Publications

Abstract

This paper addressed the question of how British English, German and Dutch listeners differ in their perception of continuation intonation both at the phonological level (Experiment 1) and at the level of phonetic implementation (Experiment 2). In Experiment 1, preference scores of pitch contours to signal continuation at the clause-boundary were obtained from these listener groups. It was found that among contours with H%, British English listeners had a strong preference for H*L H%, as predicted. Unexpectedly, British English listeners rated H* H% noticeably more favourably than L*H H%; Dutch listeners largely rated H* H% more favourably than H*L H% and L*H H%; German listeners rated these contours similarly and seemed to have a slight preference for H*L H%. In Experiment 2, the degree to which a final rise was perceived to express continuation was established for each listener group in a made-up language. It was found that although all listener groups associated a higher end pitch with a higher degree of continuation likelihood, the perceived meaning difference for a given interval of end pitch heights varied with the contour shape of the utterance final syllable. When it was comparable to H* H%, British English and Dutch listeners perceived a larger meaning difference than German listeners; when it was comparable to H*L H%, British English listeners perceived a larger difference than German and Dutch listeners. This shows that language-specificity in continuation intonation at the phonological level affects the perception of continuation intonation at the phonetic level.

Abstract

Previous work based on different groups of children has shown that four- to five-year-old children are similar to adults in both producing and comprehending the focus-toaccentuation mapping in Dutch, contra the alleged productionprecedes- comprehension asymmetry in earlier studies. In the current study, we addressed the question of whether there are individual differences in the production-comprehension (a)symmetricity. To this end, we examined the use of prosody in focus marking in production and the processing of focusrelated prosody in online language comprehension in the same group of 4- to 5-year-olds. We have found that the relationship between comprehension and production can be rather diverse at an individual level. This result suggests some degree of independence in learning to use prosody to mark focus in production and learning to process focus-related prosodic information in online language comprehension, and implies influences of other linguistic and non-linguistic factors on the production-comprehension (a)symmetricity

Abstract

Despite of the different functions of pitch in tone and nontone languages, rises and falls are common pitch patterns across different languages. In the current study, we ask what is the language specific phonetic realization of rises and falls. Chinese and Dutch speakers participated in a production experiment. We used contexts composed for conveying specific communicative purposes to elicit rises and falls. We measured both tonal alignment and tonal scaling for both patterns. For the alignment measurements, we found language specific patterns for the rises, but for falls. For rises, both peak and valley were aligned later among Chinese speakers compared to Dutch speakers. For all the scaling measurements (maximum pitch, minimum pitch, and pitch range), no language specific patterns were found for either the rises or the falls

Abstract

We explore the role of the acoustic consequences of domain-initial strengthening in spoken-word recognition. In two cross-modal identity-priming experiments, listeners heard sentences and made lexical decisions to visual targets, presented at the onset of the second word in two-word sequences containing lexical ambiguities (e.g., bus tickets, with the competitor bust). These sequences contained Intonational Phrase (IP) or Prosodic Word (Wd) boundaries, and the second word's initial Consonant and Vowel (CV, e.g., [tI]) was spliced from another token of the sequence in IP- or Wd-initial position. Acoustic analyses showed that IP-initial consonants were articulated more strongly than Wd-initial consonants. In Experiment 1, related targets were post-boundary words (e.g., tickets). No strengthening effect was observed (i.e., identity priming effects did not vary across splicing conditions). In Experiment 2, related targets were pre-boundary words (e.g., bus). There was a strengthening effect (stronger priming when the post-boundary CVs were spliced from IP-initial than from Wd-initial position), but only in Wd-boundary contexts. These were the conditions where phonetic detail associated with domain-initial strengthening could assist listeners most in lexical disambiguation. We discuss how speakers may strengthen domain-initial segments during production and how listeners may use the resulting acoustic correlates of prosodic strengthening during word recognition.

Abstract

This study tests whether potential differences in the perceptual robustness of speech sounds influence continuous-speech processes. Two phoneme-monitoring experiments examined place assimilation in Korean. In Experiment 1, Koreans monitored for targets which were either labials (/p,m/) or alveolars (/t,n/), and which were either unassimilated or assimilated to a following /k/ in two-word utterances. Listeners detected unaltered (unassimilated) labials faster and more accurately than assimilated labials; there was no such advantage for unaltered alveolars. In Experiment 2, labial–velar differences were tested using conditions in which /k/ and /p/ were illegally assimilated to a following /t/. Unassimilated sounds were detected faster than illegally assimilated sounds, but this difference tended to be larger for /k/ than for /p/. These place-dependent asymmetries suggest that differences in the perceptual robustness of segments play a role in shaping phonological patterns.

Abstract

Several studies have documented that international adoptees, who in early years have
experienced a change from a language used in their birth country to a new language
in an adoptive country, benefit from the limited early exposure to the birth language
when relearning that language’s sounds later in life. The adoptees’ relearning advantages
have been argued to be conferred by lasting birth-language knowledge obtained from
the early exposure. However, it is also plausible to assume that the advantages may
arise from adoptees’ superior ability to learn language sounds in general, as a result
of their unusual linguistic experience, i.e., exposure to multiple languages in sequence
early in life. If this is the case, then the adoptees’ relearning benefits should generalize
to previously unheard language sounds, rather than be limited to their birth-language
sounds. In the present study, adult Korean adoptees in the Netherlands and matched
Dutch-native controls were trained on identifying a Japanese length distinction to which
they had never been exposed before. The adoptees and Dutch controls did not differ
on any test carried out before, during, or after the training, indicating that observed
adoptee advantages for birth-language relearning do not generalize to novel, previously
unheard language sounds. The finding thus fails to support the suggestion that
birth-language relearning advantages may arise from enhanced ability to learn language
sounds in general conferred by early experience in multiple languages. Rather, our
finding supports the original contention that such advantages involve memory traces
obtained before adoption

Abstract

Speakers use external auditory feedback to monitor their own speech. Feedback distortion has been found to increase activity in the superior temporal areas. Using fMRI, the present study investigates the neural correlates of processing verbal feedback without distortion. In a blocked design, the following conditions were presented: (1) overt picture-naming, (2) overt picture-naming while pink noise was presented to mask external feedback, (3) covert picture-naming, (4) listening to the picture names (previously recorded from participants' own voices), and (5) listening to pink noise. The results show that auditory feedback processing involves a network of different areas related to general performance monitoring and speech-motor control. These include the cingulate cortex and the bilateral insula, supplementary motor area, bilateral motor areas, cerebellum, thalamus and basal ganglia. Our findings suggest that the anterior cingulate cortex, which is often implicated in error-processing and conflict-monitoring, is also engaged in ongoing speech monitoring. Furthermore, in the superior temporal gyrus, we found a reduced response to speaking under normal feedback conditions. This finding is interpreted in the framework of a forward model according to which, during speech production, the sensory consequence of the speech-motor act is predicted to attenuate the sensitivity of the auditory cortex. Hum Brain Mapp 2007. © 2007 Wiley-Liss, Inc.

Abstract

This study addressed how bilingual speakers switch between their first and second language when speaking. Event-related brain potentials (ERPs) and naming latencies were measured while unbalanced German (L1)-Dutch (L2) speakers performed a picture-naming task. Participants named pictures either in their L1 or in their L2 (blocked language conditions), or participants switched between their first and second language unpredictably (mixed language condition). Furthermore, form similarity between translation equivalents (cognate status) was manipulated. A cognate facilitation effect was found for L1 and L2 indicating phonological activation of the non-response language in blocked and mixed language conditions. The ERP data also revealed small but reliable effects of cognate status. Language switching resulted in equal switching costs for both languages and was associated with a modulation in the ERP waveforms (time windows 275-375 ms and 375-475 ms). Mixed language context affected especially the L1, both in ERPs and in latencies, which became slower in L1 than L2. It is suggested that sustained and transient components of language control should be distinguished. Results are discussed in relation to current theories of bilingual language processing.

