Unit 6 课文

Unit 6

T1

Can bad luck be explained?

1 Toast always lands butter side down. It always rains on bank holidays . You never win the lottery, but other people you know seem to … Do you ever get the impression that you were born unlucky? Even the most rational person can be convinced at times that there is a force out there making mishaps occur at the worst possible time. We all like to believe that Murphy's Law is true ("if it can go wrong, it will").

2 Part of the explanation for bad luck is mathematical, but part is psychological. Indeed there is a very close connection between people's perception of bad luck and interesting coincidences.

3 For example, take the belief that "bad things always happen in threes" ( just like buses …! ) This popular notion would be unlikely to stand the scrutiny of any scientific study, but it must have some basis in experience, otherwise the phrase would never have arisen in the first place. What might be the rational explanation?

4 The first question is "what is bad?"

5 Some things are only marginally bad, for example the train arriving five minutes late. Some are extremely bad, such as failing an exam or being sacked. So badness is much better represented as being on a spectrum rather than something which is there or not there.

6 A particular event may only be a misfortune because of the circumstances around it. The train arriving five minutes late is a neutral event if you are in no hurry and reading an interesting newspaper article while you wait. It is bad if you are late for an important meeting.

7 When it comes to bad things happening in threes, what may be most important of all is the duration and memorability of the first event. Take a burst pipe while you are away on holiday, for example. It may take less than an hour to flood the house, but this one bad event can remain alive and kicking for many months, with the cleaning up operation and the debate with your insurers acting as constant reminders of the original event.

8 The longer the first bad event sticks in the front of your mind, the more opportunities you will have to experience two more bad events. A month later someone bumps the back of your car and a week after that you lose your wedding ring. The mind which is already on a low from the first event will quickly leap to connect the subsequent misfortunes as part of the series. It wouldn't matter that there could be a two-month timescale over which everything happened. By the time you have recovered from the water damage you are actively looking out for the next disaster. The timescale has been extended as long as is necessary to confirm the original prophecy.

9 As with coincidences, in bad luck there is a tendency to look for the examples which confirm the theory, and ignore those which don't (because they are less interesting). Single bad events happen all the time. That alone should be enough to disprove the theory. Bad things also come in twos. But it is more likely that a friend will tell you "three bad things have happened to me, isn't that typical" than "only two bad things have happened to me, which just proves that the theory doesn't work". After all, the latter is tempting fate!

10 There is, however, at least one rational reason why bad events might cluster together. It is related to probability and independence. Unlucky events are not always independent of each other. Anybody who is made redundant is bound to suffer some depression. That will lower the body's defences, making the person vulnerable to illness, and also making them less alert and responsive (so they may be more likely to drop a precious vase, for example). So while the probability of being made redundant on any particular day and the probability of being sick may both be small, the chance of both occurring is almost certainly higher than the product of the two probabilities.

Map reading misfortunes

11 So much for the general incidents of bad luck which crop up in life. Let's get on to a specific one that everyone has encountered.

12 You are off to visit a friend who lives at the other end of the city. You look up the road in the street atlas, and discover that it is right on the edge of the page. This means that finding the precise route becomes a chore of flicking backwards and forwards from one page to the next. Either the road is half on one page and half on the other, or it's spread across the fold in the middle of the book. And if it's an ordnance survey map, then your destination is at just the point where you folded the map over.

13 It doesn't seem fair. After all a map only has a tiny bit of "edge" but plenty of "middle" in which your destination could be situated. Or has it? In fact the chance of picking a destination which is close to the edge of the map is a lot higher than you might expect.

14 Take a look at the map in the diagram.

You will have a problem if your destination is anywhere in the shaded area marked on the map. This shaded area is just 1 cm into the page all the way around. It looks insignificant. However, the shaded area adds up to 56 cm2. That represents 28 per cent of the area of the whole page of the map, which means that any specific point that you are seeking on this map has a 28 per cent chance (that's nearly one in three) of being in an awkward position within 1 cm of the edge of the page. And if you regard being within 2 cm of the edge of the page as being awkward, the chance of ill-fortune climbs to 52 per cent. In other words, you might expect this misfortune to occur on almost every other Journey.

15 As in most bad luck stories, you forget about the number of times the road doesn't land awkwardly and remember the times it does, and in this case the chance of a bad result is so high that before long you are bound to be cursing your misfortune, or the map's printer, or both. This, incidentally, is why many modern road maps allow significant overlaps between adjacent map pages. In a good road atlas, at least 30 per cent of the page is duplicated elsewhere.

