中國有句話叫：江山易改，本性難移。我們可能以為，人的個性是與生俱來的，比如天生內向或外向。但是科學家經過多年的研究發現，隨著時間流逝，人的個性會發生改變，短期內察覺不到，但長期來看很明顯。
Between adolescence and adulthood, you go through a host of changes — jobs, regrettable haircuts and relationships that come and go. But what about who you are at your core? As you grow older, does your personality change?
從青少年到成年，你經歷了許多改變——換工作、失敗的髮型和戀情變遷。但是你本質上是一個什麼樣的人呢？隨著年齡增長，你的個性會改變嗎？
Personality is the pattern of thoughts, feelings and behaviors unique to a person. People tend to think of personality as fixed. But according to psychologists, that's not how it works. "Personality is a developmental phenomenon. It's not just a static thing that you're stuck with and can't get over," said Brent Roberts, a psychologist at the University of Illinois at Urbana-Champaign.
個性是一個人特有的思維、感覺和行為模式。人們往往認為個性是固定不變的。但是心理學家表示並非如此。伊利諾伊大學厄巴納-尚佩恩分校的心理學家布倫特·羅伯茨說：「個性是一個發展的現象。它不是一個一成不變、擺脫不了的靜態事物。」
That's not to say that you're a different person each day you wake up. In the short term, change can be nearly imperceptible, Roberts told Live Science. Longitudinal studies, in which researchers survey the personalities of participants regularly over many years, suggest that our personality is actually stable on shorter time scales.
這不是說你每天早上醒來都是一個不同的人。羅伯茨告訴生命科學網站說，短期來看，改變幾乎是察覺不到的。在延續多年的縱向研究中，研究人員對參與者的個性進行了定期調查。結果顯示，實際上我們的個性在較短時間尺度內是穩定的。
In one study, published in 2000 in the journal Psychological Bulletin, researchers analyzed the results of 152 longitudinal studies on personality, which followed participants ranging in age from childhood to their early 70s. Each of these studies measured trends in the Big Five personality traits. This cluster of traits, which include extroversion, agreeableness, conscientiousness, openness to experience, and neuroticism, are a mainstay of personality research. The researchers found that individuals' levels of each personality trait, relative to other participants, tended to stay consistent within each decade of life.
在一項2000年發表在《心理學公報》期刊上的研究中，研究人員分析了152項對個性的縱向研究，這些研究跟蹤調查了從幼年到70歲出頭各個年齡段的參與者。每項研究都測評了「大五人格」的傾向。「大五人格」包括外向性、親和性、責任心、經驗開放性和情緒穩定性，這些人格特質是個性研究的重要基礎。研究人員發現，相對來說參與者的「大五人格」水平在每個十年內通常都是穩定的。
That pattern of consistency begins around age 3, and perhaps even earlier, said Brent Donnellan, professor and chair of psychology at Michigan State University. When psychologists study children, they don't measure personality traits in the same way they do for adults. Instead, they look at temperament — the intensity of a person's reactions to the world. We come into the world with unique temperaments, and research suggests that our temperaments as children — for example, whether we're easy going or prone to temper tantrums, eager or more reluctant to approach strangers — correspond to adult personality traits.
密西根州立大學的心理學系主任布倫特·唐納倫教授稱，這種穩定模式大約在三歲開始形成，甚至可能更早。心理學家對兒童進行研究時，他們不會像對待成人一樣測評人格，而是會觀察性情，也就是一個人對世界作出反應的強烈程度。我們天生就有各自的性情，研究表明，我們兒時的性情和成人後的個性特質有關，比如我們是否隨和或容易發脾氣，願不願意接觸陌生人。
Earlier temperament seems to affect later life experience. For example, one 1995 study published in the journal Child Development followed children from the age of 3 until the age of 18. The researchers found, for instance, that children who were shyer and more withdrawn tended to grow into unhappier teenagers.
