Publications

Abstract

In this dissertation the perceptual relevance of prevoicing in Dutch was investigated. Prevoicing is the presence of vocal fold vibration during the closure of initial voiced plosives (negative voice onset time). The presence or absence of prevoicing is generally used to describe the difference between voiced and voiceless Dutch plosives. The first experiment described in this dissertation showed that prevoicing is frequently absent in Dutch and that several factors affect the production of prevoicing. A detailed acoustic analysis of the voicing distinction identified several acoustic correlates of voicing. Prevoicing appeared to be by far the best predictor. Perceptual classification data revealed that prevoicing was indeed the strongest cue that listeners use when classifying plosives as voiced or voiceless. In the cases where prevoicing was absent, other acoustic cues influenced classification, such that some of these tokens were still perceived as being voiced. In the second part of this dissertation the influence of prevoicing variation on spoken-word recognition was examined. In several cross-modal priming experiments two types of prevoicing variation were contrasted: a difference between the presence and absence of prevoicing (6 versus 0 periods of prevoicing) and a difference in the amount of prevoicing (12 versus 6 periods). All these experiments indicated that primes with 12 and 6 periods of prevoicing had the same effect on lexical decisions to the visual targets. The primes without prevoicing had a different effect, but only when their voiceless counterparts were real words. Phonetic detail appears to influence lexical access only when it is useful: In Dutch, the presence versus absence of prevoicing is informative, while the amount of prevoicing is not.

Abstract

The aim of this thesis was to gain more insight into spoken-word comprehension and the influence of sentence-contextual information on these processes using ERPs. By manipulating critical words in semantically constraining sententes, in semantic or syntactic sense, and examining the consequences in the electrophysiological signal (e.g., elicitation of ERP components such as the N400, N200, LAN, and P600), three questions were tackled: I At which moment is context information used in the spoken-word recognition process? II What is the temporal relationship between lexical selection and integration of the meaning of a spoken word into a higher-order level representeation of the preceding sentence? III What is the time course of the processing of different sources of linguistic information obtained from the context, such as phonological, semantic and syntactic information, during spoken-word comprehension? From the results of this thesis it can be concluded that sentential context already exerts an influence on spoken-word processing at approximately 200 ms after word onset. In addition, semantic integration is attempted before a spoken word can be selected on the basis of the acoustic signal, i.e. before lexical selection is completed. Finally, knowledge of the syntactic category of a word is not needed before semantic integration can take place. These findings, therefore, were interpreted as providing evidence for an account of cascaded spoken-word processing that proclaims an optimal use of contextual information during spoken-word identification. Optimal use is accomplished by allowing for semantic and syntactic processing to take place in parallel after bottom-up activation of a set of candidates, and lexical integration to proceed with a limited number of candidates that still match the acoustic input

Abstract

This chapter explores grammatical gender as a linguistic phenomenon. First, I define gender in terms of agreement, and look at the parts of speech that can take gender agreement. Because it relates to assumptions underlying much psycholinguistic gender research, I also examine the reasons why gender systems are thought to emerge, change, and disappear. Then, I describe the gender system of Dutch. The frequent confusion about the number of genders in Dutch will be resolved by looking at the history of the system, and the role of pronominal reference therein. In addition, I report on three lexical- statistical analyses of the distribution of genders in the language. After having dealt with Dutch, I look at whether the genders of Dutch and other languages are more or less randomly assigned, or whether there is some system to it. In contrast to what many people think, regularities do indeed exist. Native speakers could in principle exploit such regularities to compute rather than memorize gender, at least in part. Although this should be taken into account as a possibility, I will also argue that it is by no means a necessary implication.

Abstract

This dissertation focuses on syntactic comprehension problems in patients with Broca's aphasia from an electrophysiological perspective. The central objective of this dissertation was to further explore what syntax-related event-related brain potential (ERP) effects can reveal about the nature of the deficit that underlies syntactic comprehension problems in patients with Broca's aphasia. Chapter two to four describe experiments in which event-related brain potentials were recorded while subjects (Broca patients, non-aphasic patients with a right-hemisphere lesion, and healthy elderly controls) were presented with sentences that contained either violations of syntactic constraints or were syntactically correct. Chapter two investigates ERP effects of subject-verb agreement violations in the different subject groups, and seeks to answer the following questions: Do agrammatic comprehenders show sensitivity to subject-verb agreement violations as indicated by a syntax-related ERP effect? In addition, does the severity of the syntactic comprehension impairment in the Broca patients affect the ERP responses? Chapter three describes an investigation of whether Broca patients show sensitivity to violations of word order as indicated by a syntax-related ERP effect, and whether the ERP responses in the Broca patients are affected by the severity of their syntactic comprehension impairment. Chapter four reports on ERP effects of violations of word-category. In addition, also a semantic violation condition was added to track possible dissociations in the sensitivity to semantic and syntactic information in the Broca patients. Chapter five describes the development of a paradigm in which the electrophysiological approach and the classical sentence-picture matching approach are combined. In this chapter, the ERP method is applied to study on-line thematic role assignment in Broca patients during sentence-picture matching. Also the relation between ERP effects and behavioral responses is pursued. Finally, Chapter 6 provides a summary of the main findings of the experiments and a general discussion.

Abstract

The primary goal of psycholinguistic research is to understand the architectures and mechanisms that underlie human language comprehension and production. This entails an understanding of how linguistic knowledge is represented and organized in the brain and a theory of how that knowledge is accessed when we use language. Research has traditionally emphasized purely linguistic aspects of on-line comprehension, such as the influence of lexical, syntactic, semantic and discourse constraints, and their tim -course. It has become increasingly clear, however, that nonlinguistic information, such as the visual environment, are also actively exploited by situated language comprehenders.

Abstract

Here we review evidence from cognitive neuroscience for a tight relation between language and action in the brain. We focus on two types of relation between language and action. First, we investigate whether the perception of speech and speech sounds leads to activation of parts of the cortical motor system also involved in speech production. Second, we evaluate whether understanding action-related language involves the activation of parts of the motor system. We conclude that whereas there is considerable evidence that understanding language can involve parts of our motor cortex, this relation is best thought of as inherently flexible. As we explain, the exact nature of the input as well as the intention with which language is perceived influences whether and how motor cortex plays a role in language processing.