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·柳波默斯基的時候，看到她在沒完沒了地接聽來自豐田普銳斯經銷商的電話。她最終選定型號以后，一聽對方說兩天內即可提車，竟然高興的不得了。不知柳波默斯基的熱情是否由于她的實用主義態度，但我很清楚，她購買的不僅是個人物品，還有一種新的生活體驗。普銳斯是一種油電混合動力車，對環境的影響要溫和一些，而加州法律又允許某些油電混合動力車行駛集體用車道。她家在海邊城市桑塔莫尼卡，而上班地點則在加州大學瑞夫賽德分校（國內多譯為河濱分校或濱河分校——譯者注），相距大約70英里。能走集體車道，就意味著今后往來穿梭兩地要快一些。

元月下旬，也就是柳波默斯基買車兩星期后，這個臉上常掛著微笑、總愿意為她的生活投入熱情和幽默的40歲女人，說她還是“百分之百喜歡她的普銳斯”。難道新車味道過了之后她的新車感覺一點都沒有減弱？抑或新車的感覺依然，而讓她這個天生的樂天派更開心？

柳波默斯基是一個專門從事幸福感持久性研究的實驗心理學家，她對幸福的理解要比大多數普羅百姓深刻得多。她決不會和我們一樣蠢到把自己的幸福僅僅寄托在區區一輛新車上，或者寄托在我們都會碰到的那些好運上。我們似乎總能適應一切，包括幸福感，這種適應會讓我們很快回到幸福感的正常水平（這樣就等于沒有了幸福的感覺——譯者注）。關于“幸福感的適應性現象”，70年代曾經有一次經典的研究，研究對象是樂透彩中獎者。結果表明，這些突發橫財的中獎者一年之后的幸福感覺和那些沒中過獎的人已經沒有什么差別。這種幸福感的適應性現象，可以用來解釋人生中司空見慣的現象。在我們一生中都會面對各種重大變化，如加薪、結婚、健康和住新家等，為什么這些因素對提高我們個人幸福感的作用都不大呢？不僅如此，對雙胞胎和被領養者的研究結果也表明，每個人的幸福感水平都有一半左右是生就的。這條“遺傳界線”讓 “裝著幸福的玻璃杯”看上去總有一半是空著的，因為不管往這個杯子里注入多少幸福，高于這條界線的幸福感都注定要慢慢漏掉，幸福感最終都要回到遺傳設定好的那條界線上。

密蘇里－哥倫比亞大學心理學家健能·謝爾頓是柳波默斯基的主要合作者，他說：“在幸福感方面，一直存在一種（象彈簧一樣的）應力現象。例如，有人以為人是可以干預幸福感的，只要選準了正確的人生目標，就能做到這一點。可是各種有關的研究文獻都表明，這是完全做不到的，反而表明（一種近乎殘酷的現實）：幸福感上去多少，就得回落多少。”

柳波默斯基、謝爾頓和另一名心理學家，即加州大學圣地亞哥分校德大衛·史卡德，把各有關研究成果綜合起來，并用“蛋糕圖”的形式把影響幸福感的種種因素標示出來。這塊蛋糕的一半就是遺傳設定好的那一半，而最小的那一片蛋糕表示的是環境因素，說明人們幸福感的差別有10％是由環境決定的。那么剩余的那40％是什么呢？柳波默斯基說：“由于以前沒人開展過類似的綜合研究，這一塊到現在還講不清楚。”不過她相信的一點是，如果撇開遺傳因素和環境因素不談，再剔除各種錯誤因子，那么所剩下的那一部分必然是個人的“主觀行為”，即為了抵抗適應性的下拉力而必須采取的各種心理對策與行為對策。

柳波默斯基一直在研究的就是這種行為，她希望為人們尋找一種能夠把幸福感長期保持在遺傳基線水平上的各種行為對策。從理論上講，這種行為是必然存在的，這和運動員通過加強鍛煉和飲食控制可以把體重控制在遺傳設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，這個“關于提高幸福感的研究領域存在一個很大的真空地帶”。柳波默斯基的導師、賓西法尼亞大學著名心理學家、積極心理學奠基人馬丁·舍利格曼解釋說：“有些科學研究實際上干擾了人們的正常生活，特別是樂透彩的研究，往往使人們羞于啟齒。”對幸福感的總體情況開展綜合分析的時候，主要都是通過相關的間接研究進行的，這就很難判斷幸福感以及與之相關的各種因素誰先誰后的關系，何況判斷其因果關系。因此，與其直接詢問那些孤獨的人對自己的生活是否滿意，倒不如去了解那些有廣泛社會關系的人，例如，可以向他們了解這樣一些問題：朋友是否讓他們感到快樂？或者，快樂的人是否更希望尋求更多的朋友，或者本來就吸引更多的朋友？

