The day I meet Sonja Lyubomirsky, she keeps getting calls from her Toyota Prius dealer. When she finally picks up, she is excited by the news: she can buy the car she wants in two days. Lyubomirsky wonders if her enthusiasm might come across as materialism, but I understand that she is buying an experience as much as a possession. The hybrid will be gentler on the environment, and a California state law letting some hybrids use the carpool lane promises a faster commute between her coastal Santa Monica home and her job at the University of California, Riverside, some 70 miles inland.

Two weeks later, in late January, the 40-year-old Lyubomirsky, who smiles often and seems to approach life with zest and good humor, reports that she is "totally loving the Prius." But will the feeling wear off soon after the new-car smell, or will it last, making a naturally happy person even more so?

An experimental psychologist investigating the possibility of lasting happiness, Lyubomirsky understands far better than most of us the folly of pinning our hopes on a new car--or on any good fortune that comes our way. We tend to adapt, quickly returning to our usual level of happiness. The classic example of such "hedonic adaptation" comes from a 1970s study of lottery winners, who a year after their windfall ended up no happier than nonwinners. Hedonic adaptation helps to explain why even changes in major life circumstances--such as income, marriage, physical health and where we live--do so little to boost our overall happiness. Not only that, but studies of twins and adoptees have shown that about 50 percent of each person's happiness is determined from birth. This "genetic set point" alone makes the happiness glass look half empty, because any upward swing in happiness seems doomed to fall back to near your baseline.

"There's been a tension in the field," explains Lyubomirsky's main collaborator, psychologist Kennon M. Sheldon of the University of Missouri-Columbia. "Some people were assuming you can affect happiness if, for example, you picked the right goals, but there was all this literature that suggested it was impossible, that what goes up must come down."

Lyubomirsky, Sheldon and another psychologist, David A. Schkade of the University of California, San Diego, put the existing findings together into a simple pie chart showing what determines happiness. Half the pie is the genetic set point. The smallest slice is circumstances, which explain only about 10 percent of people's differences in happiness. So what is the remaining 40 percent? "Because nobody had put it together before, that's unexplained," Lyubomirsky says. But she believes that when you take away genes and circumstances, what is left besides error must be "intentional activity," mental and behavioral strategies to counteract adaptation's downward pull.

Lyubomirsky has been studying these activities in hopes of finding out whether and how people can stay above their set point. In theory, that is possible in much the same way regular diet and exercise can keep athletes' weight below their genetic set points. But before Lyubomirsky began, there was "a huge vacuum of research on how to increase happiness," she says. The lottery study in particular "made people shy away from interventions," explains eminent University of Pennsylvania psychologist Martin E. P. Seligman, the father of positive psychology and a mentor to Lyubomirsky. When science had scrutinized happiness at all, it was mainly through correlational studies, which cannot tell what came first--the happiness or what it is linked to--let alone determine the cause and effect. Finding out that individuals with strong social ties are more satisfied with their lives than loners, for example, begs the question of whether friends make us happier or whether happy people are simply likelier to seek and attract friends.

Lyubomirsky began studying happiness as a graduate student in 1989 after an intriguing conversation with her adviser, Stanford University psychologist Lee D. Ross, who told her about a remarkably happy friend who had lost both parents to the Holocaust. Ross explains it this way: "For this person, the meaning of the Holocaust was that it was indecent or inappropriate to be unhappy about trivial things--and that one should strive to find joy in life and human relationships." Psychologists have long known that different people can see and think about the same events in different ways, but they had done little research on how these interpretations affect well-being.

So Lyubomirsky had to lay some groundwork before she could go into the lab. Back then, happiness was "a fuzzy, unscientific topic," she says, and although no instrument yet exists for giving perfectly valid, reliable and precise readings of someone's happiness from session to session, Lyubomirsky has brought scientific rigor to the emerging field. From her firm belief that it is each person's self-reported happiness that matters, she developed a four-question Subjective Happiness Scale. Lyubomirsky's working definition of happiness--"a joyful, contented life"--gets at both the feelings and judgments necessary for overall happiness. (If a sleep-deprived new mom feels fulfilled but frazzled, and an aimless party girl feels empty despite loads of fun, neither would consider herself truly happy.) To this day, she rarely sees her studies' participants; they do most exercises out in the real world and answer detailed questionnaires on the computer, often from home. To assess subjects' efforts and honesty, she uses several cross-checks, such as timing them as they complete the questionnaires.

The research needed to answer questions about lasting happiness is costly, because studies need to follow a sizable group of people over a long time. Two and a half years ago Lyubomirsky and Sheldon received a five-year, $1-million grant from the National Institute of Mental Health to do just that. Investigators have no shortage of possible strategies to test, with happiness advice coming "from the Buddha to Tony Robbins," as Seligman puts it. So Lyubomirsky started with three promising strategies: kindness, gratitude and optimism--all of which past research had linked with happiness.

