http://www.newyorker.com/science/maria-konnikova/why-are-babies-so-dumb-if-humans-are-so-smart

As aspecies/'spiʃiz/, humans are incredibly smart. We tell stories, createmagnificent/mæg’nɪfəsnt/art andastoundingtechnology, build cities, and explore space.We haven’t been around nearly as long as many other species,but in many respects/rɪ'spɛkt/we’ve accomplished more than any have before us. We eat them and they don’t eat us. We even run scientific studies on them—and are thinking about re-creating some of those that have goneextinct/ɪk'stɪŋkt/. But our intelligence comes with acurious/‘kjʊrɪəs/caveat/‘kævɪ’æt/: our babies are among thedumbest/dʌm/—or, rather/'ræðɚ/, the most helpless—that exist. A babygiraffe/dʒə'ræf/can stand within an hour of birth, and can even potentially/pə'tɛnʃəli/flee/fli/predators/'prɛdətɚ/on its first day of life. A monkey cangrasp/ɡræsp/its mother and hang on for protection andnourishment/‘nɝɪʃmənt/. A humaninfant/‘ɪnfənt/can’t even hold up its own head.

species/‘spiʃiz/n. [生物] 物种；种类

magnificent/mæg’nɪfəsnt/adj.壮丽的, 伟大的, 华丽的, 高贵的

astounding/ə’staʊndɪŋ/adj.使人震惊的

extinct/ɪk’stɪŋkt/adj. 灭绝的，绝种的；熄灭的

curious/‘kjʊrɪəs/adj.好奇的, 好求知的

caveat/‘kævɪ’æt/警告；中止诉讼手续的申请；货物出门概不退换；停止支付的广告

giraff/dʒə’ræf/长颈鹿

potentially/pə’tɛnʃəli/adv.潜在地;可能地

flee/fli/vi.逃走, 逃掉vt.逃离, 逃避

predator/‘prɛdətɚ/n. 食肉动物；掠夺者；捕食者

grasp/ɡræsp/vt. 抓住；领会

nourishment/‘nɝɪʃmənt/n.食物, 滋养品

infant/‘ɪnfənt/n.婴儿, 幼儿

dumb/dʌm/adj. 哑的，无说话能力的；不说话的，无声音的

The evolution/ˌivə'luʃən/of human intelligence isn’t something thatCeleste Kiddhad everpondered/'pɑndɚ/. A developmentalcognitive/'kɑɡnətɪv/scientist who currently works at the University ofRochester, her work had focussed mostly on learning and decision-making in children. Over years of observing young children, she became impressed with the average child’s level ofsophistication/sə,fɪstɪ'keʃən/. But when she looked at the infants she encountered, she saw abaffling/'bæflɪŋ/degree of helplessness: How could they be soincompetent/ɪn'kɑmpɪtənt/one second and so bright so soonthereafter/ˌðɛr'æftɚ/? One day, she posed/poz/the question to her colleague Steven Piantadosi. “Both of us wondered what could possibly justify/'dʒʌstə'fai/the degree of helplessness human infants exhibit/ɪɡ'zɪbɪt/,” she told me recently. “Even otherprimate/'praɪmet/babies, like babychimps/tʃɪmp/, which are closein evolutionary/ˌivə’luʃənɛri/terms, cancling/klɪŋ/onto their moms.” She began to see acontradiction/ˌkɑntrə'dɪkʃən/: humans are born quite helpless,far moreso than any other primate, but,fairly early on, we start becoming quite smart, again far more so than any other primate. What if this weren’t a contradiction so much as acausal/‘kɔzl/pathway?

sophistication/sə,fɪstɪ’keʃən/复杂；诡辩；老于世故；有教养

evolution/ˌivə’luʃən/演变；进化论；进展

ponder/‘pɑndɚ/vi. 沉思；考虑

cognitive/‘kɑɡnətɪv/adj.认知的, 认识能力的

baffling/‘bæflɪŋ/adj. 令人困惑的；阻碍的；令人丧气的；变幻的

helplessness/ˈh ɛlplɪsnɪs/n.无可奈何状态;无能为力

incompetent/ɪn’kɑmpɪtənt/adj.无能力的, 不称职的, 不胜任的

thereafter/ˌðɛr’æftɚ/adv.此后; 在那之后

pose/poz/提出 (问题)[正式]

