Publications

Abstract

Stroke is common, and its consequent brain damage can cause various cognitive impairments. Associations between where and how much brain lesion damage a patient has suffered, and the particular impairments that injury has caused (lesion-symptom associations) offer potentially compelling insights into how the brain implements cognition.1 A better understanding of those associations can also fill a gap in current stroke medicine by helping us to predict how individual patients might recover from post-stroke impairments.2 Most recent work in this area employs machine learning models trained with data from stroke patients whose mid-to-long-term outcomes are known.2-4 These machine learning models are tested by predicting new outcomes—typically scores on standardized tests of post-stroke impairment—for patients whose data were not used to train the model. Traditionally, these validation results have been shared in peer-reviewed publications describing the model and its training. But recently, and for the first time in this field (as far as we know), one of these pre-trained models has been made public—The Disconnectome Symptom Discoverer model (DSD) which draws its predictors from structural disconnection information inferred from stroke patients’ brain MRI.5

Here, we test the DSD model on wholly independent data, never seen by the model authors, before they published it. Specifically, we test whether its predictive performance is just as accurate as (i.e. not significantly worse than) that reported in the original (Washington University) dataset, when predicting new patients’ outcomes at a similar time post-stroke (∼1 year post-stroke) and also in another independent sample tested later (5+ years) post-stroke. A failure to generalize the DSD model occurs if it performs significantly better in the Washington data than in our data from patients tested at a similar time point (∼1 year post-stroke). In addition, a significant decrease in predictive performance for the more chronic sample would be evidence that lesion-symptom associations differ at ∼1 year post-stroke and >5 years post-stroke.

Abstract

Here, we report evidence for oscillatory bi-directional interactions between the nucleus accumbens and the neocortex in humans. Six patients performed a demanding covert visual attention task while we simultaneously recorded brain activity from deep-brain electrodes implanted in the nucleus accumbens and the surface electroencephalogram (EEG). Both theta and alpha oscillations were strongly coherent with the frontal and parietal EEG during the task. Theta-band coherence increased during processing of the visual stimuli. Granger causality analysis revealed that the nucleus accumbens was communicating with the neocortex primarily in the theta-band, while the cortex was communicating the nucleus accumbens in the alpha-band. These data are consistent with a model, in which theta- and alpha-band oscillations serve dissociable roles: Prior to stimulus processing, the cortex might suppress ongoing processing in the nucleus accumbens by modulating alpha-band activity. Subsequently, upon stimulus presentation, theta oscillations might facilitate the active exchange of stimulus information from the nucleus accumbens to the cortex.

Abstract

Common genetic variation has been associated with multiple symptoms in Autism Spectrum Disorder (ASD). However, our knowledge of shared genetic factor structures contributing to this highly heterogeneous neurodevelopmental condition is limited. Here, we developed a structural equation modelling framework to directly model genome-wide covariance across core and non-core ASD phenotypes, studying autistic individuals of European descent using a case-only design. We identified three independent genetic factors most strongly linked to language/cognition, behaviour and motor development, respectively, when studying a population-representative sample (N=5,331). These analyses revealed novel associations. For example, developmental delay in acquiring personal-social skills was inversely related to language, while developmental motor delay was linked to self-injurious behaviour. We largely confirmed the three-factorial structure in independent ASD-simplex families (N=1,946), but uncovered simplex-specific genetic overlap between behaviour and language phenotypes. Thus, the common genetic architecture in ASD is multi-dimensional and contributes, in combination with ascertainment-specific patterns, to phenotypic heterogeneity.

Abstract

Creativity is crucial to the progression of human civilization and has led to important scientific discoveries. Especially, individuals are more likely to have scientific discoveries if they possess certain personality traits of creativity (trait creativity), including imagination, curiosity, challenge and risk-taking. This study used voxel-based morphometry to identify the brain regions underlying individual differences in trait creativity, as measured by the Williams creativity aptitude test, in a large sample (n = 246). We found that creative individuals had higher gray matter volume in the right posterior middle temporal gyrus (pMTG), which might be related to semantic processing during novelty seeking (e.g. novel association, conceptual integration and metaphor understanding). More importantly, although basic personality factors such as openness to experience, extroversion, conscientiousness and agreeableness (as measured by the NEO Personality Inventory) all contributed to trait creativity, only openness to experience mediated the association between the right pMTG volume and trait creativity. Taken together, our results suggest that the basic personality trait of openness might play an important role in shaping an individual’s trait creativity.

Abstract

It is now well-established that anticipation of up-coming input is a key characteristic of spoken language comprehension. It has also frequently been observed that literacy influences spoken language processing. Here we investigated whether anticipatory spoken language processing is related to individuals’ word reading abilities. Dutch adults with dyslexia and a control group participated in two eye-tracking experiments. Experiment 1 was conducted to assess whether adults with dyslexia show the typical language-mediated eye gaze patterns. Eye movements of both adults with and without dyslexia closely replicated earlier research: spoken language is used to direct attention to relevant objects in the environment in a closely time-locked manner. In Experiment 2, participants received instructions (e.g., "Kijk naar deCOM afgebeelde pianoCOM", look at the displayed piano) while viewing four objects. Articles (Dutch “het” or “de”) were gender-marked such that the article agreed in gender only with the target and thus participants could use gender information from the article to predict the target object. The adults with dyslexia anticipated the target objects but much later than the controls. Moreover, participants' word reading scores correlated positively with their anticipatory eye movements. We conclude by discussing the mechanisms by which reading abilities may influence predictive language processing.

Abstract

The notion that prediction is a fundamental principle of human information processing has been en vogue over recent years. The investigation of language processing may be particularly illuminating for testing this claim. Linguists traditionally have argued prediction plays only a minor role during language understanding because of the vast possibilities available to the language user as each word is encountered. In the present review I consider four central questions of anticipatory language processing: Why (i.e. what is the function of prediction in language processing)? What (i.e. what are the cues used to predict up-coming linguistic information and what type of representations are predicted)? How (what mechanisms are involved in predictive language processing and what is the role of possible mediating factors such as working memory)? When (i.e. do individuals always predict up-coming input during language processing)? I propose that prediction occurs via a set of diverse PACS (production-, association-, combinatorial-, and simulation-based prediction) mechanisms which are minimally required for a comprehensive account of predictive language processing. Models of anticipatory language processing must be revised to take multiple mechanisms, mediating factors, and situational context into account. Finally, I conjecture that the evidence considered here is consistent with the notion that prediction is an important aspect but not a fundamental principle of language processing.

