Publications

Abstract

The apolipoprotein E {varepsilon}4 (APOE {varepsilon}4) is the main known genetic risk factor for Alzheimer's disease. Genetic assessments in combination with other diagnostic tools, such as neuroimaging, have the potential to facilitate early diagnosis. In this large-scale functional MRI (fMRI) study, we have contrasted 30 APOE {varepsilon}4 carriers (age range: 49–74 years; 19 females), of which 10 were homozygous for the {varepsilon}4 allele, and 30 non-carriers with regard to brain activity during a semantic categorization task. Test groups were closely matched for sex, age and education. Critically, both groups were cognitively intact and thus symptom-free of Alzheimer's disease. APOE {varepsilon}4 carriers showed reduced task-related responses in the left inferior parietal cortex, and bilaterally in the anterior cingulate region. A dose-related response was observed in the parietal area such that diminution was most pronounced in homozygous compared with heterozygous carriers. In addition, contrasts of processing novel versus familiar items revealed an abnormal response in the right hippocampus in the APOE {varepsilon}4 group, mainly expressed as diminished sensitivity to the relative novelty of stimuli. Collectively, these findings indicate that genetic risk translates into reduced functional brain activity, in regions pertinent to Alzheimer's disease, well before alterations can be detected at the behavioural level.

Abstract

Classically, infants are thought to point for 2 main reasons: (a) They point imperatively when they want an adult to do something for them (e.g., give them something; “Juice!”), and (b) they point declaratively when they want an adult to share attention with them to some interesting event or object (“Look!”). Here we demonstrate the existence of another motive for infants' early pointing gestures: to inform another person of the location of an object that person is searching for. This informative motive for pointing suggests that from very early in ontogeny humans conceive of others as intentional agents with informational states and they have the motivation to provide such information communicatively

Abstract

Tests of causal attribution often use verbal vignettes, with covariation information provided through statements quantified with natural language expressions. The effect of covariation information has typically been taken to show that set size information affects attribution. However, recent research shows that quantifiers provide information about discourse focus as well as covariation information. In the attribution literature, quantifiers are used to depict covariation, but they confound quantity and focus. In four experiments, we show that focus explains all (Experiment 1) or some (Experiments 2, 3 and 4) of the impact of covariation information on the attributions made, confirming the importance of the confound. Attribution experiments using vignettes that present covariation information with natural language quantifiers may overestimate the impact of set size information, and ignore the impact of quantifier-induced focus.

Abstract

A key question in categorisation is to what extent people categorise in the same way, or differently. This paper examines categorisation of the body in Punjabi, an Indo-European language spoken in Pakistan and India. First, an inventory of body part terms is presented, illustrating how Punjabi speakers segment and categorise the body. There are some noteworthy terms in the inventory, which illustrate categories in Punjabi that are unusual when compared to other languages presented in this volume. Second, Punjabi speakers’ conceptualisation of the relationship between body parts is explored. While some body part terms are viewed as being partonomically related, others are viewed as being in a locative relationship. It is suggested that there may be key ways in which languages differ in both the categorisation of the body into parts, and in how these parts are related to one another.

Abstract

For several languages, a preference for subject relative clauses over object relative clauses has been reported. However, Mak, Vonk, and Schriefers (2002) showed that there is no such preference for relative clauses with an animate subject and an inanimate object. A Dutch object relative clause as …de rots, die de wandelaars beklommen hebben… (‘the rock, that the hikers climbed’) did not show longer reading times than its subject relative clause counterpart …de wandelaars, die de rots beklommen hebben… (‘the hikers, who climbed the rock’). In the present paper, we explore the factors that might contribute to this modulation of the usual preference for subject relative clauses. Experiment 1 shows that the animacy of the antecedent per se is not the decisive factor. On the contrary, in relative clauses with an inanimate antecedent and an inanimate relative-clause-internal noun phrase, the usual preference for subject relative clauses is found. In Experiments 2 and 3, subject and object relative clauses were contrasted in which either the subject or the object was inanimate. The results are interpreted in a framework in which the choice for an analysis of the relative clause is based on the interplay of animacy with topichood and verb semantics. This framework accounts for the commonly reported preference for subject relative clauses over object relative clauses as well as for the pattern of data found in the present experiments.

Abstract

A perceptual learning experiment provides evidence that the mental lexicon cannot consist solely of detailed acoustic traces of recognition episodes. In a training lexical decision phase, listeners heard an ambiguous [f–s] fricative sound, replacing either [f] or [s] in words. In a test phase, listeners then made lexical decisions to visual targets following auditory primes. Critical materials were minimal pairs that could be a word with either [f] or [s] (cf. English knife–nice), none of which had been heard in training. Listeners interpreted the minimal pair words differently in the second phase according to the training received in the first phase. Therefore, lexically mediated retuning of phoneme perception not only influences categorical decisions about fricatives (Norris, McQueen, & Cutler, 2003), but also benefits recognition of words outside the training set. The observed generalization across words suggests that this retuning occurs prelexically. Therefore, lexical processing involves sublexical phonological abstraction, not only accumulation of acoustic episodes.

Abstract

The speech perception system must be flexible in responding to the variability in speech sounds caused by differences among speakers and by language change over the lifespan of the listener. Indeed, listeners use lexical knowledge to retune perception of novel speech (Norris, McQueen, & Cutler, 2003). In that study, Dutch listeners made lexical decisions to spoken stimuli, including words with an ambiguous fricative (between [f] and [s]), in either [f]- or [s]-biased lexical contexts. In a subsequent categorization test, the former group of listeners identified more sounds on an [εf] - [εs] continuum as [f] than the latter group. In the present experiment, listeners received the same exposure and test stimuli, but did not make lexical decisions to the exposure items. Instead, they counted them. Categorization results were indistinguishable from those obtained earlier. These adjustments in fricative perception therefore do not depend on explicit judgments during exposure. This learning effect thus reflects automatic retuning of the interpretation of acoustic-phonetic information.

