Unit 8 Nature and Nurture新编大学英语第二版第三册课文翻译

1、Unit 8 Nature and NurtureTwins, Genes, and EnvironmentHeredity or environment: which is stronger? The potentials which a person is born with determine in some way what he will do in life. Therefore heredity is fate, a kind of predestination. However, genes do not work in a vacuum; as soon as we begi

2、n considering the role that they play in the development of the individual, we see that there can be no development without the interacting environment. No characteristic is caused exclusively by either environment or genes. The relative effects of heredity and environment are most clearly observabl

3、e in identical twins. Most identical twins are raised together and are remarkably alike in both appearance and behavior. These cases demonstrate that individuals with the same genes, when raised in the same environment, will respond to it in much the same way. They do not indicate what would happen

4、if these identical individuals were raised separately. A number of studies have been made of identical twins raised apart. The twins who were the subjects of these studies lived in America, were raised in much the same physical environments, and experienced much the same nutritional histories. There

5、fore, as one might expect, they maintained the closest resemblance to each other in physical appearance, height, and weight. Exceptions occurred when one twin had developed a rather severe illness and the other had not; but on the whole everyone is impressed by the great psychological and physical l

6、ikenesses that exist between identical twins, even those who have been separated from infancy. In a study of nineteen sets of twins who had been separated from birth, investigators found that in approximately two thirds of the sets there were no more significant differences than existed among unsepa

7、rated pairs of twins. This strongly suggests the power of the genes and the limitation of the effect of environment. However, it must be remembered that, although the identical twins who were studied lived in different families far removed from each other, the environments in those families were not

8、, on the whole, substantially different. Usually every effort would be made to put each child in a home with a background similar to that of its own family, and therefore it should not be surprising to find that the twins developed similarly. But in those cases in which there had been a greater diff

9、erence in the environments of the separated twins, the differences between the twins were more substantial. The following case illustrates what happens to identical twins when they are brought up in contrasting environments. Gladys and Helen were born in a small Ohio town and were separated at about

10、 eighteen months of age. They did not meet again until they were twenty-eight years old. Helen had been adopted twice. Her first foster parents had proved to be unstable, and Helen had been returned to the orphanage after a couple of years; after several months she was again adopted, by a farmer and

11、 his wife who lived in southeastern Michigan. This was her home for the next twenty-five years. Her second foster-mother, though she had had few educational advantages herself, was determined that Helen should receive a good education; Helen eventually graduated from college, taught school for twelv

12、e years, married at twenty-six, and had a daughter. Gladys was adopted by a Canadian railroad conductor and his wife. When she was in the third grade, the family moved to a rather isolated part of the Canadian Rockies, where there were no schools, and Gladys' formal education came to an end, and

13、 was not resumed until the family moved to Ontario. She stayed at home and did housework until she was seventeen, and then went to work in a knitting mill. She went to Detroit at nineteen, got a job, and married when she was twenty-one. Helen had been healthier than Gladys, in childhood and adulthoo

14、d, but other than that, their environments had been very similar except for their educations. Their weight, height, hair color, and teeth were very similar. The differences that distinguished them were obviously associated with the different social lives they had led. Helen was confident, graceful,

15、made the most of her personal appearance, and showed considerable polish and ease in social relationships. Gladys was shy, self-conscious, quiet and without charming or graceful manners. A scientist who studied them remarked, "As an advertisement for a college education the contrast between the

16、se two twins should be quite effective." Considering the nature of their environmental experiences, the differences in Helen and Gladys are not surprising. Since psychological traits depend so much upon experience, it is to be expected that they will reflect it. On the other hand, traits that a

17、re not liable to be influenced by the environment are more likely to exhibit a high degree of similarity in identical twins. Important as they are, genes alone are never absolutely responsible for any trait. What we can do is set by the genes, but what we actually do is largely determined by the env

