People who prefer to work and play at night may have evolved to possess the so-called "Dark Triad" of psychological traits - psychopathy, narcissism, and manipulativeness, a new study suggests.
A new theory suggests that these two traits evolved together because darkness gives criminals and cheaters a way to hide from the prying eyes of others, giving them an evolutionary advantage.
The three legs of the Dark Triad can be found everywhere in the world. Magazines have labeled entire generations narcissists, psychologists create lists of the professions most likely to attract psychopaths, and Machiavellian parents turn to the godfather of political manipulation for child-rearing advice.
But psychologists say some people are walking around with a volatile cocktail of all three troubling traits. That's because the Dark Triad may be an evolutionary adaptation; possessing these traits gives some individuals a survival and reproductive advantage, studies have suggested.
A new theory from Peter Jonason of the University of Western Sydney in Australia adds another layer: People possessing the Dark Triad may have evolved to become night owls because night time is a great time to be a psychopath.
Sleep cycles and personality
Psychologists have often found that the natural sleeping and waking patterns of individuals, called "chronotypes," carry other traits along with them. These chronotypes are largely determined by genetics and regulate the time of day that we prefer to sleep, and when feel the most awake, intelligent, and alert.
Night owls feel their smartest, most creative, and most productive in the evening or night hours - much later than early-risers.
Early-risers score higher on tests for traits connected to leadership and authority and show a greater openness to change for the sake of the greater social good.
On the other hand, night owls can be very extroverted, extremely charming, and even deceptive. They have stronger individualistic tendencies, and are less agreeable than their early-to-bed peers.
Male "night owls" may have certain evolutionary advantages like increased mating success, and show increased impulsivity and risk-taking behaviour.
"Such features of the night may facilitate the casual sex, mate-poaching, and risk-taking the Dark Triad traits are linked to," they said in a paper published in the September 2013 issue of the journal Personality and Individual Differences.
Cops versus robbers
The researchers believe there is an evolutionary arms race between "cheaters" - those who engage in casual sex, crime, and other risky behaviours - and those who are likely to punish them. As a result, people with the Dark Triad might have also evolved to prefer the hours of the day when the light is low and fewer people are awake to catch them cheating or stealing.
So, essentially, early risers are cops and night owls are robbers.
To test this theory, Jonason and his colleagues selected 263 volunteers and gave them each three surveys to test for Dark Triad attributes.
The surveys asked participants how much they agreed with statements like, "I have a natural talent for influencing people" (a sign of narcissism), "I enjoy driving at high speeds" or "I think I could beat a lie detector test" (a sign of psychopathy); and "it is hard to get ahead without cutting corners here and there" (a sign of Machiavellianism).
Consistently, the researchers found that people who stay up later at night scored higher on each of the Dark Triad of personality traits than their early-to-bed peers.
The study has one important limitation, the scientists admit: Most of their subjects were college students, who may stay up later to fit the lifestyle and demands of student life.
Still, they concluded their study by saying, "those high on the Dark Triad traits like many other predators (e.g., lions, African hunting dogs, scorpions), are creatures of the night."
More from Business Insider: