Our minds are under attack. At least that’s what I keep hearing these days. Thumbing away at our text messages, we are becoming illiterate. (Or is that illiter8?) Blogs make us coarse, YouTube makes us shallow. Last summer the cover of The Atlantic posed a question: “Is Google Making Us Stoopid?” Inside the magazine, author Nicholas Carr argued that the Internet is damaging our brains, robbing us of our memories and deep thoughts. “As we come to rely on computers to mediate our understanding of the world,” he wrote, “it is our own intelligence that flattens into artificial intelligence.” I have a hard time taking these Cassandras of the Computer Age seriously. For one thing, they are much more interested in our fears than in the facts. In his new book, Txtng: The Gr8 Db8, the English linguist David Crystal demonstrates that many of the dire warnings about texting are little more than urban legends. Texting doesn’t lead to bad spelling, he finds. In fact, Crystal writes, “texting actually improves your literacy, as it gives you more practice in reading and writing.” More significantly, the ominous warnings feed on a popular misconception of how the mind works. We tend to think of the mind as separated from the world; we imagine information trickling into our senses and reaching our isolated minds, which then turn that information into a detailed picture of reality. The Internet and iPhones seem to be crashing the gate of the mind, taking over its natural work and leaving it to wither away to a mental stump. As plausible as this picture may seem, it does a bad job of explaining a lot of recent scientific research. In fact, the mind appears to be adapted for reaching out from our heads and making the world, including our machines, an extension of itself. This concept of the extended mind was first raised in 1998, right around the time Google was born, by two philosophers, Andy Clark, now at the University of Edinburgh, and David Chalmers, now at the Australian National University. In the journal Analysis, they published a short essay called “The Extended Mind” in which they asked a simple question: “Where does the mind stop and the rest of the world begin?” Most people might answer, “At the skull.” But Clark and Chalmers set out to convince their readers that the mind is not simply the product of the neurons in our brains, locked away behind a wall of bone. Rather, they argued that the mind is something more: a system made up of the brain plus parts of its environment. Clark and Chalmers asked their readers to imagine a woman named Inga. Inga hears from a friend that there’s an exhibit at the Museum of Modern Art. She decides to go see it. She thinks for a moment, recalls that the museum is on 53rd Street, and starts walking that way. She accesses her belief that MOMA is on 53rd Street from its storage place in her brain’s memory network. Now imagine a man named Otto, who has Alzheimer’s. His memory is faulty, and so he keeps with him a notebook in which he writes down important details. Like Inga, Otto hears about the museum exhibit. Since he can’t access the address in his brain, he looks it up in his notebook and then heads off in the same