Abstract

Recent experimental evidence from cognitive psychology and cognitive neuroscience shows that reading acquisition has non-trivial consequences for cognitive processes other than reading per se. In the present chapter I present evidence from three areas of cognition: phonological processing, prediction in language processing, and visual search. These findings suggest that literacy on cognition influences are far-reaching. This implies that a good understanding of the dramatic impact of literacy acquisition on the human mind is an important prerequisite for successful education policy development and guidance of educational support.

Abstract

In the present paper we describe the Enhanced Literate Mind (ELM) hypothesis. As individuals learn to read and write, they are, from then on, exposed to extensive written-language input and become literate. We propose that acquisition and proficient processing of written language (‘literacy’) leads to, both, increased language knowledge as well as enhanced language and non-language (perceptual and cognitive) skills. We also suggest that all neurotypical native language users, including illiterate, low literate, and high literate individuals, share a Basic Language Cognition (BLC) in the domain of oral informal language. Finally, we discuss the possibility that the acquisition of ELM leads to some degree of ‘knowledge parallelism’ between BLC and ELM in literate language users, which has implications for empirical research on individual and situational differences in spoken language processing.

Abstract

Literacy is in decline in many parts of the world, accompanied by drops in associated cognitive skills (including IQ) and an increasing susceptibility to fake news. It is possible that the recent explosive growth and widespread deployment of Large Language Models (LLMs) might exacerbate this trend, but there is also a chance that LLMs can help turn things around. We argue that cognitive science is ideally suited to help steer future literacy development in the right direction by challenging and informing current educational practices and policy. Cognitive scientists have the right interdisciplinary skills to study, analyze, evaluate, and change LLMs to facilitate their critical use, to encourage turn-taking that promotes rather than hinders literacy, to support literacy acquisition in diverse and equitable ways, and to scaffold potential future changes in what it means to be literate. We urge cognitive scientists to take up this mantle—the future impact of LLMs on human literacy skills is too important to be left to the large, predominately US-based tech companies.

Abstract

Bioacoustics increasingly relies on large datasets and computational methods. The need to batch-process large amounts of data and the increased focus on algorithmic processing require software tools. To optimally assist in a bioacoustician’s workflow, software tools need to be as simple and effective as possible. Five years ago, the Python package Parselmouth was released to provide easy and intuitive access to all functionality in the Praat software. Whereas Praat is principally designed for phonetics and speech processing, plenty of bioacoustics studies have used its advanced acoustic algorithms. Here, we evaluate existing usage of Parselmouth and discuss in detail several studies which used the software library. We argue that Parselmouth has the potential to be used even more in bioacoustics research, and suggest future directions to be pursued with the help of Parselmouth.

Abstract

To understand the neurocognitive mechanisms that underlie heterogeneity in cognitive ageing, recent scientific efforts have led to a growing public availability of imaging cohort data. The Advanced BRain Imaging on ageing and Memory (ABRIM) project aims to add to these existing datasets by taking an adult lifespan approach to provide a cross-sectional, normative database with a particular focus on connectivity, myelinization and iron content of the brain in concurrence with cognitive functioning, mechanisms of reserve, and sleep-wake rhythms. ABRIM freely shares MRI and behavioural data from 295 participants between 18–80 years, stratified by age decade and sex (median age 52, IQR 36–66, 53.20% females). The ABRIM MRI collection consists of both the raw and pre-processed structural and functional MRI data to facilitate data usage among both expert and non-expert users. The ABRIM behavioural collection includes measures of cognitive functioning (i.e., global cognition, processing speed, executive functions, and memory), proxy measures of cognitive reserve (e.g., educational attainment, verbal intelligence, and occupational complexity), and various self-reported questionnaires (e.g., on depressive symptoms, pain, and the use of memory strategies in daily life and during a memory task). In a sub-sample (n = 120), we recorded sleep-wake rhythms using an actigraphy device (Actiwatch 2, Philips Respironics) for a period of 7 consecutive days. Here, we provide an in-depth description of our study protocol, pre-processing pipelines, and data availability. ABRIM provides a cross-sectional database on healthy participants throughout the adult lifespan, including numerous parameters relevant to improve our understanding of cognitive ageing. Therefore, ABRIM enables researchers to model the advanced imaging parameters and cognitive topologies as a function of age, identify the normal range of values of such parameters, and to further investigate the diverse mechanisms of reserve and resilience.

Abstract

The human hard palate shows between-subject variation
that is known to influence articulatory strategies.
In order to link such variation to human speech, we
are conducting a cross-sectional MRI study on multiple
populations. A model based on Bezier curves
using only three parameters was fitted to hard palate
MRI tracings using evolutionary computation. The
fits produced consistently yield high accuracies. For
future research, this new method may be used to classify
our MRI data on ethnic origins using e.g., cluster
analyses. Furthermore, we may integrate our model
into three-dimensional representations of the vocal
tract in order to investigate its effect on acoustics and
cultural transmission.

Abstract

Children who start formal education in a second language may experience slower vocabulary growth in that language and subsequently experience disadvantages in literacy acquisition. The current study asked whether lexical specificity training can stimulate bilingual children's phonological awareness, which is considered to be a precursor to literacy. Therefore, Dutch monolingual and Turkish-Dutch bilingual children were taught new Dutch words with only minimal acoustic-phonetic differences. As a result of this training, the monolingual and the bilingual children improved on phoneme blending, which can be seen as an early aspect of phonological awareness. During training, the bilingual children caught up with the monolingual children on words with phonological overlap between their first language Turkish and their second language Dutch. It is concluded that learning minimal pair words fosters phoneme awareness, in both first and second language preliterate children, and that for second language learners phonological overlap between the two languages positively affects training outcomes, likely due to linguistic transfer

