Social, Ecological and Genetic Variables in a Model Vocal Learning System

模型学习系统中的社会、生态和遗传变量迈克尔·D·比彻在各种各样的动物群体中，使用复杂的发声进行交流是很常见的。在鸣禽(鸣禽)中，这样的发声被称为歌声，并有一个额外的、有趣的方面：它们是学习的，而且大部分学习都发生在生命的很小阶段。鸣禽的鸣叫学习已经在实验室中得到了广泛的分析，并成为研究学习的神经生物学的主要模型系统。它作为一种模式系统的价值因其与人类语言学习的许多相似之处而得到加强。这些相似之处包括早期的敏感期，对物种交流信号进行调整的感知过滤机制，听觉反馈在正常发育中的关键作用，感觉和运动学习之间的分离，以及早期的亚歌声或叽叽喳喳的阶段。在鸣禽的歌声感知和产生的神经基础上的研究揭示了鸟类的歌声神经中枢和人类的语言神经中枢之间的更多相似之处。在这种背景下，如果这个模型系统要为一般的语音交流系统的发展，特别是人类语言的发展提供一般性的见解，那么理解鸣禽鸣叫发展的正常过程就变得至关重要。不幸的是，我们对正常歌曲发展的理解出人意料地不完整，因为到目前为止，大多数关于歌曲学习的研究都是实验室实验，基本上所有的社交特征都被去除了。将进行四个系列的研究，以考察一种特定物种--歌雀--在歌唱学习过程中的社会、生态和遗传变量。在第一系列实验中，老师与被辅导者之间以及老师与老师之间的歌唱互动将被作为歌曲学习的一个潜在变量进行操作和分析；这将是实验室首次尝试这样做。这个设置将模拟四个现场歌曲导师，导师和导师之间的唱歌互动将有系统地变化；一般预测是，鸟类将从更多互动的导师那里复制更多的歌曲。第二项研究将通过比较东西方歌雀的歌唱学习来检验遗传因素的作用。在实地研究的基础上，假设这两个种群的鸟类遵循非常不同的、基于遗传的歌曲学习程序。这一假说将通过从两个种群中收集鸟类并在共同的歌曲辅导制度下饲养来检验；根据遗传假说，尽管有共同的辅导制度，但在野外观察到的差异应该会持续下去。在第三项研究中，将通过无线电跟踪幼年歌雀在野外直接检查歌唱学习，并将它们与潜在歌唱导师互动的程度和时间关联起来，以及幼鸟模仿它们歌声的程度。在第四项研究中，将进行回放实验，实验者通过在逼真的模拟中播放鸟类邻居的录音来模拟鸟类邻居，以分析两个种群的鸟类在与邻居的领土互动中如何使用它们的歌曲。田野研究表明，这两个群体的交流规则可能有很大不同，这与他们在歌曲学习计划中假定的不同是平行的。希望这些不同研究路线的结果将结合起来阐明塑造这一模式声乐学习系统发展的社会因素。反过来，这些洞察力可能有助于揭示人类疾病，如自闭症，这些疾病的特征是语言和社交缺陷共同出现。

Social, Ecological and Genetic Variables in a Model Learning SystemMichael D. BeecherThe use of elaborate acoustic vocalizations for communication is common in a wide variety of animal groups. In the oscine passerines (songbirds), such vocalizations are called song and have an additional, intriguing aspect: they are learned, with much of that learning occurring very early in life. Song learning in songbirds has been extensively analyzed in the laboratory and has become a major model system for studying the neurobiology of learning. Its value as a model system is enhanced by its many parallels with human language learning. These parallels include an early sensitive period, a perceptual filtering mechanism tuned to species communication signals, a crucial role for auditory feedback in normal development, a separation between sensory and motor learning, and an early subsong or babbling stage. Work on the neural basis of song perception and production in songbirds has revealed additional parallels between the neural centers for song in birds and those for language in humans. In this context, understanding the normal course of song development in songbirds becomes crucial if this model system is going to provide general insights into the development of vocal communication systems in general and human language in particular. Unfortunately, our understanding of normal song development is surprisingly incomplete, because most studies of song learning to date have been laboratory experiments in which essentially all social features have been removed. Four series of studies will be carried out to examine social, ecological and genetic variables in the song learning process for one particular species, the song sparrow. In the first series of experiments, singing interactions between tutor and tutee, and between tutors, will be manipulated and analyzed as a potential variable in song learning; this will be the first time this has been attempted in the laboratory. The setup will simulate four live song tutors, and both tutor-tutor and tutor-tutee singing interactions will be systematically varied; the general prediction is that birds will copy more songs from more interactive tutors. A second study will examine the role of genetic factors by comparing song learning by eastern and western song sparrows. On the basis of field studies, it has been hypothesized that birds in the two populations follow very different, genetically-based song-learning programs. This hypothesis will be tested by collecting birds from both populations and raising them in a common song-tutoring regime; according to the genetic hypothesis, the differences observed in the field should persist despite the common tutoring regime. In a third study, song learning will be directly examined in the field by radio-tracking young song sparrows through their first year and correlating the extent and timing of their interactions with potential song tutors and the degree to which the young birds copy their songs. In the fourth study, playback experiments in which the experimenter simulates a birds neighbor by playing recordings of the neighbor to the bird in a realistic simulation -- will be carried out to analyze how birds in both populations use their songs in territorial interactions with their neighbors. Field studies have suggested that the rules of communication in these two populations may be quite different, paralleling the presumed difference in their song learning programs. It is hoped that results from these different lines of research will combine to elucidate the social factors that shape the development of this model vocal learning system. In turn, such insights may shed light on human disorders such as autism that are characterized by a co-occurrence of language and social deficiencies.