Publications

Abstract

Syntax is one of the components in the architecture of language processing that allows the listener/reader to bind single-word information into a unified interpretation of multiword utterances. This paper discusses ERP effects that have been observed in relation to syntactic processing. The fact that these effects differ from the semantic N400 indicates that the brain honors the distinction between semantic and syntactic binding operations. Two models of syntactic processing attempt to account for syntax-related ERP effects. One type of model is serial, with a first phase that is purely syntactic in nature (syntax-first model). The other type of model is parallel and assumes that information immediately guides the interpretation process once it becomes available. This is referred to as the immediacy model. ERP evidence is presented in support of the latter model. Next, an explicit computational model is proposed to explain the ERP data. This Unification Model assumes that syntactic frames are stored in memory and retrieved on the basis of the spoken or written word form input. The syntactic frames associated with the individual lexical items are unified by a dynamic binding process into a structural representation that spans the whole utterance. On the basis of a meta-analysis of imaging studies on syntax, it is argued that the left posterior inferior frontal cortex is involved in binding syntactic frames together, whereas the left superior temporal cortex is involved in retrieval of the syntactic frames stored in memory. Lesion data that support the involvement of this left frontotemporal network in syntactic processing are discussed.

Abstract

This study investigated the effects of combined semantic and syntactic violations in relation to the effects of single semantic and single syntactic violations on language-related event-related brain potential (ERP) effects (N400 and P600/ SPS). Syntactic violations consisted of a mismatch in grammatical gender or number features of the definite article and the noun in sentence-internal or sentence-final noun phrases (NPs). Semantic violations consisted of semantically implausible adjective–noun combinations in the same NPs. Combined syntactic and semantic violations were a summation of these two respective violation types. ERPs were recorded while subjects read the sentences with the different types of violations and the correct control sentences. ERP effects were computed relative to ERPs elicited by the sentence-internal or sentence-final nouns. The size of the N400 effect to the semantic violation was increased by an additional syntactic violation (the syntactic boost). In contrast, the size of the P600/ SPS to the syntactic violation was not affected by an additional semantic violation. This suggests that in the absence of syntactic ambiguity, the assignment of syntactic structure is independent of semantic context. However, semantic integration is influenced by syntactic processing. In the sentence-final position, additional global processing consequences were obtained as a result of earlier violations in the sentence. The resulting increase in the N400 amplitude to sentence-final words was independent of the nature of the violation. A speeded anomaly detection task revealed that it takes substantially longer to detect semantic than syntactic anomalies. These results are discussed in relation to the latency and processing characteristics of the N400 and P600/SPS effects. Overall, the results reveal an asymmetry in the interplay between syntax and semantics during on-line sentence comprehension.

Abstract

In this study we investigate whether speakers, in line with the predictions of the Hyper- and Hypospeech theory, speed up most during the least informative parts and less during the more informative parts, when they are asked to speak faster. We expected listeners to benefit from these changes in timing, and our main goal was to find out whether making the temporal organisation of artificially time-compressed speech more like that of natural fast speech would improve intelligibility over linear time compression. Our production study showed that speakers reduce unstressed syllables more than stressed syllables, thereby making the prosodic pattern more pronounced. We extrapolated fast speech timing to even faster rates because we expected that the more salient prosodic pattern could be exploited in difficult listening situations. However, at very fast speech rates, applying fast speech timing worsens intelligibility. We argue that the non-uniform way of speeding up may not be due to an underlying communicative principle, but may result from speakers’ inability to speed up otherwise. As both prosodic and segmental information contribute to word recognition, we conclude that extrapolating fast speech timing to extremely fast rates distorts this balance between prosodic and segmental information.