The lights are always red when I'm in a hurry

16 One of the best examples of selective memory where an unfair comparison is made between good and bad is in the relative frequency of red and green lights on a journey. For once, the perception of "I always seem to get red lights when I'm in a hurry" is true and verifiable. To simplify the situation, think of a traffic light as being like tossing a coin, with a 50 per cent chance of being red, and 50 per cent of being green. (In fact most traffic lights spend more time on red.) If you encounter six traffic lights on a journey, then you are no more likely to escape a red light than you are to toss six consecutive heads, the chance of which is 1 in 64.

17 Red lights come up just as often when the driver is not in a hurry; it's just that the disadvantage of the red light is considerably less if time is not critical. The false part of the perception is that red lights happen more than green lights. The reason for this is simply that a driver has more time to think about a red light than a green light, because while the latter is gone in seconds – and indeed is an experience no different from just driving along the open road – the red light forces a change of behaviour, a moment of exertion and stress, and then a deprivation of freedom for a minute or so. Red lights stick in the mind, while green lights are instantly forgotten.

生活中的倒霉事能解释吗？

1 每次吐司掉到地上总是抹了黄油的那一面贴地。每逢公假日必定下雨。你买彩票从来没中过大奖，但是你认识的人里似乎有人……你有没有觉得自己生来就是个倒霉蛋？即使是最理智的人有时候也会对此深信不疑，认为冥冥之中有一种力量让他们在最糟糕的时期里灾祸连连。我们都愿意相信墨菲法则是对的（“该出错的，终将出错”）。

2 人之所以走背运，部分是概率的问题，部分是心理上的问题。的确，人们对背运的感知和一些有意思的巧合之间有着紧密的联系。

3 就拿“坏事成三”这种想法来说吧（就像等公交车一样，要么不来，要么一下来三辆！）。这种流传甚广的观念可能根本经不起科学的检验，但是它必定有一些现实的依据，不然的话也不会有这样的说法了。那么，什么样的解释才是合理的呢？

4 我们要考虑的第一个问题是“什么是坏事？”

5 有些事情只是稍稍有点不好，比如火车晚点五分钟。有些事情则是糟糕透顶，比如考试不及格，或是被炒了鱿鱼。所以我们更应该把事情的好坏看成是一个程度的问题，而不是非好即坏。

6 某件事情有可能因为相关的一些因素而变成了不幸的事。火车晚点五分钟，如果你边读着报纸上一篇有趣的文章边等车，并不赶时间，那么这就是一件无关紧要的事。但是如果你要去参加一个重要会议，而且马上要迟到了，那火车晚点就变成坏事了。

7 谈到坏事成三的问题，其中最关键的因素是第一件倒霉事持续的时间有多长以及给人的印象深不深。比如说，你外出度假期间家里的水管爆裂了。也许不到一个小时你的家就变成了一片汪洋，而在接下来的几个月中你的脑子会不停地想起这桩倒霉事，因为你要把房子清理干净，还要和保险公司就赔偿问题讨价还价，这些都会让你不断地想起这件事。

8 第一件倒霉事困扰你的时间越长，你遇到两件倒霉事的几率就越大。说不定一个月之后，有人开车追尾撞了你的车。又过了一个星期，你的结婚戒指不见了。出了第一件倒霉事，你的情绪本来就很低落，这时你会很快地把后来发生的事情联系到一起，把它们看作是有关联的一连串事件。即使这几件事情的时间跨度可能长达两个月之久，那也不会改变你的看法。等你从浸水事件中平复过来的时候，你已经在积极地等待下一个灾难的发生了。这个时间跨度已经被拉长了，直至能够证明你之前的预言是对的。

9 人们碰上倒霉事的时候会像遇到巧合的时候一样，去寻找一些事例来验证他们先入为主的想法，而忽略掉与这种想法有出入的事情（因为那些事情不是那么有趣）。孤立的倒霉事每时每刻都在发生。光凭这一点就可以推翻“坏事成三”的理论了。坏事也可以是成双的。但是你的朋友很可能会对你说：“我一连碰到了三件倒霉事，可真是应了那句俗话！”，而不是说：“我只碰上了两件倒霉事，这不正好证明了‘坏事成三’这个说法不成立吗？”毕竟，说后一种话是要冒风险的！

10 但是，至少有一个合理的解释可以说明为什么坏事会扎堆。这涉及到概率和独立性的问题。并不是所有的倒霉事都互无关联。任何一个人在被解雇之后都会心情抑郁，这会降低他们身体的抵抗力，使他们更容易得病，而身体反应也不像以前那么警觉灵敏（所以他们就更有可能遇上打碎贵重的花瓶这样的事）。因此，虽然人们在某一天被裁员和在某一天生病的概率都很小，但是这两件事同时发生的概率肯定要高于它们分别发生的概率。

