Publications

Abstract

Previous research has shown that, in a phoneme detection task, vowels produce longer reaction times than consonants, suggesting that they are harder to perceive. One possible explanation for this difference is based upon their respective acoustic/articulatory characteristics. Another way of accounting for the findings would be to relate them to the differential functioning of vowels and consonants in the syllabic structure of words. In this experiment, we examined the second possibility. Targets were two pairs of phonemes, each containing a vowel and a consonant with similar phonetic characteristics. Subjects heard lists of English words had to press a response key upon detecting the occurrence of a pre-specified target. This time, the phonemes which functioned as vowels in syllabic structure yielded shorter reaction times than those which functioned as consonants. This rules out an explanation for response time difference between vowels and consonants in terms of function in syllable structure. Instead, we propose that consonantal and vocalic segments differ with respect to variability of tokens, both in the acoustic realisation of targets and in the representation of targets by listeners.

Abstract

Becoming a native listener is the necessary precursor to becoming a native speaker. Babies in the first year of life undertake a remarkable amount of work; by the time they begin to speak, they have perceptually mastered the phonological repertoire and phoneme co-occurrence probabilities of the native language, and they can locate familiar word-forms in novel continuous-speech contexts. The skills acquired at this early stage form a necessary part of adult listening. However, the same native listening skills also underlie problems in listening to a late-acquired non-native language, accounting for why in such a case listening (an innate ability) is sometimes paradoxically more difficult than, for instance, reading (a learned ability).

Abstract

The recent claim by Black and Byng (1986) that lexical access in reading is subject to prosodic constraints is examined and found to be unsupported. The evidence from impaired reading which Black and Byng report is based on poorly controlled stimulus materials and is inadequately analysed and reported. An alternative explanation of their findings is proposed, and new data are reported for which this alternative explanation can account but their model cannot. Finally, their proposal is shown to be theoretically unmotivated and in conflict with evidence from normal reading.

Abstract

In three experiments, the processing of lexical tone in Cantonese was examined. Cantonese listeners more often accepted a nonword as a word when the only difference between the nonword and the word was in tone, especially when the F0 onset difference between correct and erroneous tone was small. Same–different judgments by these listeners were also slower and less accurate when the only difference between two syllables was in tone, and this was true whether the F0 onset difference between the two tones was large or small. Listeners with no knowledge of Cantonese produced essentially the same same-different judgment pattern as that produced by the native listeners, suggesting that the results display the effects of simple perceptual processing rather than of linguistic knowledge. It is argued that the processing of lexical tone distinctions may be slowed, relative to the processing of segmental distinctions, and that, in speeded-response tasks, tone is thus more likely to be misprocessed than is segmental structure.

Abstract

Research on the exploitation of prosodic information in the recognition of spoken language is reviewed. The research falls into three main areas: the use of prosody in the recognition of spoken words, in which most attention has been paid to the question of whether the prosodic structure of a word plays a role in initial contact with stored lexical representations; the use of prosody in the computation of syntactic structure, in which the resolution of global and local ambiguities has formed the central focus; and the role of prosody in the processing of discourse structure, in which there has been a preponderance of work on the contribution of accentuation and deaccentuation to integration of concepts with an existing discourse model. The review reveals that in each area progress has been made towards new conceptions of prosody's role in processing, and in particular this has involved abandonment of previously held deterministic views of the relationship between prosodic structure and other aspects of linguistic structure

Abstract

Psycholinguists strive to construct a model of human language processing in general. But this does not imply that they should confine their research to universal aspects of linguistic structure, and avoid research on language-specific phenomena. First, even universal characteristics of language structure can only be accurately observed cross-linguistically. This point is illustrated here by research on the role of the syllable in spoken-word recognition, on the perceptual processing of vowels versus consonants, and on the contribution of phonetic assimilation phonemena to phoneme identification. In each case, it is only by looking at the pattern of effects across languages that it is possible to understand the general principle. Second, language-specific processing can certainly shed light on the universal model of language comprehension. This second point is illustrated by studies of the exploitation of vowel harmony in the lexical segmentation of Finnish, of the recognition of Dutch words with and without vowel epenthesis, and of the contribution of different kinds of lexical prosodic structure (tone, pitch accent, stress) to the initial activation of candidate words in lexical access. In each case, aspects of the universal processing model are revealed by analysis of these language-specific effects. In short, the study of spoken-language processing by human listeners requires cross-linguistic comparison.

Abstract

Language production and comprehension are intimately interrelated; and models of production and comprehension should, we argue, be constrained by common architectural guidelines. Levelt et al.'s target article adopts as guiding principle Ockham's razor: the best model of production is the simplest one. We recommend adoption of the same principle in comprehension, with consequent simplification of some well-known types of models.

Abstract

Segmentation of continuous speech into its component words is a nontrivial task for listeners. Previous work has suggested that listeners develop heuristic segmentation procedures based on experience with the structure of their language; for English, the heuristic is that strong syllables (containing full vowels) are most likely to be the initial syllables of lexical words, whereas weak syllables (containing central, or reduced, vowels) are nonword-initial, or, if word-initial, are grammatical words. This hypothesis is here tested against natural and laboratory-induced missegmentations of continuous speech. Precisely the expected pattern is found: listeners erroneously insert boundaries before strong syllables but delete them before weak syllables; boundaries inserted before strong syllables produce lexical words, while boundaries inserted before weak syllables produce grammatical words.

