Publications

Abstract

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

Abstract

State-of-the-art DNA sequencing is providing ever more detailed insights into the genomes of humans, extant apes, and even extinct hominins (1–3), offering unprecedented opportunities to uncover the molecular variants that make us human. A common assumption is that the emergence of behaviorally modern humans after 200,000 years ago required—and followed—a specific biological change triggered by one or more genetic mutations. For example, Klein has argued that the dawn of human culture stemmed from a single genetic change that “fostered the uniquely modern ability to adapt to a remarkable range of natural and social circumstance” (4). But are evolutionary changes in our genome a cause or a consequence of cultural innovation (see the figure)?

Abstract

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

Abstract

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

Abstract

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

Abstract

The testimony of others and direct experience play a major role in the development of children's knowledge. Children actively use questions to seek others' testimony and explore the environment. It is unclear though whether children distinguish when it is better to ask from when it is better to try to find an answer by oneself. In 2 experiments, we examined the ability of 4- and 6-year-olds to select between looking and asking to determine visible and invisible properties of entities (e.g., hair color vs. knowledge of French). All children chose to look more often for visible than invisible properties. However, only 6-year-olds chose above chance to look for visible properties and to ask for invisible properties. Four-year-olds showed a preference for looking in one experiment and asking in the other. The results suggest substantial development in the efficacy of children's learning in early childhood.

Abstract

Language processing involves the ability to store and integrate pieces of
information in working memory over short periods of time. According to
the dominant view, information is maintained through sustained, elevated
neural activity. Other work has argued that short-term synaptic facilitation
can serve as a substrate of memory. Here, we propose an account where
memory is supported by intrinsic plasticity that downregulates neuronal
firing rates. Single neuron responses are dependent on experience and we
show through simulations that these adaptive changes in excitability pro-
vide memory on timescales ranging from milliseconds to seconds. On this
account, spiking activity writes information into coupled dynamic variables
that control adaptation and move at slower timescales than the membrane
potential. From these variables, information is continuously read back into
the active membrane state for processing. This neuronal memory mech-
anism does not rely on persistent activity, excitatory feedback, or synap-
tic plasticity for storage. Instead, information is maintained in adaptive
conductances that reduce firing rates and can be accessed directly with-
out cued retrieval. Memory span is systematically related to both the time
constant of adaptation and baseline levels of neuronal excitability. Inter-
ference effects within memory arise when adaptation is long-lasting. We
demonstrate that this mechanism is sensitive to context and serial order
which makes it suitable for temporal integration in sequence processing
within the language domain. We also show that it enables the binding of
linguistic features over time within dynamic memory registers. This work
provides a step towards a computational neurobiology of language.

Abstract

Does language influence how we perceive the world? This study examines how linguistic encoding of relational information by means of verbs implicitly affects visual processing, by measuring perceptual judgements behaviourally, and visual perception and attention in EEG. Verbal systems can vary cross-linguistically: Dutch uses posture verbs to describe inanimate object configurations (the bottle stands/lies on the table). In English, however, such use of posture verbs is rare (the bottle is on the table). Using this test case, we ask (1) whether previously attested language-perception interactions extend to more complex domains, and (2) whether differences in linguistic usage probabilities affect perception. We report three nonverbal experiments in which Dutch and English participants performed a picture-matching task. Prime and target pictures contained object configurations (e.g., a bottle on a table); in the critical condition, prime and target showed a mismatch in object position (standing/lying). In both language groups, we found similar responses, suggesting that probabilistic differences in linguistic encoding of relational information do not affect perception.

Abstract

In well-known demonstrations of lexical prediction during language comprehension, pre-nominal articles that mismatch a likely upcoming noun's gender elicit different neural activity than matching articles. However, theories differ on what this pre-nominal prediction effect means and on what is being predicted. Does it reflect mismatch with a predicted article, or ‘merely’ revision of the noun prediction? We contrasted the ‘article prediction mismatch’ hypothesis and the ‘noun prediction revision’ hypothesis in two ERP experiments on Dutch mini-story comprehension, with pre-registered data collection and analyses. We capitalized on the Dutch gender system, which marks gender on definite articles (‘de/het’) but not on indefinite articles (‘een’). If articles themselves are predicted, mismatching gender should have little effect when readers expected an indefinite article without gender marking. Participants read contexts that strongly suggested either a definite or indefinite noun phrase as its best continuation, followed by a definite noun phrase with the expected noun or an unexpected, different gender noun phrase (‘het boek/de roman’, the book/the novel). Experiment 1 (N = 48) showed a pre-nominal prediction effect, but evidence for the article prediction mismatch hypothesis was inconclusive. Informed by exploratory analyses and power analyses, direct replication Experiment 2 (N = 80) yielded evidence for article prediction mismatch at a newly pre-registered occipital region-of-interest. However, at frontal and posterior channels, unexpectedly definite articles also elicited a gender-mismatch effect, and this support for the noun prediction revision hypothesis was further strengthened by exploratory analyses: ERPs elicited by gender-mismatching articles correlated with incurred constraint towards a new noun (next-word entropy), and N400s for initially unpredictable nouns decreased when articles made them more predictable. By demonstrating its dual nature, our results reconcile two prevalent explanations of the pre-nominal prediction effect.

Abstract

The ethnographic literature has sometimes described parts of the northwest Amazon as areas of shared culture across linguistic groups. This paper illustrates how a principle of semantic transparency across languages is a key means of establishing elements of a common regional culture through practices like the calquing of ethnonyms and toponyms so that they are semantically, but not phonologically, equivalent across languages. It places the upper Rio Negro area of the northwest Amazon in a general discussion of cross-linguistic naming practices in South America and considers the extent to which a preference for semantic transparency can be linked to cases of widespread cultural ‘calquing’, in which culturally-important meanings are kept similar across different linguistic systems. It also addresses the principle of semantic transparency beyond specific referential phrases and into larger discourse structures. It concludes that an attention to semiotic practices in multilingual settings can provide new and more complex ways of thinking about the idea of shared culture.

Abstract

This paper gives an account of the pirate media economy of Ecuador and its role in the emergence of indigenous Quichua-language media spaces, identifying the different parties involved in this economy, discussing their relationship to the parallel ‘‘legitimate’’ media economy, and considering the implications of this informal media market for Quichua linguistic and cultural reproduction. As digital recording and playback technology has become increasingly more affordable and widespread over recent years, black markets have grown up worldwide, based on cheap ‘‘illegal’’ reproduction of commercial media, today sold by informal entrepreneurs in rural markets, shops and street corners around Ecuador. Piggybacking on this pirate infrastructure, Quichua-speaking media producers and consumers have begun to circulate indigenous-language video at an unprecedented rate, helped by small-scale merchants who themselves profit by supplying market demands for positive images of indigenous people. In a context of a national media that has tended to silence indigenous voices rather than amplify them, informal media producers, consumers and vendors are developing relationships that open meaningful media spaces within the particular social, economic and linguistic contexts of Ecuador.

Abstract

Several studies have reported an association between dyslexia and implicit learning deficits. It has been suggested that the weakness in implicit learning observed in dyslexic individuals may be related to sequential processing and implicit sequence learning. In the present article, we review the current literature on implicit learning and dyslexia. We describe a novel, forced-choice structural "mere exposure" artificial grammar learning paradigm and characterize this paradigm in normal readers in relation to the standard grammaticality classification paradigm. We argue that preference classification is a more optimal measure of the outcome of implicit acquisition since in the preference version participants are kept completely unaware of the underlying generative mechanism, while in the grammaticality version, the subjects have, at least in principle, been informed about the existence of an underlying complex set of rules at the point of classification (but not during acquisition). On the basis of the "mere exposure effect," we tested the prediction that the development of preference will correlate with the grammaticality status of the classification items. In addition, we examined the effects of grammaticality (grammatical/nongrammatical) and associative chunk strength (ACS; high/low) on the classification tasks (preference/grammaticality). Using a balanced ACS design in which the factors of grammaticality (grammatical/nongrammatical) and ACS (high/low) were independently controlled in a 2 × 2 factorial design, we confirmed our predictions. We discuss the suitability of this task for further investigation of the implicit learning characteristics in dyslexia.

Abstract

Objective: To combine MRI-based cortical morphometry and diffusion white matter tractography to describe the anatomical correlates of repetition deficits in patients with primary progressive aphasia (PPA).