早年的性情似乎會對以後的生活經歷造成影響。舉例而言，1995年發表在《兒童發育》期刊上的一項研究對兒童進行了跟蹤調查，從3歲跟蹤到18歲。研究人員發現，比較害羞和內向的孩子通常會長成不太快樂的青少年。
But those decades add up. Throughout all those years, our personality is still changing, but slowly, Roberts said. "It's something that's subtle," he added. You don't notice it on that five-to-10-year time scale, but in the long term, it becomes pronounced. In 1960, psychologists surveyed over 440,000 high school students. The students answered questions about everything from how they reacted to emotional situations to how efficiently they got work done. Fifty years later, researchers tracked down 1,952 of these former students and gave them the same survey. The results, published in 2018 in the Journal of Personality and Social Psychology, found that in their 60s, participants scored much higher than they had as teenagers on questions measuring calmness, self-confidence, leadership and social sensitivity.
但是一個又一個十年會對個性產生影響。羅伯茨稱，我們的個性在這些年間仍然會改變，不過是緩慢地改變。他補充道：「這是微妙的變化。」五年到十年內你注意不到，但是長期來看，就很明顯。1960年，心理學家對逾44萬名高中生進行了調查。這些學生回答了各種問題，從對情緒狀況的反應到完成工作的效率。五十年後，研究人員跟蹤調查了1952名當年的這些學生，並對他們進行了同樣的調查。這項2018年發表在《個性與社會心理學期刊》的研究結果發現，這些年逾六十的參與者在衡量冷靜、自信、領導力和社會敏感度的問卷得分比他們青少年時得分高得多。
Again and again, longitudinal studies have found similar results. Personality tends to get "better" over time. Psychologists call it "the maturity principle." People become more extraverted, emotionally stable, agreeable and conscientious as they grow older. Over the long haul, these changes are often pronounced.
各項縱向研究一次又一次地得出了相似的結果。隨著時間流逝，人們的個性通常會「變好」。心理學家將其稱之為「成熟法則」。隨著年齡增長，人們變得更外向，情緒更穩定，更隨和，也更有責任心。長期來看，這些改變通常很明顯。
Some individuals might change less than others, but in general, the maturity principle applies to everyone. That makes personality change even harder to recognize in ourselves — how your personality compares with that of your peers doesn't change as much as our overall change in personality, because everyone else is changing right along with you. "There's good evidence that the average self-control of a 30-year-old is higher than a 20-year-old," Donnellan said. "At the same time, people who are relatively self-controlled at 18 also tend to be relatively self-controlled at age 30."
一些人可能變得比其他人少，但總體來看，成熟法則適用於每個人。這使得我們的個性改變更難以被識別。你的個性相比同齡人發生的改變沒有大家整體的個性改變大，因為每個人的個性都和你一起發生著改變。唐納倫說：「充分證據表明，30歲的人平均自制力高於20歲的人。與此同時，18歲時自制力相對較強的人到了30歲也往往自制力相對較強。」
So why do we change so much? Evidence suggests it's not dramatic life events, such as marriage, the birth of a child or loss of a loved one. Some psychologists actually suggest these events reinforce your personality as you bring your characteristics with you to that particular situation, Donnellan said.
那麼為什麼我們會改變這麼多？證據顯示，我們的個性改變不是因為人生大事，比如結婚、孩子出生或失去所愛之人。唐納倫稱，一些心理學家指出實際上這些大事會強化你的個性，因為你會將自己的個性帶入到那個特別的情境中。
Instead, changing expectations placed on us — as we adjust to university, the work force, starting a family — slowly wears us in, almost like a pair of shoes, Roberts said. "Over time you are asked in many contexts across life to do things a bit differently," he said. "There's not a user manual for how to act, but there's very clear implicit norms for how we should behave in these situations." So we adapt."
羅伯茨指出，在我們適應大學、職場和成家時，外界對我們期望值的改變在慢慢地打磨我們，就像一雙鞋一樣。他說：「隨著時間過去，人生中的許多情境都會要求你用和以前不一樣的方式去做事。沒有用戶手冊來指導你如何行動，但是有非常清晰的不成文規範告訴你在這些情況下應該如何表現。於是我們就改變自己去適應。」