Publications

Abstract

In this paper we investigate acoustic differences between vowels in syllables that do or do not carry lexical stress. In doing so, we concentrated on segmental acoustic phonetic features that are conventionally assumed to differ between stressed and unstressed syllables, viz. Duration, Energy and Spectral Tilt. The speech material in this study differs from the type of material used in previous research: instead of specially constructed sentences we used phonetically rich sentences from the Dutch POLYPHONE corpus. Most of the Duration, Energy and Spectral Tilt features that we used in the investigation show statistically significant differences for the population means of stressed and unstressed vowels. However, it also appears that the distributions overlap to such an extent that automatic detection of stressed and unstressed syllables yields correct classifications of 72.6% at best. It is argued that this result is due to the large variety in the ways in which the abstract linguistic feature `lexical stress' is realized in the acoustic speech signal. Our findings suggest that a lexical stress detector has little use for a single pass decoder in an automatic speech recognition (ASR) system, but could still play a useful role as an additional knowledge source in a multi-pass decoder.

Abstract

An event-related brain potentials experiment was carried out to examine the interplay of referential and structural factors during sentence processing in discourse. Subjects read (Dutch) sentences beginning like “David told the girl that … ” in short story contexts that had introduced either one or two referents for a critical singular noun phrase (“the girl”). The waveforms showed that within 280 ms after onset of the critical noun the reader had already determined whether the noun phrase had a unique referent in earlier discourse. Furthermore, this referential information was immediately used in parsing the rest of the sentence, which was briefly ambiguous between a complement clause (“ … that there would be some visitors”) and a relative clause (“ … that had been on the phone to hang up”). A consistent pattern of P600/SPS effects elicited by various subsequent disambiguations revealed that a two-referent discourse context had led the parser to initially pursue the relative-clause alternative to a larger extent than a one-referent context. Together, the results suggest that during the processing of sentences in discourse, structural and referential sources of information interact on a word-by-word basis.

Abstract

An event-related brain potential experiment was carried out to investigate the time course of contextual influences on spoken-word recognition. Subjects were presented with spoken sentences that ended with a word that was either (a) congruent, (b) semantically anomalous, but beginning with the same initial phonemes as the congruent completion, or (c) semantically anomalous beginning with phonemes that differed from the congruent completion. In addition to finding an N400 effect in the two semantically anomalous conditions, we obtained an early negative effect in the semantically anomalous condition where word onset differed from that of the congruent completions. It was concluded that the N200 effect is related to the lexical selection process, where word-form information resulting from an initial phonological analysis and content information derived from the context interact.

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

Earlier research has established that speakers usually fixate the objects they name and that the viewing time for an object depends on the time necessary for object recognition and for the retrieval of its name. In three experiments, speakers produced pronouns and noun phrases to refer to new objects and to objects already known. Speakers looked less frequently and for shorter periods at the objects to be named when they had very recently seen or heard of these objects than when the objects were new. Looking rates were higher and viewing times longer in preparation of noun phrases than in preparation of pronouns. If it is assumed that there is a close relationship between eye gaze and visual attention, these results reveal (1) that speakers allocate less visual attention to given objects than to new ones and (2) that they allocate visual attention both less often and for shorter periods to objects they will refer to by a pronoun than to objects they will name in a full noun phrase. The experiments suggest that linguistic processing benefits, directly or indirectly, from allocation of visual attention to the referent object.

Abstract

We report a series of experiments examining the effects on word processing of insertion of an optional epenthetic vowel in word-final consonant clusters in Dutch. Such epenthesis turns film, for instance, into film. In a word-reversal task listeners treated words with and without epenthesis alike, as monosyllables, suggesting that the variant forms both activate the same canonical representation, that of a monosyllabic word without epenthesis. In both lexical decision and word spotting, response times to recognize words were significantly faster when epenthesis was present than when the word was presented in its canonical form without epenthesis. It is argued that addition of the epenthetic vowel makes the liquid consonants constituting the first member of a cluster more perceptible; a final phoneme-detection experiment confirmed that this was the case. These findings show that a transformed variant of a word, although it contacts the lexicon via the representation of the canonical form, can be more easily perceptible than that canonical form.

