Publications

Abstract

The control of language use has in its simplest form perhaps been most intensively studied using the color–word Stroop task. The authors review chronometric and neuroimaging evidence on Stroop task performance to evaluate two prominent, implemented models of control in naming and reading: GRAIN and WEAVER++. Computer simulations are reported, which reveal that WEAVER++ offers a more satisfactory account of the data than GRAIN. In particular, we report WEAVER++ simulations of the BOLD response in anterior cingulate cortex during Stroop performance. Aspects of single-word production and perception in the Stroop task are discussed in relation to the wider problem of the control of language use.

Abstract

The authors report a study in Dutch that used an on-line preparation paradigm to test the issue of semantic
dependency versus morphological autonomy in the production of polymorphemic words. Semantically
transparent complex words (like input in English) and semantically opaque complex words
(like invoice) showed clear evidence of morphological structure in word-form encoding, since both exhibited
an equally large preparation effect that was much greater than that for morphologically simple
words (like insect). These results suggest that morphemes may be planning units in the production of
complex words, without making a semantic contribution, thereby supporting the autonomy view. Language
production establishes itself as a domain in which morphology may operate “by itself” (Aronoff,
1994) without recourse to meaning.

Abstract

The present paper reports an analysis of correct wh-question production and subject–auxiliary inversion errors in one child's early wh-question data (age 2; 3.4 to 4; 10.23). It is argued that two current movement rule accounts (DeVilliers, 1991; Valian, Lasser & Mandelbaum, 1992) cannot explain the patterning of early wh-questions. However, the data can be explained in terms of the child's knowledge of particular lexically-specific wh-word+auxiliary combinations, and the pattern of inversion and uninversion predicted from the relative frequencies of these combinations in the mother's speech. The results support the claim that correctly inverted wh-questions can be produced without access to a subject–auxiliary inversion rule and are consistent with the constructivist claim that a distributional learning mechanism that learns and reproduces lexically-specific formulae heard in the input can explain much of the early multi-word speech data. The implications of these results for movement rule-based and constructivist theories of grammatical development are discussed.

Abstract

Capacity limited memory systems need to gradually forget old information in order to avoid catastrophic forgetting where all stored information is lost. This can be achieved by allowing new information to overwrite old, as in the so-called palimpsest memory. This paper describes a new such learning rule employed in an attractor neural network. The network does not exhibit catastrophic forgetting, has a capacity dependent on the learning time constant and exhibits recency e!ects in retrieval

Abstract

A realtime online learning system with capacity limits needs to gradually forget old information in order to avoid catastrophic forgetting. This can be achieved by allowing new information to overwrite old, as in a so-called palimpsest memory. This paper describes an incremental learning rule based on the Bayesian confidence propagation neural network that has palimpsest properties when employed in an attractor neural network. The network does not suffer from catastrophic forgetting, has a capacity dependent on the learning time constant and exhibits faster convergence for newer patterns.

Abstract

The structure of relative clauses has attracted considerable attention in recent years, and a number of authors have carried out analyses of the syntax of relativization. In our investigation of syntactic structure and change in New Guinea Tok Pisin, we find that the basic processes involved in relativization have much broader discourse functions, and that relativization is only a special instance of the application of general ‘bracketing’ devices used in the organization of information. Syntactic structure, in this case, can be understood as a component of, and derivative from, discourse structure.

Abstract

Two experiments investigate the effect of number congruency using picture–word interference. Native German participants were required to name pictures of single objects (Nase ‘nose’) or two instances of the same object (Nasen ‘noses’) while ignoring simultaneously presented distractor words. Distractor words either had the same number or were different in number. In addition, the type of plural formation (same or different inflectional plural suffix) and the semantic relationship (same or different semantic category) between target and distractor were varied in Experiments 1 and 2. Results showed no effect of number congruency in either experiment. Furthermore, the type of inflectional suffix did not exert an influence on naming latencies in Experiment 1, but semantic relationship led to a significant interference effect in Experiment 2. The results indicate that selection of the number feature diacritic in noun production is not a competitive process. The implications of the results for models of lexical access are discussed.