Abstract

The present study concerns individual differences in gesture production. We used correlational and multiple regression analyses to examine the relationship between individuals’ cognitive abilities and empathy levels and their gesture frequency and saliency. We chose predictor variables according to experimental evidence of the functions of gesture in speech production and communication. We examined 3 types of gestures: representational gestures, conduit gestures, and palm-revealing gestures. Higher frequency of representational gestures was related to poorer visual and spatial working memory, spatial transformation ability, and conceptualization ability; higher frequency of conduit gestures was related to poorer visual working memory, conceptualization ability, and higher levels of empathy; and higher frequency of palm-revealing gestures was related to higher levels of empathy. The saliency of all gestures was positively related to level of empathy. These results demonstrate that cognitive abilities and empathy levels are related to individual differences in gesture frequency and saliency

Abstract

This study investigated the motor strategy involved in mental rotation tasks by examining 2 types of spontaneous gestures (hand–object interaction gestures, representing the agentive hand action on an object, vs. object-movement gestures, representing the movement of an object by itself) and different types of verbal descriptions of rotation. Hand–object interaction gestures were produced earlier than object-movement gestures, the rate of both types of gestures decreased, and gestures became more distant from the stimulus object over trials (Experiments 1 and 3). Furthermore, in the first few trials, object-movement gestures increased, whereas hand–object interaction gestures decreased, and this change of motor strategies was also reflected in the type of verbal description of rotation in the concurrent speech (Experiment 2). This change of motor strategies was hampered when gestures were prohibited (Experiment 4). The authors concluded that the motor strategy becomes less dependent on agentive action on the object, and also becomes internalized over the course of the experiment, and that gesture facilitates the former process. When solving a problem regarding the physical world, adults go through developmental processes similar to internalization and symbolic distancing in young children, albeit within a much shorter time span.

Abstract

Language and action systems are highly interlinked. A critical piece of evidence is that speech and its accompanying gestures are tightly synchronized. Five experiments were conducted to test 2 hypotheses about the synchronization of speech and gesture. According to the interactive view, there is continuous information exchange between the gesture and speech systems, during both their planning and execution phases. According to the ballistic view, information exchange occurs only during the planning phases of gesture and speech, but the 2 systems become independent once their execution has been initiated. In all experiments, participants were required to point to and/or name a light that had just lit up. Virtual reality and motion tracking technologies were used to disrupt their gesture or speech execution. Participants delayed their speech onset when their gesture was disrupted. They did so even when their gesture was disrupted at its late phase and even when they received only the kinesthetic feedback of their gesture. Also, participants prolonged their gestures when their speech was disrupted. These findings support the interactive view and add new constraints on models of speech and gesture production

Abstract

In a semantic priming paradigm, the effects of different levels of processing on the N400 were assessed by changing the task demands. In the lexical decision task, subjects had to discriminate between words and nonwords and in the physical task, subjects had to discriminate between uppercase and lowercase letters. The proportion of related versus unrelated word pairs differed between conditions. A lexicality test on reaction times demonstrated that the physical task was performed nonlexically. Moreover, a semantic priming reaction time effect was obtained only in the lexical decision task. The level of processing clearly affected the event-related potentials. An N400 priming effect was only observed in the lexical decision task. In contrast, in the physical task a P300 effect was observed for either related or unrelated targets, depending on their frequency of occurrence. Taken together, the results indicate that an N400 priming effect is only evoked when the task performance induces the semantic aspects of words to become part of an episodic trace of the stimulus event.

Abstract

We present results from two cross‐modal morphological priming experiments investigating regular person and number inflection on finite verbs in German. We found asymmetries in the priming patterns between different affixes that can be predicted from the structure of the paradigm. We also report data from language disorders which indicate that inflectional errors produced by language‐impaired adults and children tend to occur within a given paradigm dimension, rather than randomly across the paradigm. We conclude that morphological paradigms are used by the human language processor and can be systematically affected in language disorders.

Abstract

“Gesture-first” theories dismiss ancestral great apes’ vocalization as a substrate for language evolution based on the claim that extant apes exhibit minimal learning and volitional control of vocalization. Contrary to this claim, we present data of novel learned and voluntarily controlled vocal behaviors produced by a human-fostered gorilla (G. gorilla gorilla). These behaviors demonstrate varying degrees of flexibility in the vocal apparatus (including diaphragm, lungs, larynx, and supralaryngeal articulators), and are predominantly performed in coordination with manual behaviors and gestures. Instead of a gesture-first theory, we suggest that these findings support multimodal theories of language evolution in which vocal and gestural forms are coordinated and supplement one another

Abstract

When we talk, we often make hand movements called gestures at the same time. Although just about everyone gestures when they talk, we usually do not even notice the gestures. Our hand gestures play an important role in helping us learn and remember! When we see other people gesturing when they talk—or when we gesture when we talk ourselves—we are more likely to remember the information being talked about than if gestures were not involved. Our hand gestures can even indicate when we are ready to learn new things! In this article, we explain how gestures can help learning. To investigate this, we studied children learning a new mathematical concept called equivalence. We hope that this article will help you notice when you, your friends and family, and your teachers are gesturing, and that it will help you understand how those gestures can help people learn.

Abstract

Three dual-task experiments investigated the capacity demands of phoneme selection in picture naming. On each trial, participants named a target picture (Task 1) and carried out a tone discrimination task (Task 2). To vary the time required for phoneme selection, the authors combined the targets with phonologically related or unrelated distractor pictures (Experiment 1) or words, which were clearly visible (Experiment 2) or masked (Experiment 3). When pictures or masked words were presented, the tone discrimination and picture naming latencies were shorter in the related condition than in the unrelated condition, which indicates that phoneme selection requires central processing capacity. However, when the distractor words were clearly visible, the facilitatory effect was confined to the picture naming latencies. This pattern arose because the visible related distractor words facilitated phoneme selection but slowed down speech monitoring processes that had to be completed before the response to the tone could be selected.

Abstract

Listeners outperform automatic speech recognition systems at every level, including the very basic level of consonant identification. What is not clear is where the human advantage originates. Does the fault lie in the acoustic representations of speech or in the recognizer architecture, or in a lack of compatibility between the two? Many insights can be gained by carrying out a detailed human-machine comparison. The purpose of the Interspeech 2008 Consonant Challenge is to promote focused comparisons on a task involving intervocalic consonant identification in noise, with all participants using the same training and test data. This paper describes the Challenge, listener results and baseline ASR performance.

Abstract

Contemporary methods of computational cognitive modeling have recently been criticized by Addyman and French (2012) on the grounds that they have not kept up with developments in computer technology and human–computer interaction. They present a manifesto for change according to which, it is argued, modelers should devote more effort to making their models accessible, both to non-modelers (with an appropriate easy-to-use user interface) and modelers alike. We agree that models, like data, should be freely available according to the normal standards of science, but caution against confusing implementations with specifications. Models may embody theories, but they generally also include implementation assumptions. Cognitive modeling methodology needs to be sensitive to this. We argue that specification, replication and experimentation are methodological approaches that can address this issue.