Abstract

The results of a word-spotting experiment are presented in which Dutch listeners tried to spot different types of bisyllabic Dutch words embedded in different types of nonsense contexts. Embedded verbs were not reliably harder to spot than embedded nouns; this suggests that nouns and verbs are recognised via the same basic processes. Iambic words were no harder to spot than trochaic words, suggesting that trochaic words are not in principle easier to recognise than iambic words. Words were harder to spot in consonantal contexts (i.e., contexts which themselves could not be words) than in longer contexts which contained at least one vowel (i.e., contexts which, though not words, were possible words of Dutch). A control experiment showed that this difference was not due to acoustic differences between the words in each context. The results support the claim that spoken-word recognition is sensitive to the viability of sound sequences as possible words.

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

This paper presents an analysis of semantic association norms for German nouns. In contrast to prior studies, we not only collected associations elicited by written representations of target objects but also by their pictorial representations. In a first analysis, we identified systematic differences in the type and distribution of associate responses for the two presentation forms. In a second analysis, we applied a soft cluster analysis to the collected target-response pairs. We subsequently used the clustering to predict noun ambiguity and to discriminate senses in our target nouns.

Abstract

The Revised Hierarchical Model (Kroll and Stewart, 1994) assumes that words in a bilingual’s languages have separate word form representations but shared conceptual representations. Two routes lead from an L2 word form to its conceptual representation: the word association route, where concepts are accessed through the corresponding L1 word form, and the concept mediation route, with direct access from L2 to concepts. To investigate word association, we presented proficient late German-Dutch bilinguals with L2 non-cognate word pairs in which the L1 translation of the first word rhymed with the second word (e.g. GRAP (joke) – Witz – FIETS (bike)). If the first word in a pair activated its L1 equivalent, then a phonological priming effect on the second word was expected. Priming was observed in lexical decision but not in semantic decision (living/non-living) on L2 words. In a control group of Dutch native speakers, no priming effect was found. This suggests that proficient bilinguals still make use of their L1 word form lexicon to process L2 in lexical decision.

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

Eye movements have been shown to reflect word recognition and language comprehension processes occurring during reading and auditory language comprehension. The present study examines whether the eye movements speakers make during object naming similarly reflect speech planning processes. In Experiment 1, speakers named object pairs saying, for instance, 'scooter and hat'. The objects were presented as ordinary line drawings or with partly dele:ed contours and had high or low frequency names. Contour type and frequency both significantly affected the mean naming latencies and the mean time spent looking at the objects. The frequency effects disappeared in Experiment 2, in which the participants categorized the objects instead of naming them. This suggests that the frequency effects of Experiment 1 arose during lexical retrieval. We conclude that eye movements during object naming indeed reflect linguistic planning processes and that the speakers' decision to move their eyes from one object to the next is contingent upon the retrieval of the phonological form of the object names.

Abstract

The goal of speech perception is understanding a speaker's message. To achieve this, listeners must recognize the words that comprise a spoken utterance. This in turn implies distinguishing these words from other minimally different words (e.g., word from bird, etc.), and this involves making phonemic distinctions. The article summarizes research on the perception of phonemic distinctions, on how listeners cope with the continuity and variability of speech signals, and on how phonemic information is mapped onto the representations of words. Particular attention is paid to theories of speech perception and word recognition.

Abstract

This study examined whether compensation for coarticulation in fricative–vowel syllables is phonologically mediated or a consequence of auditory processes. Smits (2001a) had shown that compensation occurs for anticipatory lip rounding in a fricative caused by a following rounded vowel in Dutch. In a first experiment, the possibility that compensation is due to general auditory processing was investigated using nonspeech sounds. These did not cause context effects akin to compensation for coarticulation, although nonspeech sounds influenced speech sound identification in an integrative fashion. In a second experiment, a possible phonological basis for compensation for coarticulation was assessed by using audiovisual speech. Visual displays, which induced the perception of a rounded vowel, also influenced compensation for anticipatory lip rounding in the fricative. These results indicate that compensation for anticipatory lip rounding in fricative–vowel syllables is phonologically mediated. This result is discussed in the light of other compensation-for-coarticulation findings and general theories of speech perception.

Abstract

We investigated how spoken words are recognized when they have been altered by phonological assimilation. Previous research has shown that there is a process of perceptual compensation for phonological assimilations. Three recently formulated proposals regarding the mechanisms for compensation for assimilation make different predictions with regard to the level at which compensation is supposed to occur as well as regarding the role of specific language experience. In the present study, Hungarian words and nonwords, in which a viable and an unviable liquid assimilation was applied, were presented to Hungarian and Dutch listeners in an identification task and a discrimination task. Results indicate that viably changed forms are difficult to distinguish from canonical forms independent of experience with the assimilation rule applied in the utterances. This reveals that auditory processing contributes to perceptual compensation for assimilation, while language experience has only a minor role to play when identification is required.

Abstract

In a series of 5 experiments, we investigated whether the processing of phonologically assimilated utterances is influenced by language learning. Previous experiments had shown that phonological assimilations, such as /lean#bacon/→[leam bacon], are compensated for in perception. In this article, we investigated whether compensation for assimilation can occur without experience with an assimilation rule using automatic event-related potentials. Our first experiment indicated that Dutch listeners compensate for a Hungarian assimilation rule. Two subsequent experiments, however, failed to show compensation for assimilation by both Dutch and Hungarian listeners. Two additional experiments showed that this was due to the acoustic properties of the assimilated utterance, confirming earlier reports that phonetic detail is important in compensation for assimilation. Our data indicate that compensation for assimilation can occur without experience with an assimilation rule, in line with phonetic–phonological theories that assume that speech production is influenced by speech-perception abilities.

Abstract

Vowel normalization in speech perception was investigated in three experiments. The range of the second formant in a carrier phrase was manipulated and this affected the perception of a target vowel in a compensatory fashion: A low F2 range in the carrier phrase made it more likely that the target vowel was perceived as a front vowel, that is, with a high F2. Recent experiments indicated that this effect might be moderated by the lexical status of the constituents of the carrier phrase. Manipulation of the lexical status in the present experiments, however, did not affect vowel normalization. In contrast, the range of vowels in the carrier phrase did influence vowel normalization. If the carrier phrase consisted of mid-to-high front vowels only, vowel categories shifted only for mid-to-high front vowels. It is argued that these results are a challenge for episodic models of word recognition.