Abstract

Linguistic communication is an intrinsically social activity that enables us to share thoughts across minds. Many complex social uses of language can be captured by domain-general representations of other minds (i.e., mentalistic representations) that externally modulate linguistic meaning through Gricean reasoning. However, here we show that representations of others’ attention are embedded within language itself. Across ten languages, we show that demonstratives—basic grammatical words (e.g.,“this”/“that”) which are evolutionarily ancient, learned early in life, and documented in all known languages—are intrinsic attention tools. Beyond their spatial meanings, demonstratives encode both joint attention and the direction in which the listenermmust turn to establish it. Crucially, the frequency of the spatial and attentional uses of demonstratives varies across languages, suggesting that both spatial and mentalistic representations are part of their conventional meaning. Using computational modeling, we show that mentalistic representations of others’ attention are internally encoded in demonstratives, with their effect further boosted by Gricean reasoning. Yet, speakers are largely unaware of this, incorrectly reporting that they primarily capture spatial representations. Our findings show that representations of other people’s cognitive states (namely, their attention) are embedded in language and suggest that the most basic building blocks of the linguistic system crucially rely on social cognition.

Abstract

The idea that presupposition triggers have different intrinsic properties has gradually made its way into the literature on presuppositions and become a current assumption in most approaches. The distinctions mentioned in the different works have been based on introspective data, which seem, indeed, very suggestive. In this paper, we take a different look at some of these distinctions by using a simple experimental approach based on judgment of naturalness about sentences in various contexts. We show that the alleged difference between weak (or soft) and strong (or hard) triggers is not as clear as one may wish and that the claim that they belong to different lexical classes of triggers is probably much too strong.

Abstract

The neural mechanism of leader emergence is not well understood. This study investigated (i) whether interpersonal neural synchronization (INS) plays an important role in leader emergence, and (ii) whether INS and leader emergence are associated with the frequency or the quality of communications. Eleven three-member groups were asked to perform a leaderless group discussion (LGD) task, and their brain activities were recorded via functional near infrared spectroscopy (fNIRS)-based hyperscanning. Video recordings of the discussions were coded for leadership and communication. Results showed that the INS for the leader–follower (LF) pairs was higher than that for the follower–follower (FF) pairs in the left temporo-parietal junction (TPJ), an area important for social mentalizing. Although communication frequency was higher for the LF pairs than for the FF pairs, the frequency of leader-initiated and follower-initiated communication did not differ significantly. Moreover, INS for the LF pairs was significantly higher during leader-initiated communication than during follower-initiated communications. In addition, INS for the LF pairs during leader-initiated communication was significantly correlated with the leaders’ communication skills and competence, but not their communication frequency. Finally, leadership could be successfully predicted based on INS as well as communication frequency early during the LGD (before half a minute into the task). In sum, this study found that leader emergence was characterized by high-level neural synchronization between the leader and followers and that the quality, rather than the frequency, of communications was associated with synchronization. These results suggest that leaders emerge because they are able to say the right things at the right time.

Abstract

Whereas it has long been assumed that most linguistic processes underlying language production happen automatically, accumulating evidence suggests that some form of attention is required. Here, we investigated the contribution of sustained attention, which is the ability to maintain alertness over time. First, the sustained attention ability of participants was measured using auditory and visual continuous performance tasks. Next, the participants described pictures using simple noun phrases while their response times (RTs) and gaze durations were measured. Earlier research has suggested that gaze duration reflects language planning processes up to and including phonological encoding. Individual differences in sustained attention ability correlated with individual differences in the magnitude of the tail of the RT distribution, reflecting the proportion of very slow responses, but not with individual differences in gaze duration. These results suggest that language production requires sustained attention, especially after phonological encoding.

Abstract

It has previously been shown that language production, performed simultaneously with a nonlinguistic task, involves sustained attention. Sustained attention concerns the ability to maintain alertness over time. Here, we aimed to replicate the previous finding by showing that individuals call upon sustained attention when they plan single noun phrases (e.g., "the carrot") and perform a manual arrow categorization task. In addition, we investigated whether speakers also recruit sustained attention when they produce conjoined noun phrases (e.g., "the carrot and the bucket") describing two pictures, that is, when both the first and second task are linguistic. We found that sustained attention correlated with the proportion of abnormally slow phrase-production responses. Individuals with poor sustained attention displayed a greater number of very slow responses than individuals with better sustained attention. Importantly, this relationship was obtained both for the production of single phrases while performing a nonlinguistic manual task, and the production of noun phrase conjunctions in referring to two spatially separated objects. Inhibition and updating abilities were also measured. These scores did not correlate with our measure of sustained attention, suggesting that sustained attention and executive control are distinct. Overall, the results suggest that planning conjoined noun phrases involves sustained attention, and that language production happens less automatically than has often been assumed.

Abstract

Indian Sign Language has limited resources for developing machine learning and data-driven approaches for automated language processing. Though text/audio-based language processing techniques have shown colossal research interest and tremendous improvements in the last few years, Sign Languages still need to catch up due to the need for more resources. To bridge this gap, in this work, we propose iSign: a benchmark for Indian Sign Language (ISL) Processing. We make three primary contributions to this work. First, we release one of the largest ISL-English datasets with more than video-sentence/phrase pairs. To the best of our knowledge, it is the largest sign language dataset available for ISL. Second, we propose multiple NLP-specific tasks (including SignVideo2Text, SignPose2Text, Text2Pose, Word Prediction, and Sign Semantics) and benchmark them with the baseline models for easier access to the research community. Third, we provide detailed insights into the proposed benchmarks with a few linguistic insights into the working of ISL. We streamline the evaluation of Sign Language processing, addressing the gaps in the NLP research community for Sign Languages. We release the dataset, tasks and models via the following website: https://exploration-lab.github.io/iSign/

Abstract

Unilateral anterior disc displacement (uADD) has been shown to affect the contralateral joints qualitatively. This study aims to assess the quantitative T2 values of the articular disc and retrodiscal tissue of patients with uADD at 1.5 Tesla (T). The study included 65 uADD patients and 17 volunteers. The regions of interest on T2 maps were evaluated. The affected joints demonstrated significantly higher articular disc T2 values (31.5 ± 3.8 ms) than those of the unaffected joints (28.9 ± 4.5 ms) (P < 0.001). For retrodiscal tissue, T2 values of the unaffected (37.8 ± 5.8 ms) and affected joints (41.6 ± 7.1 ms) were significantly longer than those of normal volunteers (34.4 ± 3.2 ms) (P < 0.001). Furthermore, uADD without reduction (WOR) joints (43.3 ± 6.8 ms) showed statistically higher T2 values than the unaffected joints of both uADD with reduction (WR) (33.9 ± 3.8 ms) and uADDWOR (38.9 ± 5.8 ms), and the affected joints of uADDWR (35.8 ± 4.4 ms). The mean T2 value of the unaffected joints of uADDWOR was significantly longer than that of healthy volunteers (P < 0.001). These results provided quantitative evidence for the influence of the affected joints on the contralateral joints.

