The amazing fertility of the older mind
If you ever fear that you are already too old to learn a new skill, remember Priscilla Sitienei, a midwife from Ndalat in rural Kenya. Having grown up without free primary school education, she had never learnt to read or write. As she approached her twilight years, however, she wanted to note down her experiences and knowledge to pass down to the next generation. And so, she started to attend lessons at the local school – along with six of her great-great-grandchildren. She was 90 at the time.
We are often told that “you can’t teach an old dog new tricks” – that the grizzled adult brain simply can’t absorb as much information as an impressionable young child’s. Many people would assume that you simply couldn’t pick up a complex skill like reading or writing, at the age of 90, after a lifetime of being illiterate.
The latest studies from psychology and neuroscience show that these extraordinary achievements need not be the exception. Although you may face some extra difficulties at 30, 50 – or 90 – your brain still has an astonishing ability to learn and master many new skills, whatever your age. And the effort to master a new discipline may be more than repaid in maintaining and enhancing your overall cognitive health.
But there hasn’t always been such an optimistic view of learning brand new skills from scratch as a grown adult.
The prevailing, pessimistic, view of the ageing mind can be traced back to the Ancient Greeks. In his treatise De Memoria et Reminiscentia, Aristotle compared human memory to a wax tablet. At birth, the wax is hot and pliable, but as it cools it becomes too tough and brittle to form distinct impressions – and our memory suffers as a result.
认为大脑会老化的普遍的较为悲观的看法可以追溯到古希腊。亚里士多德在他的论文《论记忆》（De Memoria et Reminiscentia）中把人类的记忆力比作一块蜡板。在出生时，蜡很烫，可塑性很强，但是随着它渐渐冷却，就会变得又硬又脆，无法形成鲜明的印象——我们的记忆力就会受到影响。
Millennia later, scientists’ understanding of the brain appeared to echo this view. Neuroscientists even use a word to describe the brain’s adaptability – neuroplasticity – that directly recalls the malleable wax of Aristotle’s “tabula rasa”, and as we age, we were thought to lose much of that plasticity.
Childhood, in particular, was thought to be the “critical period” to make those impressions. By the end of the critical period, the brain’s circuits begin to settle, making it far harder to learn many complex new skills.
Compelling evidence for this theory appeared to come from people learning a second language. Young children brought to a new country seemed to find it far easier to reach fluency than their older siblings or parents, for instance.
Yet a closer look at the data paints a somewhat rosier picture. Analysing the census records of immigrants, Ellen Bialystok at York University in Toronto showed that the immigrants fluency appeared to decline very gradually with the age at arrival, rather than a drop off a cliff predicted by a critical period. And that may have been partly due to the fact that the children simply had more opportunities to master the language, with the support of schools and their classmates. Or perhaps children are simply less inhibited and aren’t so scared about making mistakes.
不过，仔细研究数据会发现情况扑朔迷离。多伦多的约克大学（York University）的艾伦·比亚韦斯托克（Ellen Bialystok）通过分析移民的调查数据后发现来到外国的移民的语言流利程度并非在过了关键时期后就急速下滑，而是呈现随着年龄的增长逐步下滑的趋势。部分原因可能是儿童有更多的学习语言的机会，有学校和同学的帮助。或者儿童对犯错并不那么在意和害怕。
Just consider the case of Aleksander Hemon. Originally from Sarajevo in then-Yugoslavia, he found himself stranded in the US on the outbreak of the Bosnian war in 1992 – despite having little command of English. “I had this horrible, pressing need to write because things were happening. I needed to do it the same way I needed to eat, but I just had no language to write in,” he later told the New York Times. And so he set about embracing the language on the streets around him. Within three years, he had published his first piece in an American journal, a path that eventually led to three critically acclaimed novels, two short story collections, a book of autobiographical essays, and a MacArthur Genius Award.