Methods: The traditional anatomical model of language identifies a network for word repetition that includes Wernicke and Broca regions directly connected via the arcuate fasciculus. Recent tractography findings of an indirect pathway between Wernicke and Broca regions suggest a critical role of the inferior parietal lobe for repetition. To test whether repetition deficits are associated with damage to the direct or indirect pathway between both regions, tractography analysis was performed in 30 patients with PPA (64.27 ± 8.51 years) and 22 healthy controls. Cortical volume measurements were also extracted from 8 perisylvian language areas connected by the direct and indirect pathways.

Results: Compared to healthy controls, patients with PPA presented with reduced performance in repetition tasks and increased damage to most of the perisylvian cortical regions and their connections through the indirect pathway. Repetition deficits were prominent in patients with cortical atrophy of the temporo-parietal region with volumetric reductions of the indirect pathway.

Conclusions: The results suggest that in PPA, deficits in repetition are due to damage to the temporo-parietal cortex and its connections to Wernicke and Broca regions. We therefore propose a revised language model that also includes an indirect pathway for repetition, which has important clinical implications for the functional mapping and treatment of neurologic patients.

Abstract

This scientific commentary refers to ‘Metabolic lesion-deficit mapping of human cognition’ by Jha etal.

Abstract

Human implicit learning can be investigated with implicit artificial grammar learning, a paradigm that has been proposed as a simple model for aspects of natural language acquisition. In the present study we compared the typical yes–no grammaticality classification, with yes–no preference classification. In the case of preference instruction no reference to the underlying generative mechanism (i.e., grammar) is needed and the subjects are therefore completely uninformed about an underlying structure in the acquisition material. In experiment 1, subjects engaged in a short-term memory task using only grammatical strings without performance feedback for 5 days. As a result of the 5 acquisition days, classification performance was independent of instruction type and both the preference and the grammaticality group acquired relevant knowledge of the underlying generative mechanism to a similar degree. Changing the grammatical stings to random strings in the acquisition material (experiment 2) resulted in classification being driven by local substring familiarity. Contrasting repeated vs. non-repeated preference classification (experiment 3) showed that the effect of local substring familiarity decreases with repeated classification. This was not the case for repeated grammaticality classifications. We conclude that classification performance is largely independent of instruction type and that forced-choice preference classification is equivalent to the typical grammaticality classification.

Abstract

In speech, listeners extract continuously-varying spectrotemporal cues from the acoustic signal to perceive discrete phonetic categories. Spectral cues are spatially encoded in the amplitude of responses in phonetically-tuned neural populations in auditory cortex. It remains unknown whether similar neurophysiological mechanisms encode temporal cues like voice-onset time (VOT), which distinguishes sounds like /b/ and/p/. We used direct brain recordings in humans to investigate the neural encoding of temporal speech cues with a VOT continuum from /ba/ to /pa/. We found that distinct neural populations respond preferentially to VOTs from one phonetic category, and are also sensitive to sub-phonetic VOT differences within a population’s preferred category. In a simple neural network model, simulated populations tuned to detect either temporal gaps or coincidences between spectral cues captured encoding patterns observed in real neural data. These results demonstrate that a spatial/amplitude neural code underlies the cortical representation of both spectral and temporal speech cues.

Abstract

Vocabulary learning occurs throughout the lifespan, often implicitly. For foreign language learners,
this is particularly challenging as they must acquire a large number of new words with little exposure.
In the present study, we explore the effects of contextual diversity—namely, the number of texts a
word appears in—on native and foreign language word learning. Participants read several texts that
had novel pseudowords replacing high-frequency words. The total number of encounters with the
novel words was held constant, but they appeared in 1, 2, 4, or 8 texts. In addition, some participants
read the texts in Spanish (their native language) and others in English (their foreign language). We
found that increasing contextual diversity improved recall and recognition of the word, as well as the
ability to match the word with its meaning while keeping comprehension unimpaired. Using a foreign
language only affected performance in the matching task, where participants had to quickly identify
the meaning of the word. Results are discussed in the greater context of the word learning and foreign
language literature as well as their importance as a teaching tool.

Abstract

The current study focuses on how different scales with varying demands can
affect our subjective assessments. We carried out 2 experiments in which we
asked participants to rate how happy or sad morphed images of faces looked.
The two extremes were the original happy and original sad faces with 4
morphs in between. We manipulated language of the task—namely, half of
the participants carried it out in their native language, Spanish, and the other
half in their foreign language, English—and type of scale. Within type of
scale, we compared verbal and brightness scales. We found that, while
language did not have an effect on the assessment, type of scale did. The
brightness scale led to overall higher ratings, i.e., assessing all faces as
somewhat happier. This provides a limitation on the foreign language effect,
as well as evidence for the influence of the cognitive demands of a scale on
emotionality assessments.

Abstract

Learning new content and vocabulary in a foreign language can be particularly difficult. Yet,
there are educational programs that require people to study in a language they are not
native speakers of. For this reason, it is important to understand how these learning processes work and possibly differ from native language learning, as well as to develop strategies to ease this process. The current study takes advantage of emotionality—operationally
defined as positive valence and high arousal—to improve memory. In two experiments, the
present paper addresses whether participants have more difficulty learning the names of
objects they have never seen before in their foreign language and whether embedding them
in a positive semantic context can help make learning easier. With this in mind, we had participants (with a minimum of a B2 level of English) in two experiments (43 participants in
Experiment 1 and 54 in Experiment 2) read descriptions of made-up objects—either positive
or neutral and either in their native or a foreign language. The effects of language varied
with the difficulty of the task and measure used. In both cases, learning the words in a positive context improved learning. Importantly, the effect of emotionality was not modulated by
language, suggesting that the effects of emotionality are independent of language and could
potentially be a useful tool for improving foreign language vocabulary learning.

Abstract

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

Abstract

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

Abstract

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

Abstract

Because higher level cognitive processes generally involve the use of world knowledge, computational models of these processes require the implementation of a knowledge base. This article identifies and discusses 4 strategies for dealing with world knowledge in computational models: disregarding world knowledge, ad hoc selection, extraction from text corpora, and implementation of all knowledge about a simplified microworld. Each of these strategies is illustrated by a detailed discussion of a model of discourse comprehension. It is argued that seemingly successful modeling results are uninformative if knowledge is implemented ad hoc or not at all, that knowledge extracted from large text corpora is not appropriate for discourse comprehension, and that a suitable implementation can be obtained by applying the microworld strategy.

Abstract

ADHD is a neuropsychiatric disorder characterized by chronic hyperactivity, inattention and impulsivity, which affects about 5% of school-age children. ADHD persists into adulthood in at least 15% of cases. It is highly heritable and familial influences seem strongest for ADHD persisting into adulthood. However, most of the genetic research in ADHD has been carried out in children with the disorder. The gene that has received most attention in ADHD genetics is SLC6A3/DAT1 encoding the dopamine transporter. In the current study we attempted to replicate in adults with ADHD the reported association of a 10–6 SLC6A3-haplotype, formed by the 10-repeat allele of the variable number of tandem repeat (VNTR) polymorphism in the 3′ untranslated region of the gene and the 6-repeat allele of the VNTR in intron 8 of the gene, with childhood ADHD. In addition, we wished to explore the role of a recently described VNTR in intron 3 of the gene. Two hundred sixteen patients and 528 controls were included in the study. We found a 9–6 SLC6A3-haplotype, rather than the 10–6 haplotype, to be associated with ADHD in adults. The intron 3 VNTR showed no association with adult ADHD. Our findings converge with earlier reports and suggest that age is an important factor to be taken into account when assessing the association of SLC6A3 with ADHD. If confirmed in other studies, the differential association of the gene with ADHD in children and in adults might imply that SLC6A3 plays a role in modulating the ADHD phenotype, rather than causing it

Abstract

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

Abstract

Human behavioral asymmetries are commonly studied in the context of structural cortical and connectional asymmetries. Within this framework, Sreenivasan and Sridharan (1) provide intriguing evidence of a relationship between visual asymmetries and the lateralization of superior colliculi connections—a phylogenetically older mesencephalic structure. Specifically, response facilitation for cued locations (i.e., choice bias) in the contralateral hemifield was associated with differences in the connectivity of the superior colliculus. Given that the superior colliculus has a structural homolog—the optic tectum—which can be traced across all Vertebrata, these results may have meaningful evolutionary ramifications.

