Collaborative Research: A Comparative Investigation of Statistical Learning

成年人听语言时，他们的感知会受到母语语音系统的影响。例如，说日语的人很难听清英语[r]和[L]之间的区别，而说英语的人很难区分印地语[d]和[D]。相比之下，尚未掌握母语语音系统的婴儿在辨别外国对比方面的能力往往超过成年人。到12个月时，婴儿会对大多数外国对比失去敏感性，并表现出成人般的辨别模式。是什么导致了生命第一年的这种变化？在国家科学基金会的支持下，Jessica Maye博士和Daniel Weiss博士将继续他们的研究，该研究表明，婴儿对他们听到的语音中的统计规则的敏感性可能会导致对外语对比的敏感度降低，以及对母语对比的敏感度增强。他们将测量语音中不同的分布模式对人类婴儿和成年人以及棉冠金丝猴辨别能力的影响程度。此前的研究发现，罗望子鱼和人类一样，能够通过人类语音的统计特性来学习语言规律。然而，在所学知识的性质上，不同物种之间存在微妙的差异。这个项目将在另一个物种中提供统计语音学习的第一个测试，目的是找出人类和非人类之间以及婴儿和成年人之间的相似和不同之处。此外，这些实验将使用猴子叫声刺激和人类语音，以便将这些物种自己的发声与另一个物种的发声进行比较。我们习得语言的能力是人类区别于其他动物的基本特征之一。数百年来，学者们一直在争论语言习得的机制在多大程度上是人类独有的，因为很明显，只有人类最终才能获得人类语言的全部复杂性。一种这样的学习机制是根据我们听到的语言中的统计模式得出语言推理的能力。这是一种不是人类独有的能力；然而，人类和非人类计算这种规律性的单位似乎存在差异。梅耶博士和韦斯博士假设，这些差异可能是人类成为熟练的人类语言学习者的基础。同样，婴幼儿和成人学习者进行的统计计算可能存在细微的差异，这可以解释这样一个事实，即从婴儿期开始的语言习得的熟练程度远远超过后来学习的语言。这个项目将阐明这三个群体在学习语音刺激和塔玛兰语叫声中的统计规律的能力方面的异同，以回答是什么让人类，特别是婴儿如此擅长解码一种未知的语言。在实践层面上，该项目将通过培训学生进行认知科学(包括语言学、发展心理学和比较心理学)的跨学科研究，为科学基础设施做出贡献。此外，更好地理解是什么让婴儿成为如此成功的语言学习者，具有深远的临床和技术应用价值。例如，比较好的学习者(如婴儿)和差的学习者(如成年人、灵长类)的学习机制，很可能会为语言障碍者带来新的治疗方法。理解人类听者如何应对巨大的声学变化以发现所说话语的信息将有助于改进语音识别系统，目前语音识别系统的性能远远低于人类听者的水平。

When adults listen to speech, their perception is influenced by the phonetic system of their native language. For example, Japanese speakers find it very difficult to hear the difference between English [r] and [l], while English speakers have trouble discriminating Hindi [d] and [D]. In contrast, infants who have not yet acquired the phonetic system of their native language often surpass adults in their ability to discriminate foreign contrasts. By 12 months, infants lose sensitivity to most foreign contrasts and show the adult-like pattern of discrimination. What is responsible for this change over the first year of life? With support from the National Science Foundation, Drs. Jessica Maye and Daniel Weiss will follow up on their research that has demonstrated that infants' sensitivity to statistical regularities in the speech they hear may lead to decreased sensitivity to foreign language contrasts as well as enhanced sensitivity to native language contrasts. They will measure the degree to which different distributional patterns in speech affect discrimination by human infants and adults as well as cotton-top tamarin monkeys. Previous research has found that tamarins, like humans, are capable of learning linguistic regularities through statistical properties of human speech. However, there are subtle differences across species in the nature of what is learned. This project will provide the first test of statistical phonetic learning in another species, with an aim to find both similarities and differences between humans and nonhumans, as well as between infants and adults. Furthermore, these experiments will involve the use of monkey call stimuli as well as human speech, in order to compare the species on their own vocalizations versus that of another species. Our ability to acquire language is one of the fundamental traits distinguishing humans from other animals. For hundreds of years, scholars have debated the extent to which the mechanisms underlying language acquisition are unique to humans, as it is clear that only humans ultimately acquire the full complexity of human language. One such learning mechanism is the ability to draw linguistic inferences on the basis of statistical patterns in the language that we hear. This is an ability that is not exclusive to humans; however, there appear to be differences in the units over which humans and nonhumans compute such regularities. Drs. Maye and Weiss hypothesize that these differences may underlie what makes humans such adept learners of human language. Similarly, there may be subtle differences in the statistical computations performed by infant and adult learners which would account for the fact that language acquisition that begins in infancy reaches a level of proficiency far surpassing that of languages learned later in life. This project will elucidate the similarities and differences between these three populations in their ability to learn statistical regularities in both speech stimuli and tamarin calls, in order to answer the question of what makes humans, and infants in particular, so remarkably adept at decoding an unknown language. On a practical level, the project will contribute to the infrastructure of science by training students in the interdisciplinary research of cognitive science (including linguistics, developmental psychology, and comparative psychology). Furthermore, a better understanding of what makes infants such successful language learners has far reaching clinical and technological applications. For example, a comparison of the learning mechanism of good learners (e.g. infants) vs. poor learners (e.g. adults, primates) may well lead to new therapies for the language disabled. Understanding how human listeners cope with enormous amounts of acoustic variation to uncover the message of a spoken utterance will help to improve speech recognition systems, which currently perform far below the level of human listeners.