivity suggesting that he was far from being psychopathic.
Lyndon Johnson, however, ranked relatively high for fearless dominance (15th) and was among the top-five scorers for self-centered impulsivity.
"That's consistent with what we know about Johnson," Lilienfeld says. "He was a very dominant, socially bold person, at times even ruthless about getting his way. In some sense, these traits may have made him an effective leader, able to push through civil rights legislation, but they may not have been so positive in terms of personal relationships."
A report on the study was published this week in Journal of Personality and Social Psychology.