direction as Inga. In the view of Clark and Chalmers, Inga’s brain-based memory and Otto’s notebook are fundamentally the same. Inga’s mind just happens to access information stored away in her brain, while Otto’s mind draws on information stored in his notebook. The notebook, in other words, is part of his extended mind. It doesn’t make any difference that Otto keeps his notebook tucked away much of the time. After all, Inga tucks the memory of MOMA’s address out of her conscious awareness most of the time too. Clark and Chalmers concluded that real people are actually more like Otto than like Inga: We all have minds that extend out into our environments. Eleven years later, this argument continues to trigger fierce debate among philosophers, psychologists, and neuroscientists. There is no doubt that the extended mind is a weird concept. One reason it seems so strange is that our minds feel as if they are really totally self-contained. We innately believe, for example, that as we walk down a street, we are continuously filming a detailed movie of our surroundings and using that mental movie to decide what to do next. But like many beliefs we have about ourselves, this movie is an illusion. Our awareness is, in fact, remarkably narrow. One of the most spectacular demonstrations of how oblivious we can be was carried out by psychologists Daniel Simons of the University of Illinois and Christopher Chabris at Harvard University. They asked people to watch a video of students weaving around each other and passing a basketball. Half the students wore white shirts, the other half black. The subjects had to keep track of how many times the ball was passed by members of one of the teams. In the middle of the game, a gorilla (rather, a student in a gorilla costume) sauntered through the scene. Many subjects later reported that they never saw the gorilla; their brains discarded it as extraneous. Inside our heads, instead of making a perfect replica of the world, we focus our attention on tiny snippets, darting our eyes from point to point. We extract only the information we need for whatever task is at hand, whether we’re sorting the laundry or climbing a mountain. We use strikingly little information in the process. Dana Ballard, a computer scientist at the University of Texas, developed a computer game to measure just how little. He showed his subjects a pattern of colored blocks in the upper left-hand corner of the computer monitor. He then had them build a similar pattern of blocks in the lower left-hand corner. To do so, the players used a mouse to grab blocks, one by one, from a collection on the right-hand side of the screen. As the players looked from the original model to the collection of blocks to their own growing pattern, Ballard tracked their eye movements. He found that players looked at the model at the upper left before they picked up a block, and then again afterward. His experiments suggest that in each glance, the players were storing only a single piece of information. The first time they noted a block’s color. The second time they noted its position in the model. Instead of keeping a detailed picture of the blocks in mind, people