Rats can use the rhythm of human language to tell the difference between Dutch and Japanese. It is the first time an animal other than a human or monkey has been shown to have this skill.
Animals, especially mammals①, evolved some of the skills underlying the use and development of language long before language itself ever evolved, the researchers said.
A neuroscientist has done an expriment with the adult male rats. The rats were trained to respond to either Dutch or Japanese using food as a rewardat first. Then they were separated into four groups—one that heard each language spoken by a native, one that heard synthesized② speech, one that heard sentences read in either language by different speakers and a fourth that heard the languages played backwards.
Rats rewarded for responding to Japanese did not respond to Dutch and rats trained to recognize Dutch did not respond the spoken Japanese. Besides, the rats could not tell apart Japanese or Dutch played backwards.
As a result, rats could discriminate natural sentences when uttered③ by a single speaker and not when uttered by different ones, nor could they distinguish the languages when spoken by different people.Human newborns have the same problem, although tamarins can easily tell languages apart even when spoken by different people.
Therefore, the conditions that which abilities that humans use for language are shared with other animals, and which are uniquely human, and what sort of evolutionary precursors④ language might have will be great improved.
① mammaln.哺乳动物
② synthesizev. 综合;合成
③ utterv. 发出(声音等);说,讲;表达
④ precursorn. 前导;先驱;前辈;前兆
老鼠据节奏辨别语言
鼠类可以根据人类语言的特定节奏来区分荷兰语和日语。这也是迄今为止科学界首次发现一般动物而不是人或者猴子具有这种本领。
动物,特别是哺乳动物早在人类语言形成之前就已经具有了某种使用和开发语言的潜在能力。
一神经学家对成年雄性鼠进行了实验。他先以食物奖励的方法训练老鼠在分别听到日语或荷兰语时作出反应。然后再将老鼠分成4组:第1组分别听标准的荷兰语和日语;第2组听双语混合语;第3组听不同的扬声器或人用任意两种语言说话;第4组听这两种语言句子的倒放录音。
结果,那些被训练对日语作出反应才受到奖赏的老鼠,不会对荷兰语作出反应;而那些被训练识别荷兰语的老鼠,则不会对日语作出反应。另外,两类老鼠都不能辨别日语和荷兰语的倒放录音。
当只有一个扬声器发声时,老鼠可以分辨出这两种语言中的自然句;如果用不同的扬声器或不同的人说话时,老鼠则不能区分两种语言的不同。相似地,新生婴儿在语言识别方面也有这种情况,而绢毛猴的“本领”就显得大多了,因为不管是同一个人还是不同的人说话,它们都能够辨别出来。
由此,人类应用在语言上的能力哪些是与其他动物共享的,哪些是人类独有的,以及在生物进化的过程中,人类语言在正式形成之前到底是什么样子等情况都会有进一步的探索。