Abstract

Gradients capture some of the variance of the resting-state functional magnetic resonance imaging (rsfMRI) signal. Amongst these, the principal gradient depicts a functional processing hierarchy that spans from sensory-motor cortices to regions of the default-mode network. While the cortex has been well characterised in terms of gradients little is known about its underlying white matter. For instance, comprehensive mapping of the principal gradient on the largest white matter tract, the corpus callosum, is still missing. Here, we mapped the principal gradient onto the midsection of the corpus callosum using the 7T human connectome project dataset. We further explored how quantitative measures and variability in callosal midsection connectivity relate to the principal gradient values. In so doing, we demonstrated that the extreme values of the principal gradient are located within the callosal genu and the posterior body, have lower connectivity variability but a larger spatial extent along the midsection of the corpus callosum than mid-range values. Our results shed light on the relationship between the brain's functional hierarchy and the corpus callosum. We further speculate about how these results may bridge the gap between functional hierarchy, brain asymmetries, and evolution.

Abstract

High frequency words play a key role in language acquisition, with recent work suggesting they may serve both speech segmentation and lexical categorisation. However, it is not yet known whether infants can detect novel high frequency words in continuous speech, nor whether they can use them to help learning for segmentation and categorisation at the same time. For instance, when hearing “you eat the biscuit”, can children use the high-frequency words “you” and “the” to segment out “eat” and “biscuit”, and determine their respective lexical categories? We tested this in two experiments. In Experiment 1, we familiarised 12-month-old infants with continuous artificial speech comprising repetitions of target words, which were preceded by high-frequency marker words that distinguished the targets into two distributional categories. In Experiment 2, we repeated the task using the same language but with additional phonological cues to word and category structure. In both studies, we measured learning with head-turn preference tests of segmentation and categorisation, and compared performance against a control group that heard the artificial speech without the marker words (i.e., just the targets). There was no evidence that high frequency words helped either speech segmentation or grammatical categorisation. However, segmentation was seen to improve when the distributional information was supplemented with phonological cues (Experiment 2). In both experiments, exploratory analysis indicated that infants’ looking behaviour was related to their linguistic maturity (indexed by infants’ vocabulary scores) with infants with high versus low vocabulary scores displaying novelty and familiarity preferences, respectively. We propose that high-frequency words must reach a critical threshold of familiarity before they can be of significant benefit to learning.

Abstract

To acquire language, infants must learn how to identify words and linguistic structure in speech. Statistical learning has been suggested to assist both of these tasks. However, infants’ capacity to use statistics to discover words and structure together remains unclear. Further, it is not yet known how infants’ statistical learning ability relates to their language development. We trained 17-month-old infants on an artificial language comprising non-adjacent dependencies, and examined their looking times on tasks assessing sensitivity to words and structure using an eye-tracked head-turn-preference paradigm. We measured infants’ vocabulary size using a Communicative Development Inventory (CDI) concurrently and at 19, 21, 24, 25, 27, and 30 months to relate performance to language development. Infants could segment the words from speech, demonstrated by a significant difference in looking times to words versus part-words. Infants’ segmentation performance was significantly related to their vocabulary size (receptive and expressive) both currently, and over time (receptive until 24 months, expressive until 30 months), but was not related to the rate of vocabulary growth. The data also suggest infants may have developed sensitivity to generalised structure, indicating similar statistical learning mechanisms may contribute to the discovery of words and structure in speech, but this was not related to vocabulary size.

Abstract

Acquiring language is notoriously complex, yet for the majority of children this feat is accomplished with remarkable ease. Usage-based accounts of language acquisition suggest that this success can be largely attributed to the wealth of experience with language that children accumulate over the course of language acquisition. One field of research that is heavily underpinned by this principle of experience is statistical learning, which posits that learners can perform powerful computations over the distribution of information in a given input, which can help them to discern precisely how that input is structured, and how it operates. A growing body of work brings this notion to bear in the field of language acquisition, due to a developing understanding of the richness of the statistical information contained in speech. In this chapter we discuss the role that statistical learning plays in language acquisition, emphasising the importance of both the distribution of information within language, and the situation in which language is being learnt. First, we address the types of statistical learning that apply to a range of language learning tasks, asking whether the statistical processes purported to support language learning are the same or distinct across different tasks in language acquisition. Second, we expand the perspective on what counts as environmental input, by determining how statistical learning operates over the situated learning environment, and not just sequences of sounds in utterances. Finally, we address the role of variability in children’s input, and examine how statistical learning can accommodate (and perhaps even exploit) this during language acquisition.

Abstract

In list learning paradigms with free recall, written recall has been found to be less susceptible to intrusions of related concepts than spoken recall when the list items had been visually presented. This effect has been ascribed to the use of stored orthographic representations from the study phase during written recall (Kellogg, 2001). In other memory retrieval paradigms, by contrast, either better recall for modality-congruent items or an input-independent writing superiority effect have been found (Grabowski, 2005). In a series of four experiments using a paired associate learning paradigm we tested (a) whether output modality effects on verbal recall can be replicated in a paradigm that does not involve the rejection of semantically related intrusion words, (b) whether a possible superior performance for written recall was due to a slower response onset for writing as compared to speaking in immediate recall, and (c) whether the performance in paired associate word recall was correlated with performance in an additional episodic memory recall task. We observed better written recall in the first half of the recall phase, irrespective of the modality in which the material was presented upon encoding. An explanation for this effect based on longer response latencies for writing and hence more time for memory retrieval could be ruled out by showing that the effect persisted in delayed response versions of the task. Although there was some evidence that stored additional episodic information may contribute to the successful retrieval of associate words, this evidence was only found in the immediate response experiments and hence is most likely independent from the observed output modality effect. In sum, our results from a paired associate learning paradigm suggest that superior performance for written vs. spoken recall cannot be (solely) explained in terms of additional access to stored orthographic representations from the encoding phase. Our findings rather suggest a general writing-superiority effect at the time of memory retrieval.

Abstract

Background: Two distinct insomnia disorder (ID) phenotypes have been proposed, distinguished on the basis of an objective total sleep time less or more than 6 hr. In particular, it has been recently reported that patients with objective short sleep duration have a blunted response to cognitive behavioral therapy for insomnia (CBT-I). The aim of this study was to investigate the differences of CBT-I response in two groups of ID patients subdivided according to total sleep time. Methods: Two hundred forty-six ID patients were subdivided into two groups, depending on their reported total sleep time (TST) assessed by sleep diaries. Patients with a TST greater than 6 hr were classified as “normal sleepers” (NS), while those with a total sleep time less than 6 hr were classified as “short sleepers” (SS). Results: The delta between Insomnia Severity Index scores and sleep efficiency at the beginning as compared to the end of the treatment was significantly higher for SS in comparison to NS, even if they still exhibit more insomnia symptoms. No difference was found between groups in terms of remitters; however, more responders were observed in the SS group in comparison to the NS group. Conclusions: Our results demonstrate that ID patients with reported short total sleep time had a beneficial response to CBT-I of greater magnitude in comparison to NS. However, these patients may still experience the presence of residual insomnia symptoms after treatment.

Abstract

Visuospatial attention theories often propose hemispheric asymmetries underlying the control of attention. In general support of these theories, previous EEG/MEG studies have shown that spatial attention is associated with hemispheric modulation of posterior alpha power (gating by inhibition). However, since measures of alpha power are typically expressed as lateralization scores, or collapsed across left and right attention shifts, the individual hemispheric contribution to the attentional control mechanism remains unclear. This is, however, the most crucial and decisive aspect in which the currently competing attention theories continue to disagree. To resolve this long-standing conflict, we derived predictions regarding alpha power modulations from Heilman's hemispatial theory and Kinsbourne's interhemispheric competition theory and tested them empirically in an EEG experiment. We used an attention paradigm capable of isolating alpha power modulation in two attentional states, namely attentional bias in a neutral cue condition and spatial orienting following directional cues. Differential alpha modulations were found for both hemispheres across conditions. When anticipating peripheral visual targets without preceding directional cues (neutral condition), posterior alpha power in the left hemisphere was generally lower and more strongly modulated than in the right hemisphere, in line with the interhemispheric competition theory. Intriguingly, however, while alpha power in the right hemisphere was modulated by both, cue-directed leftward and rightward attention shifts, the left hemisphere only showed modulations by rightward shifts of spatial attention, in line with the hemispatial theory. This suggests that the two theories may not be mutually exclusive, but rather apply to different attentional states.

Abstract

Speakers continuously monitor what they say. Sometimes, self-monitoring malfunctions and errors pass undetected and uncorrected. In the field of action monitoring, an event-related brain potential, the error-related negativity (ERN), is associated with error processing. The present study relates the ERN to verbal self-monitoring and investigates how the ERN is affected by auditory distractors during verbal monitoring. We found that the ERN was largest following errors that occurred after semantically related distractors had been presented, as compared to semantically unrelated ones. This result demonstrates that the ERN is sensitive not only to response conflict resulting from the incompatibility of motor responses but also to more abstract lexical retrieval conflict resulting from activation of multiple lexical entries. This, in turn, suggests that the functioning of the verbal self-monitoring system during speaking is comparable to other performance monitoring, such as action monitoring.