Abstract

Three experiments addressed the question of whether pitch-accent information may be exploited in the process of recognizing spoken words in Tokyo Japanese. In a two-choice classification task, listeners judged from which of two words, differing in accentual structure, isolated syllables had been extracted ~e.g., ka from baka HL or gaka LH!; most judgments were correct, and listeners’ decisions were correlated with the fundamental frequency characteristics of the syllables. In a gating experiment, listeners heard initial fragments of words and guessed what the words were; their guesses overwhelmingly had the same initial accent structure as the gated word even when only the beginning CV of the stimulus ~e.g., na- from nagasa HLL or nagashi LHH! was presented. In addition, listeners were more confident in guesses with the same initial accent structure as the stimulus than in guesses with different accent. In a lexical decision experiment, responses to spoken words ~e.g., ame HL! were speeded by previous presentation of the same word ~e.g., ame HL! but not by previous presentation of a word differing only in accent ~e.g., ame LH!. Together these findings provide strong evidence that accentual information constrains the activation and selection of candidates for spoken-word recognition.

Abstract

Monolingual French speakers employ a syllable-based procedure in speech segmentation; monolingual English speakers use a stress-based segmentation procedure and do not use the syllable-based procedure. In the present study French-English bilinguals participated in segmentation experiments with English and French materials. Their results as a group did not simply mimic the performance of English monolinguals with English language materials and of French monolinguals with French language materials. Instead, the bilinguals formed two groups, defined by forced choice of a dominant language. Only the French-dominant group showed syllabic segmentation and only with French language materials. The English-dominant group showed no syllabic segmentation in either language. However, the English-dominant group showed stress-based segmentation with English language materials; the French-dominant group did not. We argue that rhythmically based segmentation procedures are mutually exclusive, as a consequence of which speech segmentation by bilinguals is, in one respect at least, functionally monolingual.

Abstract

One of a listener's major tasks in understanding continuous speech is segmenting the speech signal into separate words. When listening conditions are difficult, speakers can help listeners by deliberately speaking more clearly. In four experiments, we examined how word boundaries are produced in deliberately clear speech. In an earlier report we showed that speakers do indeed mark word boundaries in clear speech, by pausing at the boundary and lengthening pre-boundary syllables; moreover, these effects are applied particularly to boundaries preceding weak syllables. In English, listeners use segmentation procedures which make word boundaries before strong syllables easier to perceive; thus marking word boundaries before weak syllables in clear speech will make clear precisely those boundaries which are otherwise hard to perceive. The present report presents supplementary data, namely prosodic analyses of the syllable following a critical word boundary. More lengthening and greater increases in intensity were applied in clear speech to weak syllables than to strong. Mean F0 was also increased to a greater extent on weak syllables than on strong. Pitch movement, however, increased to a greater extent on strong syllables than on weak. The effects were, however, very small in comparison to the durational effects we observed earlier for syllables preceding the boundary and for pauses at the boundary.

Abstract

The role of accent in reference resolution was investigated by monitoring eye fixations to lexical competitors (e.g., candy and candle ) as participants followed prerecorded instructions to move objects above or below fixed geometric shapes using a computer mouse. In Experiment 1, the first utterance instructed participants to move one object above or below a shape (e.g., “Put the candle/candy below the triangle”) and the second utterance contained an accented or deaccented definite noun phrase which referred to the same object or introduced a new entity (e.g., “Now put the CANDLE above the square” vs. “Now put the candle ABOVE THE SQUARE”). Fixations to the competitor (e.g., candy ) demonstrated a bias to interpret deaccented nouns as anaphoric and accented nouns as nonanaphoric. Experiment 2 used only accented nouns in the second instruction, varying whether the referent of this second instruction was the Theme of the first instruction (e.g., “Put the candle below the triangle”) or the Goal of the first instruction (e.g., “Put the necklace below the candle”). Participants preferred to interpret accented noun phrases as referring to a previously mentioned nonfocused entity (the Goal) rather than as introducing a new unmentioned entity.

Abstract

Speech errors follow the phonotactics of the language being spoken. For example, in English, if [n] is mispronounced as [n] the [n] will always appear in a syllable coda. The authors created an analogue to this phenomenon by having participants recite lists of consonant-vowel-consonant syllables in 4 sessions on different days. In the first 2 experiments, some consonants were always onsets, some were always codas, and some could be both. In a third experiment, the set of possible onsets and codas depended on vowel identity. In all 3 studies, the production errors that occurred respected the "phonotactics" of the experiment. The results illustrate the implicit learning of the sequential constraints present in the stimuli and show that the language production system adapts to recent experience.