Abstract

A. Caramazza, A. Costa, M. Miozzo, and Y. Bi(2001) reported a series of experiments demonstrating that the ease of producing a word depends only on the frequency of that specific word but not on the frequency of a homophone twin. A. Caramazza, A. Costa, et al. concluded that homophones have separate word form representations and that the absence of frequency-inheritance effects for homophones undermines an important argument in support of 2-stage models of lexical access, which assume that syntactic (lemma) representations mediate between conceptual and phonological representations. The authors of this article evaluate the empirical basis of this conclusion, report 2 experiments demonstrating a frequency-inheritance effect, and discuss other recent evidence. It is concluded that homophones share a common word form and that the distinction between lemmas and word forms should be upheld.

Abstract

The Possible Word Constraint limits the number of lexical candidates considered in speech recognition by stipulating that input should be parsed into a string of lexically viable chunks. For instance, an isolated single consonant is not a feasible word candidate. Any segmentation containing such a chunk is disfavored. Five experiments using the head-turn preference procedure investigated whether, like adults, 12-month-olds observe this constraint in word recognition. In Experiments 1 and 2, infants were familiarized with target words (e.g., rush), then tested on lists of nonsense items containing these words in “possible” (e.g., “niprush” [nip + rush]) or “impossible” positions (e.g., “prush” [p + rush]). The infants listened significantly longer to targets in “possible” versus “impossible” contexts when targets occurred at the end of nonsense items (rush in “prush”), but not when they occurred at the beginning (tan in “tance”). In Experiments 3 and 4, 12-month-olds were similarly familiarized with target words, but test items were real words in sentential contexts (win in “wind” versus “window”). The infants listened significantly longer to words in the “possible” condition regardless of target location. Experiment 5 with targets at the beginning of isolated real words (e.g., win in “wind”) replicated Experiment 2 in showing no evidence of viability effects in beginning position. Taken together, the findings suggest that, in situations in which 12-month-olds are required to rely on their word segmentation abilities, they give evidence of observing lexical viability constraints in the way that they parse fluent speech.

Abstract

This paper presents a theory of the syntactic aspects of human sentence production. An important characteristic of unprepared speech is that overt pronunciation of a sentence can be initiated before the speaker has completely worked out the meaning content he or she is going to express in that sentence. Apparently, the speaker is able to build up a syntactically coherent utterance out of a series of syntactic fragments each rendering a new part of the meaning content. This incremental, left-to-right mode of sentence production is the central capability of the proposed Incremental Procedural Grammar (IPG). Certain other properties of spontaneous speech, as derivable from speech errors, hesitations, self-repairs, and language pathology, are accounted for as well. The psychological plausibility thus gained by the grammar appears compatible with a satisfactory level of linguistic plausibility in that sentences receive structural descriptions which are in line with current theories of grammar. More importantly, an explanation for the existence of configurational conditions on transformations and other linguistics rules is proposed. The basic design feature of IPG which gives rise to these psychologically and linguistically desirable properties, is the “Procedures + Stack” concept. Sentences are built not by a central constructing agency which overlooks the whole process but by a team of syntactic procedures (modules) which work-in parallel-on small parts of the sentence, have only a limited overview, and whose sole communication channel is a stock. IPG covers object complement constructions, interrogatives, and word order in main and subordinate clauses. It handles unbounded dependencies, cross-serial dependencies and coordination phenomena such as gapping and conjunction reduction. It is also capable of generating self-repairs and elliptical answers to questions. IPG has been implemented as an incremental Dutch sentence generator written in LISP.

Abstract

In a recent Cognition paper (Cognition 85 (2002) B21), Bornkessel, Schlesewsky, and Friederici report ERP data that they claim “show that online processing difficulties induced by word order variations in German cannot be attributed to the relative infrequency of the constructions in question, but rather appear to reflect the application of grammatical principles during parsing” (p. B21). In this commentary we demonstrate that the posited contrast between grammatical principles and construction (in)frequency as sources of parsing problems is artificial because it is based on factually incorrect assumptions about the grammar of German and on inaccurate corpus frequency data concerning the German constructions involved.