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed behavioral disorder in childhood and likely represents an extreme of normal behavior. ADHD significantly impacts learning in school-age children and leads to impaired functioning throughout the life span. There is strong evidence for a genetic etiology of the disorder, although putative alleles, principally in dopamine-related pathways suggested by candidate-gene studies, have very small effect sizes. We use affected-sib-pair analysis in 203 families to localize the first major susceptibility locus for ADHD to a 12-cM region on chromosome 16p13 (maximum LOD score 4.2; P=.000005), building upon an earlier genomewide scan of this disorder. The region overlaps that highlighted in three genome scans for autism, a disorder in which inattention and hyperactivity are common, and physically maps to a 7-Mb region on 16p13. These findings suggest that variations in a gene on 16p13 may contribute to common deficits found in both ADHD and autism.

Abstract

The temporal distribution of perceptually relevant information for consonant recognition in British English VCVs is investigated. The information distribution in the vicinity of consonantal closure and release was measured by presenting initial and final portions, respectively, of naturally produced VCV utterances to listeners for categorization. A multidimensional scaling analysis of the results provided highly interpretable, four-dimensional geometrical representations of the confusion patterns in the categorization data. In addition, transmitted information as a function of truncation point was calculated for the features manner place and voicing. The effects of speaker, vowel context, stress, and distinctive feature on the resulting information distributions were tested statistically. It was found that, although all factors are significant, the location and spread of the distributions depends principally on the distinctive feature, i.e., the temporal distribution of perceptually relevant information is very different for the features manner, place, and voicing.

Abstract

Spoken word recognition involves automatic activation of lexical candidates compatible with the perceived input. In running speech, words abut one another without intervening gaps, and syllable boundaries can mismatch with word boundaries. For instance, liaison in ’petit agneau’ creates a syllable beginning with a consonant although ’agneau’ begins with a vowel. In two cross-modal priming experiments we investigate how French listeners recognise words in liaison environments. These results suggest that the resolution of liaison in part depends on acoustic cues which distinguish liaison from non-liaison consonants, and in part on the availability of lexical support for a liaison interpretation.

Abstract

Three experiments tested young children's efficiency in recognizing words in speech referring to absent objects. Seventy-two 24-month-olds heard sentences containing target words denoting objects that were or were not present in a visual display. Children's eye movements were monitored as they heard the sentences. Three distinct patterns of response were shown. Children hearing a familiar word that was an appropriate label for the currently fixated picture maintained their gaze. Children hearing a familiar word that could not apply to the currently fixated picture rapidly shifted their gaze to the alternative picture, whether that alternative was the named target or not, and then continued to search for an appropriate referent. Finally, children hearing an unfamiliar word shifted their gaze slowly and irregularly. This set of outcomes is interpreted as evidence that by 24 months, rapid activation in word recognition does not depend on the presence of the words' referents. Rather, very young children are capable of quickly and efficiently interpreting words in the absence of visual supporting context.

Abstract

The degree to which infants represent phonetic detail in words has been a source of controversy in phonology and developmental psychology. One prominent hypothesis holds that infants store words in a vague or inaccurate form until the learning of similar–sounding neighbors forces attention to subtle phonetic distinctions. In the experiment reported here, we used a visual fixation task to assess word recognition. We present the first evidence indicating that, in fact, the lexical representations of 14– and 15–month–olds are encoded in fine detail, even when this detail is not functionally necessary for distinguishing similar words in the infant’s vocabulary. Exposure to words is sufficient for well–specified lexical representations, even well before the vocabulary spurt. These results suggest developmental continuity in infants’ representations of speech: As infants begin to build a vocabulary and learn word meanings, they use the perceptual abilities previously demonstrated in tasks testing the discrimination and categorization of meaningless syllables.