Abstract

European cooperative effort seeks best practices architecture and procedures for international sites

Abstract

The article compares the integration of topic-related additive words at different stages of untutored L2 acquisition. Data stem from an ‘‘additive-elicitation task’’ that was designed in order to capture topic-related additive words in a context that is at the same time controlled for the underlying information structure and nondeviant from other kinds of narrative discourse. We relate the distinction between stressed and nonstressed forms of the German scope particles and adverbials auch ‘also’, noch ‘another’, wieder ‘again’, and immer noch ‘still’ to a uniform, information-structure-based principle: the stressed variants have scope over the topic information of the relevant utterances. It is then the common function of these additive words to express the additive link between the topic of the present utterance and some previous topic for which the same state of affairs is claimed to hold. This phenomenon has often been referred to as ‘‘contrastive topic,’’ but contrary to what this term suggests, these topic elements are by no means deviant from the default in coherent discourse. In the underlying information structure, the validity of some given state of affairs for the present topic must be under discussion. Topic-related additive words then express that the state of affairs indeed applies to this topic, their function therefore coming close to the function of assertion marking. While this functional correspondence goes along with the formal organization of the basic stages of untutored second-language acquisition, its expression brings linguistic constraints into conflict when the acquisition of finiteness pushes learners to reorganize their utterances according to target-language syntax.

Abstract

Based on their longitudinal analysis of the acquisition of Dutch, English, French, and German, Klein and Perdue (1997) described a “basic learner variety” as valid cross-linguistically and comprising a limited number of shared syntactic patterns interacting with two types of constraints: (a) semantic—the NP whose referent has highest control comes first, and (b) pragmatic—the focus expression is in final position. These authors hypothesized that “the topic-focus structure also plays an important role in some other respects. . . . Thus, negation and (other) scope particles occur at the topic-focus boundary” (p. 318). This poses the problem of the interaction between the core organizational principles of the basic variety and optional items such as negative particles and scope particles, which semantically affect the whole or part of the utterance in which they occur. In this article, we test the validity of these authors' hypothesis for the acquisition of the additive scope particle also (and its translation equivalents). Our analysis is based on the European Science Foundation (ESF) data originally used to define the basic variety, but we also included some more advanced learner data from the same database. In doing so, we refer to the analyses of Dimroth and Klein (1996), which concern the interaction between scope particles and the part of the utterance they affect, and we make a distinction between maximal scope—that which is potentially affected by the particle—and the actual scope of a particle in relation to an utterance in a given discourse context

Abstract

This paper examines the Papuan languages of Island Melanesia, with a view to considering their typological similarities and differences. The East Papuan languages are thought to be the descendants of the languages spoken by the original inhabitants of Island Melanesia, who arrived in the area up to 50,000 years ago. The Oceanic Austronesian languages are thought to have come into the area with the Lapita peoples 3,500 years ago. With this historical backdrop in view, our paper seeks to investigate the linguistic relationships between the scattered Papuan languages of Island Melanesia. To do this, we survey various structural features, including syntactic patterns such as constituent order in clauses and noun phrases and other features of clause structure, paradigmatic structures of pronouns, and the structure of verbal morphology. In particular, we seek to discern similarities between the languages that might call for closer investigation, with a view to establishing genetic relatedness between some or all of the languages. In addition, in examining structural relationships between languages, we aim to discover whether it is possible to distinguish between original Papuan elements and diffused Austronesian elements of these languages. As this is a vast task, our paper aims merely to lay the groundwork for investigation into these and related questions.

Abstract

This paper examines the effects of language standardization and orthography design on the Chukchi linguistic ecology. The process of standardisation has not taken into consideration the gender-based sociolects of colloquial Chukchi and is based on a grammaticaldescriptionwhich does not reflectactual Chukchi use; as a result standard Chukchi has not gained a place in the Chukchi language ecology. The Cyrillic orthography developed for Chukchi is also problematic as it is based on features of Russian phonology, rather than on Chukchi itself: this has meant that a knowledge of written Chukchi is dependent on a knowledge of the principles of Russian orthography. The aspects of language planning have had a large impact on the pre-existing Chukchi language ecology which has contributed to the obsolescence of the colloquial language.

Abstract

How involved in an event is a person that possesses one of the event participants? Some languages can treat such “external possessors” as very closely involved, even marking them on the verb along with core roles such as subject and object. Other languages only allow possessors to be expressed as non-core participants. This task explores possibilities for the encoding of possessors and other related roles such as beneficiaries. The materials consist of a sequence of thirty drawings designed to elicit target construction types.

Abstract

Language is a uniquely human trait likely to have been a prerequisite for the development of human culture. The ability to develop articulate speech relies on capabilities, such as fine control of the larynx and mouth, that are absent in chimpanzees and other great apes. FOXP2 is the first gene relevant to the human ability to develop language. A point mutation in FOXP2 co-segregates with a disorder in a family in which half of the members have severe articulation difficulties accompanied by linguistic and grammatical impairment. This gene is disrupted by translocation in an unrelated individual who has a similar disorder. Thus, two functional copies of FOXP2 seem to be required for acquisition of normal spoken language. We sequenced the complementary DNAs that encode the FOXP2 protein in the chimpanzee, gorilla, orang-utan, rhesus macaque and mouse, and compared them with the human cDNA. We also investigated intraspecific variation of the human FOXP2 gene. Here we show that human FOXP2 contains changes in amino-acid coding and a pattern of nucleotide polymorphism, which strongly suggest that this gene has been the target of selection during recent human evolution.