extracted just tiny scraps of information on a need-to-know basis. Clark argues that Ballard’s subjects made the pattern of blocks part of their extended mind. It became a store of knowledge they could dip into, an external repository of information. It was as if Inga did not actually recall the address of MOMA but only the page in her notebook where she had written it down. Our memory holds a great deal of information. But the extended mind moves swiftly between outside and inside sources, showing little regard for where its information comes from. Our minds do more than take in information, of course. They also make decisions and send out commands—and those commands certainly don’t stay inside the mind. In the block-building game, for example, some commands go to neurons in the hand in order to move the computer mouse. But our brains don’t make a perfect mental replica of our hands and the mouse and the table in order to calculate where the mouse needs to go. Our hands and eyes constantly send signals to the brain, and that feedback alters the signals coming back out. Hand, eye, and brain are part of the same system. What’s even more remarkable about our brains is that they actually search for new things to make part of this feedback system. Imagine you are poking a stick into an animal’s burrow. As you poke away, you are aware of what the far end of the stick is touching, not the end you’re holding in your hand. This kind of extended sensation appears to be the result of a reorganization of the brain. Scientists have found that when test monkeys spent five minutes learning how to use a rake, some of the neurons in their hands began behaving in a new way. They began to fire in response to stimuli at the end of the rake, not on the monkey’s hand. Other neurons, in the brain, respond to things that appear to lie within arm’s reach. Training the monkeys to use the rakes caused these neurons to change—reacting to objects lying within rake’s reach rather than arm’s reach. The eagerness with which the brain merges with tools has made it possible to create some stunning mind-machine interfaces. For instance, Miguel Nicolelis of Duke University and his colleagues put electrodes in the brains of monkeys to link them to a robot arm. The monkeys quickly learned how to move the arm around with pure thought; their neurons reorganized, establishing a new feedback loop between brain and robot arm. Humans are proving just as good at this merger of mind and machine. The U.S. Navy has developed a flight suit for helicopter pilots that delivers little puffs of air on the side of the pilot’s body as his helicopter tilts in that direction. The pilot responds to the puffs by tilting away from them, and the suit passes those signals on to the helicopter’s steering controls. Pilots who train with this system can learn to fly blindfolded or to carry out complex maneuvers, such as holding the helicopter in a stationary hover. The helicopter becomes, in effect, part of the pilot’s body, linked back to his or her mind. Results like these, Clark argues, reveal a mind that is constantly seeking to extend itself, to grab on to new tools it has never experienced before