Abstract

Four probe latency experiments show that the ‘constituent boundary effect’ (transitions between constituents are more difficult than within constituents) is a retrieval and not a storage phenomenon. The experimental logic used is called paraphrastic reproduction: after verbatim memorization of some sentences, subjects were instructed to reproduce them both in their original wording and in the form of sentences that, whilst preserving the original meaning, embodied different syntactic constructions. Syntactic constructions are defined as pairs which consist of a pattern of conceptual information and a syntactic scheme, i.e. a sequence of syntactic word categories and function words. For example, the sequence noun + finite intransitive main verb (‘John runs’) expresses a conceptual actor-action relationship. It is proposed that for each overlearned and simple syntactic construction there exists a retrieval plan which does the following. It searches through the long-term memory information that has been designated as the conceptual content of the utterance(s) to be produced, looking for a token of its conceptual pattern. The retrieved information is then cast into the format of its syntactic scheme. The organization of such plans is held responsible for the constituent boundary effect.

Abstract

A series of experiments is reported in which subjects describe simple visual scenes by means of both sentential and non-sentential responses. The data support the following statements about the lexicalization (word finding) process. (1) Words used by speakers in overt naming or sentence production responses are selected by a sequence of two lexical retrieval processes, the first yielding abstract pre-phonological items (Ll -items), the second one adding their phonological shapes (L2-items). (2) The selection of several Ll-items for a multi-word utterance can take place simultaneously. (3) A monitoring process is watching the output of Ll-lexicalization to check if it is in keeping with prevailing constraints upon utterance format. (4) Retrieval of the L2-item which corresponds with a given LI-item waits until the Ld-item has been checked by the monitor, and all other Ll-items needed for the utterance under construction have become available. A coherent picture of the lexicalization process begins to emerge when these characteristics are brought together with other empirical results in the area of naming and sentence production, e.g., picture naming reaction times (Seymour, 1979), speech errors (Garrett, 1980), and word order preferences (Bock, 1982).

Abstract

Eisenberg (2002) presents data from an experiment investigating three- and four-year-old children's comprehension of restrictive relative clauses (RC). From the results she argues, contrary to Hamburger & Crain (1982), that children do not have discourse knowledge of the felicity conditions of RCs before acquiring the syntax of relativization. This note evaluates this conclusion on the basis of the methodology used, and proposes that an account of syntactic development needs to be sensitive to the real-time processing requirements acquisition places on the learner.

Abstract

Gestures that spontaneously accompany speech convey information coordinated with the concurrent speech. There has been considerable theoretical disagreement about the process by which this informational coordination is achieved. Some theories predict that the information encoded in gesture is not influenced by how information is verbally expressed. However, others predict that gestures encode only what is encoded in speech. This paper investigates this issue by comparing informational coordination between speech and gesture across different languages. Narratives in Turkish, Japanese, and English were elicited using an animated cartoon as the stimulus. It was found that gestures used to express the same motion events were influenced simultaneously by (1) how features of motion events were expressed in each language, and (2) spatial information in the stimulus that was never verbalized. From this, it is concluded that gestures are generated from spatio-motoric processes that interact on-line with the speech production process. Through the interaction, spatio-motoric information to be expressed is packaged into chunks that are verbalizable within a processing unit for speech formulation. In addition, we propose a model of speech and gesture production as one of a class of frameworks that are compatible with the data.

Abstract

Disruption of FOXP2, a gene encoding a forkhead-domain transcription factor, causes a severe developmental disorder of verbal communication, involving profound articulation deficits, accompanied by linguistic and grammatical impairments. Investigation of the neural basis of this disorder has been limited previously to neuroimaging of affected children and adults. The discovery of the gene responsible, FOXP2, offers a unique opportunity to explore the relevant neural mechanisms from a molecular perspective. In the present study, we have determined the detailed spatial and temporal expression pattern of FOXP2 mRNA in the developing brain of mouse and human. We find expression in several structures including the cortical plate, basal ganglia, thalamus, inferior olives and cerebellum. These data support a role for FOXP2 in the development of corticostriatal and olivocerebellar circuits involved in motor control. We find intriguing concordance between regions of early expression and later sites of pathology suggested by neuroimaging. Moreover, the homologous pattern of FOXP2/Foxp2 expression in human and mouse argues for a role for this gene in development of motor-related circuits throughout mammalian species. Overall, this study provides support for the hypothesis that impairments in sequencing of movement and procedural learning might be central to the FOXP2-related speech and language disorder.