Abstract

Investigation of the emotions entails reference to words and expressions conventionally used for the description of emotion experience. Important methodological issues arise for emotion researchers, and the issues are of similarly central concern in linguistic semantics more generally. I argue that superficial and/or inconsistent description of linguistic meaning can have seriously misleading results. This paper is firstly a critique of standards in emotion research for its tendency to underrate and ill-understand linguistic semantics. It is secondly a critique of standards in some approaches to linguistic semantics itself. Two major problems occur. The first is failure to distinguish between conceptually distinct meanings of single words, neglecting the well-established fact that a single phonological string can signify more than one conceptual category (i.e., that words can be polysemous). The second error involves failure to distinguish between two kinds of secondary uses of words: (1) those which are truly active “online” extensions, and (2) those which are conventionalised secondary meanings and not active (qua “extensions”) at all. These semantic considerations are crucial to conclusions one may draw about cognition and conceptualisation based on linguistic evidence.

Abstract

This article argues that it is not possible to establish distinctions between 'Lao', 'Thai', and 'Isan' as seperate languages or dialects by appealing to objective criteria. 'Lao', 'Thai', and 'Isan' are conceived linguistics varieties, and the ground-level reality reveals a great deal of variation, much of it not coinciding with the geographical boundaries of the 'Laos', 'Isan', and 'non-Isan Thailand' areas. Those who promote 'Lao', 'Thai', and/or 'Isan' as distinct linguistic varieties have subjective (e.g. political and/or sentimental) reasons for doing so. Objective linguistic criteria are not sufficient

Abstract

Anthropologists and linguists have long been aware that the body is explicitly referred to in conventional description of emotion in languages around the world. There is abundant linguistic data showing expression of emotions in terms of their imagined ‘locus’ in the physical body. The most important methodological issue in the study of emotions is language, for the ways people talk give us access to ‘folk descriptions’ of the emotions. ‘Technical terminology’, whether based on English or otherwise, is not excluded from this ‘folk’ status. It may appear to be safely ‘scientific’ and thus culturally neutral, but in fact it is not: technical English is a variety of English and reflects, to some extent, culture-specific ways of thinking (and categorising) associated with the English language. People — as researchers studying other people, or as people in real-life social association — cannot directly access the emotional experience of others, and language is the usual mode of ‘packaging’ one’s experience so it may be accessible to others. Careful description of linguistic data from as broad as possible a cross-linguistic base is thus an important part of emotion research. All people experience biological events and processes associated with certain thoughts (or, as psychologists say, ‘appraisals’), but there is more to ‘emotion’ than just these physiological phenomena. Speakers of some languages talk about their emotional experiences as if they are located in some internal organ such as ‘the liver’, yet they cannot localise feeling in this physical organ. This phenomenon needs to be understood better, and one of the problems is finding a method of comparison that allows us to compare descriptions from different languages which show apparently great formal and semantic variation. Some simple concepts including feel and body are universal or near-universal, and as such are good candidates for terms of description which may help to eradicate confusion and exoticism from cross-linguistic comparison and semantic typology. Semantic analysis reveals great variation in concepts of emotion across languages and cultures — but such analysis requires a sound and well-founded methodology. While leaving room for different approaches to the task, we suggest that such a methodology can be based on empirically established linguistic universal (or near-universal) concepts, and on ‘cognitive scenarios’ articulated in terms of these concepts. Also, we warn against the danger of exoticism involved in taking all body part references ‘literally’. Above all, we argue that what is needed is a combination of empirical cross-linguistic investigations and a theoretical and methodological awareness, recognising the impossibility of exploring other people’s emotions without keeping language in focus: both as an object and as a tool of study.

Abstract

The social world is an ecological complex in which cultural meanings and knowledges (linguistic and non-linguistic) personally embodied by individuals are intercalibrated via common attention to commonly accessible semiotic structures. This interpersonal ecology bridges realms which are the subject matter of both anthropology and linguistics, allowing the public maintenance of a system of assumptions and counter-assumptions among individuals as to what is mutually known (about), in general and/or in any particular context. The mutual assumption of particular cultural ideas provides human groups with common premises for predictably convergent inferential processes. This process of people collectively using effectively identical assumptions in interpreting each other's actions—i.e. hypothesizing as to each other's motivations and intentions—may be termed cultural logic. This logic relies on the establishment of stereotypes and other kinds of precedents, catalogued in individuals’ personal libraries, as models and scenarios which may serve as reference in inferring and attributing motivations behind people's actions, and behind other mysterious phenomena. This process of establishing conceptual convention depends directly on semiotics, since groups of individuals rely on external signs as material for common focus and, thereby, agreement. Social intelligence binds signs in the world (e.g. speech sounds impressing upon eardrums), with individually embodied representations (e.g. word meanings and contextual schemas). The innate tendency for people to model the intentions of others provides an ultimately biological account for the logic behind culture. Ethnographic examples are drawn from Laos and Australia.

Abstract

This article addresses the recognition of reduced word forms, which are frequent in casual speech. We describe two experiments on Dutch showing that listeners only recognize highly reduced forms well when these forms are presented in their full context and that the probability that a listener recognizes a word form in limited context is strongly correlated with the degree of reduction of the form. Moreover, we show that the effect of degree of reduction can only partly be interpreted as the effect of the intelligibility of the acoustic signal, which is negatively correlated with degree of reduction. We discuss the consequences of our findings for models of spoken word recognition and especially for the role that storage plays in these models.

