Publications

Abstract

The first, theoretical part of this paper sketches a framework for phonological encoding in which the speaker successively generates phonological syllables in connected speech. The final stage of this process, phonetic encoding, consists of accessing articulatory gestural scores for each of these syllables in a "mental syllabary". The second, experimental part studies various predictions derived from this theory. The main finding is a syllable frequency effect: words ending in a high-frequent syllable are named faster than words ending in a low-frequent syllable. As predicted, this syllable frequency effect is independent of and additive to the effect of word frequency on naming latency. The effect, moreover, is not due to the complexity of the word-final syllable. In the General Discussion, the syllabary model is further elaborated with respect to phonological underspecification and activation spreading. Alternative accounts of the empirical findings in terms of core syllables and demisyllables are considered.

Abstract

In this article, we present an account of developmental data regarding the acquisition of syllable types. The data come from a longitudinal corpus of phonetically transcribed speech of 12 children acquiring Dutch as their first language. A developmental order of acquisition of syllable types was deduced by aligning the syllabified data on a Guttman scale. This order could be analyzed as following from an initial ranking and subsequent rerankings in the grammar of the structural constraints ONSET, NO-CODA, *COMPLEX-O, and *COMPLEX-C; some local conjunctions of these constraints; and a faithfulness constraint FAITH. The syllable type frequencies in the speech surrounding the language learner are also considered. An interesting correlation is found between the frequencies and the order of development of the different syllable types.

Abstract

A core operation in speech production is the preparation of words from a semantic base. The theory of lexical access reviewed in this article covers a sequence of processing stages beginning with the speaker’s focusing on a target concept and ending with the initiation of articulation. The initial stages of preparation are concerned with lexical selection, which is zooming in on the appropriate lexical item in the mental lexicon. The following stages concern form encoding, i.e., retrieving a word’s morphemic phonological codes, syllabifying the word, and accessing the corresponding articulatory gestures. The theory is based on chronometric measurements of spoken word production, obtained, for instance, in picture-naming tasks. The theory is largely computationally implemented. It provides a handle on the analysis of multiword utterance production as well as a guide to the analysis and design of neuroimaging studies of spoken utterance production.

Abstract

Recent work on sentence recognition suggests that listeners use their knowledge of the language to directly infer deep structure syntactic relations from surface structure markers. Suffixes may be such clues, especially in agglutinative languages. A cross-language (Dutch-Finnish) experiment is reported, designed to investigate whether the suffix structure of Finnish words (as opposed to suffixless Dutch words) can facilitate prompted recall of sentences in case these suffixes differentiate between possible deep structures. The experiment, in which 80 subjects recall sentences at the occasion of prompt words, gives only slight confirmatory evidence. Meanwhile, another prompted recall effect (Blumenthal's) could not be replicated.

Abstract

It is quite normal for us to produce one or two million word tokens every year. Speaking is a dear occupation and producing words is at the core of it. Still, producing even a single word is a highly complex affair. Recently, Levelt, Roelofs, and Meyer (1999) reviewed their theory of lexical access in speech production, which dissects the word-producing mechanism as a staged application of various dedicated operations. The present paper begins by presenting a bird eye's view of this mechanism. We then square the complexity by asking how speakers control multiple access in generating simple utterances such as a table and a chair. In particular, we address two issues. The first one concerns dependency: Do temporally contiguous access procedures interact in any way, or do they run in modular fashion? The second issue concerns temporal alignment: How much temporal overlap of processing does the system tolerate in accessing multiple content words, such as table and chair? Results from picture-word interference and eye tracking experiments provide evidence for restricted cases of dependency as well as for constraints on the temporal alignment of access procedures.

Abstract

How do languages express ideas of movement, and how do they package different components of this domain, such as manner and path of motion? This task uses one large set of stimuli to gain knowledge of certain key aspects of motion verb meanings in the target language, and expands the investigation beyond simple verbs (e.g., go) to include the semantics of motion predications complete with adjuncts (e.g., go across something). Consultants are asked to view and briefly describe 96 animations of a few seconds each. The task is designed to get linguistic elicitations of motion predications under contrastive comparison with other animations in the same set. Unlike earlier tasks, the stimuli focus on inanimate moving items or “figures” (in this case, a ball).