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

As a preliminary to further research on musical consonance an explanatory investigation was made on the different modes of judgment of musical intervals. This was done by way of a semantic differential. Subjects rated 23 intervals against 10 scales. In a factor analysis three factors appeared: pitch, evaluation and fusion. The relation between these factors and some physical characteristics has been investigated. The scale consonant-dissonant showed to be purely evaluative (in opposition to Stumpf's theory). This evaluative connotation is not in accordance with the musicological meaning of consonance. Suggestions to account for this difference have been given.

Abstract

In two ERP experiments we investigated how and when the language comprehension system relates an incoming word to semantic representations of an unfolding local sentence and a wider discourse. In experiment 1, subjects were presented with short stories. The last sentence of these stories occasionally contained a critical word that, although acceptable in the local sentence context, was semantically anomalous with respect to the wider discourse (e.g., "Jane told the brother that he was exceptionally slow" in a discourse context where he had in fact been very quick). Relative to coherent control words (e.g., "quick"), these discourse-dependent semantic anomalies elicited a large N400 effect that began at about 200-250 ms after word onset. In experiment 2, the same sentences were presented without their original story context. Although the words that had previously been anomalous in discourse still elicited a slightly larger average N400 than the coherent words, the resulting N400 effect was much reduced, showing that the large effect observed in stories was related to the wider discourse. In the same experiment, single sentences that contained a clear local semantic anomaly elicited a standard sentence-dependent N400 effect (e.g., Kutas & Hillyard, 1980). The N400 effects elicited in discourse and in single sentences had the same time course, overall morphology, and scalp distribution. We argue that these findings are most compatible with models of language processing in which there is no fundamental distinction between the integration of a word in its local (sentence-level) and its global (discourse-level) semantic context.

Abstract

We review the implications of recent ERP evidence for when and how grammatical gender agreement constrains sentence parsing. In some theories of parsing, gender is assumed to immediately and categorically block gender-incongruent phrase structure alternatives from being pursued. In other theories, the parser initially ignores gender altogether. The ERP evidence we discuss suggests an intermediate position, in which grammatical gender does not immediately block gender-incongruent phrase structures from being considered, but is used to dispose of them shortly thereafter.

Abstract

Motor-related brain potentials were used to examine the time course of grammatical and phonological processes during noun phrase production in Dutch. In the experiments, participants named colored pictures using a no-determiner noun phrase. On half of the trials a syntactic-phonological classification task had to be performed before naming. Depending on the outcome of the classifications, a left or a right push-button response was given (go trials), or no push-button response was given (no-go trials). Lateralized readiness potentials (LRPs) were derived to test whether syntactic and phonological information affected the motor system at separate moments in time. The results showed that when syntactic information determined the response-hand decision, an LRP developed on no-go trials. However, no such effect was observed when phonological information determined response hand. On the basis of the data, it can be estimated that an additional period of at least 40 ms is needed to retrieve a word's initial phoneme once its lemma has been retrieved. These results provide evidence for the view that during speaking, grammatical processing precedes phonological processing in time.

Abstract

Sentential context effects on the identification of the Dutch function words te (to) and de (the) were examined. In Experiment 1, listeners labeled words on a [tә]-[dә] continuum more often as te when the context was te biased (Ik probeer [?ә] schieten [I try to/the shoot]) than when it was de biased (Ik probeer [?ә] schoenen [I try to/the shoes]). The effect was weaker in slower responses. In Experiment 2, disambiguation began later, in the second word after [?ә]. There was a weak context effect only in the slower responses. In Experiments 3 and 4, disambiguation occurred on the word before [?ә]: There was no context effect when one set of sentences was used, but there was an effect (larger in the faster responses) when more sentences were used. Syntactic processing affects word identification only within a limited time frame. It appears to do so not by influencing lexical access processes through feedback but, instead, by biasing decision making.