Abstract

In everyday speech, words may be reduced. Little is known about the consequences of such reductions for spoken word comprehension. This study investigated /t/-lenition in Dutch in two corpus studies and three perceptual experiments. The production studies revealed that /t/-lenition is most likely to occur after [s] and before bilabial consonants. The perception experiments showed that listeners take into account both phonological context, phonetic detail, and the lexical status of the form in the interpretation of codas that may or may not contain a lenited word-final /t/. These results speak against models of word recognition that make hard decisions on a prelexical level.

Abstract

In discourse, older adults tend to be more verbose and more disfluent than young adults, especially when the task is difficult and when it places few constraints on the content of the utterance. This may be due to (a) language-specific deficits in planning the content and syntactic structure of utterances or in selecting and retrieving words from the mental lexicon, (b) a general deficit in inhibiting irrelevant information, or (c) the selection of a specific speech style. The possibility that older adults have a deficit in lexical retrieval is supported by the results of picture naming studies, in which older adults have been found to name objects less accurately and more slowly than young adults, and by the results of definition naming studies, in which older adults have been found to experience more tip-of-the-tongue (TOT) states than young adults. The available evidence suggests that these age differences are largely due to weakening of the connections linking word lemmas to phonological word forms, though adults above 70 years of age may have an additional deficit in lemma selection.

Abstract

The present doctoral thesis investigates the temporal characteristics of the retrieval of semantic and syntactic word properties in language comprehension. In particular, an attempt is made to assess the retrieval order of semantic category and grammatical gender information, using the lateralized readiness potential and the inhibition-related N2 effect. Chapter 1 contains a general introduction. Chapter 2 reports an experiment that employs the two-choice go/nogo task in combination with EEG recordings to establish the retrieval order of semantic category and grammatical gender for written words presented in isolation. The results point to a time course where semantic information becomes available before syntactic information. Chapter 3 focuses on the retrieval of grammatical gender. In order to examine whether gender retrieval can be speeded up by context, nouns are presented in gender congruent and gender incongruent prime-target pairs and reaction times for gender decisions are measured. For stimulus onset asynchronies of 100 ms and 0 ms, gender congruent pairs show faster responses than incongruent ones, whereas there is no effect of gender congruity for a stimulus onset asynchrony of 300 ms. A simulation with a localist computational model that implements competition between gender representations (WEAVER; Roelofs, 1992) is able to capture these findings. In chapter 4, the gender congruency manipulation is transferred to another ERP experiment with the two-choice go/nogo task. As the time course of gender retrieval is altered through primes, the order relative to semantic category retrieval is assessed again. The results indicate that with gender congruent primes, grammatical gender becomes available before semantic category. Such a reversal of retrieval order, as compared to chapter 2, implies a parallel rather than a serial discrete arrangement of the retrieval processes, since the latter variant precludes changes in retrieval order. Finally, chapter 5 offers a summary and general discussion of the main findings.

Abstract

The recognition of a word makes available its semantic and
syntactic properties. Using electrophysiological recordings, we
investigated whether one set of these properties is available
earlier than the other set. Dutch participants saw nouns on a
computer screen and performed push-button responses: In
one task, grammatical gender determined response hand
(left/right) and semantic category determined response execution
(go/no-go). In the other task, response hand depended
on semantic category, whereas response execution depended
on gender. During the latter task, response preparation occurred
on no-go trials, as measured by the lateralized
readiness potential: Semantic information was used for
response preparation before gender information inhibited
this process. Furthermore, an inhibition-related N2 effect
occurred earlier for inhibition by semantics than for inhibition
by gender. In summary, electrophysiological measures
of both response preparation and inhibition indicated that
the semantic word property was available earlier than the
syntactic word property when participants read single
words.

Abstract

Muscular hypertrophy in callipyge sheep results from a single nucleotide substitution located in the genomic interval between the imprinted Delta, Drosophila, Homolog-like 1 (DLK1) and Maternally Expressed Gene 3 (MEG3). The mechanism linking the mutation to muscle hypertrophy is unclear but involves DLK1 overexpression. The mutation is contained within CLPG1 transcripts produced from this region. Herein we show that CLPG1 is expressed prenatally in the hypertrophy-responsive longissimus dorsi muscle by all four possible genotypes, but postnatal expression is restricted to sheep carrying the mutation. Surprisingly, the mutation results in nonimprinted monoallelic transcription of CLPG1 from only the mutated allele in adult sheep, whereas it is expressed biallelically during prenatal development. We further demonstrate that local CpG methylation is altered by the presence of the mutation in longissimus dorsi of postnatal sheep. For 10 CpG sites flanking the mutation, methylation is similar prenatally across genotypes, but doubles postnatally in normal sheep. This normal postnatal increase in methylation is significantly repressed in sheep carrying one copy of the mutation, and repressed even further in sheep with two mutant alleles. The attenuation in methylation status in the callipyge sheep correlates with the onset of the phenotype, continued CLPG1 transcription, and high-level expression of DLK1. In contrast, normal sheep exhibit hypermethylation of this locus after birth and CLPG1 silencing, which coincides with DLK1 transcriptional repression. These data are consistent with the notion that the callipyge mutation inhibits perinatal nucleation of regional chromatin condensation resulting in continued elevated transcription of prenatal DLK1 levels in adult callipyge sheep. We propose a model incorporating these results that can also account for the enigmatic normal phenotype of homozygous mutant sheep.

Abstract

Children are able to take multiple perspectives in talking about entities and events. But the nature of children's sensitivities to the complex patterns of perspective-taking in adult language is unknown. We examine perspective-taking in four- and six-year-old Tamil-speaking children describing placement events, as reflected in the use of a general placement verb (veyyii ‘put’) versus two fine-grained caused posture expressions specifying orientation, either vertical (nikka veyyii ‘make stand’) or horizontal (paDka veyyii ‘make lie’). We also explore whether animacy systematically promotes shifts to a fine-grained perspective. The results show that four- and six-year-olds switch perspectives as flexibly and systematically as adults do. Animacy influences shifts to a fine-grained perspective similarly across age groups. However, unexpectedly, six-year-olds also display greater overall sensitivity to orientation, preferring the vertical over the horizontal caused posture expression. Despite early flexibility, the factors governing the patterns of perspective-taking on events are undergoing change even in later childhood, reminiscent of U-shaped semantic reorganizations observed in children's lexical knowledge. The present study points to the intriguing possibility that mechanisms that operate at the level of semantics could also influence subtle patterns of lexical choice and perspective-shifts.