Abstract

Demonstratives (e.g., words such as this and that in English) pivot on relationships between the item being talked about, and features of the speech act situation (e.g., where the speaker and addressee are standing or looking). However, they are only rarely investigated multi-modally, in natural language contexts. This task is designed to build a video corpus of cross-linguistically comparable discourse data for the study of “deixis in action”, while simultaneously supporting the investigation of joint attention as a factor in speaker selection of demonstratives. In the task, two or more speakers are asked to discuss and evaluate a group of similar items (e.g., examples of local handicrafts, tools, produce) that are placed within a relatively defined space (e.g., on a table). The task can additionally provide material for comparison of pointing gesture practices.

Abstract

This entry contains: 1. An invitation to think about to what extent the grammar of space and time share lexical and morphosyntactic resources − the suggestions here are only prompts, since it would take a long questionnaire to fully explore this; 2. A suggestion about how to collect gestural data that might show us to what extent the spatial and temporal domains, have a psychological continuity. This is really the goal − but you need to do the linguistic work first or in addition. The goal of this task is to explore the extent to which time is conceptualised on a spatial basis.

Abstract

This paper confronts Kant’s (1768) view of human conceptions of space as fundamentally divided along the three planes of the human body with an empirical case study in the Mayan community of Tenejapa in southern Mexico, whose inhabitants do not use left/right distinctions to project regions in space. Tenejapans have names for the left hand and the right hand, and also a term for hand/arm in general, but they do not generalize the distinction to spatial regions -- there is no linguistic expression glossing as 'to the left' or 'on the left-hand side', for example. Tenejapans also show a remarkable indifference to incongruous counterparts. Nor is there any system of value associations with the left and the right. The Tenejapan evidence that speaks to these Kantian themes points in two directions: (a) Kant was wrong to think that the structure of spatial regions founded on the human frame, and in particular the distinctions based on left and right, are in some sense essential human intuitions; (b) Kant may have been right to think that the left/right opposition, the perception of enantiomorphs, clockwiseness, East-West dichotomies, etc., are intimately connected to an overall system of spatial conception.

Abstract

The ECHO proposal aims to bring to life the cultural heritage of Europe, through internet technology that encourages collaboration across the Humanities disciplines which interpret it – at the same time making all this scholarship accessible to the citizens of Europe. An essential part of the cultural heritage of Europe is the diverse set of languages used on the continent, in their historical, literary and spoken forms. Amongst these are the ‘hidden languages’ used by minorities but of wide interest to the general public. We take the 18 Sign Languages of the EEC – the natural languages of the deaf - as an example. Little comparative information about these is available, despite their special scientific importance, the widespread public interest and the policy implications. We propose a research project on these languages based on placing fully annotated digitized moving images of each of these languages on the internet. This requires significant development of multi-media technology which would allow distributed annotation of a central corpus, together with the development of special search techniques. The technology would have widespread application to all cultural performances recorded as sound plus moving images. Such a project captures in microcosm the essence of the ECHO proposal: cultural heritage is nothing without the humanities research which contextualizes and gives it comparative assessment; by marrying information technology to humanities research, we can bring these materials to a wider public while simultaneously boosting Europe as a research area.

Abstract

As for 'Locally-anchored spatial gestures task, version 2', a major goal of this task is to elicit locally-anchored spatial gestures across different cultures. “Locally-anchored spatial gestures” are gestures that are roughly oriented to the actual geographical direction of referents. Rather than set up an interview situation, this task involves recording informal, animated narrative delivered to a native-speaker interlocutor. Locally-anchored gestures produced in such narrative are roughly comparable to those collected in the interview task. The data collected can also be used to investigate a wide range of other topics.

Abstract

The theory of basic color terms was a crucial factor in the demise of linguistic relativity. The theory is now once again under scrutiny and fundamental revision. This article details a case study that undermines one of the central claims of the classical theory, namely that languages universally treat color as a unitary domain, to be exhaustively named. Taken together with other cases, the study suggests that a number of languages have only an incipient color terminology, raising doubts about the linguistic universality of such terminology.

