新視野大學(xué)英語讀寫教程第四冊unit7-c Section C Genetics and Environmental Factors in Creating Genius

Genetics and Environmental Factors in Creating Genius

Dr. Howard Gardner of Harvard University believes that geniuses are largely made. He has banned television from his home because he fears it might ruin the minds of his family. He makes time every day to listen to his seven-year-old son play the piano — even if it is no more than a few minutes during a phone call while he is away at a conference.

Dr. Sandra Scarr of Virginia University(弗吉尼亞大學(xué)), president of the Society for Research in Child Development(兒童發(fā)展研究會主席), believes geniuses are largely born. She says parents should not worry too much about whether to take their kids to a ball game or to a museum. Talent will out.

It seems experts are as divided as ever over the issue of which is more important, environment or genetics. This may, however, be about to change. A conference organized earlier this year brought to London some of the biggest names from both sides of the debate. Amazing results from unpublished work were revealed — and the beginning of agreement could be perceived.

The most exciting results came from those working on the biology of individual differences. Dr. Robert Plomin of Penn State University(賓夕法尼亞州立大學(xué)), hopes to announce within the next few months that he has tracked down one of the genes that plays a part in determining intelligence. A gene has been identified but the results have yet to be confirmed.

At present, it is believed that genes account for at least half of what researchers call "g" — the general thinking ability that IQ tests are supposed to measure — while environmental influences account for the other half. But so far the only evidence for a genetic component has been through statistics, the relationship being inferred mathematically from comparisons of twins and other such studies of close relatives. Plomin's method makes use of new gene mapping techniques and promises to provide direct evidence of the role that genes play.

Plomin stresses that the discovery of a first gene does not mean the puzzle of intelligence has been solved. A single gene will code for only one of the many molecules and cell proteins that are the building blocks of the brain. This means that hundreds, if not thousands, of genes must be involved in intelligence. The identification of even one gene does, however, have immense implications for the genetics/environment debate.

Another advance, a computer-controlled brain scanning device, has led to a second discovery by those seeking the biological component of mental abilities. Professor Camilla Benbow of Iowa State University(愛荷華州立大學(xué)) is head of a long-term study of children who are unusually good at math. For many years she has been puzzled as to why so many of the children in her study should be boys — at the top level, there are more boys than girls by a ratio of thirteen to one. In a soon-to-be-published paper, Benbow reveals that the talented boys' brains appear to process information concerning the location of objects in a very different way from those of average boys and even of talented girls.

The brains of children in the study were scanned while being presented with a simple visual puzzle. The boys of average ability and the gifted girls showed strong activity on both sides of their brains as they thought about the puzzle. However, the gifted boys responded very differently. There was a sudden drop in activity in the left side of the brain — the side most involved in language — and an exaggerated reaction on the right, the side strongest at thinking about the location of objects. It seems that the brains of boys with mathematical talent operate in a way that is physically unique.

Benbow says she was surprised that the talented girls should lack this pattern of response. The only explanation she has is that male brains have a tendency to become more divided during development, with different functions located on one side of the brain or the other. When this division is taken to an extreme, unusual mathematical abilities result.

Because females do not have this tendency (this brain division is known to be influenced by male sex chemicals), girls who perform well in mathematics are doing so because they are superior in their overall mental development. And because such all-round ability is less common, this would be the reason for there being fewer mathematically talented girls.

Benbow is quick to add, however, that cultural expectations probably exaggerate the difference. In China, where girls are more likely to get encouragement in mathematics, the number of gifted boys exceeds that of gifted girls by four to one, rather than the thirteen to one seen in the United States.

Both Plomin's and Benbow's findings would seem to give support to the argument that outstanding mental abilities are largely the result of genetics. But the conference heard equally strong evidence for the role that environmental factors play in creating genius. A theme repeatedly heard from the speakers was that special children invariably have special parents.

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    創(chuàng)造天才的遺傳和環(huán)境因素