Abstract

In linguistic theories of how sentences encode meaning, a distinction is often made between the context-free rule-based combination of lexical–semantic features of the words within a sentence (‘‘semantics’’), and the contributions made by wider context (‘‘pragmatics’’). In psycholinguistics, this distinction has led to the view that listeners initially compute a local, context-independent meaning of a phrase or sentence before relating it to the wider context. An important aspect of such a two-step perspective on interpretation is that local semantics cannot initially be overruled by global contextual factors. In two spoken-language event-related potential experiments, we tested the viability of this claim by examining whether discourse context can overrule the impact of the core lexical–semantic feature animacy, considered to be an innate organizing principle of cognition. Two-step models of interpretation predict that verb–object animacy violations, as in ‘‘The girl comforted the clock,’’ will always perturb the unfolding interpretation process, regardless of wider context. When presented in isolation, such anomalies indeed elicit a clear N400 effect, a sign of interpretive problems. However, when the anomalies were embedded in a supportive context (e.g., a girl talking to a clock about his depression), this N400 effect disappeared completely. Moreover, given a suitable discourse context (e.g., a story about an amorous peanut), animacyviolating predicates (‘‘the peanut was in love’’) were actually processed more easily than canonical predicates (‘‘the peanut was salted’’). Our findings reveal that discourse context can immediately overrule local lexical–semantic violations, and therefore suggest that language comprehension does not involve an initially context-free semantic analysis.

Abstract

Although we usually have no trouble finding the right antecedent for a pronoun, the co-reference relations between pronouns and antecedents in everyday language are often ‘formally’ ambiguous. But a pronoun is only really ambiguous if a reader or listener indeed perceives it to be ambiguous. Whether this is the case may depend on at least two factors: the language processing skills of an individual reader, and the contextual bias towards one particular referential interpretation. In the current study, we used event related brain potentials (ERPs) to explore how both these factors affect the resolution of referentially ambiguous pronouns. We compared ERPs elicited by formally ambiguous and non-ambiguous pronouns that were embedded in simple sentences (e.g., “Jennifer Lopez told Madonna that she had too much money.”). Individual differences in language processing skills were assessed with the Reading Span task, while the contextual bias of each sentence (up to the critical pronoun) had been assessed in a referential cloze pretest. In line with earlier research, ambiguous pronouns elicited a sustained, frontal negative shift relative to non-ambiguous pronouns at the group-level. The size of this effect was correlated with Reading Span score, as well as with contextual bias. These results suggest that whether a reader perceives a formally ambiguous pronoun to be ambiguous is subtly co-determined by both individual language processing skills and contextual bias.

Abstract

The human language processor is conceived as a system that consists of several interrelated subsystems. Each subsystem performs a specific task in the complex process of language comprehension and production. A subsystem receives a particular input, performs certain specific operations on this input and yields a particular output. The subsystems can be characterized in terms of the transformations that relate the input representations to the output representations. An important issue in describing the language processing system is to identify the subsystems and to specify the relations between the subsystems. These relations can be conceived in two different ways. In one conception the subsystems are autonomous. They are related to each other only by the input-output channels. The operations in one subsystem are not affected by another system. The subsystems are modular, that is they are independent. In the other conception, the different subsystems influence each other. A subsystem affects the processes in another subsystem. In this conception there is an interaction between the subsystems.

Abstract

The reading process depends both on the text and on the reader. When we read a text, propositions in the current input are matched to propositions in the memory representation of the previous discourse but also to knowledge structures in long‐term memory. Therefore, memory‐based text processing refers both to the bottom‐up processing of the text and to the top‐down activation of the reader's knowledge. In this article, we focus on the role of cognitive structures in the reader's knowledge. We argue that causality is an important category in structuring human knowledge and that this property has consequences for text processing. Some research is discussed that illustrates that the more the information in the text reflects causal categories, the more easily the information is processed.

Abstract

We propose that speech comprehension involves the activation of token representations of the phonological forms of current lexical hypotheses, separately from the ongoing construction of a conceptual interpretation of the current utterance. In a series of cross-modal priming experiments, facilitation of lexical decision responses to visual target words (e.g., time) was found for targets that were semantic associates of auditory prime words (e.g., date) when the primes were isolated words, but not when the same primes appeared in sentence contexts. Identity priming (e.g., faster lexical decisions to visual date after spoken date than after an unrelated prime) appeared, however, both with isolated primes and with primes in prosodically neutral sentences. Associative priming in sentence contexts only emerged when sentence prosody involved contrastive accents, or when sentences were terminated immediately after the prime. Associative priming is therefore not an automatic consequence of speech processing. In no experiment was there associative priming from embedded words (e.g., sedate-time), but there was inhibitory identity priming (e.g., sedate-date) from embedded primes in sentence contexts. Speech comprehension therefore appears to involve separate distinct activation both of token phonological word representations and of conceptual word representations. Furthermore, both of these types of representation are distinct from the long-term memory representations of word form and meaning.

Abstract

Participants made visual lexical decisions to upper-case words and nonwords, and then categorized an ambiguous N–H letter continuum. The lexical decision phase included different exposure conditions: Some participants saw an ambiguous letter “?”, midway between N and H, in N-biased lexical contexts (e.g., REIG?), plus words with unambiguousH(e.g., WEIGH); others saw the reverse (e.g., WEIG?, REIGN). The first group categorized more of the test continuum as N than did the second group. Control groups, who saw “?” in nonword contexts (e.g., SMIG?), plus either of the unambiguous word sets (e.g., WEIGH or REIGN), showed no such subsequent effects. Perceptual learning about ambiguous letters therefore appears to be based on lexical knowledge, just as in an analogous speech experiment (Norris, McQueen, & Cutler, 2003) which showed similar lexical influence in learning about ambiguous phonemes. We argue that lexically guided learning is an efficient general strategy available for exploitation by different specific perceptual tasks.