Abstract

We investigated prediction skills of adult heritage speakers and the role of written and spoken language experience on predictive processing. Using visual world eye-tracking, we focused on predictive use of case-marking cues in verb-medial and verb-final sentences in Turkish with adult Turkish heritage speakers (N = 25) and Turkish monolingual speakers (N = 24). Heritage speakers predicted in verb-medial sentences (when verb-semantic and case-marking cues were available), but not in verb-final sentences (when only case-marking cues were available) while monolinguals predicted in both. Prediction skills of heritage speakers were modulated by their spoken language experience in Turkish and written language experience in both languages. Overall, these results strongly suggest that verb-semantic information is needed to scaffold the use of morphosyntactic cues for prediction in heritage speakers. The findings also support the notion that both spoken and written language experience play an important role in predictive spoken language processing.

Abstract

When learning a spoken second language (L2), words overlapping in form and meaning with one’s native language (L1) help break into the new language. When non-signing speakers learn a sign language as L2, such forms are absent because of the modality differences (L1:speech, L2:sign). In such cases, non-signing speakers might use iconic form-meaning mappings in signs or their own gestural experience as gateways into the to-be-acquired sign language. Here, we investigated how both these factors may contribute jointly to the acquisition of sign language vocabulary by hearing non-signers. Participants were presented with three types of sign in NGT (Sign Language of the Netherlands): arbitrary signs, iconic signs with high or low gesture overlap. Signs that were both iconic and highly overlapping with gestures boosted learning most at first exposure, and this effect remained the day after. Findings highlight the influence of modality-specific factors supporting the acquisition of a signed lexicon.

Abstract

Lateralization is an important aspect of the functional brain architecture for language and other cognitive faculties. The molecular genetic basis of human brain lateralization is unknown, and recent studies have suggested that gene expression in the cerebral cortex is bilaterally symmetrical. Here we have re-analyzed two transcriptomic datasets derived from post mortem human cerebral cortex, with a specific focus on superior temporal and auditory language cortex in adults. We applied an empirical Bayes approach to model differential left-right expression, together with gene ontology analysis and meta-analysis. There was robust and reproducible lateralization of individual genes and gene ontology groups that are likely to fine-tune the electrophysiological and neurotransmission properties of cortical circuits, most notably synaptic transmission, nervous system development and glutamate receptor activity. Our findings anchor the cerebral biology of language to the molecular genetic level. Future research in model systems may determine how these molecular signatures of neurophysiological lateralization effect fine-tuning of cerebral cortical function, differently in the two hemispheres.

Abstract

The 8p23.1 duplication syndrome is a rare genetic condition with an estimated prevalence rate of 1 out of 58,000. Although the syndrome was associated with speech and language delays, a comprehensive assessment of speech and language functions has not been undertaken in this population. To address this issue, the present study reports rigorous speech and language, in addition to oral-facial and developmental, assessment of a 50-month-old Turkish-speaking boy who was diagnosed with the 8p23.1 duplication syndrome. Standardized tests of development, articulation and phonology, receptive and expressive language and a language sample analysis were administered to characterize speech and language skills in the patient. The language sample was obtained in an ecologically valid, free play and conversation context. The language sample was then analyzed and compared to a database of age-matched typically-developing children (n = 33) in terms of intelligibility, morphosyntax, semantics/vocabulary, discourse, verbal facility and percentage of errors at word and utterance levels. The results revealed mild to severe problems in articulation and phonology, receptive and expressive language skills, and morphosyntax (mean length of utterance in morphemes). Future research with larger sample sizes and employing detailed speech and language assessment is needed to delineate the speech and language profile in individuals with the 8p23.1 duplication syndrome, which will guide targeted speech and language interventions.

Abstract

Second-language learners often experience major difficulties in producing non-native speech sounds. This paper introduces a training method that uses a real-time analysis of the acoustic properties of vowels produced by non-native speakers to provide them with immediate, trial-by-trial visual feedback about their articulation alongside that of the same vowels produced by native speakers. The Mahalanobis acoustic distance between non-native productions and target native acoustic spaces was used to assess L2 production accuracy. The experiment shows that 1 h of training per vowel improves the production of four non-native Danish vowels: the learners' productions were closer to the corresponding Danish target vowels after training. The production performance of a control group remained unchanged. Comparisons of pre- and post-training vowel discrimination performance in the experimental group showed improvements in perception. Correlational analyses of training-related changes in production and perception revealed no relationship. These results suggest, first, that this training method is effective in improving non-native vowel production. Second, training purely on production improves perception. Finally, it appears that improvements in production and perception do not systematically progress at equal rates within individuals. (C) 2015 Acoustical Society of America.