Abstract

The results of a study on perceptual learning are reported. Dutch subjects made lexical decisions on a list of words and nonwords. Embedded in the list were either [f]- or [s]-final words in which the final fricative had been replaced by an ambiguous sound, midway between [f] and [s]. One group of listeners heard ambiguous [f]- final Dutch words like [kara?] (based on karaf, carafe) and unambiguous [s]-final words (e.g., karkas, carcase). A second group heard the reverse (e.g., ambiguous [karka?] and unambiguous karaf). After this training phase, listeners labelled ambiguous fricatives on an [f]- [s] continuum. The subjects who had heard [?] in [f]- final words categorised these fricatives as [f] reliably more often than those who had heard [?] in [s]-final words. These results suggest that speech recognition is dynamic: the system adjusts to the constraints of each particular listening situation. The lexicon can provide this adjustment process with a training signal.

Abstract

Although word boundaries are rarely clearly marked, listeners can rapidly recognize the individual words of spoken sentences. Some theories explain this in terms of competition between multiply activated lexical hypotheses; others invoke sensitivity to prosodic structure. We describe a connectionist model, SHORTLIST, in which recognition by activation and competition is successful with a realistically sized lexicon. Three experiments are then reported in which listeners detected real words embedded in nonsense strings, some of which were themselves the onsets of longer words. Effects both of competition between words and of prosodic structure were observed, suggesting that activation and competition alone are not sufficient to explain word recognition in continuous speech. However, the results can be accounted for by a version of SHORTLIST that is sensitive to prosodic structure.

Abstract

We introduce the papers in this special issue by summarising the current major issues in spoken word recognition. We argue that a full understanding of the process of lexical access during speech comprehension will depend on resolving several key representational issues: what is the form of the representations used for lexical access; how is phonological information coded in the mental lexicon; and how is the morphological and semantic information about each word stored? We then discuss a number of distinct access processes: competition between lexical hypotheses; the computation of goodness-of-fit between the signal and stored lexical knowledge; segmentation of continuous speech; whether the lexicon influences prelexical processing through feedback; and the relationship of form-based processing to the processes responsible for deriving an interpretation of a complete utterance. We conclude that further progress may well be made by swapping ideas among the different sub-domains of the discipline.

Abstract

In two word-spotting experiments, Japanese listeners detected Japanese words faster in vowel contexts (e.g., agura, to sit cross-legged, in oagura) than in consonant contexts (e.g., tagura). In the same experiments, however, listeners spotted words in vowel contexts (e.g., saru, monkey, in sarua) no faster than in moraic nasal contexts (e.g., saruN). In a third word-spotting experiment, words like uni, sea urchin, followed contexts consisting of a consonant-consonant-vowel mora (e.g., gya) plus either a moraic nasal (gyaNuni), a vowel (gyaouni) or a consonant (gyabuni). Listeners spotted words as easily in the first as in the second context (where in each case the target words were aligned with mora boundaries), but found it almost impossible to spot words in the third (where there was a single consonant, such as the [b] in gyabuni, between the beginning of the word and the nearest preceding mora boundary). Three control experiments confirmed that these effects reflected the relative ease of segmentation of the words from their contexts.We argue that the listeners showed sensitivity to the viability of sound sequences as possible Japanese words in the way that they parsed the speech into words. Since single consonants are not possible Japanese words, the listeners avoided lexical parses including single consonants and thus had difficulty recognizing words in the consonant contexts. Even though moraic nasals are also impossible words, they were not difficult segmentation contexts because, as with the vowel contexts, the mora boundaries between the contexts and the target words signaled likely word boundaries. Moraic rhythm appears to provide Japanese listeners with important segmentation cues.

