"薑是老的辣"有了科學依據
Behind all those canned compliments for older adults — spry! wily! wise! — is an appreciation for something that scientists have had a hard time characterizing: mental faculties that improve with age.
年長者通常會受到這樣的褒揚：思維敏捷！老謀深算！睿智！在這些稱讚的背後，是對某種東西的欣賞，科學家們一直很難描述的東西：隨着年齡增長而增強的心智能力。Knowledge is a large part of the equation, of course. People who are middle-aged and older tend to know more than young adults, by virtue of having been around longer, and score higher on vocabulary tests, crossword puzzles and other measures of so-called crystallized intelligence.
當然，在這個等式中，知識佔了很大一部分。與年輕人相比，中老年人知道的東西往往更多，因爲他們活過的年頭更長，而且在詞彙測試、填字遊戲和其他“晶態智力”測試中，中老年人的得分也比較高。
Still, young adults who consult their elders (mostly when desperate) don’t do so just to gather facts, solve crosswords or borrow a credit card. Nor, generally, are they looking for help with short-term memory or puzzle solving. Those abilities, called fluid intelligence, peak in the 20s.
不過，年輕人（主要是在絕望的時候）請教年長者，不只是爲了蒐集事實、做填字遊戲，或者借用信用卡。通常也不是爲了解決短期記憶或解謎方面的問題。這些能力稱爲“液態智力”，在20多歲時達到峯值。
No, the older brain offers something more, according to a new paper in the journal Psychological Science. Elements of social judgment and short-term memory, important pieces of the cognitive puzzle, may peak later in life than previously thought.
不，《心理科學》(Psychological Science)雜誌上的新論文表示，年長者的大腦可以提供更多的好處。社會判斷和短期記憶的一些元素是認知能力的重要組成部分，它們達到峯值的時間可能比人們之前認爲的更晚一些。The postdoctoral fellows Joshua Hartshorne of M.I.T. and Laura Germine of Harvard and Massachusetts General Hospital analyzed a huge trove of scores on cognitive tests taken by people of all ages. The researchers found that the broad split in age-related cognition — fluid in the young, crystallized in the old — masked several important nuances.
麻省理工(MIT)博士後約書亞·哈茨霍恩(Joshua Hartshorne)以及哈佛(Harvard)和馬薩諸塞州總醫院(Massachusetts General Hospital)博士後勞拉·傑米恩(Laura Germine)分析了大量由所有年齡段參加的認知測試數據，發現在涉及年齡的認知上，籠統的兩分法——年輕人液態智力高，年長者晶態智力高——掩蓋了一些重要的細微差別。“This dichotomy between early peaks and later peaks is way too coarse,” Dr. Hartshorne said. “There are a lot more patterns going on, and we need to take those into account to fully understand the effects of age on cognition.”
“早期達到高峯和較晚時候達到高峯，這種兩分法太粗略了，”哈茨霍恩博士說。“此外還存在很多的模式，我們需要考慮這些因素，來充分了解年齡對認知的影響。”The new paper is hardly the first challenge to the scientific literature on age-related decline, and it won’t be the last. A year ago, German scientists argued that cognitive “deficits” in aging were caused largely by the accumulation of knowledge — that is, the brain slows down because it has to search a larger mental library of facts. That idea has stirred some debate among scientists.
諸多科學文獻談到了和年齡有關的認知能力下降，這篇新論文既不是對相關結論的第一個挑戰，也不會是最後一個。一年前，德國科學家聲稱，年齡增長的認知“缺陷”在很大程度上是由知識的積累造成的——也就是說，大腦速度減慢，是因爲它需要在一個更大的腦部信息庫裏搜索東西。這個說法已經在科學界引起了一些爭論。Experts said the new analysis raised a different question: Are there distinct, independent elements of memory and cognition that peak at varying times of life?
一些專家稱，這份新的分析結果提出了一個不同的問題：在記憶力和認知能力中，有沒有一些與衆不同的獨立的元素，是在生命中的不同時刻達到峯值的？“I think they have more work to do to demonstrate that that’s the case,” said Denise Park, a professor of behavior and brain science at the University of Texas at Dallas. “But this is a provocative paper, and it’s going to have an impact on the field.”
“我認爲要證明這一點，他們還需要做更多工作，”德克薩斯州大學達拉斯分校(University of Texas at Dallas)行爲與腦科學教授丹尼斯·帕克(Denise Park)說。“但這篇論文已經引發了討論，它將對這一領域產生影響。”The strength of the new analysis is partly in its data. The study evaluated historic scores from the popular Wechsler intelligence test, and compared them with more recent results from tens of thousands of people who took short cognitive tests on the authors’ websites, and . The one drawback of this approach is that, because it didn’t follow the same people over a lifetime, it might have missed the effect of different cultural experiences, said K. Warner Schaie, a researcher at Penn State University.
這個最新分析結果的強大之處，一定程度上在於它所採用的數據。這份研究評估了著名的韋氏智力測驗(Wechsler intelligence test)的歷史得分數據，將它們與數萬人更近期的測試結果進行了比較。這些參與者在作者的網站上進行了簡短的認知測試，網址分別是和。賓夕法尼亞州立大學(Penn State)的研究人員K·瓦爾納·沙依(K. Warner Schaie)說，這種方法的缺陷在於，由於它不是追蹤同一批人在人生各個階段的情況，因此可能忽視了不同文化經歷產生的影響。But most previous studies have not been nearly as large, or had such a range of ages. Participants on the websites were 10 to 89 years old, and they took a large battery of tests, measuring skills like memory for abstract symbols and strings of digits, problem solving, and facility reading emotions from strangers’ eyes.