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) [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

Memorializes Martin D. S. Braine, whose research on child language acquisition and on both child and adult thinking and reasoning had a major influence on modern cognitive psychology. Addressing meaning as well as position, Braine argued that children start acquiring language by learning narrow-scope positional formulas that map components of meaning to positions in the utterance. These proposals were critical in starting discussions of the possible universality of the pivot-grammar stage and of the role of syntax, semantics,and pragmatics in children's early grammar and were pivotal to the rise of approaches in which cognitive development in language acquisition is stressed.

Abstract

This dissertation documents the emergence of a new language, Light Warlpiri, in the multilingual community of Lajamanu in northern Australia. It then examines the acquisition of Light Warlpiri language, and of the heritage language, Lajamanu Warlpiri, by children. Light Warlpiri has arisen from contact between Lajamanu Warlpiri (a Pama-Nyungan language), Kriol (an English-based creole), and varieties of English. It is a Mixed Language, meaning that none of its source languages can be considered to be the sole parent language. Most verbs and the verbal morphology are from Aboriginal English or Kriol, while most nouns and the nominal morphology are from Warlpiri. The language input to children is complex. Adults older than about thirty speak Lajamanu Warlpiri and code-switch into Aboriginal English or Kriol. Younger adults, the parents of the current cohort of children, speak Light Warlpiri and code-switch into Lajamanu Warlpiri and into Aboriginal English or Kriol. Lajamanu Warlpiri and Light Warlpiri, the two main input languages to children, both indicate A arguments with ergative case-marking (and they share one allomorph of the marker), but Lajamanu Warlpiri includes the marker much more consistently than Light Warlpiri. Word order is variable in both languages. Children learn both languages from birth, but they target Light Warlpiri as the language of their everyday interactions, and they speak it almost exclusively until four to six years of age. Adults and children show similar patterns of ergative marking and word order in Light Warlpiri. But differences between age groups are found in ergative marking in Lajamanu Warlpiri - for the oldest group of adults, ergative marking is obligatory, but for younger adults and children, it is not. Determining when children differentiate between two input languages has been a major goal in the study of bilingual acquisition. The two languages in this study share lexical and grammatical properties, making distinctions between them quite subtle. Both adults and children distribute ergative marking differently in the two languages, but show similar word order patterns in both. However the children show a stronger correlation between ergative marking and word order patterns than do the adults, suggesting that they are spearheading processes of language change. In their comprehension of sentences in both Lajamanu Warlpiri and Light Warlpiri, adults use a case-marking strategy to identify the A argument (i.e. N+erg = A argument, N-erg = O argument). The children are not adult-like in using this strategy at age 5, when they also used a word order strategy, but they gradually move towards being adult-like with increased age.

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

In this paper we try to contribute to the body of knowledge about the acquisition of English epistemic modal verbs (e.g. Mary may/has to be at school). Semantically, these verbs encode possibility or necessity with respect to available evidence. Pragmatically, the use of epistemic modals often gives rise to scalar conversational inferences (Mary may be at school -> Mary doesn’t have to be at school). The acquisition of epistemic modals is challenging for children on both these levels. In this paper, we present findings from two studies which were conducted with 5-year-old children and adults. Our findings, unlike previous work, show that 5-yr-olds have mastered epistemic modal semantics, including the notions of necessity and possibility. However, they are still in the process of acquiring epistemic modal pragmatics.

Abstract

Dyslexia is one of the most prevalent childhood cognitive disorders, affecting approximately 5% of school-age children. We have recently identified a risk haplotype associated with dyslexia on chromosome 6p22.2 which spans the TTRAP gene and portions of THEM2 and KIAA0319. Here we show that in the presence of the risk haplotype, the expression of the KIAA0319 gene is reduced but the expression of the other two genes remains unaffected. Using in situ hybridization, we detect a very distinct expression pattern of the KIAA0319 gene in the developing cerebral neocortex of mouse and human fetuses. Moreover, interference with rat Kiaa0319 expression in utero leads to impaired neuronal migration in the developing cerebral neocortex. These data suggest a direct link between a specific genetic background and a biological mechanism leading to the development of dyslexia: the risk haplotype on chromosome 6p22.2 down-regulates the KIAA0319 gene which is required for neuronal migration during the formation of the cerebral neocortex.

Abstract

The relationship between synchronous neuronal activity as measured with EEG and the blood oxygenation level dependent (BOLD) signal as measured during fMRI is not clear. This work investigates the relationship by combining EEG and fMRI measures of the strong increase in beta frequency power following movement, the so-called post-movement beta rebound (PMBR). The time course of the PMBR, as measured by EEG, was included as a regressor in the fMRI analysis, allowing identification of a region of associated BOLD signal increase in the sensorimotor cortex, with the most significant region in the post-central sulcus. The increase in the BOLD signal suggests that the number of active neurons and/or their synaptic rate is increased during the PMBR. The duration of the BOLD response curve in the PMBR region is significantly longer than in the activated motor region, and is well fitted by a model including both motor and PMBR regressors. An intersubject correlation between the BOLD signal amplitude associated with the PMBR regressor and the PMBR strength as measured with EEG provides further evidence that this region is a source of the PMBR. There is a strong intra-subject correlation between the BOLD signal amplitude in the sensorimotor cortex during movement and the PMBR strength as measured by EEG, suggesting either that the motor activity itself, or somatosensory inputs associated with the motor activity, influence the PMBR. This work provides further evidence for a BOLD signal change associated with changes in neuronal synchrony, so opening up the possibility of studying other event-related oscillatory changes using fMRI.

Abstract

En este artículo se desarrolla un método automático de segmentación de fonemas no supervisado. Este método utiliza el algoritmo de agrupación de máximo margen [1] para realizar segmentación de fonemas sobre habla continua sin necesidad de información a priori para el entrenamiento del sistema.