Abstract

A principal components analysis of the ten scales of the Worry Questionnaire revealed the existence of major worry factors or domains of social evaluation and physical threat, and these factors were confirmed in a subsequent item analysis. Those high in trait anxiety had much higher scores on the Worry Questionnaire than those low in trait anxiety, especially on those scales relating to social evaluation. Scores on the Marlowe-Crowne Social Desirability Scale were negatively related to worry frequency. However, groups of low-anxious and repressed individucores did not differ in worry. It was concluded that worry, especals formed on the basis of their trait anxiety and social desirability sially in the social evaluation domain, is of fundamental importance to trait anxiety.

Abstract

Family and twin studies of developmental dyslexia have consistently shown that there is a significant heritable component for this disorder. However, any genetic basis for the trait is likely to be complex, involving reduced penetrance, phenocopy, heterogeneity and oligogenic inheritance. This complexity results in reduced power for traditional parametric linkage analysis, where specification of the correct genetic model is important. One strategy is to focus on large multigenerational pedigrees with severe phenotypes and/or apparent simple Mendelian inheritance, as has been successfully demonstrated for speech and language impairment. This approach is limited by the scarcity of such families. An alternative which has recently become feasible due to the development of high-throughput genotyping techniques is the analysis of large numbers of sib-pairs using allele-sharing methodology. This paper outlines our strategy for conducting a systematic genome-wide search for genes involved in dyslexia in a large number of affected sib-pair familites from the UK. We use a series of psychometric tests to obtain different quantitative measures of reading deficit, which should correlate with different components of the dyslexia phenotype, such as phonological awareness and orthographic coding ability. This enable us to use QTL (quantitative trait locus) mapping as a powerful tool for localising genes which may contribute to reading and spelling disability.

Abstract

Attention deficit/hyperactivity disorder (ADHD) is a common heritable disorder with a childhood onset. Molecular genetic studies of ADHD have previously focused on examining the roles of specific candidate genes, primarily those involved in dopaminergic pathways. We have performed the first systematic genomewide linkage scan for loci influencing ADHD in 126 affected sib pairs, using a ∼10-cM grid of microsatellite markers. Allele-sharing linkage methods enabled us to exclude any loci with a λs of ⩾3 from 96% of the genome and those with a λs of ⩾2.5 from 91%, indicating that there is unlikely to be a major gene involved in ADHD susceptibility in our sample. Under a strict diagnostic scheme we could exclude all screened regions of the X chromosome for a locus-specific λs of ⩾2 in brother-brother pairs, demonstrating that the excess of affected males with ADHD is probably not attributable to a major X-linked effect. Qualitative trait maximum LOD score analyses pointed to a number of chromosomal sites that may contain genetic risk factors of moderate effect. None exceeded genomewide significance thresholds, but LOD scores were >1.5 for regions on 5p12, 10q26, 12q23, and 16p13. Quantitative-trait analysis of ADHD symptom counts implicated a region on 12p13 (maximum LOD 2.6) that also yielded a LOD >1 when qualitative methods were used. A survey of regions containing 36 genes that have been proposed as candidates for ADHD indicated that 29 of these genes, including DRD4 and DAT1, could be excluded for a λs of 2. Only three of the candidates—DRD5, 5HTT, and CALCYON—coincided with sites of positive linkage identified by our screen. Two of the regions highlighted in the present study, 2q24 and 16p13, coincided with the top linkage peaks reported by a recent genome-scan study of autistic sib pairs.

Abstract

Recent application of nonparametric-linkage analysis to reading disability has implicated a putative quantitative-trait locus (QTL) on the short arm of chromosome 6. In the present study, we use QTL methods to evaluate linkage to the 6p25-21.3 region in a sample of 181 sib pairs from 82 nuclear families that were selected on the basis of a dyslexic proband. We have assessed linkage directly for several quantitative measures that should correlate with different components of the phenotype, rather than using a single composite measure or employing categorical definitions of subtypes. Our measures include the traditional IQ/reading discrepancy score, as well as tests of word recognition, irregular-word reading, and nonword reading. Pointwise analysis by means of sib-pair trait differences suggests the presence, in 6p21.3, of a QTL influencing multiple components of dyslexia, in particular the reading of irregular words (P=.0016) and nonwords (P=.0024). A complementary statistical approach involving estimation of variance components supports these findings (irregular words, P=.007; nonwords, P=.0004). Multipoint analyses place the QTL within the D6S422-D6S291 interval, with a peak around markers D6S276 and D6S105 consistently identified by approaches based on trait differences (irregular words, P=.00035; nonwords, P=.0035) and variance components (irregular words, P=.007; nonwords, P=.0038). Our findings indicate that the QTL affects both phonological and orthographic skills and is not specific to phoneme awareness, as has been previously suggested. Further studies will be necessary to obtain a more precise localization of this QTL, which may lead to the isolation of one of the genes involved in developmental dyslexia.