Abstract

During speech production, we continuously monitor what we say. In
situations in which speech errors potentially have more severe
consequences, e.g. during a public presentation, our verbal selfmonitoring
system may pay special attention to prevent errors than in
situations in which speech errors are more acceptable, such as a casual
conversation. In an event-related potential study, we investigated
whether or not motivation affected participants’ performance using a
picture naming task in a semantic blocking paradigm. Semantic
context of to-be-named pictures was manipulated; blocks were
semantically related (e.g., cat, dog, horse, etc.) or semantically
unrelated (e.g., cat, table, flute, etc.). Motivation was manipulated
independently by monetary reward. The motivation manipulation did
not affect error rate during picture naming. However, the highmotivation
condition yielded increased amplitude and latency values of
the error-related negativity (ERN) compared to the low-motivation
condition, presumably indicating higher monitoring activity. Furthermore,
participants showed semantic interference effects in reaction
times and error rates. The ERN amplitude was also larger during
semantically related than unrelated blocks, presumably indicating that
semantic relatedness induces more conflict between possible verbal
responses.

Abstract

The present study investigated whether Short Message Service shortcuts are more difficult to process in sentence context than the spelled-out word equivalent and, if so, how any additional processing difficulty arises. Twenty-four student participants read 37 Short Message Service shortcuts and word equivalents embedded in semantically plausible and implausible contexts (e.g., He left/drank u/you a note) while their eye movements were recorded. There were effects of plausibility and spelling on early measures of processing difficulty (first fixation durations, gaze durations, skipping, and first-pass regression rates for the targets), but there were no interactions of plausibility and spelling. Late measures of processing difficulty (second run gaze duration and total fixation duration) were only affected by plausibility but not by spelling. These results suggest that shortcuts are harder to recognize, but that, once recognized, they are integrated into the sentence context as easily as ordinary words.

Abstract

We investigated whether Tagalog-speaking children incrementally interpret the first noun
as the agent, even if verbal and nominal markers for assigning thematic roles are given
early in Tagalog sentences. We asked five- and seven-year-old children and adult
controls to select which of two pictures of reversible actions matched the sentence they
heard, while their looks to the pictures were tracked. Accuracy and eye-tracking data
showed that agent-initial sentences were easier to comprehend than patient-initial
sentences, but the effect of word order was modulated by voice. Moreover, our eyetracking
data provided evidence that, by the first noun phrase, seven-year-old children
looked more to the target in the agent-initial compared to the patient-initial conditions,
but this word order advantage was no longer observed by the second noun phrase. The
findings support language processing and acquisition models which emphasize the role
of frequency in developing heuristic strategies (e.g., Chang, Dell, & Bock, 2006).

Abstract

We report on two experiments that investigated the acquisition of the Tagalog symmetrical voice system, a typologically rare feature of Western Austronesian languages in which there are more than one basic transitive construction and no preference for agents to be syntactic subjects. In the experiments, 3-, 5-, and 7-year-old Tagalog-speaking children and adults completed a structural priming task that manipulated voice and word order, with the uniqueness of Tagalog allowing us to tease apart priming of thematic role order from that of syntactic roles. Participants heard a description of a picture showing a transitive action, and were then asked to complete a sentence of an unrelated picture using a voice-marked verb provided by the experimenter. Our results show that children gradually acquire an agent-before-patient preference, instead of having a default mapping of the agent to the first noun position. We also found an earlier mastery of the patient voice verbal and nominal marker configuration (patient is the subject), suggesting that children do not initially map the agent to the subject. Children were primed by thematic role but not syntactic role order, suggesting that they prioritize mapping of the thematic roles to sentence positions.

Abstract

Acoustic allometry is the study of how animal vocalisations reflect their body size. A key aim of this research is to identify outliers to acoustic allometry principles and pinpoint the evolutionary origins of such outliers. A parallel strand of research investigates species capable of vocal learning, the experience-driven ability to produce novel vocal signals through imitation or modification of existing vocalisations. Modification of vocalizations is a common feature found when studying both acoustic allometry and vocal learning. Yet, these two fields have only been investigated separately to date. Here, we review and connect acoustic allometry and vocal learning across mammalian clades, combining perspectives from bioacoustics, anatomy and evolutionary biology. Based on this, we hypothesize that, as a precursor to vocal learning, some species might have evolved the capacity for volitional vocal modulation via sexual selection for ‘dishonest’ signalling. We provide preliminary support for our hypothesis by showing significant associations between allometric deviation and vocal learning in a dataset of 164 mammals. Our work offers a testable framework for future empirical research linking allometric principles with the evolution of vocal learning.

Abstract

Communicating species identity is a key component of many animal signals. However, whether selection for species recognition systematically increases signal diversity during clade radiation remains debated. Here we show that in woodpecker drumming, a rhythmic signal used during mating and territorial defense, the amount of species identity information encoded remained stable during woodpeckers’ radiation. Acoustic analyses and evolutionary reconstructions show interchange among six main drumming types despite strong phylogenetic contingencies, suggesting evolutionary tinkering of drumming structure within a constrained acoustic space. Playback experiments and quantification of species discriminability demonstrate sufficient signal differentiation to support species recognition in local communities. Finally, we only find character displacement in the rare cases where sympatric species are also closely related. Overall, our results illustrate how historical contingencies and ecological interactions can promote conservatism in signals during a clade radiation without impairing the effectiveness of information transfer relevant to inter-specific discrimination.

Abstract

The Perceptual Loop Theory of speech monitoring assumes that speakers routinely inspect their inner speech. In contrast, Huettig and Hartsuiker (2010) observed that listening to one’s own speech during language production drives eye-movements to phonologically related printed words with a similar time-course as listening to someone else’s speech does in speech perception experiments. This suggests that speakers listen to their own overt speech, but not to their inner speech. However, a direct comparison between production and perception with the same stimuli and participants is lacking so far. The current printed word eye-tracking experiment therefore used a within-subjects design, combining production and perception. Displays showed four words, of which one, the target, either had to be named or was presented auditorily. Accompanying words were phonologically related, semantically related, or unrelated to the target. There were small increases in looks to phonological competitors with a similar time-course in both production and perception. Phonological effects in perception however lasted longer and had a much larger magnitude. We conjecture that this difference is related to a difference in predictability of one’s own and someone else’s speech, which in turn has consequences for lexical competition in other-perception and possibly suppression of activation in self-perception.

Abstract

Our species displays remarkable linguistic diversity. While the uneven distribution of this diversity demands explanation, the drivers of these patterns have not been conclusively determined. We address this issue in two steps. First, we review previous empirical studies that have suggested environmental, geographical, and socio-cultural drivers of linguistic diversification. However, contradictory results and methodological variation make it difficult to draw general conclusions. Second, we outline a program for future research. We suggest that future analyses should account for interactions among causal factors, lack of spatial and phylogenetic independence of data, and transitory patterns. Recent analytical advances in biogeography and evolutionary biology, such as simulation modeling of diversity patterns, hold promise for testing four key mechanisms of language diversification proposed here: neutral change, population movement, contact, and selection. Future modeling approaches should also evaluate how the outcomes of these processes are influenced by demography, environmental heterogeneity, and time.

Abstract

Processing of recursion has been proposed as the foundation of human linguistic ability. Yet this ability may be shared with other domains, such as the musical or rhythmic domain. Lindenmayer grammars (L-systems) have been proposed as a recursive grammar for use in artificial grammar experiments to test recursive processing abilities, and previous work had shown that participants are able to learn such a grammar using linguistic stimuli (syllables). In the present work, we used two experimental paradigms (a yes/no task and a two-alternative forced choice) to test whether adult participants are able to learn a recursive Lindenmayer grammar composed of drum sounds. After a brief exposure phase, we found that participants at the group level were sensitive to the exposure grammar and capable of distinguishing the grammatical and ungrammatical test strings above chance level in both tasks. While we found evidence of participants’ sensitivity to a very complex L-system grammar in a non-linguistic, potentially musical domain, the results were not robust. We discuss the discrepancy within our results and with the previous literature using L-systems in the linguistic domain. Furthermore, we propose directions for future music cognition research using L-system grammars.