Abstract

Literacy and education represent essential aspects of contemporary society and subserve important aspects of socialization and cultural transmission. The study of illiterate subjects represents one approach to investigate the interactions between neurobiological and cultural factors in cognitive development, individual learning, and their influence on the functional organization of the brain. In this chapter we review some recent cognitive, neuroanatomic, and functional neuroimaging results indicating that formal education influences important aspects of the human brain. Taken together this provides strong support for the idea that the brain is modulated by literacy and formal education, which in turn change the brains capacity to interact with its environment, including the individual's contemporary culture. In other words, the individual is able to participate in, interact with, and actively contribute to the process of cultural transmission in new ways through acquired cognitive skills.

Abstract

The irrelevant speech effect illustrates that sounds that are irrelevant to a visually presented short-term memory task still interfere with neuronal function. In the present study we explore the functional and effective connectivity of such interference. The functional connectivity analysis suggested an interaction between the level of irrelevant speech and the correlation between in particular the left superior temporal region, associated with verbal working memory, and the left medial temporal lobe. Based on this psycho-physiological interaction, and to broaden the understanding of this result, we performed a network analysis, using a simple network model for verbal working memory, to analyze its interaction with the medial temporal lobe memory system. The results showed dissociations in terms of network interactions between frontal as well as parietal and temporal areas in relation to the medial temporal lobe. The results of the present study suggest that a transition from phonological loop processing towards an engagement of episodic processing might take place during the processing of interfering irrelevant sounds. We speculate that, in response to the irrelevant sounds, this reflects a dynamic shift in processing as suggested by a closer interaction between a verbal working memory system and the medial temporal lobe memory system.

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

Doubts have been cast on the strict dissociation between short- and long-term memory systems. Specifically, several neuroimaging studies have shown that the medial temporal lobe, a region almost invariably associated with long-term memory, is involved in active short-term memory maintenance. Furthermore, a recent study in hippocampally lesioned patients has shown that the hippocampus is critically involved in associating objects and their locations, even when the delay period lasts only 8 s. However, the critical feature that causes the medial temporal lobe, and in particular the hippocampus, to participate in active maintenance is still unknown. This study was designed in order to explore hippocampal involvement in active maintenance of spatial and non-spatial associations. Eighteen participants performed a delayed-match-to-sample task in which they had to maintain either object–location associations, color–number association, single colors, or single locations. Whole-brain activity was measured using event-related functional magnetic resonance imaging and analyzed using a random effects model. Right lateralized hippocampal activity was evident when participants had to maintain object–location associations, but not when they had to maintain object–color associations or single items. The present results suggest a hippocampal involvement in active maintenance when feature combinations that include spatial information have to be maintained online.

Abstract

In this study data from the first six months of 12 children s multiword speech were used to test the validity of Valian's (1991) syntactic perfor-mance-limitation account and Tomasello s (1992) verb-island account of early multiword speech with particular reference to the development of the English verb category. The results provide evidence for appropriate use of verb morphology, auxiliary verb structures, pronoun case marking, and SVO word order from quite early in development. However, they also demonstrate a great deal of lexical specificity in the children's use of these systems, evidenced by a lack of overlap in the verbs to which different morphological markers were applied, a lack of overlap in the verbs with which different auxiliary verbs were used, a disproportionate use of the first person singular nominative pronoun I, and a lack of overlap in the lexical items that served as the subjects and direct objects of transitive verbs. These findings raise problems for both a syntactic performance-limitation account and a strong verb-island account of the data and suggest the need to develop a more general lexiealist account of early multiword speech that explains why some words come to function as "islands" of organization in the child's grammar and others do not.

Abstract

Firstly, theories are reviewed on the explanation of tonal consonance as the singular nature of tone intervals with frequency ratios corresponding with small integer numbers. An evaluation of these explanations in the light of some experimental studies supports the hypothesis, as promoted by von Helmholtz, that the difference between consonant and dissonant intervals is related to beats of adjacent partials. This relation was studied more fully by experiments in which subjects had to judge simple-tone intervals as a function of test frequency and interval width. The results may be considered as a modification of von Helmholtz's conception and indicate that, as a function of frequency, the transition range between consonant and dissonant intervals is related to critical bandwidth. Simple-tone intervals are evaluated as consonant for frequency differences exceeding this bandwidth. whereas the most dissonant intervals correspond with frequency differences of about a quarter of this bandwidth. On the base of these results, some properties of consonant intervals consisting of complex tones are explained. To answer the question whether critical bandwidth also plays a rôle in music, the chords of two compositions (parts of a trio sonata of J. S. Bach and of a string quartet of A. Dvorák) were analyzed by computing interval distributions as a function of frequency and number of harmonics taken into account. The results strongly suggest that, indeed, critical bandwidth plays an important rôle in music: for a number of harmonics representative for musical instruments, the "density" of simultaneous partials alters as a function of frequency in the same way as critical bandwidth does.

Abstract

This study investigates whether the acoustic durations of derivational affixes in Dutch are affected by the frequency of the word they occur in. In a word naming experiment, subjects were presented with a large number of words containing one of the affixes ge-, ver-, ont, or -lijk. Their responses were recorded on DAT tapes, and the durations of the affixes were measured using Automatic Speech Recognition technology. To investigate whether frequency also affected durations when speech rate was high, the presentation rate of the stimuli was varied. The results show that a higher frequency of the word as a whole led to shorter acoustic realizations for all affixes. Furthermore, affixes became shorter as the presentation rate of the stimuli increased. There was no interaction between word frequency and presentation rate, suggesting that the frequency effect also applies in situations in which the speed of articulation is very high.

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

Greek is a language with lexical stress that marks stress orthographically with a special diacritic. Thus, the orthography and the lexicon constitute potential sources of stress assignment information in addition to any possible general default metrical pattern. Here, we report two experiments with secondary education children reading aloud pseudo-word stimuli, in which we manipulated the availability of lexical (using stimuli resembling particular words) and visual (existence and placement of the diacritic) information. The reliance on the diacritic was found to be imperfect. Strong lexical effects as well as a default metrical pattern stressing the penultimate syllable were revealed. Reading models must be extended to account for multisyllabic word reading including, in particular, stress assignment based on the interplay among multiple possible sources of information.