Abstract

Investigations of left hand praxis in imitation and object use in patients with callosal disconnection have yielded divergent results, inducing a debate between two theoretical positions. Whereas Liepmann suggested that the left hemisphere is motor dominant, others maintain that both hemispheres have equal motor competences and propose that left hand apraxia in patients with callosal disconnection is secondary to left hemispheric specialization for language or other task modalities. The present study aims to gain further insight into the motor competence of the right hemisphere by investigating pantomime of object use in split-brain patients. Three patients with complete callosotomy and, as control groups, five patients with partial callosotomy and nine healthy subjects were examined for their ability to pantomime object use to visual object presentation and demonstrate object manipulation. In each condition, 11 objects were presented to the subjects who pantomimed or demonstrated the object use with either hand. In addition, six object pairs were presented to test bimanual coordination. Two independent raters evaluated the videotaped movement demonstrations. While object use demonstrations were perfect in all three groups, the split-brain patients displayed apraxic errors only with their left hands in the pantomime condition. The movement analysis of concept and execution errors included the examination of ipsilateral versus contralateral motor control. As the right hand/left hemisphere performances demonstrated retrieval of the correct movement concepts, concept errors by the left hand were taken as evidence for right hemisphere control. Several types of execution errors reflected a lack of distal motor control indicating the use of ipsilateral pathways. While one split-brain patient controlled his left hand predominantly by ipsilateral pathways in the pantomime condition, the error profile in the other two split-brain patients suggested that the right hemisphere controlled their left hands. In the object use condition, in all three split-brain patients fine-graded distal movements in the left hand indicated right hemispheric control. Our data show left hand apraxia in split-brain patients is not limited to verbal commands, but also occurs in pantomime to visual presentation of objects. As the demonstration with object in hand was unimpaired in either hand, both hemispheres must contain movement concepts for object use. However, the disconnected right hemisphere is impaired in retrieving the movement concept in response to visual object presentation, presumably because of a deficit in associating perceptual object representation with the movement concepts.

Abstract

Since some patients with right hemisphere damage or with spontaneous callosal disconnection neglect the left half of space, it has been suggested that the left cerebral hemisphere predominantly attends to the right half of space. However, clinical investigations of patients having undergone surgical callosal section have not shown neglect when the hemispheres are tested separately. These observations question the validity of theoretical models that propose a left hemispheric specialisation for attending to the right half of space. The present study aims to investigate neglect and the use of space by either hand in gestural demonstrations in three split-brain patients as compared to five patients with partial callosotomy and 11 healthy subjects. Subjects were asked to demonstrate with precise gestures and without speaking the content of animated scenes with two moving objects. The results show that in the absence of primary perceptual or representational neglect, split-brain patients neglect left personal space in right-handed gestural demonstrations. Since this neglect of left personal space cannot be explained by directional or spatial akinesia, it is suggested that it originates at the conceptual level, where the spatial coordinates for right-hand gestures are planned. The present findings are at odds with the position that the separate left hemisphere possesses adequate mechanisms for acting in both halves of space and neglect results from right hemisphere suppression of this potential. Rather, the results provide support for theoretical models that consider the left hemisphere as specialised for processing the right half of space during the execution of descriptive gestures.