justify/‘dʒʌstə’fai/vt.证明…有理; 为…辩护

primate/‘praɪmet/adj. 灵长目动物的

chimp/tʃɪmp/n. （非洲的）黑猩猩

evolutionary/ˌivə’luʃənɛri/adj.进化的

cling/klɪŋ/vi. 坚持，墨守；紧贴；附着

cling onto紧紧抓住

contradiction/ˌkɑntrə’dɪkʃən/n.矛盾

causal/‘kɔzl/adj. 有原因的；因果关系的

exhibit/ɪɡ’zɪbɪt/展览；显示；提出（证据等）

fairly early on相当早

That’s the argument/'ɑrɡjumənt/that Kidd and Piantadosi make in theirnew paper, published in a June issue ofPNAS.Humans become so intelligentbecausehuman infants are so incredibly/ɪn'krɛdəbli/helpless, they argue; the onenecessitates/nə’sɛsɪtet/the other. The theory isstartling/'stɑrtlɪŋ/, but it isn’t entirely new. Researchers have been pondering thepeculiarities/pɪ'kjʊlɪ'ærəti/of our birth and its evolutionary/ˌivə'luʃənɛri/significance/sɪɡ'nɪfɪkəns/for quite some time. Humans belong to the subset of mammals/‘mæml/, called viviparous/vɪ'vɪpərəs/mammals, that give live birth to their young. This means that infants must grow to a mature/mə'tʃʊr/enough state inside the body to be born, but they can’t be so big that they are unable to come out. This leads to a trade-off/ˈtredˌɔf/: the more intelligent an animal is, the larger its head generally is, but the birth canal/kə'næl/imposes/ɪm’poz/an upper limit on just how large that head can be before it gets stuck/stʌk/. The brain, therefore, must keep maturing, and the head must continue growing, long after birth. The more intelligent an animal will eventually be, the more relatively immature/ˌɪmə'tʃʊr/its brain is at birth.

argument/‘ɑrɡjumənt/论证；论据；争吵；内容提要 n

incredibly/ɪn’krɛdəbli/

necessitates/nə’sɛsɪtet/vt. 使成为必需，需要；迫使

startling/‘stɑrtlɪŋ/adj. 令人吃惊的

peculiarities/pɪ’kjʊlɪ'ærəti/特性；特质；怪癖；奇特

viviparous/pɪ’kjʊlɪ’ærəti/adj. [脊椎] 胎生的；在母体上发芽的

significance/sɪɡ’nɪfɪkəns/n. 意义；重要性；意思

mature/mə’tʃʊr/adj. 成熟的；充分考虑的；到期的；成年人的

Researchers have long known about this trade-off, and about theconnectionbetween brain size andneural density/'dɛnsəti/and intelligence.For instance, Robin Dunbarfoundthat the ratio ofneocorticalvolume to brain size can predict the social-group sizein a number ofspecies, includingbats/bæts/,cetaceans, and primates, whileSimon Readerhasdemonstrated/‘dɛmən'stret/links in tool use and innovation/ˌɪnə'veʃən/to brain size in primates. Kidd and Piantadosi’s new idea is that increased helplessness in newborns mandates/'mændet/increased intelligence in parents—and that arunaway/'rʌnəwe/selection dynamic can account for both.Natural/'nætʃrəl/selectionfavorshumans with large brains, because those humans tend to be smarter. This may create evolutionaryincentivesfor babies that are born at an even earlier developmental stage, which require more intelligence to raise. This creates the dynamic: over time, helpless babies make parents more intelligent, which makes babies more helpless, which makes their parents more intelligent, and so on.