Abstract

Individual alpha frequency (IAF) is a promising electrophysiological marker of interindividual differences in cognitive function. IAF has been linked with trait-like differences in information processing and general intelligence, and provides an empirical basis for the definition of individualized frequency bands. Despite its widespread application, however, there is little consensus on the optimal method for estimating IAF, and many common approaches are prone to bias and inconsistency. Here, we describe an automated strategy for deriving two of the most prevalent IAF estimators in the literature: peak alpha frequency (PAF) and center of gravity (CoG). These indices are calculated from resting-state power spectra that have been smoothed using a Savitzky-Golay filter (SGF). We evaluate the performance characteristics of this analysis procedure in both empirical and simulated EEG data sets. Applying the SGF technique to resting-state data from n = 63 healthy adults furnished 61 PAF and 62 CoG estimates. The statistical properties of these estimates were consistent with previous reports. Simulation analyses revealed that the SGF routine was able to reliably extract target alpha components, even under relatively noisy spectral conditions. The routine consistently outperformed a simpler method of automated peak detection that did not involve spectral smoothing. The SGF technique is fast, open source, and available in two popular programming languages (MATLAB, Python), and thus can easily be integrated within the most popular M/EEG toolsets (EEGLAB, FieldTrip, MNE-Python). As such, it affords a convenient tool for improving the reliability and replicability of future IAF-related research.

Abstract

During conversation, interlocutors rapidly switch between speaker and listener
roles and take turns at talk. How do they achieve such fine coordination?
Most research has concentrated on the role of prediction, but listeners
must also prepare a response in advance (assuming they wish to respond)
and articulate this response at the appropriate moment. Such mechanisms
may overlap with the processes of comprehending the speaker’s incoming
turn and predicting its end. However, little is known about the stages of
response preparation and production. We discuss three questions pertaining
to such stages: (1) Do listeners prepare their own response in advance?,
(2) Can listeners buffer their prepared response?, and (3) Does buffering
lead to interference with concurrent comprehension? We argue that fine
coordination requires more than just an accurate prediction of the interlocutor’s
incoming turn: Listeners must also simultaneously prepare their own
response.

Abstract

During conversation, there is often little gap between interlocutors’ utterances. In two pairs of experiments, we manipulated the content predictability of yes/no questions to investigate whether listeners achieve such coordination by (i) preparing a response as early as possible or (ii) predicting the end of the speaker’s turn. To assess these two mechanisms, we varied the participants’ task: They either pressed a button when they thought the question was about to end (Experiments 1a and 2a), or verbally answered the questions with either yes or no (Experiments 1b and 2b). Predictability effects were present when participants had to prepare a verbal response, but not when they had to predict the turn-end. These findings suggest content prediction facilitates turn-taking because it allows listeners to prepare their own response early, rather than because it helps them predict when the speaker will reach the end of their turn.

Abstract

Single nucleotide polymorphisms (SNPs) within the MIR137, TCF4, and ZNF804A genes show genome-wide association to schizophrenia. However, the biological basis for the associations is unknown. Here, we tested the effects of these genes on brain structure in 1300 healthy adults. Using volumetry and voxel-based morphometry, neither gene-wide effects—including the combined effect of the genes—nor single SNP effects—including specific psychosis risk SNPs—were found on total brain volume, grey matter, white matter, or hippocampal volume. These results suggest that the associations between these risk genes and schizophrenia are unlikely to be mediated via effects on macroscopic brain structure.

Abstract

The multimedia annotation tool ELAN was enhanced within the Corpus NGT project by a number of new and improved functions. Most of these functions were not specific to working with sign language video data, and can readily be used for other annotation purposes as well. Their direct utility for working with large amounts of annotation files during the development and use of the Corpus NGT project is what unites the various functions, which are described in this paper. In addition, we aim to characterise future developments that will be needed in order to work efficiently with larger amounts of annotation files, for which a closer integration with the use and display of metadata is foreseen.

Abstract

This paper discusses some improvements in recent and planned versions of the multimodal annotation tool ELAN, which are targeted at improving the usability of annotated files. Increased support for multilingual documents is provided, by allowing for multilingual vocabularies and by specifying a language per document, annotation layer (tier) or annotation. In addition, improvements in the search possibilities and the display of the results have been implemented, which are especially relevant in the interpretation of the results of complex multi-tier searches.

Abstract

Collocations generated by concordancers are a standard instrument in the exploitation of text corpora for the analysis of language use. Multimodal corpora show similar types of patterns, activities that frequently occur together, but there is no tool that offers facilities for visualising such patterns. Examples include timing of eye contact with respect to speech, and the alignment of activities of the two hands in signed languages. This paper describes recent enhancements to the standard CLARIN tools ELAN and TROVA for multimodal annotation to address these needs: first of all the query and concordancing functions were improved, and secondly the tools now generate visualisations of multilayer collocations that allow for intuitive explorations and analyses of multimodal data. This will provide a boost to the linguistic fields of gesture and sign language studies, as it will improve the exploitation of multimodal corpora.

Abstract

The Corpus NGT is an ambitious effort to record and archive video data from Sign Language of the Netherlands (Nederlandse Gebarentaal: NGT), guaranteeing online access to all interested parties and long-term availability. Data are collected from 100 native signers of NGT of different ages and from various regions in the country. Parts of these data are annotated and/or translated; the annotations and translations are part of the corpus. The Corpus NGT is accommodated in the Browsable Corpus based at the Max Planck Institute for Psycholinguistics. In this paper we share our experiences in data collection, video processing, annotation/translation and licensing involved in building the corpus.

Abstract

A recent debate in the morphological literature concerns the status of derivational affixes. While some linguists (Marantz 1997, 2001; Marvin 2003) consider derivational affixes a type of functional morpheme that realizes a categorial head, others (Lowenstamm 2015; De Belder 2011) argue that derivational affixes are roots. Our proposal, which finds its empirical basis in a study of Dutch derivational affixes, takes a middle position. We argue that there are two types of derivational affixes: some that are roots (i.e. lexical morphemes) and others that are categorial heads (i.e. functional morphemes). Affixes that are roots show ‘flexible’ categorial behavior, are subject to ‘lexical’ phonological rules, and may trigger idiosyncratic meanings. Affixes that realize categorial heads, on the other hand, are categorially rigid, do not trigger ‘lexical’ phonological rules nor allow for idiosyncrasies in their interpretation.

Abstract

Phonological patterns in languages often involve groups of sounds rather than individual sounds, which may be explained if phonology operates on the abstract features shared by those groups (Troubetzkoy, 193957. Troubetzkoy , N. 1939/1969 . Principles of phonology , Berkeley : University of California Press . View all references/1969; Chomsky & Halle, 19688. Chomsky , N. and Halle , M. 1968 . The sound pattern of English , New York : Harper and Row . View all references). Such abstract features may be present in the developing grammar either because they are part of a Universal Grammar included in the genetic endowment of humans (e.g., Hale, Kissock and Reiss, 200618. Hale , M. , Kissock , M. and Reiss , C. 2006 . Microvariation, variation, and the features of universal grammar . Lingua , 32 : 402 – 420 . View all references), or plausibly because infants induce features from their linguistic experience (e.g., Mielke, 200438. Mielke , J. 2004 . The emergence of distinctive features , Ohio State University : Unpublished doctoral dissertation . View all references). A first experiment tested 7-month-old infants' learning of an artificial grammar pattern involving either a set of sounds defined by a phonological feature, or a set of sounds that cannot be described with a single feature—an “arbitrary” set. Infants were able to induce the constraint and generalize it to a novel sound only for the set that shared the phonological feature. A second study showed that infants' inability to learn the arbitrary grouping was not due to their inability to encode a constraint on some of the sounds involved.