Abstract

The present study investigates the hand choice in iconic gestures that accompany speech. In 10 right-handed subjects gestures were elicited by verbal narration and by silent gestural demonstrations of animations with two moving objects. In both conditions, the left-hand was used as often as the right-hand to display iconic gestures. The choice of the right- or left-hands was determined by semantic aspects of the message. The influence of hemispheric language lateralization on the hand choice in co-speech gestures appeared to be minor. Instead, speaking seemed to induce a sequential organization of the iconic gestures.

Abstract

Making a self-repair in speech typically proceeds in three phases. The first phase involves the monitoring of one’s own speech and the interruption of the flow of speech when trouble is detected. From an analysis of 959 spontaneous self-repairs it appears that interrupting follows detection promptly, with the exception that correct words tend to be completed. Another finding is that detection of trouble improves towards the end of constituents. The second phase is characterized by hesitation, pausing, but especially the use of so-called editing terms. Which editing term is used depends on the nature of the speech trouble in a rather regular fashion: Speech errors induce other editing terms than words that are merely inappropriate, and trouble which is detected quickly by the speaker is preferably signalled by the use of ‘uh’. The third phase consists of making the repair proper The linguistic well-formedness of a repair is not dependent on the speaker’s respecting the integriv of constituents, but on the structural relation between original utterance and repair. A bi-conditional well-formedness rule links this relation to a corresponding relation between the conjuncts of a coordination. It is suggested that a similar relation holds also between question and answer. In all three cases the speaker respects certain Istructural commitments derived from an original utterance. It was finally shown that the editing term plus the first word of the repair proper almost always contain sufficient information for the listener to decide how the repair should be related to the original utterance. Speakers almost never produce misleading information in this respect. It is argued that speakers have little or no access to their speech production process; self-monitoring is probably based on parsing one’s own inner or overt speech.

Abstract

In their comment, Dell and O'Seaghdha (1991) adduced any effect on phonological probes for semantic alternatives to the activation of these probes in the lexical network. We argue that that interpretation is false and, in addition, that the model still cannot account for our data. Furthermore, and different from Dell and O'seaghda, we adduce semantic rebound to the lemma level, where it is so substantial that it should have shown up in our data. Finally, we question the function of feedback in a lexical network (other than eliciting speech errors) and discuss Dell's (1988) notion of a unified production-comprehension system.

Abstract

Spontaneous self-corrections in speech pose a communication problem; the speaker must make clear to the listener not only that the original Utterance was faulty, but where it was faulty and how the fault is to be corrected. Prosodic marking of corrections - making the prosody of the repair noticeably different from that of the original utterance - offers a resource which the speaker can exploit to provide the listener with such information. A corpus of more than 400 spontaneous speech repairs was analysed, and the prosodic characteristics compared with the syntactic and semantic characteristics of each repair. Prosodic marking showed no relationship at all with the syntactic characteristics of repairs. Instead, marking was associated with certain semantic factors: repairs were marked when the original utterance had been actually erroneous, rather than simply less appropriate than the repair; and repairs tended to be marked more often when the set of items encompassing the error and the repair was small rather than when it was large. These findings lend further weight to the characterization of accent as essentially semantic in function.

Abstract

This is a translation of Levinson and Brown (1994).

Abstract

Most approaches to spatial language have assumed that the simplest spatial notions are (after Piaget) topological and universal (containment, contiguity, proximity, support, represented as semantic primitives suchas IN, ON, UNDER, etc.). These concepts would be coded directly in language, above all in small closed classes suchas adpositions—thus providing a striking example of semantic categories as language-specific projections of universal conceptual notions. This idea, if correct, should have as a consequence that the semantic categories instantiated in spatial adpositions should be essentially uniform crosslinguistically. This article attempts to verify this possibility by comparing the semantics of spatial adpositions in nine unrelated languages, with the help of a standard elicitation procedure, thus producing a preliminary semantic typology of spatial adpositional systems. The differences between the languages turn out to be so significant as to be incompatible withstronger versions of the UNIVERSAL CONCEPTUAL CATEGORIES hypothesis. Rather, the language-specific spatial adposition meanings seem to emerge as compact subsets of an underlying semantic space, withcertain areas being statistical ATTRACTORS or FOCI. Moreover, a comparison of systems withdifferent degrees of complexity suggests the possibility of positing implicational hierarchies for spatial adpositions. But such hierarchies need to be treated as successive divisions of semantic space, as in recent treatments of basic color terms. This type of analysis appears to be a promising approachfor future work in semantic typology.

