Lying to yourself-or self-deception, as psychologists call it-can actually have benefits. And nearly everybody does it, based on a growing body of research using new experimental techniques.

Self-deception isn't just lying or faking, but is deeper and more complicated, says Del Paulhus, psychology¹ professor at University of British Columbia and author of a widely used scale to measure self-deceptive tendencies. It involves strong psychological forces that keep us from acknowledging a threatening truth about ourselves, he says.

Believing we are more talented or intelligent than we really are can help us influence and win over others, says Robert Trivers, an anthropology² professor at Rutgers University and author of 'The Folly³ of Fools,' a 2011 book on the subject. An executive who talks himself into believing he is a great public speaker may not only feel better as he performs, but increase 'how much he fools people, by having a confident style that persuades them that he's good,' he says.

Researchers haven't studied large population samples to compare rates of self-deception or compared men and women, but they know based on smaller studies that it is very common. And scientists in many different disciplines are drawn⁴ to studying it, says Michael I. Norton, an associate professor at Harvard Business School. 'It's also one of the most puzzling things that humans do.'

Researchers disagree over what exactly happens in the brain during self-deception. Social psychologists say people deceive themselves in an unconscious effort to boost self-esteem or feel better. Evolutionary⁵ psychologists, who say different parts of the brain can harbor conflicting beliefs at the same time, say self-deception is a way of fooling others to our own advantage.

In some people, the tendency seems to be an inborn⁶ personality trait. Others may develop a habit of self-deception as a way of coping with problems and challenges.

Behavioral scientists in recent years have begun using new techniques in the laboratory to predict when and why people are likely to deceive themselves. For example, they may give subjects opportunities to inflate⁷ their own attractiveness, skill or intelligence. Then, they manipulate such variables as subjects' mood, promises of rewards or opportunities to cheat. They measure how the prevalence of self-deception changes.

In an unpublished study earlier this year, young women were asked to stand in front of a sheet of brown paper and sketch⁸ outlines of their bodies. Some were then asked to read a story about dating to put them in a romantic mood. The others were asked to read about buildings and architecture, says Carrie Keating, a psychology professor at Colgate University in Hamilton, N.Y., who led the research.

When the women were asked later to outline their bodies again, those who had read about dating sketched⁹ themselves as slimmer, with narrower waists, compared with their earlier drawings, reflecting an effort to 'block out any negative information about their bodies' and succeed at the dating game, Dr. Keating says. The women who read about buildings didn't much change their sketches¹⁰.

As early as age 3, children have what researchers call a 'positivity bias'-a tendency to see themselves as smart regardless of their abilities, and to exaggerate positive traits in others, says a 2010 study in the journal Child Development Perspectives. By adolescence¹¹, one-fourth of college-bound students rate themselves in the top 1% in their ability to get along with others, research shows.

In a separate study, female students who take leadership positions on campus score higher on measures of self-deception, based on recent research by Dr. Keating. Women who aspire¹² to leadership may have to 'conveniently forget about some negatives,' such as the fact that 'women who behave in a dominant¹³ fashion may be perceived as more masculine,' Dr. Keating says.

Many people have a way of 'fooling their inner eye' to believe they are more successful or attractive than they really are, Dr. Trivers says. When people are asked to choose the most accurate photo of themselves from an array of images that are either accurate, or altered to make them look up to 50% more or less attractive, most choose the photo that looks 20% better than reality, research shows.

Many people deceive themselves to avoid making difficult changes. For years, Greg Duval piled on pounds while telling himself 'I just needed to go for a run' to take off extra weight, he says. A former high-school quarterback, 'I had that 'man up' mentality¹⁴: 'Guys don't need personal trainers,'' says Mr. Duval, a Dallas sales executive. The rationale helped him feel as if he was in control, but gave him an excuse to put off exercise. Recently, as he approached age 50, he decided¹⁵, 'No more playing games with myself,' he says. Working with a trainer, Mallory Mansour Dubuclet, he has taken off 53 pounds since last winter. In the realm of health and fitness, Ms. Dubuclet says, 'many people kid themselves about how much they can eat, or how much exercise they are doing.'

It takes a certain amount of self-discipline to keep self-deception from becoming a hindrance¹⁶ on the job or in relationships. Getting too wrapped up in achievements or public image is one danger sign. Dodging¹⁷ a chronic¹⁸ problem by telling yourself you'll solve it in the future is another.