Abstract

A comprehensive theory of language acquisition must explain how human infants can learn any one of the world’s 7000 or so languages. As such, an important part of understanding how languages are learned is to investigate acquisition across a range of diverse languages and sociocultural contexts. To this end, cross-linguistic and cross-cultural language research has been pervasive in the field of first language acquisition since the early 1980s. In groundbreaking work, Slobin (1985) noted that the study of acquisition in cross-linguistic perspective can be used to reveal both developmental universals and language-specific acquisition patterns. Since this observation there have been several waves of cross-linguistic first language acquisition research, and more recently we have seen a rise in research investigating lesser-known languages. This special issue brings together work on several such languages, spoken in minority contexts. It is the first collection of language development research dedicated to the acquisition of under-studied or little-known languages and by extension, different cultures. Why lesser-known languages, and why minority contexts? First and foremost, acquisition theories need data from different languages, language families and cultural groups across the broadest typological array possible, and yet many theories of acquisition have been developed through analyses of English and other major world languages. Thus they are likely to be skewed by sampling bias. Languages of European origin constitute a small percentage of the total number of languages spoken worldwide. The Ethnologue (2015) lists 7102 languages spoken across the world. Of these, only 286 languages are languages of European origin, a mere 4% of the total number of languages spoken across the planet, and representing approximately only 26% of the total number of language speakers alive today. Compare this to the languages of the Pacific. The Ethnologue lists 1313 languages spoken in the Pacific, constituting 18.5% of the world’s languages. Of these, very few have been described, and even fewer have child language data available. Lieven and Stoll (2010) note that only around 70–80 languages have been the focus of acquisition studies (around 1% of the world’s languages). This somewhat alarming statistic suggests that the time is now ripe for researchers working on lesser-known languages to contribute to the field’s knowledge about how children learn a range of very different languages across differing cultures, and in doing so, for this research to make a contribution to language acquisition theory. The potential benefits are many. First, decades of descriptive work in linguistic typology have culminated in strong challenges to the existence of a Universal Grammar (Evans & Levinson, 2009), a long-held axiom of formal language acquisition theory. To be sure, cross-linguistic work in acquisition has long fuelled this debate (e.g. MacWhinney & Bates, 1989), but only as we collect a greater number of data points will we move closer toward a better understanding of the initial state of the human capacity for language and the types of social and cultural contexts in which language is successfully transmitted. A focus on linguistic diversity enables the investigation and postulation of universals in language acquisition, if and in whatever form they exist. In doing so, we can determine the sorts of things that are evident in child-directed speech, in children’s language production and in adult language, teasing out the threads at the intersection of language, culture and cognition. The study and dissemination of research into lesser-known, under-described languages with small communities significantly contributes to this aim because it not only reflects the diversity of languages present in the world, but provides a better representation of the social and economic conditions under which the majority of the world’s population acquire language (Heinrich, Heins, & Norenzayan, 2010). Related to this point, the study of smaller languages has taken on intense urgency in the past few decades due to the rapid extinction of these languages (Evans, 2010). The Language Documentation movement has toiled tirelessly in the pursuit of documenting languages before they disappear, an effort to which child language researchers have much to offer. Many children acquire smaller and minority languages in rich multilingual environments, where the influence of dominant languages affects acquisition (e.g., Stoll, Zakharko, Moran, Schikowski, & Bickel, 2015). Understanding the acquisition process where systems compete and may be in flux due to language contact, while no small task, will help us understand the social and economic conditions which favour successful preservation of minority languages, which could ultimately equip communities with the tools to stem the flow of language loss. With these points in mind we now turn to the articles in this special issue.

Abstract

Hand gestures and speech form a single integrated system of meaning during language comprehension, but is gesture processed with speech in a unique fashion? We had subjects watch multimodal videos that presented auditory (words) and visual (gestures and actions on objects) information. Half of the subjects related the audio information to a written prime presented before the video, and the other half related the visual information to the written prime. For half of the multimodal video stimuli, the audio and visual information contents were congruent, and for the other half, they were incongruent. For all subjects, stimuli in which the gestures and actions were incongruent with the speech produced more errors and longer response times than did stimuli that were congruent, but this effect was less prominent for speech-action stimuli than for speech-gesture stimuli. However, subjects focusing on visual targets were more accurate when processing actions than gestures. These results suggest that although actions may be easier to process than gestures, gestures may be more tightly tied to the processing of accompanying speech.

Abstract

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

Abstract

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

Abstract

The practices of other-initiation of repair provide speakers with a set of solutions to one of the most basic problems in conversation: troubles of speaking, hearing, and understanding. Based on a collection of 227 cases systematically identified in a corpus of English conversation, this article describes the formats and practices of other-initiations of repair attested in the corpus and reports their quantitative distribution. In addition to straight other-initiations of repair, the identification of all possible cases also yielded a substantial proportion in which speakers use other-initiations to perform other actions, including non-serious actions, such as jokes and teases, preliminaries to dispreferred responses, and displays of surprise and disbelief. A distinction is made between other-initiations that perform additional actions concurrently and those that formally resemble straight other-initiations but analyzably do not initiate repair as an action.

Abstract

The transitions between turns at talk in conversation tend to occur quickly, with only a slight gap of approximately 100 to 300 ms between them. This estimate of central tendency, however, hides a wealth of complex variation, as a number of factors, such as the type of turns involved, have been shown to influence the timing of turn transitions. This article considers one specific type of turn that does not conform to the statistical trend, namely turns that deal with troubles of speaking, hearing, and understanding, known as other-initiations of repair. The results of a quantitative analysis of 169 other-initiations of repair in face-to-face conversation reveal that the most frequent cases occur after gaps of approximately 700 ms. Furthermore, other-initiations of repair that locate a source of trouble in a prior turn specifically tend to occur after shorter gaps than those that do not, and those that correct errors in a prior turn, while rare, tend to occur without delay. An analysis of the transitions before other-initiations of repair, using methods of conversation analysis, suggests that speakers use the extra time (i) to search for a late recognition of the problematic turn, (ii) to provide an opportunity for the speaker of the problematic turn to resolve the trouble independently, (iii) and to produce visual signals, such as facial gestures. In light of these results, it is argued that other-initiations of repair take priority over other turns at talk in conversation and therefore are not subject to the same rules and constraints that motivate fast turn transitions in general

Abstract

Conversation-analytic research has argued that the timing and construction of preferred responding actions (e.g., acceptances) differ from that of dispreferred responding actions (e.g., rejections), potentially enabling early response prediction by recipients. We examined 195 preferred and dispreferred responding actions in telephone corpora and found that the timing of the most frequent cases of each type did not differ systematically. Only for turn transitions of 700 ms or more was the proportion of dispreferred responding actions clearly greater than that of preferreds. In contrast, an analysis of the timing that included turn formats (i.e., those with or without qualification) revealed clearer differences. Small departures from a normal gap duration decrease the likelihood of a preferred action in a preferred turn format (e.g., a simple “yes”). We propose that the timing of a response is best understood as a turn-constructional feature, the first virtual component of a preferred or dispreferred turn format.

