Investigating the Dynamics of Semantic Processing

这项拟议的研究解决的问题是词义是如何推导出来的。也就是说，当一个词被感知时，它的意思是如何进入脑海的？这个看似简单的过程仍然是认知科学中最大的谜题之一。在拟议的研究中，我将通过两个事实来处理这个问题：a)与不同单词相关联的意义或语义信息存在差异，以及b)这种差异会产生行为和神经后果。也就是说，单词在其含义的丰富程度上各不相同，我们的研究表明，这种语义丰富程度的差异对单词识别和记忆有影响。此外，人们可以用许多不同的方式来定义语义丰富性，并将其定义为许多不同的语义概念化的函数。通过检查在识别行为和神经活动中观察到这些不同的丰富性效应的程度，以及作为上下文的函数，可以测试各种语义处理框架的可行性。 传统上一直假设语义表示是相当稳定的，从而生成词义的过程涉及激活一组固定的属性或特征。或者，有观点认为，生成词义的过程至少在一定程度上依赖于语境，从而语境决定了激活的意义信息。最近有证据表明，从单词中获得意义的过程是一个动态的过程；这个过程随着任务背景和过去的经验而变化。这是一种更灵活的语义处理视图，其中概念的表示不是静态的，而是在依赖于上下文的过程中生成的。在这项拟议的研究中，我将研究语境如何调节词汇语义，以便我们能够更好地理解意义激活是刺激特定过程和任务特定过程相互作用的结果。这项工作将为当前的语义表征理论提供重要的见解，并将指导未来的理论发展。

The issue addressed in the proposed research is how word meaning is derived. That is, when a word is perceived, how is its meaning brought to mind? This seemingly simple process remains one of the great puzzles in Cognitive Science. In the proposed research I will approach this issue by capitalizing on two facts: a) there is variability in the meaning or semantic information associated with different words, and b) there are behavioral and neural consequences of this variability. That is, words vary in the richness of their meanings, and our research shows that this variability in semantic richness has consequences for word recognition and for memory. Furthermore, one can define semantic richness in many different ways, and as a function of many different conceptualizations of semantics. By examining the extent to which these different richness effects are observed, in recognition behavior and in neural activity and as a function of context, it is possible to test the viability of the various frameworks for semantic processing. It has traditionally been assumed that semantic representations are quite stable, such that the process of generating word meaning involves activation of a fixed set of properties or features. Alternatively, it has been argued that the process of generating word meaning is at least to some degree context dependent such that context determines the meaning information activated. There is recent evidence that the process of deriving meaning from words is a dynamic one; the process varies as a function of task context, and past experience. This is a more flexible view of semantic processing, where a concept's representation is not static but rather is generated in a context-dependent process. In the proposed research I will investigate how context modulates lexical semantics, so that we may better understand how meaning activation is the result of interaction between stimulus-specific and task-specific processes. The work will provide important insights about current theories of semantic representation and will guide future theory development.