Abstract

Does spatial language influence how people think about space? To address this question, we observed children who did not know a conventional language, and tested their performance on nonlinguistic spatial tasks. We studied deaf children living in Istanbul whose hearing losses prevented them from acquiring speech and whose hearing parents had not exposed them to sign. Lacking a conventional language, the children used gestures, called homesigns, to communicate. In Study 1, we asked whether homesigners used gesture to convey spatial relations, and found that they did not. In Study 2, we tested a new group of homesigners on a Spatial Mapping Task, and found that they performed significantly worse than hearing Turkish children who were matched to the deaf children on another cognitive task. The absence of spatial language thus went hand-in-hand with poor performance on the nonlinguistic spatial task, pointing to the importance of spatial language in thinking about space.

Abstract

Wilson disease (WD) is an autosomal recessive disorder resulting in pathological progressive copper accumulation in liver and other tissues. The worldwide prevalence (P) is about 30/million, while in Sardinia it is in the order of 1/10 000. However, all of these estimates are likely to suffer from an underdiagnosis bias. Indeed, a recent molecular neonatal screening in Sardinia reported a WD prevalence of 1:2707. In this study, we used a new approach that makes it possible to estimate the allelic frequency (q) of an autosomal recessive disorder if one knows the proportion between homozygous and compound heterozygous patients (the homozygosity index or HI) and the inbreeding coefficient (F) in a sample of affected individuals. We applied the method to a set of 178 Sardinian individuals (3 of whom born to consanguineous parents), each with a clinical and molecular diagnosis of WD. Taking into account the geographical provenance of the parents of every patient within Sardinia (to make F computation more precise), we obtained a q=0.0191 (F=7.8 × 10-4, HI=0.476) and a corresponding prevalence P=1:2732. This result confirms that the prevalence of WD is largely underestimated in Sardinia. On the other hand, the general reliability and applicability of the HI approach to other autosomal recessive disorders is confirmed, especially if one is interested in the genetic epidemiology of populations with high frequency of consanguineous marriages.

Abstract

First paragraph: The study of the transmission of sign languages can give novel insights into the transmission of spoken languages1 and, more generally, into gene–culture coevolution. Over the years, several papers related to the persistence of sign language have been
reported.2–6 All of these studies have emphasized the role of assortative (non-random) mating by deafness state (ie, a tendency for deaf individuals to partner together) for increasing the frequency of recessive deafness, and hence for the persistence of sign language in a population.

Abstract

Regional variation in African-American English (AAE) is especially salient to its speakers involved with hip-hop culture, as hip-hop assigns great importance to regional identity and regional accents are a key means of expressing regional identity. However, little is known about AAE regional variation regarding prosodic rhythm and melody. In hip-hop music, regional variation can also be observed, with different regions’ rap performances being characterized by distinct “flows” (i.e., rhythmic and melodic delivery), an observation which has not been quantitatively investigated yet. This study concerns regional variation in AAE speech and rap, specifically regarding the United States’ East and West Coasts. It investigates how East Coast and West Coast AAE prosody are distinct, how East Coast and West Coast rap flows differ, and whether the two domains follow a similar pattern: more rhythmic and melodic variation on the West Coast compared to the East Coast for both speech and rap. To this end, free speech and rap recordings of 16 prominent African-American members of the East Coast and West Coast hip-hop communities were phonetically analyzed regarding rhythm (e.g., syllable isochrony and musical timing) and melody (i.e., pitch fluctuation) using a combination of existing and novel methodological approaches. The results mostly confirm the hypotheses that East Coast AAE speech and rap are less rhythmically diverse and more monotone than West Coast AAE speech and rap, respectively. They also show that regional variation in AAE prosody and rap flows pattern in similar ways, suggesting a connection between rhythm and melody in language and music.

Abstract

According to the cue-based parsing approach (Lewis, Vasishth, & Van Dyke, 2006), sentence comprehension difficulty derives from interference from material that partially matches syntactic and semantic retrieval cues. In a 2 (low vs. high semantic interference) × 2 (low vs. high syntactic interference) fMRI study, greater activation was observed in left BA44/45 for high versus low syntactic interference conditions following sentences and in left BA45/47 for high versus low semantic interference conditions following comprehension questions. A conjunction analysis showed BA45 associated with both types of interference, while BA47 was associated with only semantic interference. Greater activation was also observed in the left STG in the high interference conditions. Importantly, the results for the LIFG could not be attributed to greater working memory capacity demands for high interference conditions. The results favor a fractionation of the LIFG wherein BA45 is associated with post-retrieval selection and BA47 with controlled retrieval of semantic information.

Abstract

To test whether the language we speak influences our behavior even when we are not speaking, we asked speakers of four languages differing in their predominant word orders (English, Turkish, Spanish, and Chinese) to perform two nonverbal tasks: a communicative task (describing an event by using gesture without speech) and a noncommunicative task (reconstructing an event with pictures). We found that the word orders speakers used in their everyday speech did not influence their nonverbal behavior. Surprisingly, speakers of all four languages used the same order and on both nonverbal tasks. This order, actor–patient–act, is analogous to the subject–object–verb pattern found in many languages of the world and, importantly, in newly developing gestural languages. The findings provide evidence for a natural order that we impose on events when describing and reconstructing them nonverbally and exploit when constructing language anew.

Abstract

Comparative thanatology encompasses the study of death-related responses in non-human animals and aspires to elucidate the evolutionary origins of human behavior in the context of death. Many reports have revealed that humans are not the only species affected by the death of group members. Non-human primates in particular show behaviors such as congregating around the deceased, carrying the corpse for prolonged periods of time (predominantly mothers carrying dead infants), and inspecting the corpse for signs of life. Here, we extend the focus on death-related responses in non-human animals by exploring whether chimpanzees are inclined to console the bereaved: the individual(s) most closely associated with the deceased. We report a case in which a chimpanzee (Pan troglodytes) mother experienced the loss of her fully developed infant (presumed stillborn). Using observational data to compare the group members’ behavior before and after the death, we found that a substantial number of group members selectively increased their affiliative expressions toward the bereaved mother. Moreover, on the day of the death, we observed heightened expressions of species-typical reassurance behaviors toward the bereaved mother. After ruling out several alternative explanations, we propose that many of the chimpanzees consoled the bereaved mother by means of affiliative and selective empathetic expressions.

Abstract

Native listeners make use of higher-level, context-driven semantic and linguistic information during the perception of speech-in-noise. In a recent behavioral study, using a new paradigm that isolated the semantic level of speech by using words, we showed that this native-language benefit is at least partly driven by semantic context (Golestani et al., 2009). Here, we used the same paradigm in a functional magnetic resonance imaging (fMRI) experiment to study the neural bases of speech intelligibility, as well as to study the neural bases of this semantic context effect in the native language. A forced-choice recognition task on the first of two auditorily presented semantically related or unrelated words was employed, where the first, 'target' word was embedded in different noise levels. Results showed that activation in components of the brain language network, including Broca's area and the left posterior superior temporal sulcus, as well as brain regions known to be functionally related to attention and task difficulty, was modulated by stimulus intelligibility. In line with several previous studies examining the role of linguistic context in the intelligibility of degraded speech at the sentence level, we found that activation in the angular gyrus of the left inferior parietal cortex was modulated by the presence of semantic context, and further, that this modulation depended on the intelligibility of the speech stimuli. Our findings help to further elucidate neural mechanisms underlying the interaction of context-driven and signal-driven factors during the perception of degraded speech, and this specifically at the semantic level. (c) 2013 Elsevier Inc. All rights reserved.

Abstract

The present article examines the proposal that typology is a major factor guiding transfer selectivity in L3/Ln acquisition. We tested first exposure in L3/Ln using two artificial languages (ALs) lexically based in English and Spanish, focusing on gender agreement between determiners and nouns, and between nouns and adjectives. 50 L1 Spanish-L2 English speakers took part in the experiment. After receiving implicit training in one of the ALs (Mini-Spanish, N = 26; Mini-English, N = 24), gender violations elicited a fronto-lateral negativity in Mini-English in the earliest time window (200–500 ms), although this was not followed by any other differences in subsequent periods. This effect was highly localized, surfacing only in electrodes of the right-anterior region. In contrast, gender violations in Mini-Spanish elicited a broadly distributed positivity in the 300–600 ms time window. While we do not find typical indices of grammatical processing such as the P600 component, we believe that the between-groups differential appearance of the positivity for gender violations in the 300–600 ms time window reflects differential allocation of attentional resources as a function of the ALs’ lexical similarity to English or Spanish. We take these differences in attention to be precursors of the processes involved in transfer source selection in L3/Ln.