Abstract

The current study investigated the role of cross-linguistic influence in Cantonese–English bilingual children's comprehension of subject- and object-extracted relative clauses (RCs). Twenty simultaneous Cantonese–English bilingual children (Mage = 8;11, SD = 2;6) and 20 vocabulary-matched Cantonese monolingual children (Mage = 6;4, SD = 1;3) completed a test of Cantonese RC comprehension. The bilingual children also completed a test of English RC comprehension. The results showed that, whereas the monolingual children were equally competent on subject and object RCs, the bilingual children performed significantly better on subject RCs. Error analyses suggested that the bilingual children were most often correctly assigning thematic roles in object RCs, but were incorrectly choosing the RC subject as the head referent. This pervasive error was interpreted to be due to the fact that both Cantonese and English have canonical SVO word order, which creates competition with structures that compete with an object RC analysis.

Abstract

Although there is strong evidence for shared abstract grammatical structure in bilingual speakers from studies of sentence production, comparable evidence from studies of comprehension is lacking. Twenty-seven (N = 27) English-German bilingual adults participated in a structural priming study where unambiguous English subject and object relative clause (RC) structures were used to prime corresponding subject and object RC interpretations of structurally ambiguous German RCs. The results showed that English object RCs primed significantly greater object RC interpretations in German in comparison to baseline and subject RC prime conditions, but that English subject RC primes did not change the participants’ baseline preferences. This is the first study to report abstract crosslinguistic priming in comprehension. The results specifically suggest that word order overlap supports the integration of syntactic structures from different languages in bilingual speakers, and that these shared representations are used in comprehension as well as production

Abstract

Somatic practices frequently use imagery, typically via verbal instructions, to scaffold sensorimotor organization and experience, a phenomenon we term “introjection”. We argue that introjection is an imagery practice in which sensorimotor and conceptual aspects are co-orchestrated, suggesting the necessity of crosstalk between somatics, phenomenology, psychology, embodied-enactive cognition, and linguistic research on embodied simulation. We presently focus on the scarcely addressed details of the process necessary to enact instructions of a literal or metaphoric nature through the body. Based on vignettes from dance, Feldenkrais, and Taichi practice, we describe introjection as a complex form of processual sense-making, in which context-interpretive, mental, attentional and physical sub-processes recursively braid. Our analysis focuses on how mental and body-related processes progressively align, inform and augment each other. This dialectic requires emphasis on the active body, which implies that uni-directional models (concept ⇒ body) are inadequate and should be replaced by interactionist alternatives (concept ⇔ body). Furthermore, we emphasize that both the source image itself and the body are specifically conceptualized for the context through constructive operations, and both evolve through their interplay. At this level introjection employs representational operations that are embedded in enactive dynamics of a fully situated person.

Abstract

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neuropsychiatric disorder with a complex genetic background. The G protein-coupled receptor kinase interacting ArfGAP 1 (GIT1) gene was previously associated with ADHD. We aimed at replicating the association of GIT1 with ADHD and investigated its role in cognitive and brain phenotypes. Gene-wide and single variant association analyses for GIT1 were performed for three cohorts: (1) the ADHD meta-analysis data set of the Psychiatric Genomics Consortium (PGC, N=19,210), (2) the Dutch cohort of the International Multicentre persistent ADHD CollaboraTion (IMpACT-NL, N=225), and (3) the Brain Imaging Genetics cohort (BIG, N=1,300). Furthermore, functionality of the rs550818 variant as an expression quantitative trait locus (eQTL) for GIT1 was assessed in human blood samples. By using Drosophila melanogaster as a biological model system, we manipulated Git expression according to the outcome of the expression result and studied the effect of Git knockdown on neuronal morphology and locomotor activity. Association of rs550818 with ADHD was not confirmed, nor did a combination of variants in GIT1 show association with ADHD or any related measures in either of the investigated cohorts. However, the rs550818 risk-genotype did reduce GIT1 expression level. Git knockdown in Drosophila caused abnormal synapse and dendrite morphology, but did not affect locomotor activity. In summary, we could not confirm GIT1 as an ADHD candidate gene, while rs550818 was found to be an eQTL for GIT1. Despite GIT1's regulation of neuronal morphology, alterations in gene expression do not appear to have ADHD-related behavioral consequences

Abstract

Unter allen Disziplinen, die sich mit der Erforschung der Sprache befassen, ist die Lexikografie die älteste und die für die Allgemeinheit wichtigste. Die ältesten, noch sehr einfachen Wörterbücher finden sich auf 4000 Jahre alten Tontafeln, und wenn sich heute in einem Haushalt überhaupt ein Buch findet, dann ist es wahrscheinlich ein Wörterbuch. In den letzten zwanzig Jahren ist die kommerzielle wie die von öffentlich finanzierten Forschungsstätten betriebene Lexikografie jedoch in einer ernsthafte Krise geraten. Die großen Wörterbuchverlage haben die Arbeit an umfassenden Wörterbüchern weitestgehend eingestellt, weil sie kaum noch gekauft werden; die Akademien geraten mit ihren Langzeitvorhaben in massive Zeit- und Finanzprobleme. Wenn wir nicht auf die umfassende Beschreibung des deutschen Wortschatzes in all einer Vielfalt und seiner geschichtlichen Entwicklung verzichten wollen, müssen ganz neue Wege gegangen werden: Wörterbücher im traditionellen Sinne müssen durch digitale lexikalische Systeme ersetzt werden, die das vorhandene lexikalische Wissen integrieren, es schrittweise systematisch ausbauen, eigene Recherchen in verlässlichen Corpora ermöglichen und von jedermann frei über das Internet nutzbar sind.

Abstract

The size of the human head is highly heritable, but genetic drivers of its variation within the general population remain unmapped. We perform a genome-wide association study on head size (N = 80,890) and identify 67 genetic loci, of which 50 are novel. Neuroimaging studies show that 17 variants affect specific brain areas, but most have widespread effects. Gene set enrichment is observed for various cancers and the p53, Wnt, and ErbB signaling pathways. Genes harboring lead variants are enriched for macrocephaly syndrome genes (37-fold) and high-fidelity cancer genes (9-fold), which is not seen for human height variants. Head size variants are also near genes preferentially expressed in intermediate progenitor cells, neural cells linked to evolutionary brain expansion. Our results indicate that genes regulating early brain and cranial growth incline to neoplasia later in life, irrespective of height. This warrants investigation of clinical implications of the link between head size and cancer.