Abstract

The present study investigated the neural correlates of infant discrimination of very similar linguistic varieties (Quebecois and Parisian French) using functional Near InfraRed Spectroscopy. In line with previous behavioral and electrophysiological data, there was no evidence that 3-month-olds discriminated the two regional accents, whereas 5-month-olds did, with the locus of discrimination in left anterior perisylvian regions. These neuroimaging results suggest that a developing language network relying crucially on left perisylvian cortices sustains infants' discrimination of similar linguistic varieties within this early period of infancy.

Abstract

Speaker diarization (answering 'who spoke when') is a widely researched subject within speech technology. Numerous experiments have been run on datasets built from broadcast news, meeting data, and call centers—the task sometimes appears close to being solved. Much less work has begun to tackle the hardest diarization task of all: spontaneous conversations in real-world settings. Such diarization would be particularly useful for studies of language acquisition, where researchers investigate the speech children produce and hear in their daily lives. In this paper, we study audio gathered with a recorder worn by small children as they went about their normal days. As a result, each child was exposed to different acoustic environments with a multitude of background noises and a varying number of adults and peers. The inconsistency of speech and noise within and across samples poses a challenging task for speaker diarization systems, which we tackled via retraining and data augmentation techniques. We further studied sources of structured variation across raw audio files, including the impact of speaker type distribution, proportion of speech from children, and child age on diarization performance. We discuss the extent to which these findings might generalize to other samples of speech in the wild.

Abstract

There are increasing reports that individual variation in behavioral and neurophysiological measures of infant speech processing predicts later language outcomes, and specifically concurrent or subsequent vocabulary size. If such findings are held up under scrutiny, they could both illuminate theoretical models of language development and contribute to the prediction of communicative disorders. A qualitative, systematic review of this emergent literature illustrated the variety of approaches that have been used and highlighted some conceptual problems regarding the measurements. A quantitative analysis of the same data established that the bivariate relation was significant, with correlations of similar strength to those found for well-established nonlinguistic predictors of language. Further exploration of infant speech perception predictors, particularly from a methodological perspective, is recommended.

Abstract

Typically, the point vowels [i,ɑ,u] are acoustically more peripheral in infant-directed speech (IDS) compared to adult-directed speech (ADS). If caregivers seek to highlight lexically relevant contrasts in IDS, then two sounds that are contrastive should become more distinct, whereas two sounds that are surface realizations of the same underlying sound category should not. To test this prediction, vowels that are phonemically contrastive ([i-ɪ] and [eɪ-ε]), vowels that map onto the same underlying category ([æ- ] and [ε- ]), and the point vowels [i,ɑ,u] were elicited in IDS and ADS by American English mothers of two age groups of infants (four- and eleven-month-olds). As in other work, point vowels were produced in more peripheral positions in IDS compared to ADS. However, there was little evidence of hyperarticulation per se (e.g. [i-ɪ] was hypoarticulated). We suggest that across-the-board lexically based hyperarticulation is not a necessary feature of IDS.

Abstract

In the wild, chimpanzees (Pan troglodytes) are often faced with clumped food resources that they may know how to access but abstain from doing so due to social pressures. To better understand how social settings influence resource acquisition, we tested fifteen semi-wild chimpanzees from two social groups alone and in the presence of others. We investigated how resource acquisition was affected by relative social dominance, whether collaborative problem solving or (active or passive) sharing occurred amongst any of the dyads, and whether these outcomes were related to relationship quality as determined from six months of observational data. Results indicated that chimpanzees, regardless of rank, obtained fewer rewards when tested in the presence of others compared to when they were tested alone. Chimpanzees demonstrated behavioral inhibition; chimpanzees who showed proficient skill when alone often abstained from solving the task when in the presence of others. Finally, individuals with close social relationships spent more time together in the problem solving space, but collaboration and sharing were infrequent and sessions in which collaboration or sharing did occur contained more instances of aggression. Group living provides benefits and imposes costs, and these findings highlight that one cost of group living may be diminishing productive individual behaviors.

Abstract

Cooperation among nonhuman animals has been the topic of much theoretical and empirical research, but few studies have examined systematically the effects of various reward payoffs on cooperative behaviour. Here, we presented heterosexual pairs of cooperatively breeding cottontop tamarins with a cooperative problem-solving task. In a series of four experiments, we examined how the tamarins’ cooperative performance changed under conditions in which (1) both actors were mutually rewarded, (2) both actors were rewarded reciprocally across days, (3) both actors competed for a monopolizable reward and (4) one actor repeatedly delivered a single reward to the other actor. The tamarins showed sensitivity to the reward structure, showing the greatest percentage of trials solved and shortest latency to solve the task in the mutual reward experiment and the lowest percentage of trials solved and longest latency to solve the task in the experiment in which one actor was repeatedly rewarded. However, even in the experiment in which the fewest trials were solved, the tamarins still solved 46 _ 12% of trials and little to no aggression was observed among partners following inequitable reward distributions. The tamarins did, however, show selfish motivation in each of the experiments. Nevertheless, in all experiments, unrewarded individuals continued to cooperate and procure rewards for their social partners.

Abstract

Recent debates have questioned the extent to which culturally-transmitted norms drive behavioral variation in resource sharing across human populations. We shed new light on this discussion by examining the group-level variation in the social dynamics and resource sharing of chimpanzees, a species that is highly social and forms long-term community associations but differs from humans in the extent to which cultural norms are adopted and enforced. We rely on theory developed in primate socioecology to guide our investigation in four neighboring chimpanzee groups at a sanctuary in Zambia. We used a combination of experimental and observational approaches to assess the distribution of resource holding potential in each group. In the first assessment, we measured the proportion of the population that gathered in a resource-rich zone, in the second we assessed naturally occurring social spacing via social network analysis, and in the third we assessed the degree to which benefits were equally distributed within the group. We report significant, stable group-level variation across these multiple measures, indicating that group-level variation in resource sharing and social tolerance is not necessarily reliant upon human-like cultural norms.

Abstract

A large amount of variability exists across human brains; revealed initially on a small scale by postmortem studies and,
more recently, on a larger scale with the advent of neuroimaging. Here we compared structural variability between human
and macaque monkey brains using grey and white matter magnetic resonance imaging measures. The monkey brain was
overall structurally as variable as the human brain, but variability had a distinct distribution pattern, with some key areas
showing high variability. We also report the first evidence of a relationship between anatomical variability and evolutionary
expansion in the primate brain. This suggests a relationship between variability and stability, where areas of low variability
may have evolved less recently and have more stability, while areas of high variability may have evolved more recently and
be less similar across individuals. We showed specific differences between the species in key areas, including the amount of
hemispheric asymmetry in variability, which was left-lateralized in the human brain across several phylogenetically recent
regions. This suggests that cerebral variability may be another useful measure for comparison between species and may add
another dimension to our understanding of evolutionary mechanisms.

Abstract

Speech processing by human listeners derives meaning from acoustic input via intermediate steps involving abstract representations of what has been heard. Recent results from several lines of research are here brought together to shed light on the nature and role of these representations. In spoken-word recognition, representations of phonological form and of conceptual content are dissociable. This follows from the independence of patterns of priming for a word's form and its meaning. The nature of the phonological-form representations is determined not only by acoustic-phonetic input but also by other sources of information, including metalinguistic knowledge. This follows from evidence that listeners can store two forms as different without showing any evidence of being able to detect the difference in question when they listen to speech. The lexical representations are in turn separate from prelexical representations, which are also abstract in nature. This follows from evidence that perceptual learning about speaker-specific phoneme realization, induced on the basis of a few words, generalizes across the whole lexicon to inform the recognition of all words containing the same phoneme. The efficiency of human speech processing has its basis in the rapid execution of operations over abstract representations.