Abstract

Lexical knowledge influences how human listeners make decisions about speech sounds. Positive lexical effects (faster responses to target sounds in words than in nonwords) are robust across several laboratory tasks, while negative effects (slower responses to targets in more word-like nonwords than in less word-like nonwords) have been found in phonetic decision tasks but not phoneme monitoring tasks. The present experiments tested whether negative lexical effects are therefore a task-specific consequence of the forced choice required in phonetic decision. We compared phoneme monitoring and phonetic decision performance using the same Dutch materials in each task. In both experiments there were positive lexical effects, but no negative lexical effects. We observe that in all studies showing negative lexical effects, the materials were made by cross-splicing, which meant that they contained perceptual evidence supporting the lexically-consistent phonemes. Lexical knowledge seems to influence phonemic decision-making only when there is evidence for the lexically-consistent phoneme in the speech signal.

Abstract

We briefly describe the Merge model of phonemic decision-making, and, in the light of general arguments about the possible role of feedback in spoken-word recognition, defend Merge's feedforward structure. Merge not only accounts adequately for the data, without invoking feedback connections, but does so in a parsimonious manner.

Abstract

A comparison of Merge, a model of comprehension, and WEAVER, a model of production, raises five issues: (1) merging models of comprehension and production necessarily creates feedback; (2) neither model is a comprehensive account of word processing; (3) the models are incomplete in different ways; (4) the models differ in their handling of competition; (5) as opposed to WEAVER, Merge is a model of metalinguistic behavior.

Abstract

Recently, a new theory of timing in sentence production has been proposed by Ferreira (1993). This theory assumes that at the phonological level, each syllable of an utterance is assigned one or more abstract timing units depending on its position in the prosodic structure. The number of timing units associated with a syllable determines the time interval between its onset and the onset of the next syllable. An interesting prediction from the theory, which was confirmed in Ferreira's experiments with speakers of American English, is that the time intervals between syllable onsets should only depend on the syllables' positions in the prosodic structure, but not on their segmental content. However, in the present experiments, which were carried out in Dutch, the intervals between syllable onsets were consistently longer for phonetically long syllables than for short syllables. The implications of this result for models of timing in sentence production are discussed.

Abstract

The central issues in the study of speech recognition by human listeners (HSR) and of automatic speech recognition (ASR) are clearly comparable; nevertheless the research communities that concern themselves with ASR and HSR are largely distinct. This paper compares the research objectives of the two fields, and attempts to draw informative lessons from one to the other.

Abstract

This paper describes recent experimental evidence which shows that models of spoken word recognition must incorporate both inhibition between competing lexical candidates and a sensitivity to metrical cues to lexical segmentation. A new version of the Shortlist [1][2] model incorporating the Metrical Segmentation Strategy [3] provides a detailed simulation of the data.

Abstract

The central thesis of the target article was that feedback is never necessary in spoken word recognition. The commentaries present no new data and no new theoretical arguments which lead us to revise this position. In this response we begin by clarifying some terminological issues which have lead to a number of significant misunderstandings. We provide some new arguments to support our case that the feedforward model Merge is indeed more parsimonious than the interactive alternatives, and that it provides a more convincing account of the data than alternative models. Finally, we extend the arguments to deal with new issues raised by the commentators such as infant speech perception and neural architecture.

Abstract

Top-down feedback does not benefit speech recognition; on the contrary, it can hinder it. No experimental data imply that feedback loops are required for speech recognition. Feedback is accordingly unnecessary and spoken word recognition is modular. To defend this thesis, we analyse lexical involvement in phonemic decision making. TRACE (McClelland & Elman 1986), a model with feedback from the lexicon to prelexical processes, is unable to account for all the available data on phonemic decision making. The modular Race model (Cutler & Norris 1979) is likewise challenged by some recent results, however. We therefore present a new modular model of phonemic decision making, the Merge model. In Merge, information flows from prelexical processes to the lexicon without feedback. Because phonemic decisions are based on the merging of prelexical and lexical information, Merge correctly predicts lexical involvement in phonemic decisions in both words and nonwords. Computer simulations show how Merge is able to account for the data through a process of competition between lexical hypotheses. We discuss the issue of feedback in other areas of language processing and conclude that modular models are particularly well suited to the problems and constraints of speech recognition.