Abstract

Humans associate abstract words with physical stimulus dimensions, such as linking upward locations with positive concepts (e.g., happy = up). These associations manifest both via subjective reports of associations and on objective performance metrics. Humans also report subjective associations between colours and abstract words (e.g., joy is linked to yellow). Here we tested whether such associations manifest on objective task performance, even when not task-relevant. Across three experiments, participants were presented with abstract words in physical colours that were either congruent with previously-reported subjective word-colour associations (e.g., victory in red and unhappy in blue), or were incongruent (e.g., victory in blue and unhappy in red). In Experiment 1, participants' task was to identify the valence of words. This congruency manipulation systematically affected objective task performance. In Experiment 2, participants completed two blocks, a valence-identification and a colour-identification task block. Both tasks produced congruency effects on performance, however, the results of the colour identification block could have reflected learning effects (i.e., associating the more common congruent colour with the word). This issue was rectified in Experiment 3, whereby participants completed the same two tasks as Experiment 2, but now matched congruent and incongruent pairs were used for both tasks. Again, both tasks produced reliable congruency effects. Item analyses in each experiment revealed that these effects demonstrated a degree of item specificity. Overall, there was clear evidence that at least some abstract word-colour pairings can systematically affect behaviour.

Abstract

Background: While persons with aphasia (PwA) are often dichotomised as fluent or nonfluent, agreement that fluency is not an all-or-nothing construct has led to the use of continuous variables as a way to quantify fluency, such as multi-dimensional rating scales, speech rate, and utterance length. Though these measures are often used in research, they provide little information about the underlying fluency deficit.
Aim: The aim of the study was to identify how well commonly used continuous measures of fluency capture variability in spontaneous speech variables at lexical, grammatical, and speech production levels. Methods & Procedures: Speech samples of 254 English-speaking PwA from the AphasiaBank database were analyzed to examine the distributions of four continuous measures of fluency: the WAB-R fluency scale, utterance length, retracing, and speech rate. Linear regression was used to identify spontaneous speech predictors contributing to each fluency outcome measure.
Outcomes & Results: All the outcome measures reflected the influence of multiple underlying dimensions, although the predictors varied. The WAB-R fluency scale, speech rate, and retracing were influenced by measures of grammatical competence, lexical retrieval, and speech production, whereas utterance length was influenced only by measures of grammatical competence and lexical retrieval. The strongest predictor of WAB-R fluency was aphasia severity, whereas the strongest predictor for all other fluency proxy measures was grammatical complexity.
Conclusions: Continuous measures allow a variety of ways to objectively quantify speech fluency; however, they reflect superficial manifestations of fluency that may be affected by multiple underlying deficits. Furthermore, the deficits underlying different measures vary, which may reduce the reliability of fluency diagnoses. Capturing these differences at the individual level is critical to accurate diagnosis and appropriately targeted therapy.

Abstract

Our aim in the present study is to measure neural correlates during spontaneous interactive sentence production. We present a novel approach using the word-by-word technique from improvisational theatre, in which two speakers jointly produce one sentence. This paradigm allows the assessment of behavioural aspects, such as turn-times, and electrophysiological responses, such as event-related-potentials (ERPs). Twenty-five participants constructed a cued but spontaneous four-word German sentence together with a confederate, taking turns for each word of the sentence. In 30% of the trials, the confederate uttered an unexpected gender-marked article. To complete the sentence in a meaningful way, the participant had to detect the violation and retrieve and utter a new fitting response. We found significant increases in response times after unexpected words and – despite allowing unscripted language production and naturally varying speech material – successfully detected significant N400 and P600 ERP effects for the unexpected word. The N400 EEG activity further significantly predicted the response time of the subsequent turn. Our results show that combining behavioural and neuroscientific measures of verbal interactions while retaining sufficient experimental control is possible, and that this combination provides promising insights into the mechanisms of spontaneous spoken dialogue.

Abstract

The aim of this study was to investigate whether early-English education benefits the perception
of English phonetic contrasts that are known to be perceptually confusable for Dutch
native speakers, comparing Dutch pupils who were enrolled in an early-English programme
at school from the age of four with pupils in a mainstream programme with English instruction
from the age of 11, and English-Dutch early bilingual children. Children were 4-5-yearolds
(start of primary school), 8-9-year-olds, or 11-12-year-olds (end of primary school).
Children were tested on four contrasts that varied in difficulty: /b/-/s/ (easy), /k/-/ɡ/ (intermediate),
/f/-/θ/ (difficult), /ε/-/æ/ (very difficult). Bilingual children outperformed the two other
groups on all contrasts except /b/-/s/. Early-English pupils did not outperform mainstream
pupils on any of the contrasts. This shows that early-English education as it is currently
implemented is not beneficial for pupils’ perception of non-native contrasts.

Abstract

The acquisition of novel phonetic categories is hypothesized to be affected by the distributional properties of the input, the relation of the new categories to the native phonology, and the availability of supervision (feedback). These factors were examined in four experiments in which listeners were presented with novel categories based on vowels of Dutch. Distribution was varied such that the categorization depended on the single dimension duration, the single dimension frequency, or both dimensions at once. Listeners were clearly sensitive to the distributional information, but unidimensional contrasts proved easier to learn than multidimensional. The native phonology was varied by comparing Spanish versus American English listeners. Spanish listeners found categorization by frequency easier than categorization by duration, but this was not true of American listeners, whose native vowel system makes more use of duration-based distinctions. Finally, feedback was either available or not; this comparison showed supervised learning to be significantly superior to unsupervised learning.

Abstract

In recent years, the influence of alpha (7–13 Hz) phase on visual processing has received a lot of attention. Magneto‐/encephalography (M/EEG) studies showed that alpha phase indexes visual excitability and task performance. Studies with transcranial alternating current stimulation (tACS) aim to modulate oscillations and causally impact task performance. Here, we applied right occipital tACS (O2 location) to assess the functional role of alpha phase in a series of experiments. We presented visual stimuli at different pre‐determined, experimentally controlled, phases of the entraining tACS signal, hypothesizing that this should result in an oscillatory pattern of visual performance in specifically left hemifield detection tasks. In experiment 1, we applied 10 Hz tACS and used separate psychophysical staircases for six equidistant tACS‐phase conditions, obtaining contrast thresholds for detection of visual gratings in left or right hemifield. In experiments 2 and 3, tACS was at EEG‐based individual peak alpha frequency. In experiment 2, we measured detection rates for gratings with (pseudo‐)fixed contrast. In experiment 3, participants detected brief luminance changes in a custom‐built LED device, at eight equidistant alpha phases. In none of the experiments did the primary outcome measure over phase conditions consistently reflect a one‐cycle sinusoid. However, post hoc analyses of reaction times (RT) suggested that tACS alpha phase did modulate RT for specifically left hemifield targets in both experiments 1 and 2 (not measured in experiment 3). This observation requires future confirmation, but is in line with the idea that alpha phase causally gates visual inputs through cortical excitability modulation.

Abstract

Researchers are beginning to uncover the neurogenetic pathways that underlie our unparalleled capacity for spoken language. Initial clues come from identification of genetic risk factors implicated in developmental language disorders. The underlying genetic architecture is complex, involving a range of molecular mechanisms. For example, rare protein-coding mutations of the FOXP2 transcription factor cause severe problems with sequencing of speech sounds, while common genetic risk variants of small effect size in genes like CNTNAP2, ATP2C2 and CMIP are associated with typical forms of language impairment. In this article, we describe how investigations of these and other candidate genes, in humans, animals and cellular models, are unravelling the connections between genes and cognition. This depends on interdisciplinary research at multiple levels, from determining molecular interactions and functional roles in neural cell-biology all the way through to effects on brain structure and activity.

Abstract

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson’s disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder.

Abstract

Absolute pitch and synesthesia are two uncommon cognitive traits that reflect increased neuronal connectivity and have been anecdotally reported to occur together in a same individual. Here we systematically evaluate the occurrence of syesthesia in a population of 768 subjects with documented absolute pitch. Out of these 768 subjects, 151(20.1%) reported synesthesia, most commonly with color. These self-reports of synesthesia were validated in a subset of 21 study subjects using an established methodology. We further carried out combined linkage analysis of 53 multiplex families with absolute pitch and 36 multiplex families with synesthesia. We observed a peak NPL LOD=4.68 on chromosome 6q, as well as evidence of linkage on chromosome 2 using a dominant model. These data establish the close phenotypic and genetic relationship between absolute pitch and synesthesia. The chromosome 6 linkage region contains 73 genes; several leading candidate genes involved in neurodevelopment were investigated by exon resequencing. However, further studies will be required to definitively establish the identity of the causative gene(s) in the region.