    哈佛大學(xué)的霍華德·加德納博士認(rèn)為天才主要是后天造成的。 他的家里不看電視，因?yàn)樗麚?dān)心電視會破壞家人的思考能力。 他每天都擠出時(shí)間來聽7歲的兒子彈鋼琴，既使在他外出開會時(shí)，也要通過電話聽幾分鐘。
    弗吉尼亞大學(xué)的桑德拉·斯卡博士，兒童發(fā)展研究會主席，認(rèn)為天才主要是天生的。 她說該帶孩子去看球賽還是參觀博物館，對此家長不必過多擔(dān)心。 才華終將顯示出來。
    哪個更重要，環(huán)境還是遺傳？對這個問題似乎專家們一向都有分歧。 然而，這一情況可能會有所改變。 在今年早些時(shí)候組織的一次會議上，論戰(zhàn)雙方的知名人物聚于倫敦， 一些未曾公開發(fā)表的令人驚訝的結(jié)果被公之于眾--雙方的趨同已初見端倪。
    研究個體生理差異的科學(xué)家?guī)砹俗盍钊伺d奮的結(jié)果。 賓夕法尼亞州立大學(xué)的羅伯特·普羅明博士已經(jīng)找到了影響智力的一種基因的蹤跡，他希望能在幾個月內(nèi)公布結(jié)果。 這樣一種基因已經(jīng)被發(fā)現(xiàn)，但結(jié)論還有待證實(shí)。
    人們目前認(rèn)為，對于研究人員稱為"g"的能力 -- 即智力測驗(yàn)所要衡量的綜合思維能力 -- 基因至少起了一半的作用，而環(huán)境影響則起到了另一半作用。 但迄今為止，遺傳基因所占比重的僅有的證據(jù)只是一些統(tǒng)計(jì)數(shù)據(jù)，即，從對雙胞胎的比較，以及對其他血緣接近者的研究中得出的數(shù)學(xué)統(tǒng)計(jì)關(guān)系。 普羅明的方法利用新的基因圖譜技術(shù)，有望對基因所起的作用提供直接證據(jù)。
    普羅明強(qiáng)調(diào)，發(fā)現(xiàn)第一個基因并不意味著解開了智力之迷。 一個基因僅僅為構(gòu)成大腦的眾多分子和細(xì)胞蛋白中的一個指定遺傳密碼。 這就是說，智力涉及的基因沒有幾千也有幾百個。 不過，哪怕辯出一個基因?qū)τ谶z傳與環(huán)境之爭也是意義重大的。
    另一進(jìn)展，一臺計(jì)算機(jī)控制的腦部掃描儀，使得尋找思維能力的生理因素的研究人員有了第二個發(fā)現(xiàn)。 愛荷華州立大學(xué)的卡米拉·班博教授領(lǐng)導(dǎo)著一項(xiàng)對具有數(shù)學(xué)特長的兒童的長期研究。 多年來，她對為何她的研究中有那么多的男孩感到困惑 -- 高級組中男孩女孩之比為13比1。 在即將發(fā)表的論文中，班博表明，天資好的男孩的腦子處理物體方位信息的過程好像與一般的男孩非常不同，甚至與天資好的女孩也不同。
    研究中，給孩子們看一道簡單的視覺難題，同時(shí)對其腦部進(jìn)行掃描。 智力一般的男孩與天資好的女孩在解題時(shí)腦子的兩半球都活躍。 但是天資好的男孩卻表現(xiàn)出極大的不同。 他們的左半腦 -- 與語言能力相關(guān)的那一半 -- 的活動急劇下降，而右半腦，擅長思考物體方位的那一半，卻做出強(qiáng)烈的反應(yīng)。 看來，具有數(shù)學(xué)天賦的男孩的大腦在生理方面的活動相當(dāng)獨(dú)特。
    班博說，天資好的女孩居然沒有這種反應(yīng)模式，這使她很吃驚。 惟一的解釋就是：男性的大腦在發(fā)育過程中有分工更明確的趨勢，大腦的兩半球各有不同的功能。 這種分工到了極致，就產(chǎn)生了不尋常的數(shù)學(xué)能力。
    因?yàn)榕圆痪邆溥@種趨勢（人腦的這種分工已知是男性激素影響的結(jié)果），數(shù)學(xué)好的女孩是因?yàn)樗齻兊恼w智力發(fā)育很好。 又因?yàn)檫@樣全面的能力并不常見，這就解釋了為何有數(shù)學(xué)天賦的女孩較為少見。
    不過，班博又迅速補(bǔ)充說，文化傳統(tǒng)上人們對孩子的期望可能更擴(kuò)大了這一差別。 在中國，人們往往更鼓勵女孩學(xué)數(shù)學(xué)，那兒有天賦的男孩與女孩的數(shù)量之比為4比1，而不像美國是13比1。
    普羅明和班博的研究結(jié)果似乎都支持了出眾的智力主要是遺傳的結(jié)果這一論斷。 但是那次會議也提出了同樣充分的證據(jù)支持環(huán)境因素在創(chuàng)造天才上的作用。 發(fā)言者們多次提到的一個主題就是不同尋常的孩子身后一定有不同尋常的家長。