and merge with them. Some people may be horrified by how passionately people are taking to their laptops and GPS trackers. But to Clark it would be surprising if we didn’t. We are, in Clark’s words, “natural-born cyborgs.” The extended mind theory doesn’t just change the way we think about the mind. It also changes how we judge what’s good and bad about today’s mind-altering technologies. There’s nothing unnatural about relying on the Internet—Google and all—for information. After all, we are constantly consulting the world around us like a kind of visual Wikipedia. Nor is there anything bad about our brains’ being altered by these new technologies, any more than there is something bad about a monkey’s brain changing as it learns how to play with a rake. Neuroscientists will soon be able to offer fresh ways to enhance our brains, whether with drugs or with implants. To say that these are immoral because they defile our true selves—our isolated, distinct minds—is to ignore biology. Our minds already extend out into the environment, and the changes we make to the environment already alter our minds. That doesn’t mean we must approve of every possible extension of the mind, and even good extensions will have some drawbacks. Socrates worried that writing would make people forgetful and unwise. Sure enough, writing did rob us of some gifts, such as the ability to recite epic poems like The Iliad from memory. But it also created a much larger pool of knowledge from which people could draw, a pool that has continued to expand (or, dare we say, continued to extend?).
我们的头脑正受到某种攻击。这种说法不知是否属实，但如今我倒经常听到这样的说法：不停地发送短信，使我们越来越像个文盲（或者说，像个WM？——此处原文为illiter8，即illiterate的短信写法变体，译者按照功能对等的原则加以处理）。博客使我们粗俗，YouTube令我们肤浅。去年夏天，《大西洋》杂志在其封面上赫然写着一个问题：“Google让我们越来越愚蠢？”文章作者尼古拉斯·卡尔在这份杂志中提出一个观点，认为互联网破坏着我们的大脑，抢夺了我们的记忆与深刻思想。他写道：“一旦我们对世界的理解（过程）离不开电脑的插足，那么我们自己的（天然）智能就会被挤压成单薄的人工智能。” 要认真对待计算机时代的这种卡桑德拉式预言，我也很不容易，因为此类预言往往罔顾事实，危言耸听。而英国语言学家大卫·克里斯托尔在他的新作《Textng：The Gr8 Db8》（即：Texting: The Great Debate <短信大论战>——还是借用信息时代的“流行语”写法——译者注）列举了大量实例，说明人们把短信（的“不规范”写法）视为洪水猛兽，也不外是一种市民式的传言而已。该书作者发现，编写短信并不会导致书写水平的退步。相反，他写道：“编写短信能够实实在在地提高人们的文化水平，因为发短信可以给人们提供更多的阅读与写作练习。” 更为显而易见的是，这些危言耸听的警告之所以有市场，正是利用了人们对大脑思考机制的普遍误解。我们总以为头脑是与外部世界相脱离的，还以为信息如涓涓细流一点一点地渗入我们的感觉而最后到达我们那个思想孤岛，然后就在这座孤岛上呈现出一幅细致逼真的现实画卷。我们还以为，互联网和iPhone好象正在摧毁我们的思想大门、彻底控制了大脑的天然机能，最后任大脑萎缩成一个没用的智力残体。这种想法就象那幅图画一样，好象是真的，却解释不了最近所取得的科学研究成果。实际上，人们的思想似乎已经学会了挣脱脑袋的束缚，学会了怎么去建设世界，包括制造各种机器即人类的“外脑”。 外脑概念是两位哲学家于1998年首次提出来的，也就是在Google诞生的前后。这两位哲学家，一位叫安迪·克拉克，现在爱丁堡大学，另一位叫大卫·查尔莫斯，现在澳大利亚民族大学。他们俩在《分析》杂志上发表一篇短文，题目就叫做《外脑》，就在这篇文章里，他们提出了一个简单的问题：“思想的终点在哪里？人脑之外的那个世界的起点又在何处？”对于这个问题，多数人都会回答说“就在脑壳里”。可是克拉克和查尔莫斯的回答令读者折服，那就是，思想并非仅仅是大脑里面那些神经元的产物，并不是被封闭在脑壳里面的一座孤岛。思想的概念要更为广泛，它是一个系统，是由人脑和人脑周围的部分环境构成的一个系统。 克拉克和查尔莫斯请读者去想象一下：有一名女子名叫印加，印加从朋友那里听说现代艺术博物馆正在举办一个展览，她决定去看看。她想了一会儿，终于想起来，博物馆就在53号大道上，就开始朝那个方向走去。印加能想起来现代艺术博物馆位于53号大道，就等于她进入了她大脑记忆系统的某个信息存放区域了。现在再想象一下，还有一个男子名叫奥托，可是他得了阿兹海默症。由于他的记忆区出了问题，他只好随身携带一本笔记本，里面记录了很多重要内容。和印加一样，奥托也听说了博物馆的那个展览，可是由于他无法进入大脑的记忆系统中，他只能查阅笔记本，从而和印加一样朝同一个方向走去。 克拉克和查尔莫斯的观点是，印加这种以人脑为基础的记忆功能与奥托的笔记本在本质上是完全一样的。印加的头脑恰好能接触到储存在她大脑中那些信息，而奥托则从储存在笔记本的内容中提取信息。换句话说，这个笔记本就是奥托延伸出来的大脑的一部分。至于奥托是否在大部分时间里把这本笔记本丢在一边不管，则关系不大。而印加在大部分时间里也是把关于现代艺术博物馆的地址信息藏在她的意识里不管的。克拉克和查尔莫斯的结论是，其实现实中的人们更像奥托，而不像印加：我们也有这样一个延伸到环境中去的头脑。 