The traits are the self-obsession of narcissism; the impulsive, thrill-seeking and callous behaviour of psychopaths; and the deceitful and exploitative nature of Machiavellianism. At their extreme, these traits would be highly detrimental for life in traditional human societies. People with these personalities risk being shunned by others and shut out of relationships, leaving them without a mate, hungry and vulnerable to predators.

But being just slightly evil could have an upside: a prolific sex life, says Peter Jonason at New Mexico State University in Las Cruces. "We have some evidence that the three traits are really the same thing and may represent a successful evolutionary strategy."

Jonason and his colleagues subjected 200 college students to personality tests designed to rank them for each of the dark triad traits. They also asked about their attitudes to sexual relationships and about their sex lives, including how many partners they'd had and whether they were seeking brief affairs.

The study found that those who scored higher on the dark triad personality traits tended to have more partners and more desire for short-term relationships, Jonason reported at the Human Behavior and Evolution Society meeting in Kyoto, Japan, earlier this month. But the correlation only held in males.

James Bond epitomises this set of traits, Jonason says. "He's clearly disagreeable, very extroverted and likes trying new things - killing people, new women." Just as Bond seduces woman after woman, people with dark triad traits may be more successful with a quantity-style or shotgun approach to reproduction, even if they don't stick around for parenting. "The strategy seems to have worked. We still have these traits," Jonason says.

This observation seems to hold across cultures. David Schmitt of Bradley University in Peoria, Illinois, presented preliminary results at the same meeting from a survey of more than 35,000 people in 57 countries. He found a similar link between the dark triad and reproductive success in men. "It is universal across cultures for high dark triad scorers to be more active in short-term mating," Schmitt says. "They are more likely to try and poach other people's partners for a brief affair."

Barbara Oakley of Oakland University in Rochester, Michigan, says that the studies "verify something a lot of people have conjectured about".

Christopher von Rueden of the University of California at Santa Barbara says that the studies are important because they confirm that personality variation has direct fitness consequences.

"They still have to explain why it hasn't spread to everyone," says Matthew Keller of the University of Colorado in Boulder. "There must be some cost of the traits." One possibility, both Keller and Jonason suggest, is that the strategy is most successful when dark triad personalities are rare. Otherwise, others would become more wary and guarded.

两项研究证实了人们长久以来的猜测：男的不坏女的不爱。这项研究有助于解释为什么那些被认为是“黑暗三性格”的反社会人格特征并没有被进化淘汰，尽管他们潜在地具有重要文化价值可能造成严重文化损失。

这三类“坏坏”的性格特征包括：自我中心（自恋者）、热爱冒险刺激且心狠手辣（心理变态者）、善于撒谎喜将人玩弄于股掌（权谋者，参见马基维利主义）。在极端情况下，这些性格特征会对传统的人类社会造成伤害。其他人会避开这类人，这可能让他们让他们成为离群、孤独、饥渴而易受攻击的人。

但轻微的邪恶却又有有利的一面：更多的性生活。新墨西哥州立大学的皮特·乔纳森说，“我们有证据证明三种性格本质上是一样的，他们或许都代表一种成功的进化策略。”

乔纳森和他的同事 主持了针对两百名大学生的人格测试，通过测试评价每种黑暗性格。他们还调查了被测者对性关系和性生活的情况，包括曾经有过的性伴侣数目和是否有过出轨。

这项研究发 现，黑暗属性值越高的人更容易有多个伴侣，并且更喜欢短暂的露水关系。乔纳森在日本京都前不久举行的人类行为和进化社会学会议（Human Behavior and Evolution Society meeting）上做了这一报告。不过，这种相关性只存在于男人中。(囧之——译者注)

坏男人的代表：詹姆士·邦德

乔纳森认为，奸姆斯·邦是这些黑暗属性的缩影。“他确实有点儿让人生厌，但他喜欢交际并热衷于尝试新鲜事物——比如说，杀人，或者不停地换新姑娘。”邦德是个十足的女性杀手，那些具有黑暗性格的人们大概也更容易在数量上取得成功，这在生物繁殖领域叫做“鸟枪法”——但是他们不会把过多精力放在养育后代上。“（在进化中）这种策略应该是奏效的，因为我们仍保留了这些属性。”乔纳森说道。

这项研究的 成果应该是具有跨文化意义的。伊利诺伊州布拉德雷大学的大卫·施密特在同一个会议上作了另一个报告，宣布了一项在57个国家、35000多人中做的调查的 初步结果。这项调查也证 实了男人的坏属性与繁殖能力之间的联系。“黑暗属性越高的男人就越喜欢短期约会，这是不受文化限制的普遍规律，”施密特说，“坏男人们更喜欢尝试并猎取别 人的伴侣，也会有更多的风流韵事。”(谨再囧——译者又注)

密歇根州奥克兰大学罗彻斯特分校的巴巴拉·奥克莱认为这两项研究“验证了许多人长期以来的猜想”。

加州大学圣塔芭芭拉分校的克里斯托弗·冯·罗登肯定了研究的重要性，因为他们证实个性变异对自然选择的结果生殖成就有直接影响^**。

“他们仍需要解释为什么这种属性没有扩散到所有人，”科罗拉多大学波尔得分校的马修·凯勒问道。“那些黑暗属性必然有一些代价，”凯勒和乔纳森都认为有这么一种可能：只有当黑暗人格属性极罕见的时候，这类策略才是最成功的。否则，其他人会对这类东西提高警惕以保护自己。