Her aim is not merely to confirm the strategies' effectiveness but to gain insights into how happiness works. For example, conventional wisdom suggests keeping a daily gratitude journal. But one study revealed that those who had been assigned to do that ended up less happy than those who had to count their blessings only once a week. Lyubomirsky therefore confirmed her hunch that timing is important. So is variety, it turned out: a kindness intervention found that participants told to vary their good deeds ended up happier than those forced into a kindness rut. Lyubomirsky is also asking about mediators: Why, for example, does acting kind make you happier? "I'm a basic researcher, not an applied researcher, so I'm interested not so much in the strategies but in how they work and what goes on behind the scenes," she explains.

Initial results with the interventions have been promising, but sustaining them is tough. Months after a study is over, the people who have stopped the exercises show a drop in happiness. Like a drug or a diet, the exercises work only if you stick with them. Instilling habits is crucial. Another key: "fit," or how well the exercise matches the person. If sitting down to imagine your best possible self (an optimism exercise) feels contrived, you will be less likely to do it.

The biggest factor may be getting over the idea that happiness is fixed--and realizing that sustained effort can boost it. "A lot of people don't apply the notion of effort to their emotional lives," Lyubomirsky declares, "but the effort it takes is enormous."

那天我去看宋佳·柳波默斯基的时候，看到她在没完没了地接听来自丰田普锐斯经销商的电话。她最终选定型号以后，一听对方说两天内即可提车，竟然高兴的不得了。不知柳波默斯基的热情是否由于她的实用主义态度，但我很清楚，她购买的不仅是个人物品，还有一种新的生活体验。普锐斯是一种油电混合动力车，对环境的影响要温和一些，而加州法律又允许某些油电混合动力车行驶集体用车道。她家在海边城市桑塔莫尼卡，而上班地点则在加州大学瑞夫赛德分校（国内多译为河滨分校或滨河分校——译者注），相距大约70英里。能走集体车道，就意味着今后往来穿梭两地要快一些。

元月下旬，也就是柳波默斯基买车两星期后，这个脸上常挂着微笑、总愿意为她的生活投入热情和幽默的40岁女人，说她还是“百分之百喜欢她的普锐斯”。难道新车味道过了之后她的新车感觉一点都没有减弱？抑或新车的感觉依然，而让她这个天生的乐天派更开心？

柳波默斯基是一个专门从事幸福感持久性研究的实验心理学家，她对幸福的理解要比大多数普罗百姓深刻得多。她决不会和我们一样蠢到把自己的幸福仅仅寄托在区区一辆新车上，或者寄托在我们都会碰到的那些好运上。我们似乎总能适应一切，包括幸福感，这种适应会让我们很快回到幸福感的正常水平（这样就等于没有了幸福的感觉——译者注）。关于“幸福感的适应性现象”，70年代曾经有一次经典的研究，研究对象是乐透彩中奖者。结果表明，这些突发横财的中奖者一年之后的幸福感觉和那些没中过奖的人已经没有什么差别。这种幸福感的适应性现象，可以用来解释人生中司空见惯的现象。在我们一生中都会面对各种重大变化，如加薪、结婚、健康和住新家等，为什么这些因素对提高我们个人幸福感的作用都不大呢？不仅如此，对双胞胎和被领养者的研究结果也表明，每个人的幸福感水平都有一半左右是生就的。这条“遗传界线”让 “装着幸福的玻璃杯”看上去总有一半是空着的，因为不管往这个杯子里注入多少幸福，高于这条界线的幸福感都注定要慢慢漏掉，幸福感最终都要回到遗传设定好的那条界线上。

密苏里－哥伦比亚大学心理学家健能·谢尔顿是柳波默斯基的主要合作者，他说：“在幸福感方面，一直存在一种（象弹簧一样的）应力现象。例如，有人以为人是可以干预幸福感的，只要选准了正确的人生目标，就能做到这一点。可是各种有关的研究文献都表明，这是完全做不到的，反而表明（一种近乎残酷的现实）：幸福感上去多少，就得回落多少。”

柳波默斯基、谢尔顿和另一名心理学家，即加州大学圣地亚哥分校德大卫·史卡德，把各有关研究成果综合起来，并用“蛋糕图”的形式把影响幸福感的种种因素标示出来。这块蛋糕的一半就是遗传设定好的那一半，而最小的那一片蛋糕表示的是环境因素，说明人们幸福感的差别有10％是由环境决定的。那么剩余的那40％是什么呢？柳波默斯基说：“由于以前没人开展过类似的综合研究，这一块到现在还讲不清楚。”不过她相信的一点是，如果撇开遗传因素和环境因素不谈，再剔除各种错误因子，那么所剩下的那一部分必然是个人的“主观行为”，即为了抵抗适应性的下拉力而必须采取的各种心理对策与行为对策。