Abstract

Developmental dyslexia, a specific impairment of reading ability despite adequate intelligence and educational opportunity, is one of the most frequent childhood disorders. Since the first documented cases at the beginning of the last century, it has become increasingly apparent that the reading problems of people with dyslexia form part of a heritable neurobiological syndrome. As for most cognitive and behavioural traits, phenotypic definition is fraught with difficulties and the genetic basis is complex, making the isolation of genetic risk factors a formidable challenge. Against such a background, it is notable that several recent studies have reported the localization of genes that influence dyslexia and other language-related traits. These investigations exploit novel research approaches that are relevant to many areas of human neurogenetics.

Abstract

Developmental dyslexia is defined as a specific and significant impairment in reading ability that cannot be explained by deficits in intelligence, learning opportunity, motivation or sensory acuity. It is one of the most frequently diagnosed disorders in childhood, representing a major educational and social problem. It is well established that dyslexia is a significantly heritable trait with a neurobiological basis. The etiological mechanisms remain elusive, however, despite being the focus of intensive multidisciplinary research. All attempts to map quantitative-trait loci (QTLs) influencing dyslexia susceptibility have targeted specific chromosomal regions, so that inferences regarding genetic etiology have been made on the basis of very limited information. Here we present the first two complete QTL-based genome-wide scans for this trait, in large samples of families from the United Kingdom and United States. Using single-point analysis, linkage to marker D18S53 was independently identified as being one of the most significant results of the genome in each scan (P< or =0.0004 for single word-reading ability in each family sample). Multipoint analysis gave increased evidence of 18p11.2 linkage for single-word reading, yielding top empirical P values of 0.00001 (UK) and 0.0004 (US). Measures related to phonological and orthographic processing also showed linkage at this locus. We replicated linkage to 18p11.2 in a third independent sample of families (from the UK), in which the strongest evidence came from a phoneme-awareness measure (most significant P value=0.00004). A combined analysis of all UK families confirmed that this newly discovered 18p QTL is probably a general risk factor for dyslexia, influencing several reading-related processes. This is the first report of QTL-based genome-wide scanning for a human cognitive trait.

Abstract

This chapter highlights the research in isolating genetic factors underlying specific language impairment (SLI), or developmental dysphasia, which exploits newly developed genotyping technology, novel statistical methodology, and DNA sequence data generated by the Human Genome Project. The author begins with an overview of results from family, twin, and adoption studies supporting genetic involvement and then goes on to outline progress in a number of genetic mapping efforts that have been recently completed or are currently under way. It has been possible for genetic researchers to pinpoint the specific mutation responsible for some speech and language disorders, providing an example of how the availability of human genomic sequence data can greatly accelerate the pace of disease gene discovery. Finally, the author discusses future prospects on how molecular genetics may offer new insight into the etiology underlying speech and language disorders, leading to improvements in diagnosis and treatment.

Abstract

The human Xp11.23-p11.22 interval has been implicated in several inherited diseases including Wiskott-Aldrich syndrome; three forms of X-linked hypercalciuric nephrolithiaisis; and the eye disorders retinitis pigmentosa 2, congenital stationary night blindness, and Aland Island eye disease. In constructing YAC contigs spanning Xp11. 23-p11.22, we have previously shown that the region around the synaptophysin (SYP) gene is refractory to cloning in YACs, but highly stable in cosmids. Preliminary analysis of the latter suggested that this might reflect a high density of coding sequences and we therefore undertook the complete sequencing of a SYP-containing cosmid. Sequence data were extensively analyzed using computer programs such as CENSOR (to mask repeats), BLAST (for homology searches), and GRAIL and GENE-ID (to predict exons). This revealed the presence of 29 putative exons, organized into three genes, in addition to the 7 exons of the complete SYP coding region, all mapping within a 44-kb interval. Two genes are novel, one (CACNA1F) showing high homology to alpha1 subunits of calcium channels, the other (LMO6) encoding a product with significant similarity to LIM-domain proteins. RT-PCR and Northern blot studies confirmed that these loci are indeed transcribed. The third locus is the previously described, but not previously localized, A4 differentiation-dependent gene. Given that the intron-exon boundaries predicted by the analysis are consistent with previous information where available, we have been able to suggest the genomic organization of the novel genes with some confidence. The region has an elevated GC content (>53%), and we identified CpG islands associated with the 5' ends of SYP, A4, and LMO6. The order of loci was Xpter-A4-LMO6-SYP-CACNA1F-Xcen, with intergenic distances ranging from approximately 300 bp to approximately 5 kb. The density of transcribed sequences in this area (>80%) is comparable to that found in the highly gene-rich chromosomal band Xq28. Further studies may aid our understanding of the long-range organization surrounding such gene-enriched regions.

Abstract

Genomewide quantitative-trait locus (QTL) linkage analysis was performed using a continuous measure of relative hand skill (PegQ) in a sample of 195 reading-disabled sibling pairs from the United Kingdom. This was the first genomewide screen for any measure related to handedness. The mean PegQ in the sample was equivalent to that of normative data, and PegQ was not correlated with tests of reading ability (correlations between −0.13 and 0.05). Relative hand skill could therefore be considered normal within the sample. A QTL on chromosome 2p11.2-12 yielded strong evidence for linkage to PegQ (empirical P=.00007), and another suggestive QTL on 17p11-q23 was also identified (empirical P=.002). The 2p11.2-12 locus was further analyzed in an independent sample of 143 reading-disabled sibling pairs, and this analysis yielded an empirical P=.13. Relative hand skill therefore is probably a complex multifactorial phenotype with a heterogeneous background, but nevertheless is amenable to QTL-based gene-mapping approaches.