Abstract

Recent studies indicate that Arabic digit knowledge rather than non-symbolic number knowledge is a key foundation for arithmetic proficiency at the start of a child’s mathematical career. We document the developmental trajectory of 4- to 7-year-olds’ proficiency in accessing magnitude information from Arabic digits in five tasks differing in magnitude manipulation requirements. Results showed that children from 5 years onwards accessed magnitude information implicitly and explicitly, but that 5-year-olds failed to access magnitude information explicitly when numerical magnitude was contrasted with physical magnitude. Performance across tasks revealed a clear developmental trajectory: children traverse from first knowing the cardinal values of number words to recognizing Arabic digits to knowing their cardinal values and, concurrently, their ordinal position. Correlational analyses showed a strong within-child consistency, demonstrating that this pattern is not only reflected in group differences but also in individual performance.

Abstract

This study investigates the effects of adult age and speaker abilities on articulatory precision for sibilant productions. Normal-hearing young adults with
better sibilant discrimination have been shown to produce greater spectral sibilant contrasts. As reduced auditory feedback may gradually impact on feedforward
commands, we investigate whether articulatory precision as indexed by spectral mean for [s] and [S] decreases with age, and more particularly with agerelated
hearing loss. Younger, middle-aged and older adults read aloud words starting with the sibilants [s] or [S]. Possible effects of cognitive, perceptual, linguistic and sociolinguistic background variables
on the sibilants’ acoustics were also investigated. Sibilant contrasts were less pronounced for male than female speakers. Most importantly, for the fricative
[s], the spectral mean was modulated by individual high-frequency hearing loss, but not age. These results underscore that even mild hearing loss already affects articulatory precision.

Abstract

Multimodal rhythmic signalling abounds across animal taxa. Studying its mechanisms and functions can highlight adaptive components in highly complex rhythmic behaviours, like dance and music. Pinnipeds, such as the harbour seal, Phoca vitulina, are excellent comparative models to assess rhythmic capacities. Harbour seals engage in rhythmic percussive behaviours which, until now, have not been described in detail. In our study, eight zoo-housed harbour seals (two pups, two juveniles and four adults) were passively monitored by audio and video during their pupping/breeding season. All juvenile and adult animals performed percussive signalling with their fore flippers in agonistic conditions, both on land and in water. Flipper slap sequences produced on the ground or on the seals' bodies were often highly regular in their interval duration, that is, were quasi-isochronous, at a 200–600 beats/min pace. Three animals also showed significant lateralization in slapping. In contrast to slapping on land, display slapping in water, performed only by adult males, showed slower tempo by one order of magnitude, and a rather motivic temporal structure. Our work highlights that percussive communication is a significant part of harbour seals' behavioural repertoire. We hypothesize that its forms of rhythm production may reflect adaptive functions such as regulating internal states and advertising individual traits.

Abstract

Representing brain morphology as a network has the advantage that the regional morphology of ‘isolated’ structures can be described statistically based on graph theory. However, very few studies have investigated brain morphology from the holistic perspective of complex networks, particularly in individual brains. We proposed a new network framework for individual brain morphology. Technically, in the new network, nodes are defined as regions based on a brain atlas, and edges are estimated using our newly-developed inter-regional relation measure based on regional morphological distributions. This implementation allows nodes in the brain network to be functionally/anatomically homogeneous but different with respect to shape and size. We first demonstrated the new network framework in a healthy sample. Thereafter, we studied the graph-theoretical properties of the networks obtained and compared the results with previous morphological, anatomical, and functional networks. The robustness of the method was assessed via measurement of the reliability of the network metrics using a test-retest dataset. Finally, to illustrate potential applications, the networks were used to measure age-related changes in commonly used network metrics. Results suggest that the proposed method could provide a concise description of brain organization at a network level and be used to investigate interindividual variability in brain morphology from the perspective of complex networks. Furthermore, the method could open a new window into modeling the complexly distributed brain and facilitate the emerging field of human connectomics.

Abstract

We examined the extent to which cognate facilitation effects occurred in simultaneous bilingual children’s production and comprehension and how these were modulated by language dominance and language context. Bilingual Dutch-German children, ranging from Dutch-dominant to German-dominant, performed picture naming and auditory lexical decision tasks in single-language and dual-language contexts. Language context was manipulated with respect to the language of communication (with the experimenter and in instructional videos) and by means of proficiency tasks. Cognate facilitation effects emerged in both production and comprehension and interacted with both dominance and context. In a single-language context, stronger cognate facilitation effects were found for picture naming in children’s less dominant language, in line with previous studies on individual differences in lexical activation. In the dual-language context, this pattern was reversed, suggesting inhibition of the dominant language at the decision level. Similar effects were observed in lexical decision. These findings provide evidence for an integrated bilingual lexicon in simultaneous bilingual children and shed more light on the complex interplay between lexicon-internal and lexicon-external factors modulating the extent of lexical cross-linguistic influence more generally.

Abstract

In a between-language lexical priming study, we examined to what extent the two languages in a simultaneous bilingual child's lexicon interact, while taking individual differences in language exposure into account. Primary-school-aged Dutch–Greek bilinguals performed a primed picture selection task combined with eye-tracking. They matched pictures to auditorily presented Dutch target words preceded by Greek prime words. Their reaction times and eye movements were recorded. We tested for effects of between-language phonological priming, translation priming, and phonological priming through translation. Priming effects emerged in reaction times and eye movements in all three conditions, at different stages of processing, and unaffected by language exposure. These results extend previous findings for bilingual toddlers and bilingual adults. Processing similarities between these populations indicate that, across different stages of development, bilinguals have an integrated lexicon that is accessed in a language-nonselective way and is susceptible to interactions within and between different types of lexical representation.