Abstract

In processing connected speech, listeners must parse a highly variable signal. We investigate processing of a particular type of production variability, namely epenthetic stops between nasals and obstruents. Using a phoneme monitoring task and a dictation task, we test listeners' perception of epenthetic stops (which are not part of the string of segments intended by the speaker). We confirm that the epenthetic stop perceived is the one predicted by articulatory accounts of how such stops are produced, and that the likelihood of an epenthetic stop being perceived as a real stop is related to the strength of acoustic cues in the signal. We show that the probability of listeners mis-parsing epenthetic stops as real is influenced by language-specific syllable structure constraints, and depends on processing demands. We further show, through reaction time data, that even when epenthetic stops are perceived, they impose a greater processing load than stops which were intended by the speaker. These results show that processing of phonetic variability is affected by several factors, including language-specific phonology, even though the mis-timing of articulations that creates epenthetic stops is universally possible.

Abstract

In this paper, we use articulatory measures to determine whether Dutch schwa epenthesis is an abstract phonological process or a concrete phonetic process depending on articulatory timing. We examine tongue position during /l/ before underlying schwa and epenthetic schwa and in coda position. We find greater tip raising before both types of schwa, indicating light /l/ before schwa and dark /l/ in coda position. We argue that the ability of epenthetic schwa to condition the /l/ alternation shows that Dutch schwa epenthesis is an abstract phonological process involving insertion of some unit, and cannot be accounted for within Articulatory Phonology.

Abstract

This study investigates whether the mora is used in controlling timing in Japanese speech, or is instead a structural unit in the language not involved in timing. Unlike most previous studies of mora-timing in Japanese, this article investigates timing in spontaneous speech. Predictability of word duration from number of moras is found to be much weaker than in careful speech. Furthermore, the number of moras predicts word duration only slightly better than number of segments. Syllable structure also has a significant effect on word duration. Finally, comparison of the predictability of whole words and arbitrarily truncated words shows better predictability for truncated words, which would not be possible if the truncated portion were compensating for remaining moras. The results support an accumulative model of variance with a final lengthening effect, and do not indicate the presence of any compensation related to mora-timing. It is suggested that the rhythm of Japanese derives from several factors about the structure of the language, not from durational compensation.

Abstract

Four phoneme-detection studies tested the conclusion from recent research that spoken-language processing is inhibited by violation of obligatory assimilation processes in the listeners’ native language. In Experiment 1, native listeners of German detected a target fricative in monosyllabic Dutch nonwords, half of which violated progressive German fricative place assimilation. In contrast to the earlier findings, listeners detected the fricative more quickly when assimilation was violated than when no violation occurred. This difference was not due to purely acoustic factors, since in Experiment 2 native Dutch listeners, presented with the same materials, showed no such effect. In Experiment 3, German listeners again detected the fricative more quickly when violation occurred in both monosyllabic and bisyllabic native nonwords, further ruling out explanations based on non-native input or on syllable structure. Finally Experiment 4 tested whether the direction in which the rule operates (progressive or regressive) controls the direction of the effect on phoneme detection responses.When regressive German place assimilation for nasals was violated, German listeners detected stops more slowly, exactly as had been observed in previous studies of regressive assimilation. It is argued that a combination of low expectations in progressive assimilation and novel popout causes facilitation of processing,whereas not fulfilling high expectations in regressive assimilation causes inhibition.

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.

Abstract

A combination of Southern blot analysis on a panel of tumor-derived somatic cell hybrids and fluorescence in situ hybridization techniques was used to map YACs, cosmids and DNA markers from the Xp11.2 region relative to the X chromosome breakpoint of the renal cell carcinoma-associated t(X;1)(p11;q21). The position of the breakpoint could be determined as follows: Xcen-OATL2-DXS146-DXS255-SYP-t(X;1)-TFE 3-OATL1-Xpter. Fluorescence in situ hybridization experiments using TFE3-containing YACs and cosmids revealed split signals indicating that the corresponding DNA inserts span the breakpoint region. Subsequent Southern blot analysis showed that a 2.3-kb EcoRI fragment which is present in all TFE3 cosmids identified, hybridizes to aberrant restriction fragments in three independent t(X;1)-positive renal cell carcinoma DNAs. The breakpoints in these tumors are not the same, but map within a region of approximately 6.5 kb. Through preparative gel electrophoresis an (X;1) chimaeric 4.4-kb EcoRI fragment could be isolated which encompasses the breakpoint region present on der(X). Preliminary characterization of this fragment revealed the presence of a 150-bp region with a strong homology to the 5' end of the mouse TFE3 cDNA in the X-chromosome part, and a 48-bp segment in the chromosome 1-derived part identical to the 5' end of a known EST (accession number R93849). These observations suggest that a fusion gene is formed between the two corresponding genes in t(X;1)(p11;q21)-positive papillary renal cell carcinomas.