Abstract

Family and twin studies consistently demonstrate a significant role for genetic factors in the aetiology of the reading disorder dyslexia. However, dyslexia is complex at both the genetic and phenotypic levels, and currently the nature of the core deficit or deficits remains uncertain. Traditional approaches for mapping disease genes, originally developed for single-gene disorders, have limited success when there is not a simple relationship between genotype and phenotype. Recent advances in high-throughput genotyping technology and quantitative statistical methods have made a new approach to identifying genes involved in complex disorders possible. The method involves assessing the genetic similarity of many sibling pairs along the lengths of all their chromosomes and attempting to correlate this similarity with that of their phenotypic scores. We are adopting this approach in an ongoing genome-wide search for genes involved in dyslexia susceptibility, and have already successfully applied the method by replicating results from previous studies suggesting that a quantitative trait locus at 6p21.3 influences reading disability.

Abstract

A locus on chromosome 2p12-16 has been implicated in dyslexia susceptibility by two independent linkage studies, including our own study of 119 nuclear twin-based families, each with at least one reading-disabled child. Nonetheless, no variant of any gene has been reported to show association with dyslexia, and no consistent clinical evidence exists to identify candidate genes with any strong a priori logic. We used 21 microsatellite markers spanning 2p12-16 to refine our 1-LOD unit linkage support interval to 12cM between D2S337 and D2S286. Then, in quantitative association analysis, two microsatellites yielded P values<0.05 across a range of reading-related measures (D2S2378 and D2S2114). The exon/intron borders of two positional candidate genes within the region were characterized, and the exons were screened for polymorphisms. The genes were Semaphorin4F (SEMA4F), which encodes a protein involved in axonal growth cone guidance, and OTX1, encoding a homeodomain transcription factor involved in forebrain development. Two non-synonymous single nucleotide polymorphisms were found in SEMA4F, each with a heterozygosity of 0.03. One intronic single nucleotide polymorphism between exons 12 and 13 of SEMA4F was tested for quantitative association, but no significant association was found. Only one single nucleotide polymorphism was found in OTX1, which was exonic but silent. Our data therefore suggest that linkage with reading disability at 2p12-16 is not caused by coding variants of SEMA4F or OTX1. Our study outlines the approach necessary for the identification of genetic variants causing dyslexia susceptibility in an epidemiological population of dyslexics.

Abstract

Dyslexia, a disorder of reading and spelling, is a heterogeneous neurological syndrome with a complex genetic and environmental aetiology. People with dyslexia differ in their individual profiles across a range of cognitive, physiological, and behavioural measures related to reading disability. Some or all of the subtypes of dyslexia might have partly or wholly distinct genetic causes. An understanding of the role of genetics in dyslexia could help to diagnose and treat susceptible children more effectively and rapidly than is currently possible and in ways that account for their individual disabilities. This knowledge will also give new insights into the neurobiology of reading and language cognition. Genetic linkage analysis has identified regions of the genome that might harbour inherited variants that cause reading disability. In particular, loci on chromosomes 6 and 18 have shown strong and replicable effects on reading abilities. These genomic regions contain tens or hundreds of candidate genes, and studies aimed at the identification of the specific causal genetic variants are underway.

Abstract

Theeffects of spatial filtering in functional magnetic resonance imaging were investigated by reevaluating the data of a previous study of episodic memory encoding at 2 × 2 × 4-mm3 resolution with use of a SPM99 analysis involving a Gaussian kernel of 8-mm full width at half maximum. In addition, a multisubject analysis of activated regions was performed by normalizing the functional images to an approximate Talairach brain atlas. In individual subjects, spatial filtering merged activations in anatomically separated brain regions. Moreover, small foci of activated pixels which originated from veins became blurred and hence indistinguishable from parenchymal responses. The multisubject analysis resulted in activation of the hippocampus proper, a finding which could not be confirmed by the activation maps obtained at high resolution. It is concluded that the validity of multisubject fMRI analyses can be considerably improved by first analyzing individual data sets at optimum resolution to assess the effects of spatial filtering and minimize the risk of signal contamination by macroscopically visible vessels.

Abstract

Languages, like molecules, document evolutionary history. Darwin(1) observed that evolutionary change in languages greatly resembled the processes of biological evolution: inheritance from a common ancestor and convergent evolution operate in both. Despite many suggestions(2-4), few attempts have been made to apply the phylogenetic methods used in biology to linguistic data. Here we report a parsimony analysis of a large language data set. We use this analysis to test competing hypotheses - the "express-train''(5) and the "entangled-bank''(6,7) models - for the colonization of the Pacific by Austronesian-speaking peoples. The parsimony analysis of a matrix of 77 Austronesian languages with 5,185 lexical items produced a single most-parsimonious tree. The express-train model was converted into an ordered geographical character and mapped onto the language tree. We found that the topology of the language tree was highly compatible with the express-train model.