18、ironment. 基因、环境与双胞胎遗传与环境究竟哪一个影响更大呢？从某种程度上讲，一个人生来具有的潜力将决定他一生的作为。因此遗传即命运，是命中注定的东西。然而，基因并不是在真空中发挥作用的；一旦我们开始认识到基因在个人发展中所起的作用，我们就会明白，没有与其相互作用的环境，就不可能有任何个人的发展。没有一个特点是完全由环境或者完全由基因造成的。遗传和环境的相互影响在同卵双胞胎中最易观察到。大多数的同卵双胞胎是在一起抚养长大的，因而无论在外表还是行为上都惊人的相像。这些实例说明，若在同样的环境中抚养长大，具有相同基因的个体就会以几乎同样的方式对环境做出反应。但这些例子并不能说明如果把这些同

19、卵双胞胎分开抚养会发生什么情况。对分开抚养的同卵双胞胎已进行了许多研究。被研究的这些双胞胎都生活在美国，成长的自然环境几乎相同，并且具有几乎相同的营养史。因而，正如所料，他们在外表、身高和体重上极其相似。但也有例外：一对双胞胎中的一个患了相当严重的疾病而另一个却没生病；但是总体而言，同卵双胞胎，甚至从婴儿时就分离的同卵双胞胎，在心理和身体上会如此相似，给每个人留下了深刻的印象。在对从一出生就分离的19对双胞胎的研究中，研究者发现，其中约三分之二的双胞胎之间的差异与一起长大的双胞胎之间的差异一样不明显。这有力地说明了基因的影响力和环境作用的局限性。然而，必须记住的是，尽管被研究的同卵双胞胎生活在

20、不同家庭里且相距甚远，但总体而言，那些家庭的环境基本上没有什么差异。人们通常都会千方百计地将每个孩子安置在和他自己原来的家庭背景相同的家庭里，因而发现这些双胞胎成长中有不少相似之处就不足为奇了。但是在那些分开抚养的双胞胎的生长环境有较大差异的实例中，双胞胎之间的差异就很大了。下面的例子说明了在对比度很大的环境中成长的同卵双胞胎的情况。格拉迪斯和海伦出生于俄亥俄州的一个小镇，在大约18个月大时被分开抚养。她们直到18岁才再次相遇。海伦被领养了两次。由于她最初的养父母靠不住，两年后海伦又被送回到孤儿院。过了几个月，她再一次被住在密歇根东南部的一对农场主夫妇领养。此后25年她一直住在那里。她的第二个

21、仰慕尽管本身没受过什么教育，却下决心要让海伦得到良好的教育；海伦最终大学毕业，教了12年的书，26岁时结婚，并有了一个女儿。格拉迪斯被加拿大的一个列车乘务员及其妻子领养。她读三年级的那一年，全家搬到了加拿大落基山脉一带一个相当偏僻的地方，那儿没有学校，格拉迪斯的正是教育也就此结束，知道全家搬到安大略省后才得以继续。于是格拉迪斯就呆在家里干家务，一直到她17岁，随后在一家针织厂工作。19岁那年她去了底特律，找到了一份工作，21岁时结了婚。海伦在儿童和成年时期都一直比格拉迪斯健康，但除了这一点以及各自所受的教育不同之外，她们的生活环境十分相似。她们的体重、身高、发色和牙齿都十分相似。她们之间的区别

22、显然与她们各自的社交生活不同有关。 海伦自信、举止得体、充分利用了她外表的优势，在社交中也显得很从容、有修养。格拉迪斯则害羞、忸怩、沉默寡言，缺乏迷人或优雅的风度。一位研究她们的科学家曾经说过：“这两个双胞胎之间的悬殊差异真可谓是大学教育的颇有说服力的广告。”考虑到她们在环境方面的经历的本质不同，海伦和格拉迪斯之间的差异也就不足为怪了。由于心理特点在很大程度上取决于经历，可想而知心理特点也反映经历。另一方面，那些不易受环境影响的特点更有可能在同卵双胞胎中表现出高度的相似性。尽管基因十分重要，但是基因本身绝不能完全决定任何一个特点。我们的能力会达到什么程度由基因注定，而我们真正做了什么则主要由环

23、境决定。Science Looks Twice at Twins1   If twins interest you, Twinsburg will fascinate you.2   Every summer since 1976, this little town outside Cleveland, Ohio, has been invaded by twins. Last summer 2,356 sets of twins showed up from around the world to watch and take part in para

24、des, fireworks, magic acts, a 5 K race, and more than 100 contests: contests to honor the oldest twins, the youngest, the most alike, the least alike, the twins with the widest combined smile.3   Had you been there, you might have noticed a large group of scientists who also attend the fes