看地图时碰到的倒霉事

11 关于日常生活中突发的普通倒霉事我们就说到这里。下面让我们来看一个每个人都会碰到的事情。

12 你要去拜访一个朋友，他住在城市的另一头。你在街道地图册上寻找去他家的路线，结果发现这条路线恰恰就在这页地图的边上。这意味着要找到一条精确的路线，你就必须从这一页翻到下一页，不停地翻来翻去，很是麻烦。这条路线不是一半在这一页一半在下一页，就是被地图中间的书脊夹着。如果你手里拿的是全国地形测量局的地图，那么你的目的地可能正好就在地图册的折合处。

13 这似乎很不公平。毕竟一个地图的“边缘”只有那么一点儿，而“中间”的地方那么大，你要去的地方完全可以在中间啊！事实果真如此吗？实际上，你随便挑一个地方，它出现在靠近地图边缘的几率比你想象的要大得多。

14 看一看下面的地图。

如果你的目的地在地图上标出的那个阴影区域里，你就遇到麻烦了。这个阴影区域离地图四周的边缘处只有一厘米的距离，这似乎微不足道。但是这些阴影区域的面积加起来有56平方厘米。差不多占了整页地图面积的28%，这意味着任何一个你要找的地方都有28%（差不多是三分之一）的几率出现在离页边不到一厘米的尴尬的地方。假如你设定离页边两厘米为阅读不便的话，那你遇上坏运气的几率就攀升到了52%。换句话说，差不多每隔一次你就会碰到这样的倒霉事。

15 在大多数有关倒霉事的故事中，你会忘掉路线好找的次数，只记得路线不好找的次数，在这种情况下，你倒霉的几率肯定会很高，以致于过不了多久你就又会诅咒自己的运气，诅咒地图的出版商，或者两个一起诅咒。顺便说一下，这正是现在许多地图允许相邻的两页有很大重合部分的原因。一份制作精良的地图册，每页至少有30%的部分会在其他页上重复出现。

我赶时间的时候总是碰上红灯

16 关于选择性记忆，即人们对好运气和坏运气所做的不公正的比较，最好的一个例子就是路上红绿灯的相对频率问题。至少有一次，“我赶时间的时候，总是碰上红灯”这种说法是真实可靠的。为了便于理解，我们可以把红绿灯看作是投掷一枚硬币，出现红灯和绿灯的几率各为50%。（事实上大多数红绿灯，红灯的时间更长一点。）如果在路上碰上六个红绿灯，全部是绿灯就和扔硬币连续六次都是人头朝上的概率是一样的，为六十四分之一。

17 司机不赶时间的时候碰到的红灯其实和赶时间的时候一样多；只是如果时间不紧急，红灯带来的不便要小得多。认为红灯出现的次数比绿灯多其实是一种错觉。产生这种错觉的原因很简单，因为司机有更多的时间去想红灯，而绿灯的时候，车子几秒钟之内就疾驰而过了——这其实和在畅通的公路上开车没有任何区别——而红灯却迫使司机改变行为，一小会儿的时间里要强迫自己努力一下，承受点压力，还要失去一两分钟的自由。所以红灯会深深地印在司机的脑海里，而绿灯转瞬间就被抛到了脑后。

T2

Science: fact or fiction?

1 Students aren't what they used to be. These days, it seems, some of them never even open a book. Such is the depressing picture painted by popular science writer Steve Jones in his book The Single Helix, laying the finger of blame on modern communication systems. The message is the medium ; once upon a time there were books, but now, Jones says, "The medium is, or so it seems, anything but lines of print on a page." Many students are just not used to reading books anymore – they're such an outdated form of communication.

2 So how do you get them to learn about science? Well, if you go into a campus bookstore you can find out. There are songbooks for biochemists, with chemical formulae set to music to make them easier to remember. Relativity is explained in a video game which is a simulation of a rocket journey through space: You can play tennis on board as the rocket speeds up or slows down. And there are cartoons to make even the most obscure scientific subjects accessible, and fun as well.

3 But even these methods of generating interest have become conventional. Rather more radical is the proposal which a physics professor has come up with – to learn science from the mistakes in science fiction films. Some of the films may be dreadful, but they hide a lot of helpful messages. Students just have to sit back, relax, enjoy the film, and soak up a bit of science at the same time.