不妨看看亚历山大·埃蒙（Aleksander Hemon）的例子。他原本来自前南斯拉夫的萨拉热窝（Sarajevo）。在1992年波斯尼亚战争爆发后，他被困在美国——尽管他几乎不会讲英语。"因为发生了很多事情，所以我迫不及待的要写作，就像吃饭的需要一样，但是我不会书面语言。"他后来这样告诉《纽约时报》。于是，他开始到街上去，学习身边的语言。在三年内，他就在美国的期刊发表了第一篇文章，后来他写出三部受到好评的小说，两部短篇小说集，一部自传式散文集，并获得了麦克阿瑟天才奖（MacArthur Genius Award）。
Hemon’s profound mastery of expression should have been near impossible if language acquisition had to fall within a critical period for us to achieve true fluency. But his sheer determination and the urgency of the situation fuelled his power to learn.
Admittedly, children may still find it easier to master certain skills, particularly those that revolve around the fine-tuning of our perception. A linguist may struggle to exactly match a native’s accent, while a new musician may never be able to acquire the refined perception of “absolute pitch” shown by stars like Ella Fitzgerald or Jimi Hendrix. But as Hemon shows, you can still be an award-winning novelist without sounding like a native, and many accomplished musicians do not have perfect pitch. Amazing progress is still possible in many different fields, and adults may find that they can make up for some of the deficits with their greater capacity for analysis, self-reflection – and discipline.
诚然，儿童学习技能仍然较为容易，尤其是那些与精细的感知能力有关的技能。语言学家可能很难精确模仿母语者的口音，而初出茅庐的音乐家可能很难掌握艾拉·费兹洁拉（Ella Fitzgerald）或吉米·亨德里克斯（Jimi Hendrix）这样的明星对"绝对音感"的把握。但是，埃蒙的例子说明，不需要口音和母语者一样也可以成为获奖小说家，很多功成名就的音乐家也不具备绝对音感。在很多不同的领域仍然有可能实现惊人的进步。而且成年人还可以通过较强的分析能力、自我反省能力和纪律性弥补一部分劣势。
The scientific literature is now dotted with case studies of older adults performing amazing mnemonic feats, including a septuagenarian who learnt to recite all 10,565 lines of John Milton’s Paradise Lost for public performance. Such extended neuroplasticity also seems to be reflected in more recent studies of the brain’s anatomy, revealing that the adult brain is far more fertile than expected, and more than capable of sprouting the connections necessary for profound learning.
科学文献中现在有一些案例研究发现成年人展现出惊人的记忆术。一位七旬老人背诵了约翰·弥尔顿（John Milton）的《失乐园》（Paradise Lost）全文10,565行，并公开表演。最近对大脑的解剖学研究也反映出这种超长记忆术，揭示出成人大脑的能力远远超出预期，绝不限于建立深奥学问所需的神经联系。
Keeping in shape seems to be particularly important for maintaining that plasticity, as exercise helps to release a flood of neurotransmitters and hormones that are known to promote the growth of new brain cells and synapses.
A simple lack of confidence may present the biggest barrier – particularly for older learners, past retirement, who may have already started to fear a more general cognitive decline.
Through a string of recent experiments, Dayna Touron at the University of North Carolina at Greensboro has shown that older adults (60 and over) frequently underestimate the power of their own memories, leading to some bad habits that fail to make the best use of their minds.
位于格林斯伯勒（Greensboro）的北卡罗来纳大学（University of North Carolina）的黛娜·图尔农（Dayna Touron）最近通过一连串的实验发现60岁以上的成年人常常低估自己的记忆能力，养成了一些坏习惯，无法充分发挥大脑的能力。
In one (deliberately tedious) study, Touron’s participants had to compare a reference table of word pairings (like ‘dog’ and ‘table’) with a second list, and then identify which words had not appeared in the original table. The word pairings were not difficult to learn, and by the end most people – of all ages – would have been able recite them. But the older adults – aged 60 and over – were more reluctant to rely on their memory, preferring instead to laboriously cross-reference the two tables, even though it took significantly more time. For some reason, they weren’t confident that they had learnt the pairs accurately – and so took the more cautious, but time-consuming, strategy.
