The role of learning mechanisms in understanding spoken language

近年来，有几个值得注意的证据表明，学习单词及其含义的能力在我们的成年生活中仍然很重要。学习机制不仅使我们能够获得全新的信息（例如，“twitter”一词的社交网络意义（2），见相关的学生），但它们也可以修改我们现有的关于单词的知识，我们已经知道，以加强他们的后续处理。这种学习机制明显有益的一种情况是促进对具有多种含义的单词（如“bark”）的处理。这种形式的歧义在语言中无处不在，超过80%的单词有一个以上的字典定义。学习机制可以在经验的基础上调整其含义的可用性，从而对我们理解这些棘手单词的能力做出重要贡献。例如，单词“spade”既可以指“挖掘工具”，也可以指“纸牌套装”，我们对这个词的偏好解释可能会受到我们最近是否把园艺或打牌作为一种爱好的影响。通过学习我们最近使用这些词的经验，我们可以更好地预测未来更有可能遇到的含义。有几个理由相信，这种学习机制确实对理解歧义词做出了重要贡献。首先，许多研究表明，对于整个语言中最常见的含义，有很强的处理优势（4），例如，单词“pen”在短语中更容易理解，如“the blue pen”，它使用其主要含义，而“the pig pen”则使用其低频含义。这些发现间接地表明，我们对一生中遇到替代词义的总体频率很敏感。此外，我们最近提供了第一个直接证据，表明听众对词义的偏好受到最近遇到的一个词义的强烈影响，这样，在听到像“the farmers put the sheep in the pen”（农民把羊放进羊圈）这样的句子后，“pen”的低频含义就变得更容易理解了（5）尽管有证据表明学习机制在我们理解歧义词的能力中起着关键作用，但当前的歧义消解模型在解释这些机制时显着不足。拟议的研究的主要目的是获得全面的实证证据，听众如何以及何时可以使用他们的经验，以调整他们的偏好，个别的单词的含义。首先，我们将确定听众是否从所有遇到一个歧义词或学习发生的特定条件（实验1，6）。第二，我们将测量听众的近期和长期经验的相对贡献与模糊的话，以确定我们如何整合信息获得我们的生命（实验2-5，9）。最后，我们将探讨是否意义偏好可以调制的因素，如身份或口音的发言者（实验7，8）。这些数据将指导开发一种新的模糊性解决模型，该模型指定了这些学习机制的性质。这一新的研究方向为在这一重要课题上取得快速进展提供了机会，通过了解这些过程在健康成年人中是如何运作的，我们也将提供经验证据，使未来的研究能够评估那些已知有困难的个体中加工和学习缺陷的贡献。理解包含歧义词的句子（见影响总结）。

In recent years there have been several notable demonstrations that the ability to learn about words and their meanings continues to be important throughout our adult life (1). Not only do learning mechanisms allow us to acquire entirely new information (e.g., the social-networking meaning of the word "twitter" (2), see associated studentship), but they can also modify our existing knowledge about words that we already know in order to enhance their subsequent processing. One case where such a learning mechanism would be of clear benefit is to facilitate the processing of words like "bark" that have multiple meanings. This form of ambiguity is ubiquitous in language, with over 80% of words having more than one dictionary definition (3). Learning mechanisms could make an important contribution to our ability to understand these tricky words by adjusting the availability of their meanings on the basis of experience. For example the word "spade" can refer to either a "digging tool" or "card suit", and our preferred interpretation of this word could be influenced by whether we had recently taken up gardening or card-playing as a hobby. By learning from our recent experience with such words, we can make better predictions about which meaning is more likely to be encountered in the future. There are several reasons to believe that such learning mechanisms do indeed make an important contribution to understanding ambiguous words. First, numerous studies have shown a strong processing benefit for the meaning that is most frequent in the language as a whole (4), such that the word "pen" is easier to understand in a phrase like "the blue pen", which uses its dominant meaning compared a with the phrase like "the pig pen" where its low frequency meaning is used. These findings suggest, indirectly, that that we are sensitive to the overall frequency with which we encounter alternative word meanings across our life-time. In addition, we have recently provided the first direct evidence that listeners' preferences for word meanings are strongly influenced by a single recent encounter with one of its meanings, such that the low-frequency meaning of "pen" would become more readily available after hearing a sentence like "the farmer put the sheep in the pen"(5).Despite this evidence that learning mechanisms play a key role in our ability to understand ambiguous words, current models of ambiguity resolution are remarkably inadequate when it comes to explaining these mechanisms. The primary aim of the proposed research is to obtain comprehensive empirical evidence about how and when listeners can use their experience to adjust their preferences for individual word meanings. First we will establish whether listeners learn from all encounters with an ambiguous word or if particular conditions necessary for learning to occur (Experiment 1, 6). Second, we will measure the relative contributions of listeners' recent and longer-term experience with ambiguous words to determine how we integrate information acquired across our lifespan (Experiments 2-5, 9). Finally we will explore whether meaning preferences can be modulated by factors such as the identity or accent of the speaker (Experiments 7, 8). These data will guide the development of a new model of ambiguity resolution which specifies the nature of these learning mechanisms. This novel line of research offers an opportunity to make rapid progress on this important topic, and may lead to a radically different understanding of this critical aspect of language comprehension.By understanding how these processes operate within healthy adults we will also provide the empirical evidence that will allow future research to assess the contributions of both processing and learning deficits in those individuals who are known to have difficulties understanding sentences that contain ambiguous words (see Impact Summary).