Abstract

Although children's knowledge of the sound patterns of words has been a focus of debate for many years, little is known about the lexical representations very young children use in word recognition. In particular, researchers have questioned the degree of specificity encoded in early lexical representations. The current study addressed this issue by presenting 18–23-month-olds with object labels that were either correctly pronounced, or mispronounced. Mispronunciations involved replacement of one segment with a similar segment, as in ‘baby–vaby’. Children heard sentences containing these words while viewing two pictures, one of which was the referent of the sentence. Analyses of children's eye movements showed that children recognized the spoken words in both conditions, but that recognition was significantly poorer when words were mispronounced. The effects of mispronunciation on recognition were unrelated to age or to spoken vocabulary size. The results suggest that children's representations of familiar words are phonetically well-specified, and that this specification may not be a consequence of the need to differentiate similar words in production.

Abstract

A growing number of researchers in the sentence processing community are using eye movements to address issues in spoken language comprehension. Experiments using this paradigm have shown that visually presented referential information, including properties of referents relevant to specific actions, influences even the earliest moments of syntactic processing. Methodological concerns about task-specific strategies and the linking hypothesis between eye movements and linguistic processing are identified and discussed. These concerns are addressed in a review of recent studies of spoken word recognition which introduce and evaluate a detailed linking hypothesis between eye movements and lexical access. The results provide evidence about the time course of lexical activation that resolves some important theoretical issues in spoken-word recognition. They also demonstrate that fixations are sensitive to properties of the normal language-processing system that cannot be attributed to task-specific strategies

Abstract

This paper presents electrophysiological evidence of an impairment in the on-line processing of word class information in patients with Broca’s aphasia with agrammatic comprehension. Event-related brain potentials (ERPs) were recorded from the scalp while Broca patients and non-aphasic control subjects read open- and closed-class words that appeared one at a time on a PC screen. Separate waveforms were computed for open- and closed-class words. The non-aphasic control subjects showed a modulation of an early left anterior negativity in the 210–325 ms as a function of vocabulary class (VC), and a late left anterior negative shift to closed-class words in the 400–700 ms epoch. An N400 effect was present in both control subjects and Broca patients. We have taken the early electrophysiological differences to reflect the first availability of word-category information from the mental lexicon. The late differences can be related to post-lexical processing. In contrast to the control subjects, the Broca patients showed no early VC effect and no late anterior shift to closed-class words. The results support the view that an incomplete and/or delayed availability of word-class information might be an important factor in Broca’s agrammatic comprehension.

Abstract

The existence of nominal classification systems has long been thought of as one of the defining features of the Papuan languages of island New Guinea. However, while almost all of these languages do have nominal classification systems, they are, in fact, extremely divergent from each other. This paper examines these systems in the East Papuan languages in order to examine the question of the relationship between these Papuan outliers. Nominal classification systems are often archaic, preserving older features lost elsewhere in a language. Also, evidence shows that they are not easily borrowed into languages (although they can be). For these reasons, it is useful to consider nominal classification systems as a tool for exploring ancient historical relationships between languages. This paper finds little evidence of relationship between the nominal classification systems of the East Papuan languages as a whole. It argues that the mere existence of nominal classification systems cannot be used as evidence that the East Papuan languages form a genetic family. The simplest hypothesis is that either the systems were inherited so long ago as to obscure the genetic evidence, or else the appearance of nominal classification systems in these languages arose through borrowing of grammatical systems rather than of morphological forms.

Abstract

This paper explores the issue of documenting an endangered language from the perspective of a community with low levels of literacy, I first discuss the background of the language community with whom I work, the Lavukal people of Solomon Islands, and discuss whether, and to what extent, Lavukaleve is an endangered language. I then go on to discuss the documentation project. My main point is that while low literacy levels and a nonreading culture would seem to make documentation a strange choice as a tool for language maintenance, in fact both serve as powerful cultural symbols of the importance and prestige of Lavukaleve. It is well known that a common reason for language death is that speakers choose not to transmit their language to the next generation (e.g. Winter 1993). Lavukaleve is particularly vulnerable in this respect. By utilizing cultural symbols of status and prestige, the standing of Lavukaleve can be enhanced, thus helping to ensure the transmission of Lavukaleve to future generations.