25、tival. Some come seeking clues to the causes of health problemsskin diseases, cancer, and heart attack, for example. Others are interested in how it feels to be a twin. But of all the scientists, perhaps the ones doing the most importantand most controversialwork are those who study nature and

26、nurture, that age-old question of how we come to be the kind of people we are.4   Why are some of us good at math, or writing, while others excel at art or basketball? What causes the differences in our intelligence, talents, and tastes? Are they largely determined by the genes we inh

27、erit from our parents (nature)? How much do our experiences in life (nurture)the social environment we grow up inhave to do with it?5   If you were a scientist interested in this question, wouldnt you love to study identical twins? Just think of it: two people who developed from

28、the same fertilized egg. That is, two people with the exact same set of genes. Any differences between suchidentical twins would have to be the result of differences in their environment. But could you also say that any similarities were the result of having the same genes?6   Not really.

29、Remember, most twins share a similar environmentsame house, food, relatives, and so on. The only way you could accurately measure the effects of nature and nurture would be to study identical twins raised apart, in different environments.7   Over the last ten years, a team of scientis

30、ts led by psychologist Thomas J. Bouchard Jr. has studied about 65 pairs of identical twins who were raised apart. Theyve also studied about 45 fraternal twins who were raised apart.8   The scientists bring each pair of twins to the University of Minnesota for a week of intensive testing.

31、Doctors and dentists on the team give the twins thorough physical examinations. They record the twins height, weight, eye color, ear shape, and head length.9   Meanwhile, psychologists give the twins IQ and personality tests. To measure personality, the psychologists try to determine thing

32、s like how much the twins worry, whether they are cautious or reckless, and how creative they are. They measure these and other traits by the twins responses to statements such as: “I rarely, if ever, do anything reckless,” and “The flames of a wood fire stimulate my imagination.” By the end of the

33、week, each twin has answered about 15,000 questions.10  Bouchards team has been startled by the similarities between twins raised apart. The twins often have surprisingly similar gestures and postures, for instance. In pictures, many of the twins strike nearly identical poses. And some of the i

34、dentical twins discover they have led remarkably similar lives.11  The first set of identical twins Bouchard studied, the “Jim twins,” were adopted by different families four weeks after they were born. They grew up in Ohio, 45 miles away from each other. When they were reunited at the age of 3

35、9, they discovered a series of striking similarities. Both were named Jim. Both drove the same model blue Chevrolet, liked woodworking, chewed their fingernails, and owned dogs named Toy. Both started having late-afternoon headaches at the age of 18.12  The sort of similarities the Jim twins di

36、scovered are common with the twins the Minnesota team has studied. Some critics of the Minnesota study say the coincidences are not surprising. They argue that everyones life has enough details that a number of coincidences are bound to exist. Whats more, for every coincidence discovered by a pair o

37、f identical twins raised apart, a skeptic could point to a vast number of undiscovered differences. The same two twins might have different model television sets and support different football teams. But the differences would go unreported since they would not surprise anyone.13  But beyon

38、d the coincidences, the Minnesota scientists have gathered and analyzed a mountain of data about the twins health, intelligence, and personalities. And according to Bouchard, the data on the identical twins raised apart show clearly that naturethe genes we inheritexerts a notably strong influence ov

39、er our lives. The Minnesota team has found that these identical twins are remarkably similar in physical traits such as height, fingerprints and heart rates. Adult identical twins also tend to have similar medical histories, developing the eye disease glaucoma at the same time, for example.14 

40、The Minnesota team has reported that intelligence also seems to be influenced much more by genes than by environment. Despite being raised by different families, separated identical twins studied by Bouchards team earned identical or nearly identical scores on adult intelligence tests.15  But m

41、ost surprisingly, the Minnesota team finds that genes play a big part in shaping our personalities-helping to determine whether we respect tradition and like to follow rules, for example, or whether were dedicated nonconformists. According to Bouchard, the genes you were born with have a lot to do w

42、ith whether you are confident, cheerful, and optimistic, or whether you have a negative view of the world. “The study shows in a very persuasive way that genes influence every aspect of behavior,” says Nancy Segal, a psychologist with the Minnesota team.16  Other scientists disagree. How can yo