Abstract

Listeners heard an ambiguous /f-s/ in nonword contexts where only one of /f/ or /s/ was legal (e.g., frul/*srul or *fnud/snud). In later categorisation of a phonetic continuum from /f/ to /s/, their category boundaries had shifted; hearing -rul led to expanded /f/ categories, -nud expanded /s/. Thus phonotactic sequence information alone induces perceptual retuning of phoneme category boundaries; lexical access is not required.

Abstract

In two experiments, Mandarin listeners resolved potential syntactic ambiguities in spoken utterances in (a) their native language (L1) and (b) English which they had learned as a second language (L2). A new disambiguation task was used, requiring speeded responses to select the correct meaning for structurally ambiguous sentences. Importantly, the ambiguities used in the study are identical in Mandarin and in English, and production data show that prosodic disambiguation of this type of ambiguity is also realised very similarly in the two languages. The perceptual results here showed however that listeners’ response patterns differed for L1 and L2, although there was a significant increase in similarity between the two response patterns with increasing exposure to the L2. Thus identical ambiguity and comparable disambiguation patterns in L1 and L2 do not lead to immediate application of the appropriate L1 listening strategy to L2; instead, it appears that such a strategy may have to be learned anew for the L2.

Abstract

Using a phoneme detection task, the present series of
experiments examines whether listeners can entrain to
different combinations of prosodic cues to predict where focus
will fall in an utterance. The stimuli were recorded by four
female native speakers of Australian English who happened to
have used different prosodic cues to produce sentences with
prosodic focus: a combination of duration cues, mean and
maximum F0, F0 range, and longer pre-target interval before
the focused word onset, only mean F0 cues, only pre-target
interval, and only duration cues. Results revealed that listeners
can entrain in almost every condition except for where
duration was the only reliable cue. Our findings suggest that
listeners are flexible in the cues they use for focus processing.

Abstract

Dutch listeners outperform native listeners in identifying syllable stress in English. This is because lexical stress is more useful in recognition of spoken words of Dutch than of English, so that Dutch listeners pay greater attention to stress in general. We examined Dutch listeners’ use of the acoustic correlates of English stress. Primary- and secondary-stressed syllables differ significantly on acoustic measures, and some differences, in F0 especially, correlate with data of earlier listening experiments. The correlations found in the Dutch responses were not paralleled in data from native listeners. Thus the acoustic cues which distinguish English primary versus secondary stress are better exploited by Dutch than by native listeners.

Abstract

Speech recognition in noise is harder in second (L2) than first languages (L1). This could be because noise disrupts speech processing more in L2 than L1, or because L1 listeners recover better though disruption is equivalent. Two similar prior studies produced discrepant results: Equivalent noise effects for L1 and L2 (Dutch) listeners, versus larger effects for L2 (Spanish) than L1. To explain this, the latter experiment was presented to listeners from the former population. Larger noise effects on consonant identification emerged for L2 (Dutch) than L1 listeners, suggesting that task factors rather than L2 population differences underlie the results discrepancy.

Abstract

In contrast to initial L1 vocabularies, which of necessity depend largely on heard exemplars, L2 vocabulary construction can draw on a variety of knowledge sources. This can lead to richer stored knowledge about the phonology of the L2 than the listener's prelexical phonetic processing capacity can support, and thus to mismatch between the level of detail required for accurate lexical mapping and the level of detail delivered by the prelexical processor. Experiments on spoken word recognition in L2 have shown that phonetic contrasts which are not reliably perceived are represented in the lexicon nonetheless. This lexical representation of contrast must be based on abstract knowledge, not on veridical representation of heard exemplars. New experiments confirm that provision of abstract knowledge (in the form of spelling) can induce lexical representation of a contrast which is not reliably perceived; but also that experience (in the form of frequency of occurrence) modulates the mismatch of phonetic and lexical processing. We conclude that a correct account of word recognition in L2 (as indeed in L1) requires consideration of both abstract and episodic information.

Abstract

The difficulty of listening to speech in noise is exacerbated when the speech is in the listener’s L2 rather than L1. In this study, Spanish and Dutch users of English as an L2 identified American English consonants in a constant intervocalic context. Their performance was compared with that of L1 (British English) listeners, under quiet conditions and when the speech was masked by speech from another talker or by noise. Masking affected performance more for the Spanish listeners than for the L1 listeners, but not for the Dutch listeners, whose performance was worse than the L1 case to about the same degree in all conditions. There were, however,large differences in the pattern of results across individual consonants, which were consistent with differences in how consonants are identified in the respective L1s.

Abstract

Listeners adapt rapidly to previously unheard talkers by
adjusting phoneme categories using lexical knowledge, in a
process termed lexically-guided perceptual learning. Although
this is firmly established for listening in the native language
(L1), perceptual flexibility in second languages (L2) is as yet
less well understood. We report two experiments examining L1
and L2 perceptual learning, the first in Mandarin-English late
bilinguals, the second in Australian learners of Mandarin. Both
studies showed stronger learning in L1; in L2, however,
learning appeared for the English-L1 group but not for the
Mandarin-L1 group. Phonological mapping differences from
the L1 to the L2 are suggested as the reason for this result.

Abstract

Speech signals originate as a sequence of linguistic units selected by speakers, but these units are necessarily realised in the suprasegmental dimensions of time, frequency and amplitude. For this reason prosodic structure has been viewed as a mandatory target of language processing by both speakers and listeners. In apparent contradiction, however, prosody has also been argued to be ancillary rather than core linguistic structure, making processing of prosodic structure essentially optional. In the present tribute to one of the luminaries of prosodic research for the past quarter century, we review evidence from studies of the processing of lexical stress and focal accent which reconciles these views and shows that both claims are, each in their own way, fully true.

Abstract

Vocabularies contain hundreds of thousands of words built from only a handful of phonemes; longer words inevitably tend to contain shorter ones. Recognising speech thus requires distinguishing intended words from accidentally present ones. Acoustic information in speech is used wherever it contributes significantly to this process; but as this review shows, its contribution differs across languages, with the consequences of this including: identical and equivalently present information distinguishing the same phonemes being used in Polish but not in German, or in English but not in Italian; identical stress cues being used in Dutch but not in English; expectations about likely embedding patterns differing across English, French, Japanese.

Abstract

SPEECH, in any language, is continuous; speakers provide few reliable cues to the boundaries of words, phrases, or other meaningful units. To understand speech, listeners must divide the continuous speech stream into portions that correspond to such units. This segmentation process is so basic to human language comprehension that psycholinguists long assumed that all speakers would do it in the same way. In previous research1,2, however, we reported that segmentation routines can be language-specific: speakers of French process spoken words syllable by syllable, but speakers of English do not. French has relatively clear syllable boundaries and syllable-based timing patterns, whereas English has relatively unclear syllable boundaries and stress-based timing; thus syllabic segmentation would work more efficiently in the comprehension of French than in the comprehension of English. Our present study suggests that at this level of language processing, there are limits to bilingualism: a bilingual speaker has one and only one basic language.

