科學(xué)家發(fā)現(xiàn)人類在學(xué)習(xí)語(yǔ)言的時(shí)候,，大腦中會(huì)進(jìn)行大量而復(fù)雜的運(yùn)算,。
講話以及聽人說(shuō)話在生活中似乎是件很平常的事，大概很少人會(huì)想到為什么自己能夠在一句長(zhǎng)而流利毫不間斷的話語(yǔ)之中,，能夠聽出每個(gè)字,，并且了解每個(gè)字的涵意,。因此我們聽人家說(shuō)話才會(huì)有「大珠小珠落玉盤」般，字字分明的感覺(jué),。在Rochester University中,，由Elissa Newport以及Richard Aslin所領(lǐng)導(dǎo)的團(tuán)隊(duì)正在研究這樣的問(wèn)題。
首先他們創(chuàng)造了一種語(yǔ)言,，這個(gè)語(yǔ)言當(dāng)中利用一些音節(jié)組成沒(méi)有意義的字,，然后以隨機(jī)的組合讓受試者聽20分鐘。在聽的時(shí)候,，受試者會(huì)接受音節(jié)的信息,，像是音節(jié)出現(xiàn)的頻率以及音節(jié)之間的關(guān)系等等，聽完了20分鐘之后再做測(cè)試,。
實(shí)驗(yàn)結(jié)果發(fā)現(xiàn),，在成人的受試者當(dāng)中，高達(dá)85％的時(shí)候他們可以分辨出哪些是剛剛聽到的字,，哪些是其它用英文中前綴字尾音節(jié)所組合的字,，甚至連五歲小孩也可以分辨得出來(lái)。因此他們認(rèn)為人類的大腦有能力對(duì)特定音節(jié)出現(xiàn)的頻率以及音節(jié)與音節(jié)之間的關(guān)系去進(jìn)行復(fù)雜的運(yùn)算,。
接著他們?cè)O(shè)計(jì)了另外一個(gè)實(shí)驗(yàn),，在實(shí)驗(yàn)當(dāng)中包含三種語(yǔ)言，每種語(yǔ)言的字都是三個(gè)音節(jié),。
第一種語(yǔ)言是非相鄰音節(jié)（non-adjacent syllables）的規(guī)則性,，也就是第一跟第三音節(jié)不變，只改變第二個(gè)音節(jié),。
第二種語(yǔ)言是使用固定的子音,，但是改變?cè)簦袷牵簉ing,、rang,、rung。
第三種語(yǔ)言則是固定元音,，改變子音,，在土耳其語(yǔ)當(dāng)中就存在這種型式的規(guī)則性。
成人的受試者對(duì)于第一種語(yǔ)言的辨識(shí)率極低,，不過(guò)對(duì)于第二種及第三種語(yǔ)言的辨識(shí)率就提高很多,，科學(xué)家推測(cè)這可能是因?yàn)槿藗兛梢苑直婺承┳右絷P(guān)系的規(guī)則性，并且利用它們作為斷句的依據(jù),。實(shí)驗(yàn)結(jié)果也顯示,，人類對(duì)于已經(jīng)存在于目前人類語(yǔ)言當(dāng)中的非相鄰式規(guī)則性的辨識(shí)率，會(huì)比那些不存在于目前人類語(yǔ)言中的非相鄰式規(guī)則性的辨識(shí)率來(lái)得好,。因此他們推測(cè),，也許在語(yǔ)言成形時(shí),，人類在先天上就有某些偏好的擷取音節(jié)方式，而且這種偏好在語(yǔ)言形成上可能扮演了某種重要的角色,。
另外他們也使用棉冠狨猴（Cotton- top tamarin）進(jìn)行同樣的實(shí)驗(yàn),，結(jié)果發(fā)現(xiàn)狨猴對(duì)于第一種跟第三種語(yǔ)言的表現(xiàn)較佳，這顯示人類與其它靈長(zhǎng)類在感知語(yǔ)言及計(jì)算音節(jié)的能力上也許是有所不同的,。
由此看來(lái)，能聽得懂別人在說(shuō)些什么,，還真是一件不簡(jiǎn)單的事?。?/p>
原始論文：
Elissa L. Newport, Richard N. Aslin. Learning at a distance I. Statistical learning of non-adjacent dependencies, Cognitive Psychology , Volume 48, Issue 2, March 2004, Pages 127-162.