十一年后，这个论点还在引起哲学家、心理学家及神经科学家的剧烈争论。毫无疑问，所谓“外脑”，确是一个匪夷所思的概念。之所以让人觉得匪夷所思，理由之一就是我们自己的头脑以为自己处在一种完全封闭的状态。比如说，我们与生俱来的认识是：当我们在大街上走着的时候，我们就象一台摄像机一样，一刻不停的把身边的一切详细摄录下来，然后再运用所拍摄到的“精神影片”来判断下一步该做什么（该往何处走）。但是，就像我们对自己形成的各种认识一样，这个影片其实是一种幻觉，我们的意识视野实际上是很狭小的。 伊利诺伊斯大学的丹尼尔·西蒙斯及哈佛大学的克里斯托夫·查伯利斯两位心理学家所设计的那个实验，最能清晰地说明我们有多么“有眼无珠”。在实验中，两位学者请人们观看一段录像，录像里有学生在交叉跑动传递篮球，学生中有一半穿着白色衬衫，另一半穿的是黑色的。受测试者的任务是紧盯住其中一队，统计该队总共传递了多少次篮球。就在比赛进行到半程的时候，赛场上突然闯进一头黑猩猩（原来是一个穿着猩猩衣服的学生），然后在里面大摇大摆地随便走动着。结果表明：很多受试者事后对比赛进行回忆的时候，都说没看见那头黑猩猩。原来，他们的大脑早就把这一切抛进九霄云外了。 在我们的大脑中，我们并非把世界的一切准确无误地复制下来，只能把注意力放在一些鸡毛蒜皮的小事上，我们的视线也只能对事物进行点对点式的扫描。我们只能根据手头上要做的事务去获取所需的信息，而不管这些事物是对要洗的衣物进行分类，还是去攀登山峰。 在上述过程中，我们对信息的捕捉能力简直低得吓人。德州大学计算机科学家丹纳·巴拉德就开发了一种电脑游戏，可用于测验这种能力的高低。首先，他让受测者记住显示器左上方显示的、构成一定图案的彩色积木，然后要求受试者尽量在显示器的左下角组合出所看到的积木图案来。参加这一游戏的人可用鼠标从屏幕右边一块块地抓取积木。在玩游戏者的视线从模型转移到他们自己正在组装的图案的过程中，巴拉德就一直在跟踪着他们眼球的动态。结果发现，玩游戏的人总是先看好原始图案左上方的一块，然后才开始抓取相应的积木，接下去就这么按顺序一个一个抓下去。巴拉德的实验表明，游戏者每看一眼，都只能记住单一的信息碎片：第一眼只是记住积木的颜色，第二眼才是记住积木在原始图案中的位置。人们并没有在头脑中记住积木的详细情形，而是根据需要，一次只捕捉一丁点信息。 克拉克的观点是，接受巴拉德试验的人实际上已把那些积木的组合方式变成他们的外脑，这个外脑就成为接受试验者可以不断挖掘的知识储备库，是信息的外部呼吸系统。这就好像印加实际上并没能想起来现代艺术博物馆的位置一样，真正给予她记忆的那些信息其实早已存放在她脑子里的那个笔记本的某一页上。人脑的记忆区里存放着大量信息，而外脑则能够在内、外两个资源库之间进行快速转换，而并不太在意这些信息来自何处。 当然，人脑并不仅仅是一个接受信息的装置而已，它还有决策和发布命令的功能——而这些命令当然不是存放在大脑中的。例如，在积木游戏中，为了移动电脑鼠标，有些指令是发送到手臂的神经元上的。可是，（在上述过程中），大脑是无法先把双手的动作、鼠标的走向及整个游戏进程表原原本本复制下来再去计算鼠标到底该怎么走才合适的。我们的双手和眼睛不停地把各种信号送给大脑，但是反馈作用会对发送回来的信号进行修改。于是，手、眼、大脑实际上是同一个系统的组成部分。 人脑还有一个更加特别之处，那就是它会对一些新事物进行搜索，然后把这些新事物变成反馈系统的组成部分。大家不妨设想一下这样的情景：将一根枝条插进动物的洞穴里。在往里插的过程中，你在意的只是枝条的远端能够触碰到什么东西，而不是你抓在手里这一端如何如何。这种感觉的延伸似乎正是大脑认知过程的结果。科学家通过猴子学习过程的实验，已经发现一种现象：在猴子用五分钟去学习如何使用钉耙的时候，猴子手臂神经元的行为方式就会是全新的。这些神经元会对钉耙的远端所感受到的刺激物做出反射式放电，而对猴子手里抓着的这一端则没有反射。而（猴子）脑子里的其它神经元则只对猴子的手臂够得着的范围内的事物有反射作用。让猴子接受钉耙使用训练的过程会改变神经元的反射方式，即神经元变成能够对钉耙够得着的范围内的事物有反射，而不是对手臂够得着的范围内的事物有反射。 人脑与外部工具之间相结合十分紧密，使得人脑与机器之间建立某种不可思议的协同界面成为可能。例如，杜克大学的米吉尔·尼克勒利斯和他的同事就做了这么一个实验：他们把电极安装在猴子大脑里，再连接到机器人手上，结果猴子很快据学会单纯用意念去控制机械手的本领。猴子的神经元形成了新的协同结构，从而在大脑和机械手之间形成了新的反馈环。 现已证明，人类在建立这种大脑-机器紧密联系方面的本领也不差。美国海军已经为直升机飞行员开发出一种新的飞行服，这种飞行服可以在飞机倾斜时给飞行员身体的同向倾斜一侧传送一种微弱的气流，而飞行员只要让身体坐正，就可以对这一气流做出反应，这种身体反应又能够反过来把信号传送到直升机方向操纵杆上。经过训练而能熟练操作这种系统的飞行员就可以实现盲飞，或者进行某种复杂的飞行动作，例如让直升机稳定地停定在半空中。这时候，直升机实际上已变成飞行员身体的一部分，连接在飞行员的大脑上了。 克拉克认为，这些实验结果揭示了一个事实，即人脑总是在想方设法去延伸自己，去掌握人脑以前从未接触过的各种新工具，并与这些新工具融合为一体。人们对手提电脑和GPS定位仪的热衷程度让另外一些人觉得很可怕，可是对于克拉克来说，不热衷才真正让他觉得可怕，因为用克拉克的话说，人们对机电设备的依赖完全是一种天然的需要。 外脑理论所改变的并不仅仅是我们对自己大脑的想法，还能改变我们对今天各种能改变我们思想的技术的好坏所作出的评判。现在看来，今天我们为获取信息而对互联网——不管是Google还是其他——的依赖就一点都不奇怪了。说到底，我们不是一直就像在查询一个看到见摸得着的维基百科那样在了解这个世界么？这些新技术对人脑的改变也不会有任何坏处，就像猴子的大脑因猴子学会如何使用钉耙而发生了改变一样，有什么不好呢？ 神经科学家很快就会为提高人脑的技能而发明出各种新方法的，不管用药物的办法还是用植入（芯片）的办法，一定会有办法的。如果说这么做不道德，因为这样就等于违背了我们真正的自己，也就是违背了我们那个孤立的、独特的头脑，那么这种说法就是罔顾生物学原理了。我们的头脑早已延伸到外部环境里去了，而我们对环境造成的改变也早已反过来改变着我们的头脑。 这也并不是说，我们必须把人脑技能的方方面面都提高到无以复加的程度，也不是说，再好的脑力延伸总有其反面作用。苏格拉底不是曾经担心过：书写会使人健忘，使人糊涂吗？书写确实剥夺了人们的某些天赋，比如背诵如《伊利亚特》这样的史诗。可是，书写不也同时为人类开辟了一个广阔得多的学识天地么？有了这片新的知识天地，人们才得以从中吸取知识，而这个知识天地一直都处于不断扩展之中（是否也可以大胆地说，处在不断地延伸之中？）。 任何企图斩断人脑内部与外界联系的做法都是毫无意义的，相反，我们也许应该把精力集中在如何管理和增进这些联系方面上。例如，我们就应该下大力气，想办法使我们从网络上获取的信息得到过滤，使我们不会出现被集体误导的情形。可能有人会认为，想要对人脑与互联网业已形成的联系加以微调，是完全不可能的事情。但是，假如从克拉克和查尔莫斯发表的那篇《外脑》文章开始，我们就已经学到某些知识，那么我们就不会低估人脑对这个变化着的世界的适应能力了。 （江天梦 译自The Discovery Magazine） |
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