美国国家公共电台 NPR--Encore: Communication among monkeys could help explain how humans evolved to talk

Encore: Communication among monkeys could help explain how humans evolved to talk

Transcript¹

Some monkeys make complex vocalizations, others don't. The reason why could help explain how the human brain evolved to produce speech. (Story first aired on All Things Considered on June 21, 2022.)

A MARTINEZ, HOST:

Some monkeys have astounding³ vocal² abilities; others not so much. NPR's Jon Hamilton explains why that could provide scientific clues about the origins of human speech.

(SOUNDBITE OF ARCHIVED NPR BROADCAST)

JON HAMILTON, BYLINE⁴: This is a tale of two kinds of monkeys. The first is the macaque. It's larger and lives in Asia and North Africa. Christina Cerkevich at the University of Pittsburgh says when it comes to vocalizing, macaques are kind of limited.

(SOUNDBITE OF MACAQUES VOCALIZING)

CHRISTINA CERKEVICH: They don't seem to have a lot of control over their vocalizations. They don't change the pitch. They don't change the internal timing⁵. A lot of times, their calls don't have syllables⁶.

HAMILTON: The second monkey is the marmoset. It's smaller and lives primarily in South America. Cerkevich says the vocal skills of marmosets are remarkable⁷.

(SOUNDBITE OF MARMOSETS VOCALIZING)

CERKEVICH: These guys have wonderful control over their vocalizations. They'll change the pitch, get louder because somebody's far away. They'll change the timing so that if you keep artificially cutting them off, they'll wait for the noise to go away so they can get their message heard.

HAMILTON: Both species have the same basic vocal tract⁸, so the team figured the difference must be in how their brains control the vocal muscles. Cerkevich says the team decided⁹ to focus on one particular muscle in the larynx.

CERKEVICH: It's this tiny little muscle, especially in the marmosets because they're very small. This muscle, when it contracts, it increases tension on the vocal cords so that the pitch goes up.

HAMILTON: The team designed an experiment to identify the brain areas that control this tiny muscle. Peter Strick, a neurobiologist, says the experiment used a substance that follows the nerve pathways from muscle tissue to the brain.

PETER STRICK: And so we said, look; if we inject the same muscle, we might be able to see what's changed in the marmoset that allows it to vocalize.

HAMILTON: The experiment worked, and the results are published in the journal PNAS. The team found differences in two areas of the brain. One area seems to help shape a particular sound. The other appears to control the timing and sequence of sounds. Strick says, in both of these areas, the South American marmosets had many more brain cells sending signals to the tiny muscle in the larynx.

STRICK: We believe that these two areas are really key in enabling marmoset complex vocalization.

HAMILTON: These areas are separate from what's known as the primary motor cortex, which is involved in planning and executing all kinds of muscle movement. But Strick says the areas work together with the primary motor cortex to help a monkey vocalize.

STRICK: In a sense, it has multiple separate computers running at the same time to deal with that complex task.

HAMILTON: Strick says that's also true in people who devote a lot of brainpower to speech.

STRICK: Speech is remarkably¹⁰ complex. You have to control breathing appropriately. You have to control your lips and your tongue and produce sound.

HAMILTON: And you have to have very fine control of muscles in the larynx. Dr. Eddie Chang of the University of California, San Francisco, has spent years mapping the brain areas involved in human speech.

EDDIE CHANG: What's been a missing piece of the puzzle in all of this is whether or not the part of the brain that controls the larynx is similar in other species, including some of our closest relatives - monkeys.

HAMILTON: Chang says now it looks like that puzzle piece has been found. And he says the discovery of brain areas that give marmosets a vocal advantage over macaques could explain how humans took the next evolutionary¹¹ step.

CHANG: This new paper suggests that it's the elaboration of these parts of the brain that might have evolved for humans to speak and have language.

HAMILTON: A skill that appeared at least 50,000 years ago.

Jon Hamilton, NPR News.

1 transcript   

n.抄本，誊本，副本，肄业证书

参考例句：

• A transcript of the tapes was presented as evidence in court.一份录音带的文字本作为证据被呈交法庭。
• They wouldn't let me have a transcript of the interview.他们拒绝给我一份采访的文字整理稿。

2 vocal   

adj.直言不讳的；嗓音的；n.[pl.]声乐节目

参考例句：

• The tongue is a vocal organ.舌头是一个发音器官。
• Public opinion at last became vocal.终于舆论哗然。

3 astounding   

adj.使人震惊的vt.使震惊，使大吃一惊astound的现在分词)

参考例句：

• There was an astounding 20% increase in sales. 销售量惊人地增加了20%。
• The Chairman's remarks were so astounding that the audience listened to him with bated breath. 主席说的话令人吃惊，所以听众都屏息听他说。 来自《简明英汉词典》

4 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

5 timing   

n.时间安排，时间选择

参考例句：

• The timing of the meeting is not convenient.会议的时间安排不合适。
• The timing of our statement is very opportune.我们发表声明选择的时机很恰当。

6 syllables   

n.音节( syllable的名词复数 )

参考例句：

• a word with two syllables 双音节单词
• 'No. But I'll swear it was a name of two syllables.' “想不起。不过我可以发誓，它有两个音节。” 来自英汉文学 - 双城记

7 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

8 tract   

n.传单，小册子，大片(土地或森林)

参考例句：

• He owns a large tract of forest.他拥有一大片森林。
• He wrote a tract on this subject.他曾对此写了一篇短文。

9 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

10 remarkably   

ad.不同寻常地，相当地

参考例句：

• I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
• He made a remarkably swift recovery. 他康复得相当快。

11 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。