In another experiment, the participants had to work through a list of calculations, with many of the sums appearing repeatedly through the list. The younger participants soon started to recall their previous answers, while the older subjects instead decided to perform the calculations from scratch each time. Again, this did not seem to reflect an actual hole in their memory – many could remember their answers, if they had to, but had simply chosen not to. “We do see some adults who come into the lab and who never shift to using their memory,” says Touron. “They say they know the information, they just prefer not to rely on it.”
By asking her participants to keep detailed diaries of their routine, Touron has shown this habit of “memory avoidance” may limit their cognitive performance in many everyday activities. Older people may be more likely to rely on GPS when driving, for instance – even if they remember the route – or they may follow a recipe line by line, rather than attempting to recall the steps.
Eventually, that lack of confidence may become a self-fulfilling prophecy – as your memory skills slowly decline through lack of use. On the plus side, she has found that simply giving the older adults feedback on their performance – and underlining the accuracy of their memory – can encourage them to rely more on their recall. “I think it does offer an optimistic picture,” she says.
Break through those psychological barriers to learning, and you may soon see some widespread and profound benefits, including a sharper mind overall. As evidence, Touron points to research by Denise Park at the Center for Vital Longevity at the University of Texas at Dallas.
只要打破这些心理障碍，你就可能很快发现影响深远的益处，头脑整体都变聪明了。图尔农指出，一个证据是位于达拉斯的得克萨斯大学（University of Texas）的"活力老年中心"（Center for Vital Longevity）的丹尼斯·帕克（Denise Park）进行的研究。
Park first divided her 200 participants into groups and assigned them to a programme of different activities for 15 hours a week for three months. Some were offered the opportunity to learn new skills – quilting, digital photography, or both – that would challenge their long-term memory and attention as they followed complex instructions. Others were given more passive tasks, such as listening to classical music or completing crossword puzzles, or social activities – such as field trips to local sites of interest. At the beginning and the end of the three months, Parks also gave the participants a memory test.
Of all the participants, only the subjects learning the quilting or the photography enjoyed a significant improvement – with 76% of the photographers showing a higher score at the second memory test, for instance. A later brain scan found that this seemed to be reflected in lasting changes to circuits in the medial frontal, lateral temporal, and parietal cortex - areas associated with attention and concentration. Overall, the more active pastime of learning a new skill led to the more efficient brain activity you might observe in a younger brain, while the passive activities like listening to music brought no changes. Crucially, these benefits were long-lasting, lingering for more than a year after the participants had completed their course.
Park emphasises that she still needs to replicate the study with other groups of participants. But if the results are consistent with her earlier findings, then the brain boost of taking up a new hobby may trump so-called “brain training” computer games and apps, with study after study finding that these programs fail to bring about meaningful benefits in real life.
Although the specific activities that Park chose – photography or quilting – may not appeal to everyone, she suspects the same benefits could emerge from many other hobbies. The essential point is to choose something that is unfamiliar, and which requires prolonged and active mental engagement as you cultivate a new set of behaviours. “it’s important that the task is novel and that it challenges you personally,” Park says. If you are a pianist, you might find greater benefits from learning a language say, than attempting to pick up the organ; if you are a painter, you might take up a sport like tennis.
You may be surprised by how much you enjoy the challenge itself. “The participants got more confidence in themselves,” Park says. One man went on to take photographs for his local newspaper; another woman had at first reluctantly attended the quilting class, despite having no real interest in the skill. She still wasn’t convinced by the end, but her successes had nevertheless inspired her to take up a new hobby – painting – instead. “I didn’t like quilting, but I had learnt how to learn,” she told Park.
So why not give it a go yourself and attempt to stretch your mind beyond its comfort zone? As Priscilla Sitienei – the 90-year-old Kenyan great-great-grandmother – put it: “Education has no age limit.”