Abstract

This study investigated different accounts of early argument structure acquisition and verb paradigm building through the detailed examination of the acquisition of the verb Go. Data from 11 children followed longitudinally between the ages of 2;0 and 3;0 were examined. Children's uses of the different forms of Go were compared with respect to syntactic structure and the semantics encoded. The data are compatible with the suggestion that the children were not operating with a single verb representation that differentiated between different forms of Go but rather that their knowledge of the relationship between the different forms of Go varied depending on the structure produced and the meaning encoded. However, a good predictor of the children's use of different forms of Go in particular structures and to express particular meanings was the frequency of use of those structures and meanings with particular forms of Go in the input. The implications of these findings for theories of syntactic category formation and abstract rule-based descriptions of grammar are discussed.

Abstract

This paper presents a cognitive theory on the production and shaping of selfrepairs during speaking. In an extensive experimental study, a new technique is tried out: artificial elicitation of self-repairs. The data clearly indicate that two mechanisms for computing the shape of self-repairs should be distinguished. One is based on the repair strategy called reformulation, the second one on lemma substitution. W. Levelt’s (1983, Cognition, 14, 41- 104) well-formedness rule, which connects self-repairs to coordinate structures, is shown to apply only to reformulations. In case of lemma substitution, a totally different set of rules is at work. The linguistic unit of central importance in reformulations is the major syntactic constituent; in lemma substitutions it is a prosodic unit. the phonological phrase. A parametrization of the model yielded a very satisfactory fit between observed and reconstructed scores.

Abstract

Computer simulations in an instructional context can be characterized according to four aspects (themes): simulation models, learning goals, learning processes and learner activity. The present paper provides an outline of these four themes. The main classification criterion for simulation models is quantitative vs. qualitative models. For quantitative models a further subdivision can be made by classifying the independent and dependent variables as continuous or discrete. A second criterion is whether one of the independent variables is time, thus distinguishing dynamic and static models. Qualitative models on the other hand use propositions about non-quantitative properties of a system or they describe quantitative aspects in a qualitative way. Related to the underlying model is the interaction with it. When this interaction has a normative counterpart in the real world we call it a procedure. The second theme of learning with computer simulation concerns learning goals. A learning goal is principally classified along three dimensions, which specify different aspects of the knowledge involved. The first dimension, knowledge category, indicates that a learning goal can address principles, concepts and/or facts (conceptual knowledge) or procedures (performance sequences). The second dimension, knowledge representation, captures the fact that knowledge can be represented in a more declarative (articulate, explicit), or in a more compiled (implicit) format, each one having its own advantages and drawbacks. The third dimension, knowledge scope, involves the learning goal's relation with the simulation domain; knowledge can be specific to a particular domain, or generalizable over classes of domains (generic). A more or less separate type of learning goal refers to knowledge acquisition skills that are pertinent to learning in an exploratory environment. Learning processes constitute the third theme. Learning processes are defined as cognitive actions of the learner. Learning processes can be classified using a multilevel scheme. The first (highest) of these levels gives four main categories: orientation, hypothesis generation, testing and evaluation. Examples of more specific processes are model exploration and output interpretation. The fourth theme of learning with computer simulations is learner activity. Learner activity is defined as the ‘physical’ interaction of the learner with the simulations (as opposed to the mental interaction that was described in the learning processes). Five main categories of learner activity are distinguished: defining experimental settings (variables, parameters etc.), interaction process choices (deciding a next step), collecting data, choice of data presentation and metacontrol over the simulation.