Abstract

Magnetoencephalographic (MEG) recordings are a rich source of information about the neural dynamics underlying cognitive processes in the brain, with excellent temporal and good spatial resolution. In recent years there have been considerable advances in MEG hardware developments as well as methodological developments. Sophisticated analysis techniques are now routinely applied and continuously improved, leading to fascinating insights into the intricate dynamics of neural processes. However, the rapidly increasing level of complexity of the different steps in a MEG study make it difficult for novices, and sometimes even for experts, to stay aware of possible limitations and caveats. Furthermore, the complexity of MEG data acquisition and data analysis requires special attention when describing MEG studies in publications, in order to facilitate interpretation and reproduction of the results. This manuscript aims at making recommendations for a number of important data acquisition and data analysis steps and suggests details that should be specified in manuscripts reporting MEG studies. These recommendations will hopefully serve as guidelines that help to strengthen the position of the MEG research community within the field of neuroscience, and may foster discussion within the community in order to further enhance the quality and impact of MEG research.

Abstract

The most well-described example of an inherited speech and language disorder is that observed in the multigenerational KE family, caused by a heterozygous missense mutation in the FOXP2 gene. Affected individuals are characterized by deficits in the learning and production of complex orofacial motor sequences underlying fluent speech and display impaired linguistic processing for both spoken and written language. The FOXP2 transcription factor is highly similar in many vertebrate species, with conserved expression in neural circuits related to sensorimotor integration and motor learning. In this study, we generated mice carrying an identical point mutation to that of the KE family, yielding the equivalent arginine-to-histidine substitution in the Foxp2 DNA-binding domain. Homozygous R552H mice show severe reductions in cerebellar growth and postnatal weight gain but are able to produce complex innate ultrasonic vocalizations. Heterozygous R552H mice are overtly normal in brain structure and development. Crucially, although their baseline motor abilities appear to be identical to wild-type littermates, R552H heterozygotes display significant deficits in species-typical motor-skill learning, accompanied by abnormal synaptic plasticity in striatal and cerebellar neural circuits.

Abstract

To understand the underlying principles of categorisation and classification of sensory input semantic analyses must be based on both language and culture. The senses are not only physiological phenomena, but they are also linguistic, cultural, and social. The goal of this task is to explore and describe sociocultural patterns relating language of perception, ideologies of perception, and perceptual practice in our speech communities.

Abstract

The aim of this article is to analyze the funerary customs and ritual for the souls among contemporary Yucatec Maya in order to better understand their relations with pre-Hispanic burial patterns. It is suggested that the souls of the dead are considered as ancestors that can be distinguished between family and collective ancestors considering several criteria: the place of burial, the place of ritual performance and the ritual treatment. In this proposition, funerary practices as well as ritual categories of ancestors (family or collective), are considered as reminiscences of ancient practices whose traces can be found throughout historical sources. Through an analyze of the current funerary practices and their variations, this article aims to demonstrate that over the time and despite socio-economical changes, ancient funerary practices (specifically from the post-classic period) had kept some homogeneity, preserving some essential characteristics that can be observed in the actuality.

Abstract

A key strength of connectionist modelling is its ability to simulate both intact cognition and the behavioural effects of neural damage. We survey the literature, showing that models have been damaged in a variety of ways, e.g. by removing connections, by adding noise to connection weights, by scaling weights, by removing units and by adding noise to unit activations. While these different implementations of damage have often been assumed to be behaviourally equivalent, some theorists have made aetiological claims that rest on nonequivalence. They suggest that related deficits with different aetiologies might be accounted for by different forms of damage within a single model. We present two case studies that explore the effects of different forms of damage in two influential connectionist models, each of which has been applied to explain neuropsychological deficits. Our results indicate that the effect of simulated damage can indeed be sensitive to the way in which damage is implemented, particularly when the environment comprises subsets of items that differ in their statistical properties, but such effects are sensitive to relatively subtle aspects of the model’s training environment. We argue that, as a consequence, substantial methodological care is required if aetiological claims about simulated neural damage are to be justified, and conclude more generally that implementation assumptions, including those concerning simulated damage, must be fully explored when evaluating models of neurological deficits, both to avoid over-extending the explanatory power of specific implementations and to ensure that reported results are replicable.

Abstract

This chapter explores what L2 learners' gestures reveal about L2 grammar. The focus is on learners’ difficulties with maintaining reference in discourse caused by their incomplete mastery of pronouns. The study highlights the systematic parallels between properties of L2 speech and gesture, and the parallel effects of grammatical development in both modalities. The validity of a communicative account of interlanguage grammar in this domain is tested by taking the cohesive properties of the gesture-speech ensemble into account. Specifically, I investigate whether learners use gestures to compensate for and to license over-explicit reference in speech. The results rule out a communicative account for the spoken variety of maintained reference. In contrast, cohesive gestures are found to be multi-functional. While the presence of cohesive gestures is not communicatively motivated, their spatial realisation is. It is suggested that gestures are exploited as a grammatical communication strategy to disambiguate speech wherever possible, but that they may also be doing speaker-internal work. The methodological importance of considering L2 gestures when studying grammar is also discussed.

Abstract

Gestures, the symbolic movements speakers perform while they speak, are systematically related to speech and language at multiple levels, and reflect cognitive and linguistic activities in non-trivial ways. This chapter presents an overview of what gestures can tell us about the processes of second language acquisition. It focuses on two key aspects, (a) gestures and the developing language system and (b) gestures and learning, and discusses some implications of an expanded view of language acquisition that takes gestures into account.

Abstract

The purpose of the current paper is to outline how gestures can contribute to the study of some key issues in language development. Specifically, we (1) briefly summarise what is already known about gesture in the domains of first and second language development, and development or changes over the life span more generally; (2) highlight theoretical and empirical issues in these domains where gestures can contribute in important ways to further our understanding; and (3) summarise some common themes in all strands of research on language development that could be the target of concentrated research efforts.

Abstract

The title of this special issue, Gesture and SLA: Toward an Integrated Approach, stems in large part from the idea known as integrationism, principally set forth by Harris (2003, 2005), which posits that it is time to “demythologize” linguistics, moving away from the “orthodox exponents” that have idealized the notion of language. The integrationist approach intends a view that focuses on communication—that is, language in use, language as a “fact of life” (Harris, 2003, p. 50). Although not all gesture studies embrace an integrationist view—indeed, the field applies numerous theories across various disciplines—it is nonetheless true that to study gesture is to study what has traditionally been called paralinguistic modes of interaction, with the paralinguistic label given on the assumption that gesture is not part of the core meaning of what is rendered linguistically. However, arguably, most researchers within gesture studies would maintain just the opposite: The studies presented in this special issue reflect a view whereby gesture is regarded as a central aspect of language in use, integral to how we communicate (make meaning) both with each other and with ourselves.

Abstract

This study explores how French adults and children aged four and six years talk and gesture about voluntary motion, examining (1) how they encode path and manner in speech, (2) how they encode this information in accompanying gestures; and (3) whether gestures are co-expressive with speech or express other information. When path and manner are equally relevant, children’s and adults’ speech and gestures both focus on path, rather than on manner. Moreover, gestures are predominantly co-expressive with speech at all ages. However, when they are non-redundant, adults tend to gesture about path while talking about manner, whereas children gesture about both path and manner while talking about path. The discussion highlights implications for our understanding of speakers’ representations and their development.

Abstract

What is the long‐term trajectory of semantic memory deficits in patients who have suffered structural brain damage? Memory is, per definition, a changing faculty. The traditional view is that after an initial recovery period, the mature human brain has little capacity to repair or reorganize. More recently, it has been suggested that the central nervous system may be more plastic with the ability to change in neural structure, connectivity, and function. The latter observations are, however, largely based on normal learning in healthy subjects. Here, we report a patient who suffered bilateral ventro‐medial damage after presumed herpes encephalitis in 1971. He was seen regularly in the eighties, and we recently had the opportunity to re‐assess his semantic memory deficits. On semantic category fluency, he showed a very clear category‐specific deficit performing better that control data on non‐living categories and significantly worse on living items. Recent testing showed that his impairments have remained unchanged for more than 40 years. We suggest cautiousness when extrapolating the concept of brain plasticity, as observed during normal learning, to plasticity in the context of structural brain damage.

Abstract

Claims that neuroscientific data do not contribute to our understanding of psychological functions have been made recently. Here I argue that these criticisms are solely based on an analysis of functional magnetic resonance imaging (fMRI) studies. However, fMRI is only one of the methods in the toolkit of cognitive neuroscience. I provide examples from research on event-related brain potentials (ERPs) that have contributed to our understanding of the cognitive architecture of human language functions. In addition, I provide evidence of (possible) contributions from fMRI measurements to our understanding of the functional architecture of language processing. Finally, I argue that a neurobiology of human language that integrates information about the necessary genetic and neural infrastructures will allow us to answer certain questions that are not answerable if all we have is evidence from behavior.

