Women find happy men less sexually attractive than those with expressions that show pride or hint that they have done wrong and know it, according to Canadian researchers.

　　The study published online Tuesday in the American Psychological Association journal Emotion showed pictures of the opposite sex to both men and women. Participants were then asked for their initial reactions on sexual attractiveness based on the expressions they saw.

　　"Men who smile were considered fairly unattractive by women," said Jessica Tracy, a University of British Columbia psychology professor who directed the study.

　　"So to the extent that men think that smiling is a good thing to do if they want to be found sexually attractive our findings suggest that's not the case," Tracy said.

　　The men's reaction was just the opposite.

　　"Women who smile are absolutely very attractive. That was by far the most attractive expression women showed," Tracy said in an interview.

　　The researchers admit they are not sure why men and women reacted differently to smiles. In a man, a big smile may make him appear too feminine or more desperate for sex.

　　The study also adds fuel to the notion that women are attracted to bad boys.

　　"Women are attracted to guys like James Dean, Edward the vampire. The guys who are flawed, but who know it and are tortured by it," Tracy said.

　　A slightly downcast expression of shame is an appeasement gesture that hints at a need for sympathy.

　　Men also found sexual attractiveness in women whose expressions and body language hinted at shame.

　　The researchers stressed they looked only at initial reactions of sexual attractiveness, and were not recommending men adopt a no-smile policy for a long-term relationship.

　　"When people want a long-term relationship they take much more into account than sexual attractiveness. How nice a person is, is a big thing," Tracy said.

　　"So we're not saying, don't be a nice guy," she said.

　　想要做个性感男人，俘获女人的心吗？那就不要笑得太多。你应该看起来深沉些或露出一点害羞的神色。如果你是女人，以上的建议就当耳边风吧。

　　加拿大研究人员发现，女人认为快乐的男人没有那些表情高傲或看起来似乎曾经犯错并自知的男人性感。

　　这一研究分别向男性和女性展示了异性的照片，并让参与者根据他们所看到的表情说出对照片中人物的性吸引力的第一反应。该研究周二发表在美国心理学会期刊《情感》的网刊上。

　　带头开展这一研究的加拿大英属哥伦比亚大学心理学教授杰西卡?特蕾西说：“女人认为露出笑容的男人相当没有吸引力。”

　　特蕾西说：“所以，如果男性认为微笑可以让自己看起来性感，那么我们的研究结果显示事实并非如此。”

　　男人的反应则恰恰相反。

　　特蕾西在一个访谈中说：“露出笑容的女人看起来十分有魅力，这是确定无疑的。这是女性迄今为止最有吸引力的表情。”

　　研究人员承认，他们不确定为什么男性和女性对笑容的反应不同。如果一个男人笑容满面，可能会给人过于女性化或对性更饥渴的感觉。

　　研究还进一步证实女人会被坏男人所吸引。

　　特蕾西说：“女人喜欢詹姆斯?迪恩、吸血鬼爱德华这样的男人。那些有污点并自知、而且因自己的过错而饱受煎熬的男人。”

　　略带羞愧的悲哀表情是一种暗示着自己需要同情的安抚姿势。

　　男人还认为那些流露出害羞的表情和身体语言的女人更性感。

　　研究人员强调，他们观察的只是人们对性吸引力的第一反应，并不是建议男性在长期恋情中采取不苟言笑的策略。

　　特蕾西说：“当人们想要发展长期恋情时，他们关注的就不只是性吸引力了，还要考虑很多其他因素。一个人是否和善是很重要的。”

　　她说：“所以我们并不是在告诉你，不要做个好男人。”