1989年，柳波默斯基本來正在攻讀研究生，后來由于和自己的導師有一次高深的對話，而決定研究幸福感。她的導師里·羅素是斯坦福大學心理學家，向她說起他的一個特別懂得快樂的朋友，給她的印象實在太深刻了。羅素說，這個朋友的父母雙親都在納粹大屠殺中命赴黃泉。羅素解釋說，對于這個懂得快樂的人而言，大屠殺給人的啟示就是，一個人如果因雞毛蒜皮一類的事情而不開心，那就太不合適，甚至太不儒雅了，相反，人應該在生活中、在人與人的關系中努力找到自己的快樂。盡管心理學家早就知道，不同的人對于同樣的事情可以有不同看法，可是這些看法對個人的幸福感到底有著怎樣的影響，則沒有什么研究。

這樣一來，為了能在實驗室里順利開展實驗，柳波默斯基只好先開展一些基礎性工作。她說，在當時看來，所謂“幸福感”，只不過是只可意會不可言傳的話題，根本不是什么科學命題，再說也沒什么科學儀器可以一層一層地對人的幸福感進行掃描和記錄，并得到完全有效、可靠而又精確的讀數。盡管如此，柳波默斯基還是給這門新生學科注入了科學活力。她堅信的一點就是，個人主觀上所感覺得到的那種幸福感才是最重要的，因此她設計了包含四個問題的“主觀幸福尺度”。柳波默斯基給幸福下了一個實用的定義，認為幸福就是指快樂而又滿足的人生。有了這個定義，就可以給總體幸福提供必要的感覺和判斷依據。（如果一個剛做媽媽的女人由于睡眠被嬰兒剝奪而感到疲勞不堪；或者一個置身某個晚會的女孩，因為毫無目的，盡管面對的是歡樂的場面仍感到空虛，那么這樣的情形按照柳波默斯基的標準都不能叫做真正的幸福。）如今，柳波默斯基已很少直接面對那些被她研究的對象了，她的研究對象要么在現實世界里做一些練習題，要么直接在家里通過電腦回答詳細的調查問卷。為了檢驗研究對象的真心程度和誠實水平，她還需要進行交叉比對，例如他們每做完一份問卷，就馬上給他們計時，等等。

由于研究對象必須達到一定人數，研究周期又比較長，因此通過設定問題來提問維持幸福感的研究方式所需要的費用是很可觀的。好在兩年半前，柳波默斯基和謝爾頓就從國家心理健康研究所那里得到一百萬美元的研究經費，才有條件開展這個為期五年的研究項目。正如舍利格曼所說的那樣，研究人員根本不愁沒有可供測試用的幸福策略，從佛教的教義到托尼·羅賓斯的幸福觀，盡可選取一些來測試。柳波默斯基選擇了三種公認的幸福對策，即友愛、感恩和樂觀，這三方面同時也是以前的科學研究認為和個人幸福與否關系最大的因素。

柳波默斯基的目的并非僅僅為了檢驗這些對策的有效性，更主要的是為了深入考察產生幸福感的心理機制。例如，“每天都要隨身帶著一本感恩日記”本是老生常談的哲理，可是有研究表明，接受這一做法的人最后卻沒有那些每周計算一次自己的幸運事件的人來得快活。因此，柳波默斯基證實了自己的直覺：設定時間很重要。其實變化本身也很重要。研究表明：友愛干預法實驗就發現，那些接受實驗人員建議，經常調整做好事內容的受試者，最后都要比那些死抱著單一友善教條的受試者快樂。柳波默斯基也會問一些與實驗無關的中間人類似的問題：為什么友愛的行為會讓你感到開心呢？她自己解釋說：“我從事的是基礎研究，并非應用研究，因此我對那些策略性的東西本身并不是特別感興趣，我只會專注研究這些可讓人產生幸福感的對策背后的機制。”

干預實驗取得的初步成果還是很有前景的，但是要保住幸福成果難度就大了。實驗結束幾個月后，停止練習的人的幸福感都有所下降。這也許就象服藥或節食一樣，只有持之以恒才能見效。培養好習慣是最關鍵的。還有一個辦法，就是訓練內容必須因人而異，也就是符合度的問題。如果坐下來想象自己最有可能的最佳形象（即樂觀訓練）的方法讓你覺得有些勉強，那你是很難堅持下去的。

最重要的一點也許是盡快克服“幸福水平一成不變”的想法，而應該認識到，持續的努力是可以提高幸福感水平的。柳波默斯基大膽認為：“很多人并沒有努力為自己的情感生活傾注心血，但要付出的心血確實是巨大的。”