neuraladj. 神经的；神经系统的；背的；神经中枢的

density/‘dɛnsəti/n. 密度

neocorticalˌniːoʊ’kɔːrteks[解]新(大脑) 皮质

in a number of ways:在许多方面

bat/bæts/蝙蝠；球棒；球拍；批处理文件的扩展名

cetacean/sɪ’teʃən/adj. 鲸类的；鲸鱼的 | n. 鲸鱼；鲸类动物

primates/prai'meiti:z/灵长类

demonstrate/‘dɛmən’stret/vt. 证明；展示；论证

mandate/‘mændet/n.授权；命令，指令；委托管理；受命进行的工作vt. 授权；托管

runaway/‘rʌnəwe/adj. 逃亡的；逃走的 |n. 逃跑；逃走的人

developmental stage 发育阶段

incentive/ɪn’sɛntɪv/n. 动机；刺激 |adj. 激励的；刺激的

dynamic/daɪ’næmɪk/adj. 动态的；动力的；动力学的；有活力的

Natural/'nætʃrəl/selection 自然选择

Over time随着时间的过去；超时

During their investigation, Kidd and Piantadosi realized something important that strengthened/'strɛŋθn/their theory. It turns out that another variable/'vɛrɪəbl/has an even highercorrelation/ˌkɔrə'leʃən/with intelligence than brain size—time tomaturity/mə'tʃʊrəti/, orweaningtime.In other words, the time it takes toshepherd/ˈʃɛpəd/newborns/ˈnjuːˌbɔːn/through absolute helplessness to a point of relativeself-sufficiency/'selfsə'fiʃənsi/predicts primate intelligence more strongly than the best measure that has previously beenproposed/prəu'pəuzd/, namely, headcircumference. Orangutans/ˌɔræŋ'ʊtæn/have smarter babies thanbaboons/bə'bu:n/and theyweanthem longer. Baboon babies, in turn, are weaned longer, and are smarter, thanlemur/ˈlimɚ/babies.

strengthen/‘strɛŋθn/vt. 加强；巩固

correlation/ˌkɔrə’leʃən/n. [数] 相关，关联；相互关系

maturity/mə’tʃʊrəti/n. 成熟；到期；完备

weaning/'wi:niŋ/adj. 断奶的

shepherd/ˈʃɛpəd/vt牧羊；带领；指导；看管  |牧羊人；牧师；指导者

self-sufficiency/‘selfsə’fiʃənsi/n. 自给自足；自负

proposed/prəu’pəuzd/adj. 被提议的；所推荐的

circumference/sɚ’kʌmfərəns/圆周；周长；胸围

orangutan/ˌɔræŋ’ʊtæn/[脊椎] 猩猩（等于orangoutang）

baboon/bə'bu:n/[脊椎] 狒狒

lemur/ˈlimɚ/[脊椎] 狐猴

Putting these facts together helped Kidd and Piantadosi develop theirhypothesis/haɪ'pɑθəsɪs/.The connection between head size and intelligence does create incentives for babies to arrive earlier. But it’s the connection between weaning time and intelligence that may really be driving/'draɪvɪŋ/the cycle/'saɪkl/. You need to be smarter to care for more helpless creatures, which means you need a larger brain—which means that babies have to enter the world at an even more helpless stage of development, since there is afinitesize to their brain at birth, mandated by thephysiologyof live birth. And so the cycle continues.

hypothesis/haɪ’pɑθəsɪs/假设

drivingvt. 推动，发动（机器等）；驾驶（马车，汽车等）；驱赶

the cycle/‘saɪkl/周期

Of course, the theory is just that—a model.Ideally/aɪ'diəli/, to prove it you would look at head size, birth time, and intelligence over the span of human evolution, to see if we were born earlier as we got smarter—data that areunavailable/'ʌnə'veləbl/. (Kidd alsostresses/strɛs/repeatedly that this theorysupplements/'sʌpləmənt/, but does notsupplant/sə'plænt/, earlier ones: it cancoexist/ˌkoɪɡ'zɪst/quite naturally with both the social-groupaccount ofintelligence—the Dunbar/'dʌnbɑ:/approach—and what’s called themetabolic/ˌmɛtə'bɑlɪk/accounts of intelligence, whichposits/‘pɑzɪt/that ourdigestive/daɪ’dʒɛstɪv/system hasallowedfor our brain’s highmetabolicneeds, and that we grew smarter to be able to find and sharedifficult-to-gatherfood.) But there are someintriguing/ɪnˈtri:gɪŋ/converging/kən'və:dʒiŋ/pieces of evidence. For one, other animals that arenotviviparous/vɪ'vɪpərəs/have not evolved the same levels of intelligence, suggesting aninherent/ɪn'hɪrənt/link between live birth andbrainpower/ˈbrenˌpaʊɚ/. And in modern humans, a few pieces of evidence appear to suggest that smarter parents are more likely to have offspring that survive. Inone limited sample/'sæmpl/—two hundred and twenty-two Serbian/'sə:biən/Roma/'rɔmə/women—maternal/mə’tɝnl/I.Q. and childmortality/mɔr’tæləti/were negatively correlated (that is, higher I.Q. meant lowermortality), even controlling for education, age, and a number of other factors. In alarger sampleof Californian parents, in 1978, years of education were linked to infant-mortality rates. Globalepidemiologicalstudiessuggest/sə'dʒɛst/a decrease in mortality that equals between seven and nine per cent for each year of a mother’s education. None of this isdecisive, of course, but it is suggestive.