Abstract

This paper focuses on what electrical and magnetic recordings of human brain activity reveal about spoken language understanding. Based on the high temporal resolution of these recordings, a fine-grained temporal profile of different aspects of spoken language comprehension can be obtained. Crucial aspects of speech comprehension are lexical access, selection and semantic integration. Results show that for words spoken in context, there is no ‘magic moment’ when lexical selection ends and semantic integration begins. Irrespective of whether words have early or late recognition points, semantic integration processing is initiated before words can be identified on the basis of the acoustic information alone. Moreover, for one particular event-related brain potential (ERP) component (the N400), equivalent impact of sentence- and discourse-semantic contexts is observed. This indicates that in comprehension, a spoken word is immediately evaluated relative to the widest interpretive domain available. In addition, this happens very quickly. Findings are discussed that show that often an unfolding word can be mapped onto discourse-level representations well before the end of the word. Overall, the time course of the ERP effects is compatible with the view that the different information types (lexical, syntactic, phonological, pragmatic) are processed in parallel and influence the interpretation process incrementally, that is as soon as the relevant pieces of information are available. This is referred to as the immediacy principle.

Abstract

In an event-related potential experiment with Chinese discourses as material, we investigated how and when accentuation influences spoken discourse comprehension in relation to the different information states of the critical words. These words could either provide new or old information. It was shown that variation of accentuation influenced the amplitude of the N400, with a larger amplitude for accented than deaccented words. In addition, there was an interaction between accentuation and information state. The N400 amplitude difference between accented and deaccented new information was smaller than that between accented and deaccented old information. The results demonstrate that, during spoken discourse comprehension, listeners rapidly extract the semantic consequences of accentuation in relation to the previous discourse context. Moreover, our results show that the N400 amplitude can be larger for correct (new,accented words) than incorrect (new, deaccented words) information. This, we argue, proves that the N400 does not react to semantic anomaly per se, but rather to semantic integration load, which is higher for new information.

Abstract

A neurobiological model of language is discussed that overcomes the shortcomings of the classical Wernicke-Lichtheim-Geschwind model. It is based on a subdivision of language processing into three components: Memory, Unification, and Control. The functional components as well as the neurobiological underpinnings of the model are discussed. In addition, the need for extension of the model beyond the classical core regions for language is shown. Attentional networks as well as networks for inferential processing are crucial to realize language comprehension beyond single word processing and beyond decoding propositional content. It is shown that this requires the dynamic interaction between multiple brain regions.

Abstract

This chapter sketches in very general terms the cognitive architecture of both language comprehension and production, as well as the neurobiological infrastructure that makes the human brain ready for language. Focus is on spoken language, since that compares most directly to processing music. It is worth bearing in mind that humans can also interface with language as a cognitive system using sign and text (visual) as well as Braille (tactile); that is to say, the system can connect with input/output processes in any sensory modality. Language processing consists of a complex and nested set of subroutines to get from sound to meaning (in comprehension) or meaning to sound (in production), with remarkable speed and accuracy. The fi rst section outlines a selection of the major constituent operations, from fractionating the input into manageable units to combining and unifying information in the construction of meaning. The next section addresses the neurobiological infrastructure hypothesized to form the basis for language processing. Principal insights are summarized by building on the notion of “brain networks” for speech–sound processing, syntactic processing, and the construction of meaning, bearing in mind that such a neat three-way subdivision overlooks important overlap and shared mechanisms in the neural architecture subserving language processing. Finally, in keeping with the spirit of the volume, some possible relations are highlighted between language and music that arise from the infrastructure developed here. Our characterization of language and its neurobiological foundations is necessarily selective and brief. Our aim is to identify for the reader critical questions that require an answer to have a plausible cognitive neuroscience of language processing.

Abstract

First paragraph:
MacDonald (2013) proposes that distributional properties of language and processing biases in language comprehension can to a large extent be attributed to consequences of the language production process. In essence, the account is derived from the principle of least effort that was formulated by Zipf, among others (Zipf, 1949; Levelt, 2013). However, in Zipf's view the outcome of the least effort principle was a compromise between least effort for the speaker and least effort for the listener, whereas MacDonald puts most of the burden on the production process.

Abstract

Beim Sprechen und beim Sprachverstehen findet man die Wortbedeutung im Gedächtnis auf und kombiniert sie zu größeren Einheiten (Unifikation). Solche Unifikations-Operationen laufen auf unterschiedlichen Ebenen der Sprachverarbeitung ab. In diesem Beitrag wird ein Rahmen vorgeschlagen, in dem psycholinguistische Modelle mit neurobiologischer Sprachbetrachtung in Verbindung gebracht werden. Diesem Vorschlag zufolge spielt der linke inferiore frontale Gyrus (LIFG) eine bedeutende Rolle bei der Unifi kation

Abstract

Children’s songs are a great source for linguistic learning. Here we explore whether children can acquire novel words in a second language by playing a game featuring children’s songs in a playhouse. The playhouse is designed by the Noplica foundation (www.noplica.nl) to advance language learning through unsupervised play. We present data from three experiments that serve to scientifically proof the functionality of one game of the playhouse: the Energy Center. For this game, children move three hand-bikes mounted on a panel within the playhouse. Once the children cycle, a song starts playing that is accompanied by musical instruments. In our experiments, children executed a picture-selection task to evaluate whether they acquired new vocabulary from the songs presented during the game. Two of our experiments were run in the field, one at a Dutch and one at an Indian pre-school. The third experiment features data from a more controlled laboratory setting. Our results partly confirm that the Energy Center is a successful means to support vocabulary acquisition in a second language. More research with larger sample sizes and longer access to the Energy Center is needed to evaluate the overall functionality of the game. Based on informal observations at our test sites, however, we are certain that children do pick up linguistic content from the songs during play, as many of the children repeat words and phrases from the songs they heard. We will pick up upon these promising observations during future studies.

Abstract

Infants exploit acoustic boundaries to perceptually organize phrases in speech. This prosodic parsing ability is well‐attested and is a cornerstone to the development of speech perception and grammar. However, infants also receive linguistic input in child songs. This study provides evidence that infants parse songs into meaningful phrasal units and replicates previous research for speech. Six‐month‐old Dutch infants (n = 80) were tested in the song or speech modality in the head‐turn preference procedure. First, infants were familiarized to two versions of the same word sequence: One version represented a well‐formed unit, and the other contained a phrase boundary halfway through. At test, infants were presented two passages, each containing one version of the familiarized sequence. The results for speech replicated the previously observed preference for the passage containing the well‐formed sequence, but only in a more fine‐grained analysis. The preference for well‐formed phrases was also observed in the song modality, indicating that infants recognize phrase structure in song. There were acoustic differences between stimuli of the current and previous studies, suggesting that infants are flexible in their processing of boundary cues while also providing a possible explanation for differences in effect sizes.

Abstract

The present study investigated the developmental interrelationships between play, gesture use and spoken language development in children aged 18–31 months. The children completed two tasks: (i) a structured measure of pretend (or ‘symbolic’) play and (ii) a measure of vocabulary knowledge in which children have been shown to gesture. Additionally, their productive spoken language knowledge was measured via parental report. The results indicated that symbolic play is positively associated with children’s gesture use, which in turn is positively associated with spoken language knowledge over and above the influence of age. The tripartite relationship between gesture, play and language development is discussed with reference to current developmental theory.

Abstract

This paper studies the robustness of exemplar effects in word comprehension by means of four long-term priming experiments with lexical decision tasks in Dutch. A prime and target represented the same word type and were presented with the same or different degree of reduction. In Experiment 1, participants heard only a small number of trials, a large proportion of repeated words, and stimuli produced by only one speaker. They recognized targets more quickly if these represented the same degree of reduction as their primes, which forms additional evidence for the exemplar effects reported in the literature. Similar effects were found for two speakers who differ in their pronunciations. In Experiment 2, with a smaller proportion of repeated words and more trials between prime and target, participants recognized targets preceded by primes with the same or a different degree of reduction equally quickly. Also, in Experiments 3 and 4, in which listeners were not exposed to one but two types of pronunciation variation (reduction degree and speaker voice), no exemplar effects arose. We conclude that the role of exemplars in speech comprehension during natural conversations, which typically involve several speakers and few repeated content words, may be smaller than previously assumed.