Abstract

Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and any likely location of a word boundary, as cued in the speech signal. The experiments examined cases where the residue was either a CVC syllable with a schwa, or a CV syllable with a lax vowel. Although neither of these syllable contexts is a possible lexical word in English, word-spotting in both contexts was easier than in a context consisting of a single consonant. Two control lexical-decision experiments showed that the word-spotting results reflected the relative segmentation difficulty of the words in different contexts. The PWC appears to be language-universal rather than language-specific.

Abstract

Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC) [1] is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavours parses which leave an impossible residue between the end of a candidate word and a known boundary. The experiments examined cases where the residue was either a CV syllable with a lax vowel, or a CVC syllable with a schwa. Although neither syllable context is a possible word in English, word-spotting in both contexts was easier than with a context consisting of a single consonant. The PWC appears to be language-universal rather than language-specific.

Abstract

Simulations explored the inability of the TRACE model of spoken-word recognition to model the effects on human listening of subcategorical mismatch in word forms. The source of TRACE's failure lay not in interactive connectivity, not in the presence of inter-word competition, and not in the use of phonemic representations, but in the need for continuously optimised interpretation of the input. When an analogue of TRACE was allowed to cycle to asymptote on every slice of input, an acceptable simulation of the subcategorical mismatch data was achieved. Even then, however, the simulation was not as close as that produced by the Merge model, which has inter-word competition, phonemic representations and continuous optimisation (but no interactive connectivity).

Abstract

Recent functional brain imaging studies have shown that sensory-specific brain regions that are activated during perception/encoding of sensory-specific information are reactivated during memory retrieval of the same information. Here we used PET to examine whether verbal retrieval of action phrases is associated with reactivation of motor brain regions if the actions were overtly or covertly performed during encoding. Compared to a verbal condition, encoding by means of overt as well as covert activity was associated with differential activity in regions in contralateral somatosensory and motor cortex. Several of these regions were reactivated during retrieval. Common to both the overt and covert conditions was reactivation of regions in left ventral motor cortex and left inferior parietal cortex. A direct comparison of the overt and covert activity conditions showed that activation and reactivation of left dorsal parietal cortex and right cerebellum was specific to the overt condition. These results support the reactivation hypothesis by showing that verbal-explicit memory of actions involves areas that are engaged during overt and covert motor activity.

Abstract

A database is presented of relative familiarity ratings for 24 sets of Japanese words, each set comprising words overlapping in the initial portions. These ratings are useful for the generation of material sets for research in the recognition of spoken words.

Abstract

Current models of spoken-word recognition assume automatic activation of multiple candidate words fully or partially compatible with the speech input. We propose that listeners make use of this concurrent activation in word play such as punning. Distortion in punning should ideally involve no more than a minimal contrastive deviation between two words, namely a phoneme. Moreover, we propose that this metric of similarity does not presuppose phonemic awareness on the part of the punster. We support these claims with an analysis of modern and traditional puns in Japanese (in which phonemic awareness in language users is not encouraged by alphabetic orthography). For both data sets, the results support the predictions. Punning draws on basic processes of spokenword recognition, common across languages.

Abstract

The study of illiterate subjects, which for specific socio-cultural reasons did not have the opportunity to acquire basic reading and writing skills, represents one approach to study the interaction between neurobiological and cultural factors in cognitive development and the functional organization of the human brain. In addition the naturally occurring illiteracy may serve as a model for studying the influence of alphabetic orthography on auditory-verbal language. In this paper we have reviewed some recent behavioral and functional neuroimaging data indicating that learning an alphabetic written language modulates the auditory-verbal language system in a non-trivial way and provided support for the hypothesis that the functional architecture of the brain is modulated by literacy. We have also indicated that the effects of literacy and formal schooling is not limited to language related skills but appears to affect also other cognitive domains. In particular, we indicate that formal schooling influences 2D but not 3D visual naming skills. We have also pointed to the importance of using ecologically relevant tasks when comparing literate and illiterate subjects. We also demonstrate the applicability of a network approach in elucidating differences in the functional organization of the brain between groups. The strength of such an approach is the ability to study patterns of interactions between functionally specialized brain regions and the possibility to compare such patterns of brain interactions between groups or functional states. This complements the more commonly used activation approach to functional neuroimaging data, which characterize functionally specialized regions, and provides important data characterizing the functional interactions between these regions.