然而，以往的多數研究都沒有達到如此大的規模，也沒有覆蓋這麼廣的年齡段。網站上的參與者年齡在10歲到89歲之間，他們參與了大量的測試，評估了對抽象符號和數字串的記憶力、解決問題的能力，以及根據眼神解讀陌生人情緒的能力。At least as important, the researchers looked at the effect of age on each type of test. Previous research had often grouped related tests together, on the assumption that they captured a single underlying attribute in the same way a coach might rate, say, athleticism based on a person’s speed, strength and vertical leaping ability.
同樣重要的是，研究人員觀察了年齡對每一項測試的影響。以往的研究經常把相關的測試分爲一組，想當然地認爲它們捕捉到了一項基本屬性，就像教練可以根據一個人的速度、力量和彈跳能力評估他的運動能力一樣。The result of the new approach? “We found different abilities really maturing or ripening at different ages,” Dr. Germine said. “It’s a much richer picture of the life span than just calling it aging.”
這種新方法的結果如何？“我們發現不同的能力的確會在不同的年齡臻於成熟，”傑米恩說。“它反映了人生中豐富得多的變化，而不只是衰老。”Processing speed — the quickness with which someone can manipulate digits, words or images, as if on a mental sketch board — generally peaks in the late teens, Dr. Germine and Dr. Hartshorne confirmed, and memory for some things, like names, does so in the early 20s. But the capacity of that sketch board, called working memory, peaks at least a decade later and is slow to decline. In particular, the ability to recall faces and do some mental manipulation of numbers peaked about age 30, the study found, “a fact difficult to assimilate into the fluid/crystalized intelligence dichotomy.”
傑米恩博士和哈茨霍恩博士證實，信息處理速度——如同頭腦中有一塊素描板，一個人在上面處理數字、單詞或圖像的速度——基本上在十八九歲的時候達到峯值；對一些事情的記憶力，比如對一些名字的記憶，會在20歲出頭的時候達到頂峯。但這個素描板的容量，即工作記憶，至少還要10年之後才能達到峯值，而且下降的速度很慢。特別值得一提的是，研究發現，記憶一些人的長相以及心算的能力，會在30歲左右達到峯值，“這個事實很難用液態/晶態的智力二分法來解釋。”The researchers also analyzed results from the Reading the Mind in the Eyes test. The test involves looking at snapshots of strangers’ eyes on a computer screen and determining their moods from a menu of options like “tentative,” “uncertain” and “skeptical.”
研究人員還分析了“眼神讀心能力測試”的結果。在這項測試中，測試者需要看着計算機屏幕上陌生人眼睛的照片，從一些選項中選出他們的心情，比如“猶豫”、“不確定”和“懷疑”。“It’s not an easy test, and you’re not sure afterward how well you did,” Dr. Germine said. “I thought I’d done poorly but in fact did pretty well.” Yet people in their 40s or 50s consistently did the best, the study found, and the skill declined very slowly later in life.
“這個測試並不容易，你做完之後心裏沒底，”傑米恩說。“我以爲我做的很糟糕，但實際上成績相當不錯。”然而研究發現，四五十歲的人成績最好，而且隨着年齡的進一步增長，這種能力下降得十分緩慢。The picture that emerges from these findings is of an older brain that moves more slowly than its younger self, but is just as accurate in many areas and more adept at reading others’ moods — on top of being more knowledgeable. That’s a handy combination, given that so many important decisions people make intimately affects others.
這些發現所反映的情況是，年長者的大腦的運轉速度比年輕時慢，但在許多領域同樣敏銳，而且更擅長察覺他人的情緒——不光是知識更淵博了。考慮到人們做出的許多重要決定都會密切地影響他人，這是一個不錯的狀態。No one needs a cognitive scientist to explain that it’s better to approach a boss about a raise when he or she is in a good mood. But the older mind may be better able to head off interpersonal misjudgments and to navigate tricky situations.
沒人需要一名認知科學家來告訴自己，爲什麼在老闆心情好的時候，更適合找他談漲薪。但年長一些的人可能更加擅長避免人際關係上的誤判，以及應付棘手的局面。“As in, ‘that person’s not happy with all your quick thinking and young person’s processing speed — he’s about to punch you,’” said Zach Hambrick, a psychology professor at Michigan State University.
“比如，‘那個人看不慣你思維太快，那種年輕人的信息處理速度——他就要給你一拳了，’”密歇根大學的心理學教授扎克·漢布里克(Zach Hambrick)說。The details of this more textured picture of the aging brain are still far from clear, and social measures like the Reading the Mind in the Eyes test have not been used much in this kind of research, Dr. Hambrick and other experts said. And it is not apparent from the new analysis whether changes in cognition with age result from a single cause — like a decline in the speed of neural transmission — or to multiple ones.
漢布里克和其他專家說，大腦衰老過程中更復雜情況的細節還很不清楚，眼神讀心能力等社會化衡量標準也沒有被大量用於此類研究。此外，最新的分析結果也沒有告訴我們，認知能力隨年齡增長而發生的改變是單一因素——比如神經傳輸速度的下降——還是多種原因造成的。But for now, the new research at least gives some meaning to the empty adjective “wily.”
但就目前而言，這項新研究至少給“老謀深算”這個空洞的形容詞賦予了一些意義。