Abstract

Comment on Sperber and Wilson

Abstract

In an earlier article (Levinson, 1987b), I raised the possibility that a Gricean theory of implicature might provide a systematic partial reduction of the Binding Conditions; the briefest of outlines is given in Section 2.1 below but the argumentation will be found in the earlier article. In this article I want, first, to show how that account might be further justified and extended, but then to introduce a radical alternative. This alternative uses the same pragmatic framework, but gives an account better adjusted to some languages. Finally, I shall attempt to show that both accounts can be combined by taking a diachronic perspective. The attraction of the combined account is that, suddenly, many facts about long-range reflexives and their associated logophoricity fall into place.

Abstract

This paper is one in a series that develops a pragmatic framework in loose confederation with Jay Atlas and Larry Horn: thus they may or may not be responsible for the ideas contained herein. Jay Atlas provided many comments which I have utilized or perverted as the case may be. The Australian data to which this framework is applied was collected with the financial and personal assistance of many people and agencies acknowledged separately below; but I must single out for special thanks John Haviland, who recommended the study of Guugu Yimidhirr anaphora to me and upon whose grammatical work on Guugu Yimidhirr this paper is but a minor (and perhaps flawed) elaboration. A grant from the British Academy allowed me to visit Haviland in September 1986 to discuss many aspects of Guugu Yimidhirr with him, and I am most grateful to the Academy for funding this trip and to Haviland for generously making available his time, his texts (from which I have drawn many examples, not always with specific acknowledgement) and most especially his expertise. Where I have diverged from his opinion I may well learn to regret it. I must also thank Nigel Vincent for putting me in touch with a number of recent relevant developments in syntax (only some of which I have been able to address) and for suggestions for numerous improvements. In addition, I have benefited immensely for comments on a distinct but related paper (Levinson, 1987) kindly provided by Jay Atlas, John Haviland, John Heritage, Phil Johnson-Laird, John Lyons, Tanya Reinhart, Emanuel Schegloff and an anonymous referee; and from comments on this paper by participants in the Cambridge Linguistics Department seminar where it was first presented (especial thanks to John Lyons and Huang Yan for further comments, and Mary Smith for a counter-example). Despite all this help, there are sure to be errors of data and analysis that I have persisted in. Aid in gathering the Australian data is acknowledged separately below.

Abstract

Recent research suggests that 12-month-old infants in German cultural settings have the motive of sharing their attention to and interest in various events with a social interlocutor. To do so, these preverbal infants predominantly use the pointing gesture (in this case the extended arm with or without extended index finger) as a means to direct another person’s attention. This task systematically investigates different types of motives underlying infants’ pointing. The occurrence of a protodeclarative (as opposed to protoimperative) motive is of particular interest because it requires an understanding of the recipient’s psychological states, such as attention and interest, that can be directed and accessed.

Abstract

The posterior medial parietal cortex and the left prefrontal cortex have both been implicated in the recollection of past episodes. In order to clarify their functional significance, we performed this functional magnetic resonance imaging study, which employed event-related source memory and item recognition retrieval of words paired with corresponding imagined or viewed pictures. Our results suggest that episodic source memory is related to a functional network including the posterior precuneus and the left lateral prefrontal cortex. This network is activated during explicit retrieval of imagined pictures and results from the retrieval of item-context associations. This suggests that previously imagined pictures provide a context with which encoded words can be more strongly associated.