Abstract

Objective: Stimulation-based language mapping approaches that are used pre- and intra-operatively employ predominantly overt language tasks requiring sufficient language pro-duction abilities. Yet, these production-based setups are often not feasible in brain tumor patients with severe expressive aphasia. This pilot study evaluated the feasibility and reliability of a newly developed language comprehension task with preoperative navigated transcranial magnetic stimulation (nTMS).
Methods: Fifteen healthy subjects and six brain tumor patients with severe expressiven aphasia unable to perform classic overt naming tasks underwent preoperative nTMS language mapping based on an auditory single-word Comprehension TAsk for Perioperative mapping (CompreTAP). Comprehension was probed by button-press responses to auditory stimuli, hence not requiring overt language responses. Positive comprehension areas were identified when stimulation elicited an incorrect or delayed button press. Error categories,case-wise cortical error rate distribution and inter-rater reliability between two experienced specialists were examined.
Results: Overall, the new setup showed to be feasible. Comprehension-disruptions induced by nTMS manifested in no responses, delayed or hesitant responses, searching behavior or selection of wrong target items across all patients and controls and could be performed even in patients with severe expressive aphasia. The analysis agreement between both specialists was substantial for classifying comprehension-positive and -negative sites. Extensive left-hemispheric individual cortical comprehension sites were identified for all patients. Apart from one case presenting with transient worsening of aphasic symptoms.

Abstract

The current study investigated gender (control) and number (target) agreement processing in Northern and non-Northern Norwegians living in Northern Norway. Participants varied in exposure to Northern Norwegian (NN) dialect(s), where number marking differs from most other Norwegian dialects. In a comprehension task involving reading NN dialect writing, P600 effects for number agreement were significantly affected by NN exposure. The more exposure the NN nonnatives had, the larger the P600 was, driven by the presence of number agreement (ungrammatical in NN). In contrast, less exposure correlated to the inverse: P600 driven by the absence of number agreement (ungrammatical in most other dialects). The NN natives showed P600 driven by the presence of number agreement regardless of exposure. These findings suggests that bilectalism entails the representation of distinct mental grammars for each dialect. However, like all instances of bilingualism, bilectalism exists on a continuum whereby linguistic processing is modulated by linguistic experience.

Abstract

A substantial literature exists using the syntactic priming methodology with children to test hypotheses regarding the acquisition of syntax, under the assumption that priming effects reveal both the presence of syntactic knowledge and the underlying nature of learning mechanisms supporting the acquisition of grammar. Here we present the first meta-analysis of syntactic priming studies in children. We identified 37 eligible studies and extracted 108 effect sizes corresponding to 76 samples of 2,378 unique participants. Our analysis confirmed a medium-to-large syntactic priming effect. The overall estimate of the priming effect was a log odds ratio of 1.44 (Cohen’s d = 0.80). This is equivalent to a structure that occurs 50 % of the time when unprimed occurring 81 % of the time when primed. Several variables moderated the magnitude of priming in children, including (i) within- or between-subjects design, (ii) lexical overlap, (iii) structural alternation investigated and, (iv) the animacy configuration of syntactic arguments. There was little evidence of publication bias in the size of the main priming effect, however, power analyses showed that, while studies typically have enough power to identify the basic priming effect, they are typically underpowered when their focus is on moderators of priming. The results provide a foundation for future research, suggesting several avenues of enquiry.

Abstract

Instrumental music and language are both syntactic systems, employing complex, hierarchically-structured sequences built using implicit structural norms. This organization allows listeners to understand the role of individual words or tones in the context of an unfolding sentence or melody. Previous studies suggest that the brain mechanisms of syntactic processing may be partly shared between music and language. However, functional neuroimaging evidence for anatomical overlap of brain activity involved in linguistic and musical syntactic processing has been lacking. In the present study we used functional magnetic resonance imaging (fMRI) in conjunction with an interference paradigm based on sung sentences. We show that the processing demands of musical syntax (harmony) and language syntax interact in Broca’s area in the left inferior frontal gyrus (without leading to music and language main effects). A language main effect in Broca’s area only emerged in the complex music harmony condition, suggesting that (with our stimuli and tasks) a language effect only becomes visible under conditions of increased demands on shared neural resources. In contrast to previous studies, our design allows us to rule out that the observed neural interaction is due to: (1) general attention mechanisms, as a psychoacoustic auditory anomaly behaved unlike the harmonic manipulation, (2) error processing, as the language and the music stimuli contained no structural errors. The current results thus suggest that two different cognitive domains—music and language—might draw on the same high level syntactic integration resources in Broca’s area.

Abstract

Only a small number of studies have assessed structural differences between the two hemispheres during childhood and adolescence. However, the existing findings lack consistency or are restricted to a particular brain region, a specific brain feature, or a relatively narrow age range. Here, we investigated associations between brain asymmetry and age as well as sex in one of the largest pediatric samples to date (n = 4265), aged 1–18 years, scanned at 69 sites participating in the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) consortium. Our study revealed that significant brain asymmetries already exist in childhood, but their magnitude and direction depend on the brain region examined and the morphometric measurement used (cortical volume or thickness, regional surface area, or subcortical volume). With respect to effects of age, some asymmetries became weaker over time while others became stronger; sometimes they even reversed direction. With respect to sex differences, the total number of regions exhibiting significant asymmetries was larger in females than in males, while the total number of measurements indicating significant asymmetries was larger in males (as we obtained more than one measurement per cortical region). The magnitude of the significant asymmetries was also greater in males. However, effect sizes for both age effects and sex differences were small. Taken together, these findings suggest that cerebral asymmetries are an inherent organizational pattern of the brain that manifests early in life. Overall, brain asymmetry appears to be relatively stable throughout childhood and adolescence, with some differential effects in males and females.

Abstract

We review a number of recent studies that have identified either correlations between different linguistic features (e.g., implicational universals) or correlations between linguistic features and nonlinguistic properties of speakers or their environment (e.g., effects of geography on vocabulary). We compare large-scale quantitative studies with more traditional theoretical and historical linguistic research and identify divergent assumptions and methods that have led linguists to be skeptical of correlational work. We also attempt to demystify statistical techniques and point out the importance of informed critiques of the validity of statistical approaches. Finally, we describe various methods used in recent correlational studies to deal with the fact that, because of contact and historical relatedness, individual languages in a sample rarely represent independent data points, and we show how these methods may allow us to explore linguistic prehistory to a greater time depth than is possible with orthodox comparative reconstruction.