Abstract

Previous work has shown that illiterate subjects are better at naming two-dimensional representations of real objects when presented as colored photos as compared to black and white drawings. This raises the question if color or textural details selectively improve object recognition and naming in illiterate compared to literate subjects. In this study, we investigated whether the surface texture and/or color of objects is used to access stored object knowledge in illiterate subjects. A group of illiterate subjects and a matched literate control group were compared on an immediate object naming task with four conditions: color and black and white (i.e., grey-scaled) photos, as well as color and black and white (i.e., grey-scaled) drawings of common everyday objects. The results show that illiterate subjects perform significantly better when the stimuli are colored and this effect is independent of the photographic detail. In addition, there were significant differences between the literacy groups in the black and white condition for both drawings and photos. These results suggest that color object information contributes to object recognition. This effect was particularly prominent in the illiterate group

Abstract

A case of a word/letter dissociation is described. The present patient has a quasi-normal word reading performance (both at the level of speed and accuracy) while he has major problems in nonword and letter reading. More specifically, he has strong difficulties in retrieving letter names but preserved abilities in letter identification. This study complements previous cases reporting a similar word/letter dissociation by focusing more specifically on word reading and letter naming latencies. The results provide new constraints for modeling the role of letter knowledge within reading processes and during reading acquisition or rehabilitation.

Abstract

Rotokas is famous for possessing one of the world’s smallest phoneme inventories. According to one source, the Central dialect of Rotokas possesses only 11 segmental phonemes (five vowels and six consonants) and lacks nasals while the Aita dialect possesses a similar-sized inventory in which nasals replace voiced stops. However, recent fieldwork reveals that the Aita dialect has, in fact, both voiced and nasal stops, making for an inventory of 14 segmental phonemes (five vowels and nine consonants). The correspondences between Central and Aita Rotokas suggest that the former is innovative with respect to its consonant inventory and the latter conservative, and that the small inventory of Central Rotokas arose by collapsing the distinction between voiced and nasal stops.

Abstract

Does the spelling of a word mandatorily constrain spoken word production, or does it do so only
when spelling is relevant for the production task at hand? Damian and Bowers (2003) reported spelling
effects in spoken word production in English using a prompt–response word generation task. Preparation
of the response words was disrupted when the responses shared initial phonemes that differed
in spelling, suggesting that spelling constrains speech production mandatorily. The present experiments,
conducted in Dutch, tested for spelling effects using word production tasks in which spelling
was clearly relevant (oral reading in Experiment 1) or irrelevant (object naming and word generation
in Experiments 2 and 3, respectively). Response preparation was disrupted by spelling inconsistency
only with the word reading, suggesting that the spelling of a word constrains spoken word production
in Dutch only when it is relevant for the word production task at hand.

Abstract

In a recent series of papers, Caramazza and Miozzo [Caramazza, A., 1997. How many levels of processing are there in lexical access? Cognitive Neuropsychology 14, 177-208; Caramazza, A., Miozzo, M., 1997. The relation between syntactic and phonological knowledge in lexical access: evidence from the 'tip-of-the-tongue' phenomenon. Cognition 64, 309-343; Miozzo, M., Caramazza, A., 1997. On knowing the auxiliary of a verb that cannot be named: evidence for the independence of grammatical and phonological aspects of lexical knowledge. Journal of Cognitive Neuropsychology 9, 160-166] argued against the lemma/lexeme distinction made in many models of lexical access in speaking, including our network model [Roelofs, A., 1992. A spreading-activation theory of lemma retrieval in speaking. Cognition 42, 107-142; Levelt, W.J.M., Roelofs, A., Meyer, A.S., 1998. A theory of lexical access in speech production. Behavioral and Brain Sciences, (in press)]. Their case was based on the observations that grammatical class deficits of brain-damaged patients and semantic errors may be restricted to either spoken or written forms and that the grammatical gender of a word and information about its form can be independently available in tip-of-the-tongue stales (TOTs). In this paper, we argue that though our model is about speaking, not taking position on writing, extensions to writing are possible that are compatible with the evidence from aphasia and speech errors. Furthermore, our model does not predict a dependency between gender and form retrieval in TOTs. Finally, we argue that Caramazza and Miozzo have not accounted for important parts of the evidence motivating the lemma/lexeme distinction, such as word frequency effects in homophone production, the strict ordering of gender and pho neme access in LRP data, and the chronometric and speech error evidence for the production of complex morphology.

Abstract

In five language production experiments it was examined which aspects of words are activated in memory by context pictures and words. Context pictures yielded Stroop-like and semantic effects on response times when participants generated gender-marked noun phrases in response to written words (Experiment 1A). However, pictures yielded no such effects when participants simply read aloud the noun phrases (Experiment 2). Moreover, pictures yielded a gender congruency effect in generating gender-marked noun phrases in response to the written words (Experiments 3A and 3B). These findings suggest that context pictures activate lemmas (i.e., representations of syntactic properties), which leads to effects only when lemmas are needed to generate a response (i.e., in Experiments 1A, 3A, and 3B, but not in Experiment 2). Context words yielded Stroop-like and semantic effects in picture naming (Experiment 1B). Moreover, words yielded Stroop-like but no semantic effects in reading nouns (Experiment 4) and in generating noun phrases (Experiment 5). These findings suggest that context words activate the lemmas and forms of their names, which leads to semantic effects when lemmas are required for responding (Experiment 1B) but not when only the forms are required (Experiment 4). WEAVER++ simulations of the results are presented.

Abstract

Cognitive control includes the ability to formulate goals and plans of action and to follow these while facing distraction. Previous neuroimaging studies have shown that the presence of conflicting response alternatives in Stroop-like tasks increases activity in dorsal anterior cingulate cortex (ACC), suggesting that the ACC is involved in cognitive control. However, the exact nature of ACC function is still under debate. The prevailing conflict detection hypothesis maintains that the ACC is involved in performance monitoring. According to this view, ACC activity reflects the detection of response conflict and acts as a signal that engages regulative processes subserved by lateral prefrontal brain regions. Here, we provide evidence from functional MRI that challenges this view and favors an alternative view, according to which the ACC has a role in regulation itself. Using an arrow–word Stroop task, subjects responded to incongruent, congruent, and neutral stimuli. A critical prediction made by the conflict detection hypothesis is that ACC activity should be increased only when conflicting response alternatives are present. Our data show that ACC responses are larger for neutral than for congruent stimuli, in the absence of response conflict. This result demonstrates the engagement of the ACC in regulation itself. A computational model of Stroop-like performance instantiating a version of the regulative hypothesis is shown to account for our findings.