43、u study whether intelligence is inherited, they ask, when there are so many different ways just to define intelligence? The problem applies7 to other traits, they say.17  Bouchard himself makes the point that even the most closely matched twins he has studied are different from each other. So e

44、ven though genes may have a strong influence over our lives, theyre not the only influence. Our day-to-day experiences help to mold us too.18  You know what that means: you still have to study for tests! 科学再次关注双胞胎如果你对双胞胎感兴趣的话，那么双胞胎镇会使你着迷。从1976年起的每个夏天，这个位于俄亥俄州克利夫兰郊外的小镇都会挤满众多的双胞胎。去年夏天，有2356对

45、双胞胎从世界各地来到这里，参加并观看游行、焰火、魔术表演、五公里赛跑以及100多项的比赛：评选出年纪最大的、年纪最小的、最像的、最不像的，以及两人相加笑起来嘴咧得最大的双胞胎。你要是去过那儿的话，你可能会注意到有很多科学家也参加了这个盛会。有些科学家是来寻找引起疾病的缘由例如皮肤病、癌症、心脏病。另外一些科学家则对双胞胎自身的感受感兴趣。但是在所有的科学家中，从事最重要的也是最有争议的工作的是这样一些科学家，他们专门研究先天遗传和后天培养这个由来已久的问题，即研究我们是如何发展成现在这个样子的。为什么我们有些人精通数学或擅长写作，而另外一些人则在艺术或篮球上出类拔萃？是什么造成了我们在智力、才

46、能和品味上的差异？这些主要是由我们从父母那里继承来的基因（先天遗传）决定的吗？同我们的生活经历（后天培养），也就是我们成长的社会环境又有多大关系呢？如果你是一个对这个问题感兴趣的科学家，你难道不想研究一下同卵双胞胎吗？想一想，从同一受精卵发育出来了两个人。也就是说，两个人有完全相同的基因。同卵双胞胎之间存在的任何不同都只能是他们成长环境不同的结果。但是你能说他们之间的任何相同点都是基因相同的缘故吗？不一定吧。记住，大多数双胞胎都有相似的成长环境同样的房子，同样的饮食，同样的亲戚等等。研究在不同环境下抚养的同卵双胞胎，或许是你能准确衡量先天遗传和后天培养所起的作用的唯一方法。在过去的10年间，由

47、心理学家小托马斯·J·布沙尔带领的一组科学家研究了大约65对分开抚养的同卵双胞胎。他们还研究了大约45对分开抚养的异卵双胞胎。科学家们把每对双胞胎带到明尼苏达大学进行为期一周、深入细致的检测。小组里的医生和牙医们给这些双胞胎进行了全面的体检。他们记录了双胞胎的身高、体重、眼睛颜色、耳朵的形状和头围。同时，心理学家们还对双胞胎进行了智商和性格测试。为了测试性格，心理学家们设法测定了：双胞胎们对事情担忧的程度，他们是谨慎型的还是鲁莽型的，以及他们的创造力如何。他们根据双胞胎们对一些陈述的回答来衡量这些方面以及其他一些性格特征，这些陈述包括“我很少鲁莽行事”，“木柴燃烧的火焰激发

48、我的想象力”等。一周结束时，每个双胞胎都回答了大约15000个问题。布沙尔小组对分开抚养的双胞胎之间的相似之处感到非常吃惊。例如他们的手势和姿势经常很相似，真是令人惊奇。在照片上，很多双胞胎摆出的姿势几乎一模一样。有些同卵双胞胎还发现他们的生活方式极其相似。“吉姆兄弟”是布沙尔研究的第一对同卵双胞胎，他们出生四周后就被不同的家庭领养。他们都在俄亥俄州长大，彼此相隔45英里。当他们在39岁重逢时，发现了一系列惊人的相同之处：两个人都叫吉姆，都开同一型号的蓝色雪佛兰，都喜欢做木工，都有啃手指甲的习惯，养的狗都叫“Toy”。两个人都有傍晚头痛的毛病，都是在18岁时开始的。在吉姆兄弟之间所发现的相同点