Abstract

It has previously been suggested that the activity in sensory regions of the brain can be modulated by attentional mechanisms during parallel cognitive processing. To investigate whether such attention-related modulations are present in the processing of pain, the regional cerebral blood ¯ow was measured using [15O]butanol and positron emission tomography in conditions involving both pain and parallel cognitive demands. The painful stimulus consisted of the standard cold pressor test and the cognitive task was a computerised perceptual maze test. The activations during the maze test reproduced findings in previous studies of the same cognitive task. The cold pressor test evoked signi®cant activity in the contralateral S1, and bilaterally in the somatosensory association areas (including S2), the ACC and the mid-insula. The activity in the somatosensory association areas and periaqueductal gray/midbrain were significantly modified, i.e. relatively decreased, when the subjects also were performing the maze task. The altered activity was accompanied with significantly lower ratings of pain during the cognitive task. In contrast, lateral orbitofrontal regions showed a relative increase of activity during pain combined with the maze task as compared to only pain, which suggests the possibility of the involvement of frontal cortex in modulation of regions processing pain

Abstract

In this paper hypothesis‐testing behaviour is compared to risk‐taking behaviour. It is proposed that choosing a suitable test for a given hypothesis requires making a preposterior analysis of two aspects of such a test: the probability of obtaining supporting evidence and the evidential value of this evidence. This consideration resembles the one a gambler makes when choosing among bets, each having a probability of winning and an amount to be won. A confirmatory testing strategy can be defined within this framework as a strategy directed at maximizing either the probability or the value of a confirming outcome. Previous theories on testing behaviour have focused on the human tendency to maximize the probability of a confirming outcome. In this paper, two experiments are presented in which participants tend to maximize the confirming value of the test outcome. Motivational factors enhance this tendency dependent on the context of the testing situation. Both this result and the framework are discussed in relation to other studies in the field of testing behaviour.

Abstract

Two experiments examined phonological priming effects on reaction times, error rates, and event-related brain potential (ERP) measures in an auditory lexical decision task. In Experiment 1 related prime-target pairs rhymed, and in Experiment 2 they alliterated (i.e., shared the consonantal onset and vowel). Event-related potentials were recorded in a delayed response task. Reaction times and error rates were obtained both for the delayed and an immediate response task. The behavioral data of Experiment 1 provided evidence for phonological facilitation of word, but not of nonword decisions. The brain potentials were more negative to unrelated than to rhyming word-word pairs between 450 and 700 msec after target onset. This negative enhancement was not present for word-nonword pairs. Thus, the ERP results match the behavioral data. The behavioral data of Experiment 2 provided no evidence for phonological Facilitation. However, between 250 and 450 msec after target onset, i.e., considerably earlier than in Experiment 1, brain potentials were more negative for unrelated than for alliterating word and word-nonword pairs. It is argued that the ERP effects in the two experiments could be modulations of the same underlying component, possibly the N400. The difference in the timing of the effects is likely to be due to the fact that the shared segments in related stimulus pairs appeared in different word positions in the two experiments.

Abstract

ASA conference abstract

Abstract

The modulatory influence of literacy on the cognitive system of the human brain has been indicated in behavioral, neuroanatomic, and functional neuroimaging studies. In this study we explored the functional consequences of formal education and the acquisition of an alphabetic written language on two- and three-dimensional visual naming. The results show that illiterate subjects perform significantly worse on immediate naming of two-dimensional representations of common everyday objects compared to literate subjects, both in terms of accuracy and reaction times. In contrast, there was no significant difference when the subjects named the corresponding real objects. The results suggest that formal education and learning to read and to write modulate the cognitive process involved in processing two- but not three-dimensional representations of common everyday objects. Both the results of the reaction time and the error pattern analyses can be interpreted as indicating that the major influence of literacy affects the visual system or the interaction between the visual and the language systems. We suggest that the visual system in a wide sense and/or the interface between the visual and the language system are differently formatted in literate and illiterate subjects. In other words, we hypothesize that the pattern of interactions in the functional–anatomical networks subserving visual naming, that is, the interactions within and between the visual and language processing networks, differ in literate and illiterate subjects

