科学家发现小海豹可以改变声音语调——以及像鹦鹉学舌一样的模仿说话
- Nov 25, 2021
- 4 min read
译者：Eric Li
科学家发现，海豹是极少数能够改变声音语调的哺乳动物之一，这使它们能够像鹦鹉一样模仿人类。
一项新的研究表明，海洋生物会根据周围环境的声音改变它们的叫声。
可以教海豹像鹦鹉一样模仿人类的语言，用粗鲁的口音吠叫标语，比如“过来”。
但是，虽然声音学习（模仿声音的能力）在哺乳动物中是一种罕见的特征，但只有少数物种可以调整声音的音调以提高或降低声音。
现在，马克斯·普朗克心理语言学研究所的科学家们发现，海豹幼崽在具有音量控制功能的动物名单中。
资深作者 Andrea Ravignani 博士说：“通过观察少数可能能够学习声音的其他哺乳动物之一，我们可以更好地了解我们人类是如何获得语言的，以及最终为什么我们是这样健谈的动物。”
研究人员对 8 只 1 到 3 周大的斑海豹幼崽进行了研究，这些幼崽在被放回野外之前被关押在荷兰康复中心。
他们记录了附近瓦登海的噪音，然后将它们播放给幼崽，音量从无声到 65 分贝不等，但保持与动物叫声相同的音高。
然后，他们记录了幼犬自发的叫声，看它们是否改变了语调以适应海浪声。
研究人员发现，海豹幼崽在听到更大的海浪声时会降低他们的语调并保持更稳定的音调。
但其中一只动物表现出所谓的伦巴第效应，当噪音变大时，它会发出更大的叫声。
这也是人类语音的典型特征，因为人们通常会提高自己的声音，以便在嘈杂的环境中更好地理解。
Ravignani 博士说：“海豹幼崽对发声的控制能力比迄今为止所假设的要先进。
“这种控制似乎只在几周大时就已经存在。
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“这令人惊讶，因为似乎很少有其他哺乳动物能够做到这一点。”
然而，当暴露在不同程度的海浪声中时，幼崽并没有发出更多或更长的叫声。
Ravignani 博士谈到发表在《英国皇家学会哲学汇刊 B：生物科学》上的研究结果时说：“迄今为止，人类似乎是唯一一种在皮层（大脑的外层）和喉部之间具有直接神经连接的哺乳动物。 ——我们用来产生语调的东西”。
“这些结果表明，海豹可能是最有希望找到这些直接联系并解开语言之谜的物种。”
Seals are one of the very few mammals to change the tone of their voices, allowing them to mimic humans like a parrot, scientists have found.
The sea creatures change the pitch of their calls depending on the sounds of their surroundings, according to a new study.
Seals can be taught to copy human speech like parrots, barking catchphrases in gruff accents like “come over here.”
But while vocal learning, the ability to mimic sounds, is a rare trait among mammals, only a few species can adjust their voice’s pitch to sound higher or lower.
Now scientists at the Max Planck Institute for Psycholinguistics have found seal pups are on the short list of animals with volume control.
Senior author Dr Andrea Ravignani said, “By looking at one of the few other mammals who may be capable of learning sounds, we can better understand how we, humans, acquire speech, and ultimately why we are such chatty animals.”
Eight harbor seal pups aged one to three weeks old who were being held in a Dutch rehabilitation center before being released back into the wild were studied by the researchers.
They recorded noises from the nearby Wadden Sea before playing them back to the pups at volumes ranging from no sound to 65 decibels, but keeping the same tone height as the animal’s calls.
They then recorded the pup’s spontaneous calls to see whether they changed their tone of voice to match the sea sounds.
Seal pups lowered their tone of voice and kept a more steady pitch when hearing louder sea noises, the researchers found.
But one of the animal’s displayed the so-called Lombard effect, producing louder calls when the noise got louder.
This is also typical of human speech, as people generally raise their voices to be better understood in noisy situations.
Dr Ravignani said, “Seal pups have a more advanced control over their vocalizations than assumed up until now.
“This control seems to be already present at only a few weeks of age.
“This is astonishing, as few other mammals seem capable of that.”
Pups did not however produce more or longer calls when exposed to different levels of sea sounds.
Dr Ravignani said of the findings, published in the Philosophical Transactions of the Royal Society B: Biological Sciences, “To date, humans seem to be the only mammals with direct neural connections between the cortex—the outer layer of the brain, and the larynx—what we use to produce tone of voice’.
“These results show that seals may be the most promising species to find these direct connections, and unravel the mystery of speech.”
信息来源：https://www.goodnewsnetwork.org/baby-seals-one-of-very-few-mammals-to-change-tone-of-their-voices/
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