49、在明尼苏达小组研究的双胞胎身上都普遍存在的。有些对明尼苏达小组研究工作持批评态度的人说“这些巧合没什么可奇怪的”。他们认为每个人的生活里都有很多的细节，因此必然会有巧合。而且，对于异地抚养的同卵双胞胎之间发现的任何一个巧合，持怀疑态度者都能指出大量未被发现的不同点。同一对双胞胎可能有不同型号的电视机，支持不同的足球队。但不同点是不会被报道的，因为它们不会使人吃惊。但是除了巧合之外，明尼苏达的科学家们收集并分析了有关双胞胎的健康、智力和个性方面的大量数据。布沙尔认为，有关异地抚养的同卵双胞胎的数据清楚地显示了：先天遗传，即我们所继承的基因，对我们的生活有显著的影响。该小组发现，这些同卵双胞胎在身

50、高、指纹和心率等生理特征方面极其相似。成年的同卵双胞胎还往往有相似的病史，例如同时得了青光眼。明尼苏达小组报告说智力似乎也更受基因的影响而不是环境。尽管由不同的家庭抚养长大，布沙尔小组研究的同卵双胞胎在成人智力测验中所得的分数完全相同或几乎相同。但是最令人吃惊的是，明尼苏达小组发现基因对于个性的形成起着重要作用，例如，会决定我们是尊重传统、循规蹈矩，还是会成为坚定的离经叛道者。根据布沙尔的看法，你与生俱来的基因对你是否自信、快乐、乐观或者对世界上的事是否持消极态度有很大影响。明尼苏达小组的一位心理学家南希·西格尔说：“这项研究令人信服地表明：基因影响人们行为的每个方面。”另一些科学家

51、不同意这个说法。他们质问：既然光是对智力的定义就多种多样，你们又怎么能够去研究智力是否是遗传的呢？他们认为同样的问题也存在于其它的性格特征中。布沙尔本人表示了这样的观点：即使是他所研究过的最相似的双胞胎也是彼此不同的。因此即便基因对我们的生活有很大的影响，它们也不是唯一起影响作用的因素。我们的日常经历也有助于塑造我们。你知道这意味着什么：为了考试，你还得学习！Talkative Parents Make Kids SmarterAn exhaustive study of how "typical" parents talk with their children duri

52、ng the first few years of their life has yielded a mountain of valuable data and some initial findings with serious social implications. There are striking class differences in the nature and extent of parental interaction with children between the age of 9 months and 3 years. This results in a cons

53、iderable intellectual boost for kids in white-collar families, a modest lift for those in blue-collar households, and a disturbingly weak assist for children in welfare families. Young children whose parents talk extensively to them score much higher on later IQ tests than those exposed to minimal a

54、mounts of parental talk, assert study codirectors Betty Hart of the University of Kansas and Todd Risley of the University of Alaska. "The more parents talk with their young children, the more good things happen intellectually to those kids later on," Risley contends. "But the massive

55、 class differences in this parental behavior surprised us and suggest that children in welfare families face problems that cannot be reversed by a few hours of Head Start classes every week." Hart and Risley presented their findings, based on observations of forty-two families in their homes lo

56、cated in the Kansas City area, at the annual meeting of the American Psychological Association in Toronto last week. The study has intensified an already intense debate over the relative influence of genes and environment on IQ and intellectual potential, both in individuals and racial groups. The 2

57、.5-year investigation, followed by 3 years during which researchers analyzed a mountain of written and tape-recorded observations, adds a new dimension to the nurture side of the controversy. Families in Hart and Risley's study functioned well and exhibited no serious problems, such as child abu

58、se or psychiatric illness. Thirteen professional families included at least one parent who worked in a white-collar occupation; in twenty-three working-class families, jobs included electrician and plumber; six families subsisted mainly on welfare. The families represented a range of racial and ethn

59、ic groups; eight were single-parent families. The families ranged in size from a single child to seven children. Trained observers spent 1 hour every 2 months tape-recording and writing down the nature of all at-home interactions with a designated child in each family beginning at 9 months of age. O

60、bservers focused only on that child and whoever talked or interacted with him or her. They never offered advice to parents, even when asked. The parent or parents in each family displayed a characteristic level of talk with their young children, month after month, Risley asserts. Overall, parents in professional families prov