Abstract

Physiological data from a range of human populations living in different environments can provide valuable information for testing evolutionary hypotheses about human adaptation. By taking into account the effects of population history, phylogenetic comparative methods can help us determine whether variation results from selection due to particular environmental variables. These selective forces could even be due to cultural traits-which means that gene-culture co-evolution may be occurring. In this paper, we outline two examples of the use of these approaches to test adaptive hypotheses that explain global variation in two physiological traits: the first is lactose digestion capacity in adults, and the second is population sex-ratio at birth. We show that lower than average sex ratio at birth is associated with high fertility, and argue that global variation in sex ratio at birth has evolved as a response to the high physiological costs of producing boys in high fertility populations.

Abstract

The time course of spoken word recognition depends largely on the frequencies of a word and its competitors, or neighbors (similar-sounding words). However, variability in natural lexicons makes systematic analysis of frequency and neighbor similarity difficult. Artificial lexicons were used to achieve precise control over word frequency and phonological similarity. Eye tracking provided time course measures of lexical activation and competition (during spoken instructions to perform visually guided tasks) both during and after word learning, as a function of word frequency, neighbor type, and neighbor frequency. Apparent shifts from holistic to incremental competitor effects were observed in adults and neural network simulations, suggesting such shifts reflect general properties of learning rather than changes in the nature of lexical representations.

Abstract

There are three main strands of research which have investigated people’s intuitive knowledge of objects in motion. (1) Knowledge of the trajectories of objects in motion; (2) knowledge of the causes of motion; and (3) the categorisation of motion as to whether it has been produced by something animate or inanimate. We provide a brief introduction to each of these areas. We then point to some linguistic and cultural differences which may have consequences for people’s knowledge of objects in motion. Finally, we describe two experimental tasks and an ethnographic task that will allow us to collect data in order to establish whether, indeed, there are interesting cross-linguistic/cross-cultural differences in lay theories of objects in motion.

Abstract

The human capacity for acquiring speech and language must derive, at least in part, from the genome. In 2001, a study described the first case of a gene, FOXP2, which is thought to be implicated in our ability to acquire spoken language. In the present article, we discuss how this gene was discovered, what it might do, how it relates to other genes, and what it could tell us about the nature of speech and language development. We explain how FOXP2 could, without being specific to the brain or to our own species, still provide an invaluable entry-point into understanding the genetic cascades and neural pathways that contribute to our capacity for speech and language.

Abstract

Replication of linkage results for complex traits has been exceedingly difficult, owing in part to the inability to measure the precise underlying phenotype, small sample sizes, genetic heterogeneity, and statistical methods employed in analysis. Often, in any particular study, multiple correlated traits have been collected, yet these have been analyzed independently or, at most, in bivariate analyses. Theoretical arguments suggest that full multivariate analysis of all available traits should offer more power to detect linkage; however, this has not yet been evaluated on a genomewide scale. Here, we conduct multivariate genomewide analyses of quantitative-trait loci that influence reading- and language-related measures in families affected with developmental dyslexia. The results of these analyses are substantially clearer than those of previous univariate analyses of the same data set, helping to resolve a number of key issues. These outcomes highlight the relevance of multivariate analysis for complex disorders for dissection of linkage results in correlated traits. The approach employed here may aid positional cloning of susceptibility genes in a wide spectrum of complex traits.

Abstract

Magnuson, McMurray, Tanenhaus, and Aslin [Cogn. Sci. 27 (2003) 285] suggest that they have evidence of lexical feedback in speech perception, and that this evidence thus challenges the purely feedforward Merge model [Behav. Brain Sci. 23 (2000) 299]. This evidence is open to an alternative explanation, however, one which preserves the assumption in Merge that there is no lexical-prelexical feedback during on-line speech processing. This explanation invokes the distinction between perceptual processing that occurs in the short term, as an utterance is heard, and processing that occurs over the longer term, for perceptual learning.