Abstract

Listeners' recognition of spoken language involves complex decoding processes: The continuous speech stream must be segmented into its component words, and words must be recognized despite great variability in their pronunciation (due to talker differences, or to influence of phonetic context, or to speech register) and despite competition from many spuriously present forms supported by the speech signal. L1 listeners deal more readily with all levels of this complexity than L2 listeners. Fortunately, the decoding processes necessary for competent L2 listening can be taught in the classroom. Evidence-based methodologies targeted at the development of efficient speech decoding include teaching of minimal pairs, of phonotactic constraints, and of reduction processes, as well as the use of dictation and L2 video captions.

Abstract

An acoustically invariant one-word segment occurred in two versions of one syntactic context. In one version, the preceding intonation contour indicated that a stress would fall at the point where this word occurred. In the other version, the preceding contour predicted reduced stress at that point. Reaction time to the initial phoneme of the word was faster in the former case, despite the fact that no acoustic correlates of stress were present. It is concluded that a part of the sentence comprehension process is the prediction of upcoming sentence accents.

Abstract

Two lexical decision experiments in Cantonese are described in which the recognition of spoken target words as a function of phonological similarity to a preceding prime is investigated. Phonological similaritv in first syllables produced inhibition, while similarity in second syllables led to facilitation. Differences between syllables in tonal and segmental structure had generally similar effects.

Abstract

This chapter highlights that most language behavior consists of speaking and listening. The chapter also reveals differences and similarities between speaking and listening. The laboratory study of word production raises formidable problems; ensuring that a particular word is produced may subvert the spontaneous production process. Word production is investigated via slips and tip-of-the-tongue (TOT), primarily via instances of processing failure and via the technique of via the picture-naming task. The methodology of word production is explained in the chapter. The chapter also explains the phenomenon of interaction between various stages of word production and the process of speech recognition. In this context, it explores the difference between sound and meaning and examines whether or not the comparisons are appropriate between the processes of recognition and production of spoken words. It also describes the similarities and differences in the structure of the recognition and production systems. Finally, the chapter highlights the common issues in recognition and production research, which include the nuances of frequency of occurrence, morphological structure, and phonological structure.

Abstract

A model of speech segmentation in a stress language is proposed, according to which the occurrence of a strong syllable triggers segmentation of the speech signal, whereas occurrence of a weak syllable does not trigger segmentation. We report experiments in which listeners detected words embedded in nonsense bisyllables more slowly when the bisyllable had two strong syllables than when it had a strong and a weak syllable; mint was detected more slowly in mintayve than in mintesh. According to our proposed model, this result is an effect of segmentation: When the second syllable is strong, it is segmented from the first syllable, and successful detection of the embedded word therefore requires assembly of speech material across a segmentation position. Speech recognition models involving phonemic or syllabic recoding, or based on strictly left-to-right processes, do not predict this result. It is argued that segmentation at strong syllables in continuous speech recognition serves the purpose of detecting the most efficient locations at which to initiate lexical access. (C) 1988 by the American Psychological Association

Abstract

Two experiments examined the dynamics of lexical activation in spoken-word recognition. In both, the key materials were pairs of onset-matched picturable nouns varying in frequency. Pictures associated with these words, plus two distractor pictures were displayed. A gating task, in which participants identified the picture associated with gradually lengthening fragments of spoken words, examined the availability of discriminating cues in the speech waveforms for these pairs. There was a clear frequency bias in participants’ responses to short, ambiguous fragments, followed by a temporal window in which discriminating information gradually became available. A visual-world experiment examined speech contingent eye movements. Fixation analyses suggested that frequency influences lexical competition well beyond the point in the speech signal at which the spoken word has been fully discriminated from its competitor (as identified using gating). Taken together, these data support models in which the processing dynamics of lexical activation are a limiting factor on recognition speed, over and above the temporal unfolding of the speech signal.

Abstract

The neural mechanism for selectively tuning in to a target speaker while tuning out the others in a multi-speaker situation (i.e., the cocktail-party effect) remains elusive. Here we addressed this issue by measuring brain activity simultaneously from a listener and from multiple speakers while they were involved in naturalistic conversations. Results consistently show selectively enhanced interpersonal neural synchronization (INS) between the listener and the attended speaker at left temporal–parietal junction, compared with that between the listener and the unattended speaker across different multi-speaker situations. Moreover, INS increases significantly prior to the occurrence of verbal responses, and even when the listener’s brain activity precedes that of the speaker. The INS increase is independent of brain-to-speech synchronization in both the anatomical location and frequency range. These findings suggest that INS underlies the selective process in a multi-speaker situation through neural predictions at the content level but not the sensory level of speech.

Abstract

Different linguistic structures allow us to highlight distinct aspects of a situation. The aim of this survey is to investigate similarities and differences in the expression of situations or events as “stative” (maintaining a state), “inchoative” (adopting a state) and “agentive” (causing something to be in a state). The questionnaire focuses on the encoding of stative, inchoative and agentive possibilities for the translation equivalents of a set of English verbs.

Abstract

Expressions of human activities and states are a rich area for cross-linguistic comparison. Some languages of the world treat human posture verbs (e.g., sit, lie, kneel) as a special class of predicates, with distinct formal properties. This survey examines lexical, semantic and grammatical patterns for posture verbs, with special reference to contrasts between “stative” (maintaining a posture), “inchoative” (adopting a posture), and “agentive” (causing something to adopt a posture) constructions. The enquiry is thematically linked to the more general questionnaire 'Intransitive Predicate Form Class Survey'.

Abstract

This work was supported by grants from the French Agence Nationale de la Recherche (ANR-2010-BLAN-1901) and from French Fondation de France to Anne Christophe, from the National Institute of Child Health and Human Development (HD054448) to Cynthia Fisher, Fondation Fyssen and Ecole de Neurosciences de Paris to Alex Cristia, and a PhD fellowship from the Direction Générale de l'Armement (DGA, France) supported by the PhD program FdV (Frontières du Vivant) to Isabelle Dautriche. We thank Isabelle Brunet for the recruitment, Michel Dutat for the technical support, and Hernan Anllo for his puppet mastery skill. We are grateful to the families that participated in this study. We also thank two anonymous reviewers for their comments on an earlier draft of this manuscript.

Abstract

In the present study, we explore whether multiple data sources may be more effective than single sources at predicting the words that language learners are likely to know. Second language researchers have hypothesized that there is a relationship between word frequency and the likelihood that words will be encountered or used by second language learners, but it is not yet clear how this relationship should be effectively measured. An analysis of word frequency measures showed that spoken language frequency alone may predict the occurrence of words in learner textbooks, but that multiple corpora as well as textbook status can improve predictions of learner usage.

Abstract

The relationship between semantic and grammatical processing in sentence comprehension was investigated by examining event-related potential (ERP) and event-related power changes in response to semantic and grammatical violations. Sentences with semantic, phrase structure, or number violations and matched controls were presented serially (1.25 words/s) to 20 participants while EEG was recorded. Semantic violations were associated with an N400 effect and a theta band increase in power, while grammatical violations were associated with a P600 effect and an alpha/beta band decrease in power. A quartile analysis showed that for both types of violations, larger average violation effects were associated with lower relative amplitudes of oscillatory activity, implying an inverse relation between ERP amplitude and event-related power magnitude change in sentence processing.

Abstract

The causal correlations between human genetic variants and linguistic (typological) features could represent the mechanism required for gradual, accretionary models of language evolution. The causal link is mediated by the process of cultural transmission of language across generations in a population of genetically biased individuals. The particular case of Tone, ASPM and Microcephalin is discussed as an illustration. It is proposed that this type of genetically-influenced linguistic bias, coupled with a fundamental role for genetic and linguistic diversities, provides a better explanation for the evolution of language and linguistic universals.