Abstract

The use of computer simulations in education and training can have substantial advantages over other approaches. In comparison with alternatives such as textbooks, lectures, and tutorial courseware, a simulation-based approach offers the opportunity to learn in a relatively realistic problem-solving context, to practise task performance without stress, to systematically explore both realistic and hypothetical situations, to change the time-scale of events, and to interact with simplified versions of the process or system being simulated. However, learners are often unable to cope with the freedom offered by, and the complexity of, a simulation. As a result many of them resort to an unsystematic, unproductive mode of exploration. There is evidence that simulation-based learning can be improved if the learner is supported while working with the simulation. Constructing such an instructional environment around simulations seems to run counter to the freedom the learner is allowed to in ‘stand alone’ simulations. The present article explores instructional measures that allow for an optimal freedom for the learner. An extensive discussion of learning goals brings two main types of learning goals to the fore: conceptual knowledge and operational knowledge. A third type of learning goal refers to the knowledge acquisition (exploratory learning) process. Cognitive theory has implications for the design of instructional environments around simulations. Most of these implications are quite general, but they can also be related to the three types of learning goals. For conceptual knowledge the sequence and choice of models and problems is important, as is providing the learner with explanations and minimization of error. For operational knowledge cognitive theory recommends learning to take place in a problem solving context, the explicit tracing of the behaviour of the learner, providing immediate feedback and minimization of working memory load. For knowledge acquisition goals, it is recommended that the tutor takes the role of a model and coach, and that learning takes place together with a companion. A second source of inspiration for designing instructional environments can be found in Instructional Design Theories. Reviewing these shows that interacting with a simulation can be a part of a more comprehensive instructional strategy, in which for example also prerequisite knowledge is taught. Moreover, information present in a simulation can also be represented in a more structural or static way and these two forms of presentation provoked to perform specific learning processes and learner activities by tutor controlled variations in the simulation, and by tutor initiated prodding techniques. And finally, instructional design theories showed that complex models and procedures can be taught by starting with central and simple elements of these models and procedures and subsequently presenting more complex models and procedures. Most of the recent simulation-based intelligent tutoring systems involve troubleshooting of complex technical systems. Learners are supposed to acquire knowledge of particular system principles, of troubleshooting procedures, or of both. Commonly encountered instructional features include (a) the sequencing of increasingly complex problems to be solved, (b) the availability of a range of help information on request, (c) the presence of an expert troubleshooting module which can step in to provide criticism on learner performance, hints on the problem nature, or suggestions on how to proceed, (d) the option of having the expert module demonstrate optimal performance afterwards, and (e) the use of different ways of depicting the simulated system. A selection of findings is summarized by placing them under the four themes we think to be characteristic of learning with computer simulations (see de Jong, this volume).

Abstract

This paper addresses the question of whether noun incorporation is a syntactically base-generated or a syntactically derived construction. Focusing on so-called 'raised possessors' in West Greenlandic noun incorporating constructions and presenting some new data, I discuss some problems that arise if we use the derivational framework of Bittner and Hale (1996) to analyze them. I show that if we make the predication relations in noun incorporating constructions overt in their syntax and if we adopt a dynamic approach to semantics, a base-generated syntactic input enriched with a coindexation system is all that we need to arrive at an adequate semantic interpretation of these constructions.

Abstract

Based on the results of an event-related brain potentials (ERP) experiment (van Berkum, Brown, & Hagoort. 1999a, b), we have recently argued that discourse-level referential context can be taken into account extremely rapidly by the parser. Moreover, our ERP results indicated that local grammatical gender information, although available within a few hundred milliseconds from word onset, is not always used quickly enough to prevent the parser from considering a discourse-supported, but agreement-violating, syntactic analysis. In a comment on our work, Brysbaert and Mitchell (2000) have raised concerns about the methodology of our ERP experiment and have challenged our interpretation of the results. In this reply, we argue that these concerns are unwarranted and, that, in contrast to our own interpretation, the alternative explanations provided by Brysbaert and Mitchell do not account for the full pattern of ERP results.

Abstract

Three experiments investigated semantic and syntactic effects in the production of phrases in Dutch. Bilingual participants were presented with English nouns and were asked to produce an adjective + noun phrase in Dutch including the translation of the noun. In 2 experiments, the authors blocked items by either semantic category or grammatical gender. Participants performed the task slower when the target nouns were of the same semantic category than when they were from different categories and faster when the target nouns had the same gender than when they had different genders. In a final experiment, both manipulations were crossed. The authors replicated the results of the first 2 experiments, and no interaction was found. These findings suggest a feedforward flow of activation between lexico-semantic and lexico-syntactic information.