Abstract

Three experiments examined the time course of phonological encoding in speech production. A new methodology is introduced in which subjects are required to monitor their internal speech production for prespecified target segments and syllables. Experiment 1 demonstrated that word initial target segments are monitored significantly faster than second syllable initial target segments. The addition of a concurrent articulation task (Experiment 1b) had a limited effect on performance, excluding the possibility that subjects are monitoring a subvocal articulation of the carrier word. Moreover, no relationship was observed between the pattern of monitoring latencies and the timing of the targets in subjects′ overt speech. Subjects are not, therefore, monitoring an internal phonetic representation of the carrier word. Experiment 2 used the production monitoring task to replicate the syllable monitoring effect observed in speech perception experiments: responses to targets were faster when they corresponded to the initial syllable of the carrier word than when they did not. We conclude that subjects are monitoring their internal generation of a syllabified phonological representation. Experiment 3 provides more detailed evidence concerning the time course of the generation of this representation by comparing monitoring latencies to targets within, as well as between, syllables. Some amendments to current models of phonological encoding are suggested in light of these results.

Abstract

The purpose of this paper is to question some of the basic assumpiions concerning motion verbs. In particular, it examines the assumption that "come" and "go" are lexical universals which manifest a universal deictic Opposition. Against the background offive working hypotheses about the nature of'come" and ''go", this study presents a comparative investigation of t wo unrelated languages—Mparntwe Arrernte (Pama-Nyungan, Australian) and Longgu (Oceanic, Austronesian). Although the pragmatic and deictic "suppositional" complexity of"come" and "go" expressions has long been recognized, we argue that in any given language the analysis of these expressions is much more semantically and systemically complex than has been assumed in the literature. Languages vary at the lexical semantic level äs t o what is entailed by these expressions, äs well äs differing äs t o what constitutes the prototype and categorial structure for such expressions. The data also strongly suggest that, ifthere is a lexical universal "go", then this cannof be an inherently deictic expression. However, due to systemic Opposition with "come", non-deictic "go" expressions often take on a deictic Interpretation through pragmatic attribution. Thus, this crosslinguistic investigation of "come" and "go" highlights the need to consider semantics and pragmatics äs modularly separate.

Abstract

The three Olutec stories from Oluta, Veracruz, werenarrated by Antonio Asistente Maldonado. Roberto Zavala presents amorpheme-by-morpheme analysis of the texts with a sketch of the majorgrammatical and typological features of this language. Olutec is spoken bythree dozen speakers. The grammatical structure of this language has not beendescribed before. The sketch contains information on verb and noun morphology,verb dasses, clause types, inverse/direct patterns, grammaticalizationprocesses, applicatives, incorporation, word order type, and discontinuousexpressions. The stories presented here are the first Olutec texts everpublished. The motifs of the stories are well known throughout Middle America.The story of "the Rabbit who wants to be big" explains why one of the mainprotagonists of Middle American folktales acquired long ears. The story of "theDevil who is inebriated by the people of a village" explains how theinhabitants of a village discover the true identity of a man who likes to dancehuapango and decide to get rid of him. Finally the story of "theshit-sellers" presents two compadres, one who is lazy and the otherone who works hard. The hard-worker asks the lazy compadre how he surviveswithout working. The latter lies to to him that he sells shit in theneighboring village. The hard-working compadre decides to become a shit-sellerand in the process realizes that the lazy compadre deceived him. However, he islucky and meets with the Devil who offers him money in compensation for havingbeen deceived. When the lazy compadre realizes that the hard-working compadrehas become rich, he tries to do the same business but gets beaten in theprocess.