Abstract

This article surveys what is currently known about the complex interplay between genetics and the language sciences. It focuses not only on the genetic architecture of language and speech, but also on their interactions on the cultural and evolutionary timescales. Given the complexity of these issues and their current state of flux and high dynamism, this article surveys the main findings and topics of interest while also briefly introducing the main relevant methods, thus allowing the interested reader to fully appreciate and understand them in their proper context. Of course, not all the relevant publications and resources are mentioned, but this article aims to select the most relevant, promising, or accessible for nonspecialists.

Abstract

One of the best-known types of non-independence between languages is caused by genealogical relationships due to descent from a common ancestor. These can be represented by (more or less resolved and controversial) language family trees. In theory, one can argue that language families should be built through the strict application of the comparative method of historical linguistics, but in practice this is not always the case, and there are several proposed classifications of languages into language families, each with its own advantages and disadvantages. A major stumbling block shared by most of them is that they are relatively difficult to use with computational methods, and in particular with phylogenetics. This is due to their lack of standardization, coupled with the general non-availability of branch length information, which encapsulates the amount of evolution taking place on the family tree. In this paper I introduce a method (and its implementation in R) that converts the language classifications provided by four widely-used databases (Ethnologue, WALS, AUTOTYP and Glottolog) intothe de facto Newick standard generally used in phylogenetics, aligns the four most used conventions for unique identifiers of linguistic entities (ISO 639-3, WALS, AUTOTYP and Glottocode), and adds branch length information from a variety of sources (the tree's own topology, an externally given numeric constant, or a distance matrix). The R scripts, input data and resulting Newick trees are available under liberal open-source licenses in a GitHub repository (https://github.com/ddediu/lgfam-newick), to encourage and promote the use of phylogenetic methods to investigate linguistic diversity and its temporal dynamics.

Abstract

The correlations between interpopulation genetic and linguistic diversities are mostly noncausal (spurious), being due to historical processes and geographical factors that shape them in similar ways. Studies of such correlations usually consider allele frequencies and linguistic groupings (dialects, languages, linguistic families or phyla), sometimes controlling for geographic, topographic, or ecological factors. Here, we consider the relation between allele frequencies and linguistic typological features. Specifically, we focus on the derived haplogroups of the brain growth and development-related genes ASPM and Microcephalin, which show signs of natural selection and a marked geographic structure, and on linguistic tone, the use of voice pitch to convey lexical or grammatical distinctions. We hypothesize that there is a relationship between the population frequency of these two alleles and the presence of linguistic tone and test this hypothesis relative to a large database (983 alleles and 26 linguistic features in 49 populations), showing that it is not due to the usual explanatory factors represented by geography and history. The relationship between genetic and linguistic diversity in this case may be causal: certain alleles can bias language acquisition or processing and thereby influence the trajectory of language change through iterated cultural transmission.

Abstract

Here we re-evaluate our 2013 paper on the antiquity of language (Dediu and Levinson, 2013) in the light of a surge of new information on human evolution in the last half million years. Although new genetic data suggest the existence of some cognitive differences between Neanderthals and modern humans — fully expected after hundreds of thousands of years of partially separate evolution, overall our claims that Neanderthals were fully articulate beings and that language evolution was gradual are further substantiated by the wealth of new genetic, paleontological and archeological evidence briefly reviewed here.

Abstract

It has recently been proposed (Dediu, D., Ladd, D.R., 2007. Linguistic tone is related to the population frequency of the adaptive haplogroups of two brain size genes, ASPM and Microcephalin. Proc Natl Acad Sci USA 104, 10944-10949) that genetically coded linguistic biases can influence the trajectory of language change. However, the nature of such biases and the conditions under which they can become manifest have remained vague. The present paper explores computationally two plausible types of linguistic acquisition biases in a population of agents implementing realistic genetic, linguistic and demographic processes. One type of bias represents an innate asymmetric initial state (Initial Expectation bias) while the other an innate asymmetric facility of acquisition (Rate of Learning bias). It was found that only the second type of bias produces detectable effects on language through cultural transmission across generations and that such effects are produced even by weak biases present at low frequencies in the population. This suggests that learning preference asymmetries, very small at the individual level and not very frequent at the population level, can bias the trajectory of language change through the process of cultural transmission.

Abstract

In this article we investigate the relation between discourse markers and turn-transition strategies in face-to-face conversations and Instant Messaging (IM), that is, unplanned, real-time, text-based, computer-mediated communication. By means of a quantitative corpus study of utterances containing a discourse marker, we show that utterance-final discourse markers are used more often in IM than in face-to-face conversations. Moreover, utterance-final discourse markers are shown to occur more often at points of turn-transition compared with points of turn-maintenance in both types of conversation. From our results we conclude that the discourse markers in utterance-final position can function as a turn-transition mechanism, signaling that the turn is over and the floor is open to the hearer. We argue that this linguistic turn-taking strategy is essentially similar in face-to-face and IM communication. Our results add to the evidence that communication in IM is more like speech than like writing.

Abstract

Recurrent de novo variants in the TBR1 transcription factor are implicated in the etiology of sporadic autism spectrum disorders (ASD). Disruptions include missense variants located in the T-box DNA-binding domain and previous work has demonstrated that they disrupt TBR1 protein function. Recent screens of thousands of simplex families with sporadic ASD cases uncovered additional T-box variants in TBR1 but their etiological relevance is unclear. We performed detailed functional analyses of de novo missense TBR1 variants found in the T-box of ASD cases, assessing many aspects of protein function, including subcellular localization, transcriptional activity and protein-interactions. Only two of the three tested variants severely disrupted TBR1 protein function, despite in silico predictions that all would be deleterious. Furthermore, we characterized a putative interaction with BCL11A, a transcription factor that was recently implicated in a neurodevelopmental syndrome involving developmental delay and language deficits. Our findings enhance understanding of molecular functions of TBR1, as well as highlighting the importance of functional testing of variants that emerge from next-generation sequencing, to decipher their contributions to neurodevelopmental disorders like ASD.

Abstract

Next-generation sequencing recently revealed that recurrent disruptive mutations in a few genes may account for 1% of sporadic autism cases. Coupling these novel genetic data to empirical assays of protein function can illuminate crucial molecular networks. Here we demonstrate the power of the approach, performing the first functional analyses of TBR1 variants identified in sporadic autism. De novo truncating and missense mutations disrupt multiple aspects of TBR1 function, including subcellular localization, interactions with co-regulators and transcriptional repression. Missense mutations inherited from unaffected parents did not disturb function in our assays. We show that TBR1 homodimerizes, that it interacts with FOXP2, a transcription factor implicated in speech/language disorders, and that this interaction is disrupted by pathogenic mutations affecting either protein. These findings support the hypothesis that de novo mutations in sporadic autism have severe functional consequences. Moreover, they uncover neurogenetic mechanisms that bridge different neurodevelopmental disorders involving language deficits.