The trick, Dr. Norton says, is finding the line. While 'a little bit of self-deception isn't an unhealthy thing, a lot is an extremely unhealthy thing.' Benefits tend to come, research shows, when people simply block out negative thoughts, envision themselves enjoying future successes or take an optimistic view of their abilities-all of which tend to improve performance or persuasive¹⁹ ability.

For some people, self-deception becomes a habit, spinning out of control and providing a basis for more lies. In research co-written by Dr. Norton and published last year in Proceedings²⁰ of the National Academy of Science, college students who were given an answer key to an intelligence test, allowing them to cheat, scored higher than a control group. They later predicted, however, that they also would score higher on a second test without being allowed to cheat. They were 'deceiving themselves into believing their strong performance was a reflection of their ability,' the study says.

Giving them praise, a certificate of recognition, made the self-deception even worse: The students inflated²¹ their predicted future scores even more.

Just as phony war heroes come to believe they actually won medals for valor²², cheaters come to believe their own lies, Dr. Norton says. 'They forget very quickly,' he says, 'that there were situational factors that propelled them forward.'

How Honest Are You With Yourself?

Answer on a seven-point scale, with 1 being 'not true,' 4 being 'somewhat true,' and 7 being 'very true.'

1. My first impressions are always right.

2. I don't care to know what other people really think of me.

3. Once I've made up my mind, other people can seldom change my opinion.

4. I am fully in control of my own fate.

5. I never regret my decisions.

6. I am a completely rational person.

7. I am very confident of my judgments²³.

-ANSWER KEY: For each question, give yourself one point for answering 6 or 7. The higher your score, the more self-deceptive you tend to be.

-SOURCE: Del Paulhus, University of British Columbia对自己说谎──按照心理学术语来说就是“自我欺骗”──其实并不一定不好。而且，采用新实验技术进行的大量研究也表明，几乎所有人都对自己说过谎。

英属哥伦比亚大学(University of British Columbia)心理学教授德尔·保卢斯(Del Paulhus)表示，自欺并非仅仅是说谎或假装那么简单，而是有更深层次和更为复杂的含意。他说，我们不愿承认有关自己的某个危险的事实，是受到强大的心理因素的驱动。保卢斯制定的用于评估自欺倾向的标准已经被广泛采用。

罗格斯大学(Rutgers University)人类学教授罗伯特·特里弗斯(Robert Trivers)表示，相信自己比实际更有天分或者更聪明，能让我们感染甚至说服他人。特里弗斯在2011年出版了《愚人愚道》(The Folly of Fools)一书，着重探讨了这个问题。一名高管如果成功让自己相信自己具有出色的公开演讲能力，也许在演讲时他不仅不再紧张，还会有出色发挥。特里弗斯说，“他越是装出一副信心十足的样子，人们就越容易相信他真的很棒。”

研究人员还没有基于大样本人群对自欺比率或者男性女性之间的不同进行比较，但小样本的研究结果均表明这种现象非常普遍。哈佛商学院(Harvard Business School)副教授迈克尔·诺顿(Michael I. Norton)称，来自不同领域的科学家们都禁不住要研究这个问题，“这也是人类最令人费解的行为之一。”

那么，人类在自欺过程中，大脑里究竟发生了什么？研究人员也莫衷一是。社会心理学家称，人们下意识地自我欺骗，是出于自尊或为了让自己感觉好受些。进化心理学家则认为，大脑的不同部位可以同时处理相互矛盾的想法，因此自我欺骗也是愚人利己的一种倾向。

有些人的自欺倾向似乎是与生俱来的，有些人则可能是在应对各种问题和挑战的过程中后天形成的。

近年来，行为科学家们开始利用新的实验手段，预测人们可能会在什么时间、出于什么原因进行自我欺骗。例如，研究人员可能先给被调查者创造夸大自身吸引力、技能或智能的机会，然后，他们通过影响或调整一些变量，如被调查者的情绪、奖励许诺、欺骗机会等，以评测自欺倾向的高低变化。

今年早些时候，纽约州汉密尔顿市科尔盖特大学(Colgate University)的心理学教授凯利·基廷(Carrie Keating)领导了一项成果尚未公开发表的研究活动。根据研究人员的要求，一批年轻女性先在摆在其面前的一张牛皮纸上勾勒出自己的外形轮廓，然后，这批女性被分为两组，第一组看一篇关于约会的故事（给她们营造浪漫气氛），第二组则看些关于房屋建筑的内容。