Elissa L. Newport , Marc D. Hauser , Geertrui Spaepen and Richard N. Aslin. Learning at a distance II. Statistical learning of non-adjacent dependencies in a non-human primate, Cognitive Psychology, Available online 3 March 2004.
Human brain works heavy statistics learning language
A team at the University of Rochester has found that the human brain makes much more extensive use of highly complex statistics when learning a language than scientists ever realized. The research, appearing in a recent issue of Cognitive Psychology, shows that the human brain is wired to quickly grasp certain relationships between spoken sounds even though those relationships may be so complicated they're beyond our ability to consciously comprehend.
"We're starting to learn just how intuitively our minds are able to analyze amazingly complex information without our even being aware of it," says Elissa Newport, professor of brain and cognitive sciences at the University and lead author of the study. "There is a powerful correlation between what our brains are able to do and what language demands of us."
Newport and Richard Aslin, professor of brain and cognitive sciences, began by looking at how people are able to recognize the division between spoken words when spoken language is really a stream of unbroken syllables. They wanted to know how it is that we perceive breaks between spoken words, when in fact there are no pauses. This is why it often seems as if speakers of foreign languages are talking very quickly; we don't perceive pauses.
So how is a baby supposed to make out where one word begins and another ends? Newport and Aslin devised a test where babies and adults listened to snippets of a synthetic language: a few syllables arranged into nonsense words and played in random order for 20 minutes. During that time, the listeners were taking in information about the syllables, such as how often each occurred, and how often they occurred in relation to other syllables. For instance, in the real words "pretty baby," the syllable "pre" is followed by "ty," which happens more frequently in English than the syllable "ty" being followed by "ba"--thus the brain notes that "ty" is more likely to be associated with "pre" than with "ba," and so we hear a pause between those two syllables.
After listening to the synthesized string of syllables for the full 20 minutes, adults were played some of the invented words along with some words made up of syllables from the beginning and ending of words--like "ty-ba." More than 85 percent of the time, adults were able to recognize words from non-words. Five-year-olds also reacted definitively to words and non-words, showing that the human mind is wired to statistically track how often certain sounds arise in relationship to other sounds.
"If you were given paper and a calculator, you'd be hard-pressed to figure out the statistics involved," says Newport. "Yet after listening for a while, certain syllables just pop out at you and you start imagining pauses between the 'words.' It's a reflection of the fact that somewhere in your brain you're actually absorbing and processing a staggering amount of information."
Newport and Aslin take the research a step farther in the Cognitive Psychology piece. Language does not only consist of relationships between adjacent syllables or other language elements. For instance, in the sentence, "He is going," the element "is" is linked to the element "ing," even though they are not adjacent to each other. Newport and Aslin devised a new, more complex, synthetic language where three-syllable words had constant first and last syllables, but the middle syllable was interchangeable. Despite being somewhat similar to the original test, "people were terrible at this," notes Newport. One test subject never identified a single pattern, despite taking the test numerous times.
Though the new test was significantly more complicated than the first, Newport and Aslin were surprised that people performed so poorly. The team looked carefully at the non-adjacent aspects of languages, like Hebrew, which is replete with non-adjacent elements, and discovered that while whole syllables were rarely related in this way, vowels and consonants often were. They restructured the test so that the invented words had consistent consonants and variable vowels--like "ring", "rang," and "rung." Immediately, test scores skyrocketed. People were able to distinguish the regularity of certain consonant relationships and use them to properly divide the stream of sounds into words even though the statistics involved were at least as complicated as the earlier test that was universally failed.
Even switching the roles of consonants and vowels so that the vowels remained steady as the consonants varied, resulted in the test subjects picking out the words with great accuracy. Turkish, as an example, uses this "vowel harmony" quite regularly.
"These results suggest that human learning ability is not just limited to a few elementary computations, but encompasses a variety of mechanisms," says Newport. "A question to explore now is: How complex and extensive are these learning mechanisms, and what kinds of computational abilities do people bring to the process of learning languages?"