Abstract

Assays based on Bioluminescence Resonance Energy Transfer (BRET) provide a sensitive and reliable means to monitor protein-protein interactions in live cells. BRET is the non-radiative transfer of energy from a ‘donor’ luciferase enzyme to an ‘acceptor’ fluorescent protein. In the most common configuration of this assay, the donor is Renilla reniformis luciferase and the acceptor is Yellow Fluorescent Protein (YFP). Because the efficiency of energy transfer is strongly distance-dependent, observation of the BRET phenomenon requires that the donor and acceptor be in close proximity. To test for an interaction between two proteins of interest in cultured mammalian cells, one protein is expressed as a fusion with luciferase and the second as a fusion with YFP. An interaction between the two proteins of interest may bring the donor and acceptor sufficiently close for energy transfer to occur. Compared to other techniques for investigating protein-protein interactions, the BRET assay is sensitive, requires little hands-on time and few reagents, and is able to detect interactions which are weak, transient, or dependent on the biochemical environment found within a live cell. It is therefore an ideal approach for confirming putative interactions suggested by yeast two-hybrid or mass spectrometry proteomics studies, and in addition it is well-suited for mapping interacting regions, assessing the effect of post-translational modifications on protein-protein interactions, and evaluating the impact of mutations identified in patient DNA.

Abstract

Prion diseases are fatal neurodegenerative disorders that include Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in animals. They are unique in terms of their biology because they are caused by the conformational re-arrangement of a normal host-encoded prion protein, PrPC, to an abnormal infectious isoform, PrPSc. Currently the precise mechanism behind prion-mediated neurodegeneration remains unclear. It is hypothesised than an unknown toxic gain of function of PrPSc, or an intermediate oligomeric form, underlies neuronal death. Increasing evidence suggests a role for the ubiquitin proteasome system (UPS) in prion disease. Both wild-type PrPC and disease-associated PrP isoforms accumulate in cells after proteasome inhibition leading to increased cell death, and abnormal beta-sheet-rich PrP isoforms have been shown to inhibit the catalytic activity of the proteasome. Here we review potential interactions between prions and the proteasome outlining how the UPS may be implicated in prion-mediated neurodegeneration.

Abstract

Retinoic acid-related orphan receptor alpha gene (RORa) and the microRNA MIR137 have both recently been identified as novel candidate genes for neuropsychiatric disorders. RORa encodes a ligand-dependent orphan nuclear receptor that acts as a transcriptional regulator and miR-137 is a brain enriched small non-coding RNA that interacts with gene transcripts to control protein levels. Given the mounting evidence for RORa in autism spectrum disorders (ASD) and MIR137 in schizophrenia and ASD, we investigated if there was a functional biological relationship between these two genes. Herein, we demonstrate that miR-137 targets the 3'UTR of RORa in a site specific manner. We also provide further support for MIR137 as an autism candidate by showing that a large number of previously implicated autism genes are also putatively targeted by miR-137. This work supports the role of MIR137 as an ASD candidate and demonstrates a direct biological link between these previously unrelated autism candidate genes

Abstract

FOXP2 was the first gene shown to cause a Mendelian form of speech and language disorder. Although developmentally expressed in many organs, loss of a single copy of FOXP2 leads to a phenotype that is largely restricted to orofacial impairment during articulation and linguistic processing deficits. Why perturbed FOXP2 function affects specific aspects of the developing brain remains elusive. We investigated the role of FOXP2 in neuronal differentiation and found that FOXP2 drives molecular changes consistent with neuronal differentiation in a human model system. We identified a network of FOXP2 regulated genes related to retinoic acid signaling and neuronal differentiation. FOXP2 also produced phenotypic changes associated with neuronal differentiation including increased neurite outgrowth and reduced migration. Crucially, cells expressing FOXP2 displayed increased sensitivity to retinoic acid exposure. This suggests a mechanism by which FOXP2 may be able to increase the cellular differentiation response to environmental retinoic acid cues for specific subsets of neurons in the brain. These data demonstrate that FOXP2 promotes neuronal differentiation by interacting with the retinoic acid signaling pathway and regulates key processes required for normal circuit formation such as neuronal migration and neurite outgrowth. In this way, FOXP2, which is found only in specific subpopulations of neurons in the brain, may drive precise neuronal differentiation patterns and/or control localization and connectivity of these FOXP2 positive cells

Abstract

Intellectual disability (ID) is a severe neurodevelopmental disorder with genetically heterogeneous causes. Large-scale sequencing has led to the identification of many gene-disrupting mutations; however, a substantial proportion of cases lack a molecular diagnosis. As such, there remains much to uncover for a complete understanding of the genetic underpinnings of ID. Genetic variants present in non-coding regions of the genome have been highlighted as potential contributors to neurodevelopmental disorders given their role in regulating gene expression. Nevertheless the functional characterization of non-coding variants remains challenging. We describe the identification and characterization of de novo non-coding variation in 3′UTR regulatory regions within an ID cohort of 50 patients. This cohort was previously screened for structural and coding pathogenic variants via CNV, whole exome and whole genome analysis. We identified 44 high-confidence single nucleotide non-coding variants within the 3′UTR regions of these 50 genomes. Four of these variants were located within predicted miRNA binding sites and were thus hypothesised to have regulatory consequences. Functional testing showed that two of the variants interfered with miRNA-mediated regulation of their target genes, AMD1 and FAIM. Both these variants were found in the same individual and their functional consequences may point to a potential role for such variants in intellectual disability.

Abstract

Understanding the genetic factors underlying neurodevelopmental and neuropsychiatric disorders is a major challenge given their prevalence and potential severity for quality of life. While large-scale genomic screens have made major advances in this area, for many disorders the genetic underpinnings are complex and poorly understood. To date the field has focused predominantly on protein coding variation, but given the importance of tightly controlled gene expression for normal brain development and disorder, variation that affects non-coding regulatory regions of the genome is likely to play an important role in these phenotypes. Herein we show the importance of 3 prime untranslated region (3'UTR) non-coding regulatory variants across neurodevelopmental and neuropsychiatric disorders. We devised a pipeline for identifying and functionally validating putatively pathogenic variants from next generation sequencing (NGS) data. We applied this pipeline to a cohort of children with severe specific language impairment (SLI) and identified a functional, SLI-associated variant affecting gene regulation in cells and post-mortem human brain. This variant and the affected gene (ARHGEF39) represent new putative risk factors for SLI. Furthermore, we identified 3′UTR regulatory variants across autism, schizophrenia and bipolar disorder NGS cohorts demonstrating their impact on neurodevelopmental and neuropsychiatric disorders. Our findings show the importance of investigating non-coding regulatory variants when determining risk factors contributing to neurodevelopmental and neuropsychiatric disorders. In the future, integration of such regulatory variation with protein coding changes will be essential for uncovering the genetic causes of complex neurological disorders and the fundamental mechanisms underlying health and disease

Abstract

One of the first steps infants take in learning their native language is to discover its set of speech-sound categories. This early development is shown when infants begin to lose the ability to differentiate some of the speech sounds their language does not use, while retaining or improving discrimination of language-relevant sounds. However, this aspect of early phonological tuning is not sufficient for language learning. Children must also discover which of the phonetic cues that are used in their language serve to signal lexical distinctions. Phonetic variation that is readily discriminable to all children may indicate two different words in one language but only one word in another. Here, we provide evidence that the language background of 1.5-year-olds affects their interpretation of phonetic variation in word learning, and we show that young children interpret salient phonetic variation in language-specific ways. Three experiments with a total of 104 children compared Dutch- and English-learning 18-month-olds' responses to novel words varying in vowel duration or vowel quality. Dutch learners interpreted vowel duration as lexically contrastive, but English learners did not, in keeping with properties of Dutch and English. Both groups performed equivalently when differentiating words varying in vowel quality. Thus, at one and a half years, children's phonological knowledge already guides their interpretation of salient phonetic variation. We argue that early phonological learning is not just a matter of maintaining the ability to distinguish language-relevant phonetic cues. Learning also requires phonological interpretation at appropriate levels of linguistic analysis.