Abstract

Five chronometric experiments examined the functional architecture of naming dice, digits, and number words. Speakers named pictured dice, Arabic digits, or written number words, while simultaneously trying to ignore congruent or incongruent dice, digit, or number word distractors presented at various stimulus onset asynchronies (SOAs). Stroop-like interference and facilitation effects were obtained from digits and words on dice naming latencies, but not from dice on digit and word naming latencies. In contrast, words affected digit naming latencies and digits affected word naming latencies to the same extent. The peak of the interference was always around SOA = 0 ms, whereas facilitation was constant across distractor-first SOAs. These results suggest that digit naming is achieved like word naming rather than dice naming. WEAVER++simulations of the results are reported.

Abstract

Phonological encoding is the process by which speakers retrieve phonemic segments for morphemes from memory and use
the segments to assemble phonological representations of words to be spoken. When conversing in one language, bilingual
speakers have to resist the temptation of encoding word forms using the phonological rules and representations of the other
language. We argue that the activation of phonological representations is not restricted to the target language and that the
phonological representations of languages are not separate. We advance a view of bilingual control in which condition-action
rules determine what is done with the activated phonological information depending on the target language. This view is
computationally implemented in the WEAVER++ model. We present WEAVER++ simulations of the cognate facilitation effect
(Costa, Caramazza and Sebasti´an-Gall´es, 2000) and the between-language phonological facilitation effect of spoken
distractor words in object naming (Hermans, Bongaerts, de Bot and Schreuder, 1998).

Abstract

According to most models of speech production, the planning of spoken words involves the independent retrieval of segments and metrical frames followed by segment-to-frame association. In some models, the metrical frame includes a specification of the number and ordering of consonants and vowels, but in the word-form encoding by activation and verification (WEAVER) model (A. Roelofs, 1997), the frame specifies only the stress pattern across syllables. In 6 implicit priming experiments, on each trial, participants produced 1 word out of a small set as quickly as possible. In homogeneous sets, the response words shared word-initial segments, whereas in heterogeneous sets, they did not. Priming effects from shared segments depended on all response words having the same number of syllables and stress pattern, but not on their having the same number of consonants and vowels. No priming occurred when the response words had only the same metrical frame but shared no segments. Computer simulations demonstrated that WEAVER accounts for the findings.

Abstract

This article reports 7 experiments investigating whether utterances are planned in a parallel or rightward incremental fashion during language production. The experiments examined the role of linear order, length, frequency, and repetition in producing Dutch verb–particle combinations. On each trial, participants produced 1 utterance out of a set of 3 as quickly as possible. The responses shared part of their form or not. For particle-initial infinitives, facilitation was obtained when the responses shared the particle but not when they shared the verb. For verb-initial imperatives, however, facilitation was obtained for the verbs but not for the particles. The facilitation increased with length, decreased with frequency, and was independent of repetition. A simple rightward incremental model accounts quantitatively for the results.

Abstract

Studies based on naturalistic data are a core tool in the field of language acquisition research and have provided thorough descriptions of children's speech. However, these descriptions are inevitably confounded by differences in the relative frequency with which children use words and language structures. The purpose of the present work was to investigate the impact of sampling constraints on estimates of the productivity of children's utterances, and on the validity of error rates. Comparisons were made between five different sized samples of wh-question data produced by one child aged 2;8. First, we assessed whether sampling constraints undermined the claim (e.g. Tomasello, 2000) that the restricted nature of early child speech reflects a lack of adultlike grammatical knowledge. We demonstrated that small samples were equally likely to under- as overestimate lexical specificity in children's speech, and that the reliability of estimates varies according to sample size. We argued that reliable analyses require a comparison with a control sample, such as that from an adult speaker. Second, we investigated the validity of estimates of error rates based on small samples. The results showed that overall error rates underestimate the incidence of error in some rarely produced parts of the system and that analyses on small samples were likely to substantially over- or underestimate error rates in infrequently produced constructions. We concluded that caution must be used when basing arguments about the scope and nature of errors in children's early multi-word productions on analyses of samples of spontaneous speech.

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

A key mechanism in the organization of turns at talk in conversation is the ability to anticipate or PROJECT the moment of completion of a current speaker’s turn. Some authors suggest that this is achieved via lexicosyntactic cues, while others argue that projection is based on intonational contours. We tested these hypotheses in an on-line experiment, manipulating the presence of symbolic (lexicosyntactic) content and intonational contour of utterances recorded in natural conversations. When hearing the original recordings, subjects can anticipate turn endings with the same degree of accuracy attested in real conversation. With intonational contour entirely removed (leaving intact words and syntax, with a completely flat pitch), there is no change in subjects’ accuracy of end-of-turn projection. But in the opposite case (with original intonational contour intact, but with no recognizable words), subjects’ performance deteriorates significantly. These results establish that the symbolic (i.e. lexicosyntactic) content of an utterance is necessary (and possibly sufficient) for projecting the moment of its completion, and thus for regulating conversational turn-taking. By contrast, and perhaps surprisingly, intonational contour is neither necessary nor sufficient for end-of-turn projection.

Abstract

As Rose (2006) discusses in the lead article, two camps can be identified in the field of gesture research: those who believe that gesticulation enhances communication by providing extra information to the listener, and on the other hand those who believe that gesticulation is not communicative, but rather that it facilitates speaker-internal word finding processes. I review a number of key studies relevant for this controversy, and conclude that the available empirical evidence is supporting the notion that gesture is a communicative device which can compensate for problems in speech by providing information in gesture. Following that, I discuss the finding by Rose and Douglas (2001) that making gestures does facilitate word production in some patients with aphasia. I argue that the gestures produced in the experiment by Rose and Douglas are not guaranteed to be of the same kind as the gestures that are produced spontaneously under naturalistic, communicative conditions, which makes it difficult to generalise from that particular study to general gesture behavior. As a final point, I encourage researchers in the area of aphasia to put more emphasis on communication in naturalistic contexts (e.g., conversation) in testing the capabilities of people with aphasia.