之后，这些参与实验的女性在纸上重新勾勒自己的外形轮廓，结果，与第一次的勾勒相比，第一组的女性把自己画得更苗条、腰身更细。基廷博士表示，这显示出“遮挡自己身形中不理想部分”以使约会成功的努力。而第二组的女性前后两次素描的差别并不大。

儿童发育展望》(Child Development Perspectives)杂志2010年刊登的一篇研究论文称，早在三岁时，人类就已经表现出被研究人员称之为“正偏差”的倾向，即容易无视自身真实能力的高低而自视聪明，并容易夸大他人身上的积极特质。研究还显示，处于青春期的中学生中，有四分之一的人认为自己与他人相处的能力非常强，属于最优秀的那1%。

基廷博士最近进行的另一项研究显示，在学生团体中担任一定领导角色的女生的自欺评分相对较高。她分析道，有领导欲的女性可能不得不“有意忽略掉一些消极的东西”，例如，“处在主导地位的女性会让人觉得比较男性化”之类的事实。

特里弗斯博士表示，很多人都有办法“自我蒙蔽”，相信自己比实际更成功或者更有吸引力。如果提供一组本人照片，其中有些是未经任何处理的真实照片，有些则是经过了至多50%的美化或丑化处理，让人们从中选出与其本人最接近的一张时，大多数人都会选择美化了20%的那张。

很多人选择自我欺骗是不愿做出艰难的改变。曾在高中橄榄球队担任四分卫的格雷格·杜瓦尔(Greg Duval)表示，多年来，他一边跟自己说“我只要去跑个步”就能甩掉赘肉了，一边体重还在不停增加。目前在达拉斯担任销售主管的他说，“我曾经抱着‘大男子主义’的心理，认为‘男人不需要私人教练’。”这种想法让他觉得一切都在自己掌控之下，但也给了他拖延锻炼的借口。前段时间，年近50的他决定“不再给自己找借口了”。自从去年冬季聘请私人教练马洛里·曼苏尔·杜布莱特(Mallory Mansour Dubuclet)以来，杜瓦尔已经成功减掉了53磅。杜布莱特表示，“在保持健康和体形方面，很多人对自己应该控制的饮食量和实际完成的运动量掩耳盗铃。”

要防止自我欺骗成为工作或人际交往中的绊脚石，绝对也需要一定的自律能力。在个人成就或公众形象上太过自以为是就是一个危险的信号。留着“沉疴旧疾”，老是跟自己说“以后会去解决”，也是很危险的信号。

诺顿博士表示，关键在于找到平衡点。虽然“一定的自律是不错，但过度自律就不好了。”研究表明，拒绝消极思想、畅想未来的成功或是乐观看待自身的才能，这样的倾向往往会带来好处，帮助当事人提高绩效或变得更加令人信服。

对于有些人来说，自我欺骗成为一种习惯，失去了控制，会让他们说出越来越多的谎言。诺顿博士参与撰写的一份研究报告去年发表在了《美国国家科学院院刊》(Proceedings of the National Academy of Science)上。在此项研究中，一组大学生在获准作弊的情况下进行了智力测验，结果得分高于对照组。之后，这组大学生竟然预计自己在不得作弊的情况下进行第二次测验时，得分也会更高。研究人员总结道，这些大学生“欺骗了自己，让自己觉得是凭真本事在第一次测验中取得了好成绩”。

如果奖励他们，认可他们的成绩，会进一步加重他们自我欺骗的倾向：这些学生会认为自己在下次测验中能取得更加好的成绩。

诺顿博士指出，就像模拟战的胜者会真以为自己骁勇善战一样，谎话说多了的人有时连自己也会忘记了真伪。诺顿博士说，“他们很容易就忘了是彼时彼刻的情势促使他们说了谎。”

你容易自我欺骗吗？

按1-7分由低到高给下面每道问题打分，1代表“不正确”，4代表“差不多”，7代表“非常正确”。

1. 我的第一印象总是很准确。

2. 我不在乎别人怎么看我。

3. 一旦我做了决定，别人很难让我改变主意。

4. 我的命运完全由我自己掌控。

5. 我从不后悔自己做过的决定。

6. 我是非常理性的一个人。

7. 我对自己的判断很有信心。

─评估标准：七道问题中，凡得分不低于6的计一分。累计计分越高的人，自欺倾向就越高。

─评估方法来自：英属哥伦比亚大学心理学教授德尔·保卢斯