4 A few examples will show what the professor has in mind. In The Day the Earth Caught Fire (1961), the Earth is pushed towards the sun as a result of two simultaneous atomic explosions. But this contravenes Newton's Third Law of Motion – namely, that action and reaction are equal and opposite. Since the Earth weighs six thousand billion billion tons, a huge blast would be needed to push it into the right direction. Supposing it hurled a hundred million tons of rock and debris into space. This explosion would require a bomb far greater than any that has ever exploded. But a few basic sums would show that such a blast, as well as killing every single inhabitant of the Earth, would only shift the Earth about a quarter of an inch out of its orbit.

5 So the film is fiction without the science. The same could be said of the 1986 film Aliens. In this film the crew saunter around the spaceship as if they were at home on earth – whereas they should be floating, in a gravity-free environment. The producers of Aliens would fail a first-year physics exam, but Stanley Kubrick and Arthur Clarke, the brains behind 2001: A Space Odyssey, would pass the same exam with flying colours. On board the spaceship a giant wheel rotates, generating centripetal force and giving the astronauts on board a sense of "up" and "down".

6 The treatment of relativity in science fiction films is even more confusing. Take Star Trek: The Voyage Home (1987). As the spaceship revolves round the sun, it gathers so much speed that it moves backwards into history. But this is nonsense, not relativity. As Jones puts it, "Einstein said that nothing travels at more than the speed of light, not that the clocks will run the other way if you go fast enough. " Even Superman (1978) is baffled by the concept. It takes him a split second to fly round the earth anticlockwise to save Lois Lane, who has fallen victim to an earthquake. Jones: "Time is not like a car. It has no reverse gear."

7 Finally, what about those giant insects like the ones in Empire of the Ants, the 1977 film based on a story by H.G.Wells? The problem is their lungs, or rather, the lack of them. Ants don't have lungs, so they get oxygen by absorbing it through the tissues of their bodies. The bigger the ant, the longer it would take to absorb the oxygen – and their body parts would not be able to function well. So an ant the size of a human would be more likely to be gasping for breath than biting off the head of a reckless teenager.

科学：事实还是虚构?

1 学生已今非昔比。如今，似乎有些学生从来就没有翻开过书本。这是科普作家斯蒂夫•琼斯在其《单螺旋线》一书中描绘的令人沮丧的情景，他把批评的矛头指向现代通信系统。信息即媒介；从前有书本，可是现在，琼斯说：“媒介是，或者说似乎是，一切，但绝不是纸上印的一行行字。”许多学生就是不再习惯读书了——书是老掉牙的沟通方式。

2 那么怎样使他们学习科学呢？好吧，你要是走进校园书店，就会找到办法。那里有生物化学家的歌本，其中化学分子式被配上乐曲以便记忆。相对论是用电子游戏来解释的，那是个虚拟乘火箭在空间旅行的游戏：你可以在火箭加速或减速飞行时在上面打网球。还有卡通，它们使哪怕最艰涩的科学话题都变得有趣易懂。

3 可是就连这些激发兴趣的方法也已变得老套了。更激进的方法是一个物理学教授提出来的：从科幻电影的错误中学习科学。有些电影也许糟透了，但其中隐藏有大量有益的信息。学生只需舒舒服服地坐着、放松、欣赏电影，同时吸收一点科学知识。

4 有几个例子可以说明教授的想法。在《地球着火之日》（1961）中，两颗同时爆炸的原子弹把地球推向太阳。可是这违反了牛顿的第三运动定律——即，作用力和反作用力相等且方向相反。既然地球重达六千艾吨，那就需要特大的爆炸才能把它推入正确的方向。假设爆炸将一亿吨岩石和碎渣抛入宇宙，那么这个炸弹的威力要比任何以往的炸弹都要大。但是，稍做运算就能说明，这样一场爆炸除了会把地球上的生物全部杀死之外，充其量也只能让地球偏离轨道大约四分之一英寸。

5 所以，这部电影是没有科学含量的虚构作品。1986年出品的电影《异形》也是同样。在这部影片中，宇航员们在宇宙飞船中走来走去，就好像在地球上的家里一样——而实际上他们应当在无重力环境中漂浮才对。《异形》的制片人可能会在大学一年级的物理学考试中不及格，但是《2001：太空漫游》背后的智囊斯坦利•库布里克和亚瑟•克拉克却会在同样的考试中以高分通过。宇宙飞船上有一巨大的轮子转动着，产生向心力，并给船上的宇航员一种“起伏”感。