Abstract

To study the time course of sentence formulation, we monitored the eye movements of speakers as they described simple events. The similarity between speakers' initial eye movements and those of observers performing a nonverbal event-comprehension task suggested that response-relevant information was rapidly extracted from scenes, allowing speakers to select grammatical subjects based on comprehended events rather than salience. When speaking extemporaneously, speakers began fixating pictured elements less than a second before naming them within their descriptions, a finding consistent with incremental lexical encoding. Eye movements anticipated the order of mention despite changes in picture orientation, in who-did-what-to-whom, and in sentence structure. The results support Wundt's theory of sentence production.

Abstract

Since listeners usually look at the speaker's face, gestural information has to be absorbed through peripheral visual perception. In the literature, it has been suggested that listeners look at gestures under certain circumstances: 1) when the articulation of the gesture is peripheral; 2) when the speech channel is insufficient for comprehension; and 3) when the speaker him- or herself indicates that the gesture is worthy of attention. The research here reported employs eye tracking techniques to study the perception of gestures in face-to-face interaction. The improved control over the listener's visual channel allows us to test the validity of the above claims. We present preliminary findings substantiating claims 1 and 3, and relate them to theoretical proposals in the literature and to the issue of how visual and cognitive attention are related.

Abstract

In this study, event-related brain potential ffects of speech processing are obtained and compared to similar effects in sentence reading. In two experiments sentences were presented that contained three different types of grammatical violations. In one experiment sentences were presented word by word at a rate of four words per second. The grammatical violations elicited a Syntactic Positive Shift (P600/SPS), 500 ms after the onset of the word that rendered the sentence ungrammatical. The P600/SPS consisted of two phases, an early phase with a relatively equal anterior-posterior distribution and a later phase with a strong posterior distribution. We interpret the first phase as an indication of structural integration complexity, and the second phase as an indication of failing parsing operations and/or an attempt at reanalysis. In the second experiment the same syntactic violations were presented in sentences spoken at a normal rate and with normal intonation. These violations elicited a P600/SPS with the same onset as was observed for the reading of these sentences. In addition two of the three violations showed a preceding frontal negativity, most clearly over the left hemisphere.

Abstract

In this study, event-related brain potential effects of speech processing are obtained and compared to similar effects insentence reading. In two experiments spoken sentences were presented with semantic violations in sentence-signal or mid-sentence positions. For these violations N400 effects were obtained that were very similar to N400 effects obtained in reading. However, the N400 effects in speech were preceded by an earlier negativity (N250). This negativity is not commonly observed with written input. The early effect is explained as a manifestation of a mismatch between the word forms expected on the basis of the context, and the actual cohort of activated word candidates that is generated on the basis of the speech signal.

Abstract

The central issue of this study concerns the claim that the processing of gender agreement in online sentence comprehension is a syntactic rather than a conceptual/semantic process. This claim was tested for the grammatical gender agreement in Dutch between the definite article and the noun. Subjects read sentences in which the definite article and the noun had the same gender and sentences in which the gender agreement was violated, While subjects read these sentences, their electrophysiological activity was recorded via electrodes placed on the scalp. Earlier research has shown that semantic and syntactic processing events manifest themselves in different event-related brain potential (ERP) effects. Semantic integration modulates the amplitude of the so-called N400.The P600/SPS is an ERP effect that is more sensitive to syntactic processes. The violation of grammatical gender agreement was found to result in a P600/SPS. For violations in sentence-final position, an additional increase of the N400 amplitude was observed. This N400 effect is interpreted as resulting from the consequence of a syntactic violation for the sentence-final wrap-up. The overall pattern of results supports the claim that the on-line processing of gender agreement information is not a content driven but a syntactic-form driven process.

Abstract

In a study by Milberg, Blumstein, and Dworetzky (1987), normal control subjects and Wernicke's and Broca's aphasics performed a lexical decision task on the third element of auditorily presented triplets of words with either a word or a nonword as target. In three of the four types of word triplets, the first and the third words were related to one or both meanings of the second word, which was semantically ambiguous. The fourth type of word triplet consisted of three unrelated, unambiguous words, functioning as baseline. Milberg et al. (1987) claim that the results for their control subjects are similar to those reported by Schvaneveldt, Meyer, and Becker's original study (1976) with the same prime types, and so interpret these as evidence for a selective lexical access of the different meanings of ambiguous words. It is argued here that Milberg et al. only partially replicate the Schvaneveldt et al. results. Moreover, the results of Milberg et al. are not fully in line with the selective access hypothesis adopted. Replication of the Milberg et al. (1987) study with Dutch materials, using both a design without and a design with repetition of the same target words for the same subjects led to the original pattern as reported by Schvaneveldt et al. (1976). In the design with four separate presentations of the same target word, a strong repetition effect was found. It is therefore argued that the discrepancy between the Milberg et al. results on the one hand, and the Schvaneveldt et al. results on the other, might be due to the absence of a control for repetition effects in the within-subject design used by Milberg et al. It is concluded that this makes the results for both normal and aphasic subjects in the latter study difficult to interpret in terms of a selective access model for normal processing.