unavailable/‘ʌnə’veləbl/难以获得的；不能利用的；不近便的

stress/strɛs/强调；使紧张；加压力于；用重音读

supplement/‘sʌpləmənt/增补，补充；补充物；增刊，副刊

supplant/sə'plænt/代替；排挤掉

coexist/ˌkoɪɡ’zɪst/共存；和平共处vi

metabolic/ˌmɛtə’bɑlɪk/变化的；新陈代谢的

posit/‘pɑzɪt/vt. 安置；假定

digestive/daɪ’dʒɛstɪv/消化的；助消化的

intriguing/ɪnˈtri:gɪŋ/有趣的；迷人的

converging/kən'və:dʒiŋ/adj. 会聚的，收敛

brainpower/ˈbrenˌpaʊɚ/智能；智囊团

maternal/mə'tɝnl/母亲的；母性的；母系的；母体遗传的

mortality/mɔr’tæləti/死亡数，死亡率；必死性，必死的命运

link to把…和…联系起来

suggest/sə’dʒɛst/vt提议，建议；启发；使人想起；显示；暗示

epidemiologicalhttps://en.wikipedia.org/wiki/Epidemiology[ˌepɪˌdiːmiə’lɒdʒɪkl] 流行病的

epidemiology[ˌepɪˌdiːmi’ɑːlədʒi]传染病学；流行病学

Epidemiologyis the study and analysis of thepatterns,causes, and effects ofhealthanddiseaseconditionsin definedpopulations.

decisive/dɪ’saɪsɪv/. 决定性的；果断的，坚定的

suggestive/sə’dʒɛstɪv/提示的，示意的；暗示的；引起联想的

There is, of course, one follow-up question: Why did this cycle/'saɪkl/happen to humans and not tolemurs?When I asked Kidd about this, she told me that their theory cannot offer an answer—likely as not, it’s a matter of pure genetic/dʒə’nɛtɪk/luck that became self-reinforcing. As we grew smarter, we were better able to take care of our infants, so they could be born more helpless and allow us to grow even smarter.

likely as not

as likely as not:很可能；多半；说不定

genetic/dʒə’nɛtɪk/遗传的；基因的；起源的

self-reinforcing/ˌriɪn’fɔrs/vt. 加强，加固；强化；补充

One intriguing way to test the hypothesis/haɪ'pɑθəsɪs/further: look at twins. Typically/'tɪpɪkli/,twins are not carried to full term/tɝm/.Does that mean that twins are more intelligent than non-twins, since they require longer weaning time—and would a mother who is a twin, in turn, give birth to smarter children? “It’s a really good question, to look at the types of twins that run in families and whether that leads to higher intelligence,” Kidd said. “It’s a predictable/prɪ'dɪktəbl/hypothesis,” and one that they may well include in their ongoing research on trainheritability/ˌheritə'biləti/in twins. And it’s a hypothesis that came, of all places, from a five-year-old—Kidd was being interviewed about twins for apodcast/pɔd'kʌst/by the daughter of Sindya Bhanoo, a formercolumnist/'kɑləmnɪst/at theTimes. Dumb babies, maybe, but oh so smart, oh so soon thereafter.

typically/‘tɪpɪkli/adv. 代表性地；作为特色地

term/tɝm/术语；学期；期限；条款；(代数式等的)项

predictable/prɪ’dɪktəbl/可预言的

heritability/ˌheritə’biləti/遗传可能性

podcast/pɔd’kʌst/播客

columnist/‘kɑləmnɪst/专栏作家

Maria Konnikova is acontributing/kən’trɪbjut/ writer for newyorker.com, where she writes regularly on psychology/saɪ’kɑlədʒi/ and science.

contribute/kən’trɪbjut/投稿

psychology/saɪ’kɑlədʒi/心理学；心理状态