6 科幻电影中对相对论的处理更是令人摸不着头脑。以《星舰迷航：回家之旅》（1987）为例：宇宙飞船围绕太阳飞行，速度越来越快，最后竟然飞回到了历史之中。但这是瞎编乱造，而不是相对论。正如琼斯所说：“爱因斯坦说没有什么比光速更快；但没有说如果你跑得够快，钟表就会倒转。”就连《超人》（1978）也被此概念所困惑。他在瞬间往逆时针方向绕地球一周去救地震受难者洛伊斯•莱恩。琼斯说：“时间不像汽车，它没有倒挡。”

7 最后，1977年根据H.G.威尔斯的小说拍摄的《蚂蚁帝国》里的那些巨型昆虫又如何呢？问题在于它们的肺，或者说，它们根本没有肺。蚂蚁没有肺，它们是通过身体组织吸收氧气的。蚂蚁越大，吸收氧气的时间就越长——这样它们身体的各部件就不能良好地运作。所以像人那么大的蚂蚁更可能老是在大口喘气，而不是把冒失少年的脑袋咬掉。

T3

Are boys more intelligent than girls?

1 It's an old idea. Boys are better than girls at science. Girls may be better at verbal skills, but when it comes to "hard" subjects like maths and physics, senior school and university classes in the UK and the US are predominantly male. With younger learners things are different: Recent research in US schools showed that in the fourth grade about the same number of boys and girls (67 per cent) said they liked science and might want to become scientists when they grow up. But by the time they reached the eighth grade the picture is very different. Twice as many boys as girls say they like science, and the number of girls taking higher-level science courses falls dramatically.

2 But why is this? Several reasons have been suggested by researchers. The first is simply that girls comply to the traditional idea that science is not for them. This idea is sometimes reinforced by their parents, and sometimes by teachers who tend to ignore girls in science classes and ask boys all the questions. As children grow older, science becomes more and more a "male" territory, and some girls feel intimidated by science laboratories, which they find unfriendly.

3 But there is a more radical – and controversial – theory. According to Simon Baron Cohen of the University of Cambridge, girls' brains are different from boys' brains – they have "empathizing" brains, while boys' brains are "systemizing". An empathizing brain tries to understand other people's thoughts and emotions, while a systemizing brain wants to understand the rules which govern the behaviour of a system. So girls make better carers, and boys are more able to make sense out of a map – a distinction that many teachers would agree with.

4 This may be true, but it doesn't mean that boys are more intelligent than girls. Nor does the theory imply that all girls have "empathizing" brains. On the contrary, data from the OECD consistently shows that girls do better at school – especially in reading skills – across the world, from Korea to Finland. This is confirmed by some simple facts from the UK. More girls than boys choose biology and chemistry for A levels, probably because they are needed to study medicine at university – and medicine is a "caring" career. But the few girls who decide to take physics – less than 25 per cent of all students – get much better exam results than the boys.

男生比女生聪明吗？

1 这是个老观念了：在理科方面，男生比女生强。女生可能在语言技能方面强一些，但一遇到数学和物理之类的“难”科目，英国和美国的高中和大学课堂上则大多是男性。情况在年龄更小的学生中有所不同：最近在美国中小学所做的研究表明，在四年级，约有同样数量的男生和女生（67％）说他们喜欢理科，长大后想当科学家。可是等他们上了八年级的时候，情况就非常不同了。比女生多一倍的男生说他们喜欢理科，而选修高等理科课程的女生人数则大幅下降。

2 这是为什么呢？研究者提供了若干原因。首先，很简单，就是女生服从传统观念，以为理科不适合她们。这种观念有时被父母，有时被老师所强化。在理科课上老师往往忽视女生，总是向男生提问。随着孩子们年龄的增长，理科越来越变成“男性”领域 ；有些女生觉得科学实验室气氛不友好，因而感到胆怯。

3 但是有一种更激进——也颇有争议——的理论。据剑桥大学的西蒙•拜伦•科恩说，女孩的大脑与男孩的不一样——她们的大脑是“同感化的”，而男孩的大脑是“系统化的”。同感化大脑总是试图理解人们的思想和感情，而系统化大脑总是想要理解主导系统行为的规律。所以女生较关心人，而男生更善于看地图——许多教师都会同意这一区别。

4 这也许是真的，但这并不意味着男孩比女孩更聪明。这种理论也并不是说，所有女孩都拥有“同感化”大脑。相反，来自经合组织的数据一贯表明，在从韩国到芬兰的世界范围内，女生在学校成绩更好——尤其是在阅读技能方面。这被来自英国的一些简单事实所证实。比男生更多的女生在高考时选择生物学和化学，很可能是因为上大学学医需要这两门知识——而医学是一种“关心人的”事业。但是少数决定选学物理的女生——占全部学生人数不到 25％——比男生的考试成绩要好得多。