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

Recent studies of wh-question acquisition have tended to come from the nativist side of the language acquisition debate with little input from a constructivist perspective. The present work was designed to redress the balance, first by presenting a detailed description of young children's wh-question acquisition data, second, by providing detailed critiques of two nativist theories of wh- question acquisition, and third, by presenting a preliminary account of young children's wh-question development from a constructivist perspective. Analyses of the data from twelve 2 to 3 year old children collected over a year and of data from an older child (Adam from the Brown corpus, 1973) are described and three conclusions are drawn. First it is argued that the data suggest that children's knowledge of how to form wh-questions builds up gradually as they learn how to combine lexical items such as wh-words and auxiliaries in specific ways. Second, it is concluded that two nativist theories of grammatical development (Radford, 1990, 1992, 1995, 1996, Valian, Lasser & Mandelbaum, 1992) fail to account successfully for the wh-question data produced by the children. Third, it is asserted that the lexically-specific nature of children's early wh-questions is compatible with a lexical constructivist view of development, which proposes that the language learning mechanism learns by picking up high frequency lexical patterns from the input. The implications of these conclusions for theories of language development and future research 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

The strength of a memory trace is modulated by a variety of factors such as arousal, attention, context, type of processing during encoding, salience and novelty of the experience. Some of these factors can be modeled as a variable plasticity level in the memory system, controlled by arousal or relevance-estimating systems. We demonstrate that a Bayesian confidence propagation neural network with learning time constant modulated in this way exhibits enhanced recall of an item tagged as salient. Proactive and retroactive inhibition of other items is also demonstrated as well as an inverted U-shape response to overall plasticity

Abstract

So far most attempts to automate Directory Assistance services focused on private listings, because it is not known precisely how callers will refer to a business listings. The research described in this paper, carried out in the SMADA project, tries to fill this gap. The aim of the research is to model the expressions people use when referring to a business listing by means of rules, in order to automatically create a vocabulary, which can be part of an automated DA service. In this paper a rule-base procedure is proposed, which derives rules from the expressions people use. These rules are then used to automatically create expressions from directory listings. Two categories of businesses, viz. hospitals and the hotel and catering industry, are used to explain this procedure. Results for these two categories are used to discuss the problem of the over- and undergeneration of expressions.

Abstract

This work focuses on efficient use of the training material by selecting the optimal set of model topologies. We do this by training multiple word models of each word class, based on a subclassification according to a priori knowledge of the training material. We will examine classification criteria with respect to duration of the word, gender of the speaker, position of the word in the utterance, pauses in the vicinity of the word, and combinations of these. Comparative experiments were carried out on a corpus consisting of Dutch spoken connected digit strings and isolated digits, which are recorded in a wide variety of acoustic conditions. The results show, that classification based on gender of the speaker, position of the digit in the string, pauses in the vicinity of the training tokens, and models based on a combination of these criteria perform significantly better than the set with single models per digit.

Abstract

This study reports data from two dysgraphic patients, TH and PB, whose errors in spelling most often occurred in the final part of words. The probability of making an error increased monotonically towards the end of words. Long words were affected more than short words, and performance was similar across different output modalities (writing, typing and oral spelling). This error performance was found despite the fact that both patients showed normal ability to repeat the same words orally and to access their full spelling in tasks that minimized the involvement of working memory. This pattern of performance locates their deficit to the mechanism that keeps graphemic representations active for further processing, and shows that the functioning of this mechanism is not controlled or "refreshed" by phonological (or articulatory) processes. Although the overall performance pattern is most consistent with a deficit to the graphemic buffer, the strong tendency for errors to occur at the ends of words is unlike many classic "graphemic buffer patients" whose errors predominantly occur at word-medial positions. The contrasting patterns are discussed in terms of different types of impairment to the graphemic buffer.