Abstract

Graded interference effects were tested in a naming task, in parallel for objects and actions. Participants named either object or action pictures presented in the context of other pictures (blocks) that were either semantically very similar, or somewhat semantically similar or semantically dissimilar. We found that naming latencies for both object and action words were modulated by the semantic similarity between the exemplars in each block, providing evidence in both domains of graded semantic effects.

Abstract

We present the design, implementation and simulation results of a psycholinguistic model of human syntactic processing that meets major empirical criteria. The parser operates in conjunction with a lexicalist grammar and is driven by syntactic information associated with heads of phrases. The dynamics of the model are based on competition by lateral inhibition ('competitive inhibition'). Input words activate lexical frames (i.e. elementary trees anchored to input words) in the mental lexicon, and a network of candidate 'unification links' is set up between frame nodes. These links represent tentative attachments that are graded rather than all-or-none. Candidate links that, due to grammatical or 'treehood' constraints, are incompatible, compete for inclusion in the final syntactic tree by sending each other inhibitory signals that reduce the competitor's attachment strength. The outcome of these local and simultaneous competitions is controlled by dynamic parameters, in particular by the Entry Activation and the Activation Decay rate of syntactic nodes, and by the Strength and Strength Build-up rate of Unification links. In case of a successful parse, a single syntactic tree is returned that covers the whole input string and consists of lexical frames connected by winning Unification links. Simulations are reported of a significant range of psycholinguistic parsing phenomena in both normal and aphasic speakers of English: (i) various effects of linguistic complexity (single versus double, center versus right-hand self-embeddings of relative clauses; the difference between relative clauses with subject and object extraction; the contrast between a complement clause embedded within a relative clause versus a relative clause embedded within a complement clause); (ii) effects of local and global ambiguity, and of word-class and syntactic ambiguity (including recency and length effects); (iii) certain difficulty-of-reanalysis effects (contrasts between local ambiguities that are easy to resolve versus ones that lead to serious garden-path effects); (iv) effects of agrammatism on parsing performance, in particular the performance of various groups of aphasic patients on several sentence types.

Abstract

Previous studies have shown that spoken-language processing is inhibited by violation of obligatory regressive assimilation. Weber (2001) replicated this inhibitory effect in a phoneme-monitoring study examining regressive place assimilation of nasals, but found facilitation for violation of progressive assimilation. German listeners detected the velar fricative [x] more quickly when fricative assimilation was violated (e.g., *[bIxt] or *[blInx@n]) than when no violation occurred (e.g., [baxt] or [blu:x@n]). It was argued that a combination of two factors caused facilitation:(1) progressive assimilation creates different restrictions for the monitoring target than regressive assimilation does, and (2) the sequences violating assimilation (e.g., *[Ix]) are novel for German listeners and therefore facilitate fricative detection (novel popout). The present study tested progressive assimilation violation in non-novel sequences using the palatal fricative [C]. Stimuli either violated fricative assimilation (e.g., *[ba:C@l ]) or did not (e.g., [bi: C@l ]). This manipulation does not create novel sequences: sequences like *[a:C] can occur across word boundaries, while *[Ix] cannot. No facilitation was found. However, violation also did not significantly inhibit processing. The results confirm that facilitation depends on the combination of progressive assimilation with novelty of the sequence.

Abstract

Dichoptic mixtures of equiluminous components of different wavelengths were matched with a binocularly presented "monocular" mixture of appropriate chosen amounts of the same colour components. Stimuli were chosen from the region of 490-630 nm. Although satisfactory colour matches could be obtained, dichoptic mixtures differed from normal mixtures to a considerable extent. Midspectral stimuli tended to be more dominant in the dichoptic mixtures than either short or long wavelength stimuli. An attempt was made to describe the relation between monocular and dichoptic mixtures with one function containing a wavelength variable and an eye dominance parameter.