柳波默斯基一直在研究的就是这种行为，她希望为人们寻找一种能够把幸福感长期保持在遗传基线水平上的各种行为对策。从理论上讲，这种行为是必然存在的，这和运动员通过加强锻炼和饮食控制可以把体重控制在遗传设定的天生水平以下的做法完全是一回事。可在柳波默斯基之前，这个“关于提高幸福感的研究领域存在一个很大的真空地带”。柳波默斯基的导师、宾西法尼亚大学著名心理学家、积极心理学奠基人马丁·舍利格曼解释说：“有些科学研究实际上干扰了人们的正常生活，特别是乐透彩的研究，往往使人们羞于启齿。”对幸福感的总体情况开展综合分析的时候，主要都是通过相关的间接研究进行的，这就很难判断幸福感以及与之相关的各种因素谁先谁后的关系，何况判断其因果关系。因此，与其直接询问那些孤独的人对自己的生活是否满意，倒不如去了解那些有广泛社会关系的人，例如，可以向他们了解这样一些问题：朋友是否让他们感到快乐？或者，快乐的人是否更希望寻求更多的朋友，或者本来就吸引更多的朋友？

1989年，柳波默斯基本来正在攻读研究生，后来由于和自己的导师有一次高深的对话，而决定研究幸福感。她的导师里·罗素是斯坦福大学心理学家，向她说起他的一个特别懂得快乐的朋友，给她的印象实在太深刻了。罗素说，这个朋友的父母双亲都在纳粹大屠杀中命赴黄泉。罗素解释说，对于这个懂得快乐的人而言，大屠杀给人的启示就是，一个人如果因鸡毛蒜皮一类的事情而不开心，那就太不合适，甚至太不儒雅了，相反，人应该在生活中、在人与人的关系中努力找到自己的快乐。尽管心理学家早就知道，不同的人对于同样的事情可以有不同看法，可是这些看法对个人的幸福感到底有着怎样的影响，则没有什么研究。

这样一来，为了能在实验室里顺利开展实验，柳波默斯基只好先开展一些基础性工作。她说，在当时看来，所谓“幸福感”，只不过是只可意会不可言传的话题，根本不是什么科学命题，再说也没什么科学仪器可以一层一层地对人的幸福感进行扫描和记录，并得到完全有效、可靠而又精确的读数。尽管如此，柳波默斯基还是给这门新生学科注入了科学活力。她坚信的一点就是，个人主观上所感觉得到的那种幸福感才是最重要的，因此她设计了包含四个问题的“主观幸福尺度”。柳波默斯基给幸福下了一个实用的定义，认为幸福就是指快乐而又满足的人生。有了这个定义，就可以给总体幸福提供必要的感觉和判断依据。（如果一个刚做妈妈的女人由于睡眠被婴儿剥夺而感到疲劳不堪；或者一个置身某个晚会的女孩，因为毫无目的，尽管面对的是欢乐的场面仍感到空虚，那么这样的情形按照柳波默斯基的标准都不能叫做真正的幸福。）如今，柳波默斯基已很少直接面对那些被她研究的对象了，她的研究对象要么在现实世界里做一些练习题，要么直接在家里通过电脑回答详细的调查问卷。为了检验研究对象的真心程度和诚实水平，她还需要进行交叉比对，例如他们每做完一份问卷，就马上给他们计时，等等。

由于研究对象必须达到一定人数，研究周期又比较长，因此通过设定问题来提问维持幸福感的研究方式所需要的费用是很可观的。好在两年半前，柳波默斯基和谢尔顿就从国家心理健康研究所那里得到一百万美元的研究经费，才有条件开展这个为期五年的研究项目。正如舍利格曼所说的那样，研究人员根本不愁没有可供测试用的幸福策略，从佛教的教义到托尼·罗宾斯的幸福观，尽可选取一些来测试。柳波默斯基选择了三种公认的幸福对策，即友爱、感恩和乐观，这三方面同时也是以前的科学研究认为和个人幸福与否关系最大的因素。

柳波默斯基的目的并非仅仅为了检验这些对策的有效性，更主要的是为了深入考察产生幸福感的心理机制。例如，“每天都要随身带着一本感恩日记”本是老生常谈的哲理，可是有研究表明，接受这一做法的人最后却没有那些每周计算一次自己的幸运事件的人来得快活。因此，柳波默斯基证实了自己的直觉：设定时间很重要。其实变化本身也很重要。研究表明：友爱干预法实验就发现，那些接受实验人员建议，经常调整做好事内容的受试者，最后都要比那些死抱着单一友善教条的受试者快乐。柳波默斯基也会问一些与实验无关的中间人类似的问题：为什么友爱的行为会让你感到开心呢？她自己解释说：“我从事的是基础研究，并非应用研究，因此我对那些策略性的东西本身并不是特别感兴趣，我只会专注研究这些可让人产生幸福感的对策背后的机制。”

干预实验取得的初步成果还是很有前景的，但是要保住幸福成果难度就大了。实验结束几个月后，停止练习的人的幸福感都有所下降。这也许就象服药或节食一样，只有持之以恒才能见效。培养好习惯是最关键的。还有一个办法，就是训练内容必须因人而异，也就是符合度的问题。如果坐下来想象自己最有可能的最佳形象（即乐观训练）的方法让你觉得有些勉强，那你是很难坚持下去的。

最重要的一点也许是尽快克服“幸福水平一成不变”的想法，而应该认识到，持续的努力是可以提高幸福感水平的。柳波默斯基大胆认为：“很多人并没有努力为自己的情感生活倾注心血，但要付出的心血确实是巨大的。”