Publications

Abstract

The primary aim of this paper is to assess patterns of morphological variation in the mandible to investigate changes during the last 500 years in the Netherlands. Three-dimensional geometric morphometrics is used on data collected from adults from three populations living in the Netherlands during three time-periods. Two of these samples come from Dutch archaeological sites (Alkmaar, 1484-1574, n = 37; and Middenbeemster, 1829-1866, n = 51) and were digitized using a 3D laser scanner. The third is a modern sample obtained from MRI scans of 34 modern Dutch individuals. Differences between mandibles are dominated by size. Significant differences in size are found among samples, with on average, males from Alkmaar having the largest mandibles and females from Middenbeemster having the smallest. The results are possibly linked to a softening of the diet, due to a combination of differences in food types and food processing that occurred between these time-periods. Differences in shape are most noticeable between males from Alkmaar and Middenbeemster. Shape differences between males and females are concentrated in the symphysis and ramus, which is mostly the consequence of sexual dimorphism. The relevance of this research is a better understanding of the anatomical variation of the mandible that can occur over an evolutionarily short time, as well as supporting research that has shown plasticity of the mandibular form related to diet and food processing. This plasticity of form must be taken into account in phylogenetic research and when the mandible is used in sex estimation of skeletons.

Abstract

The acquisition of literacy has a profound impact on the functional specialization and lateralization of the visual cortex. Due to the overall lateralization of the language network, specialization for printed words develops in the left occipitotemporal cortex, allegedly inducing a secondary shift of visual face processing to the right, in literate as compared to illiterate subjects. Applying the same logic to the acquisition of high-level musical literacy, we predicted that, in musicians as compared to non-musicians, occipitotemporal activations should show a leftward shift for music reading, and an additional rightward push for face perception. To test these predictions, professional musicians and non-musicians viewed pictures of musical notation, faces, words, tools and houses in the MRI, and laterality was assessed in the ventral stream combining ROI and voxel-based approaches. The results supported both predictions, and allowed to locate the leftward shift to the inferior temporal gyrus and the rightward shift to the fusiform cortex. Moreover, these laterality shifts generalized to categories other than music and faces. Finally, correlation measures across subjects did not support a causal link between the leftward and rightward shifts. Thus the acquisition of an additional perceptual expertise extensively modifies the laterality pattern in the visual system

Abstract

This study explores how adults and children describe placement events (e.g., putting a book on a table) in a range of different languages (Finnish, English, German, Russian, Hindi, Tzeltal Maya, Spanish, and Turkish). Results show that the eight languages grammatically encode placement events in two main ways (Talmy, 1985, 1991), but further investigation reveals fine-grained crosslinguistic variation within each of the two groups. Children are sensitive to these finer-grained characteristics of the input language at an early age, but only when such features are perceptually salient. Our study demonstrates that a unitary notion of 'event' does not suffice to characterize complex but systematic patterns of event encoding crosslinguistically, and that children are sensitive to multiple influences, including the distributional properties of the target language, in constructing these patterns in their own speech.

Abstract

Reprinted from: Bowerman, M. (1990). Mapping thematic roles onto syntactic functions: Are children helped by innate linking rules? Linguistics, 28, 1253-1289.

Abstract

Reprinted from Bowerman, M. (1973). Structural relationships in children's utterances: Semantic or syntactic? In T. Moore (Ed.), Cognitive development and the acquisition of language (pp. 197 213). New York: Academic Press

Abstract

Aim

To examine the phenomenology of stuttering across the lifespan in the largest prospective cohort to date.
Method

Participants aged 7 years and older with a history of developmental stuttering were recruited. Self-reported phenotypic data were collected online including stuttering symptomatology, co-occurring phenotypes, genetic predisposition, factors associated with stuttering severity, and impact on anxiety, education, and employment.
Results

A total of 987 participants (852 adults: 590 males, 262 females, mean age 49 years [SD = 17 years 10 months; range = 18–93 years] and 135 children: 97 males, 38 females, mean age 11 years 4 months [SD = 3 years; range = 7–17 years]) were recruited. Stuttering onset occurred at age 3 to 6 years in 64.0%. Blocking (73.2%) was the most frequent phenotype; 75.9% had sought stuttering therapy and 15.5% identified as having recovered. Half (49.9%) reported a family history. There was a significant negative correlation with age for both stuttering frequency and severity in adults. Most were anxious due to stuttering (90.4%) and perceived stuttering as a barrier to education and employment outcomes (80.7%).
Interpretation

The frequent persistence of stuttering and the high proportion with a family history suggest that stuttering is a complex trait that does not often resolve, even with therapy. These data provide new insights into the phenotype and prognosis of stuttering, information that is critically needed to encourage the development of more effective speech therapies.

Abstract

Structural priming is a useful laboratory-based technique for investigating how children respond to temporary changes in the distribution of structures in their input. In the current study we investigated whether increasing the number of object relative clauses (RCs) in German-speaking children’s input changes their processing preferences for ambiguous RCs. Fifty-one 6-year-olds and 54 9-year-olds participated in a priming task that (i) gauged their baseline interpretations for ambiguous RC structures, (ii) primed an object-RC interpretation of ambiguous RCs, and (iii) determined whether priming persevered beyond immediate prime-target pairs. The 6-year old children showed no priming effect, whereas the 9-year-old group showed robust priming that was long lasting. Unlike in studies of priming in production, priming did not increase in magnitude when there was lexical overlap between prime and target. Overall, the results suggest that increased exposure to object RCs facilitates children’s interpretation of this otherwise infrequent structure, but only in older children. The implications for acquisition theory are discussed.

Abstract

Subject–verb agreement errors are common in sentence production. Many studies have used experimental paradigms targeting the production of subject–verb agreement from a sentence preamble (The key to the cabinets) and eliciting verb errors (… *were shiny). Through reanalysis of previous data (50 experiments; 102,369 observations), we show that this paradigm also results in many errors in preamble repetition, particularly of local noun number (The key to the *cabinet). We explore the mechanisms of both errors in parallelism in producing syntax (PIPS), a model in the Gradient Symbolic Computation framework. PIPS models sentence production using a continuous-state stochastic dynamical system that optimizes grammatical constraints (shaped by previous experience) over vector representations of symbolic structures. At intermediate stages in the computation, grammatical constraints allow multiple competing parses to be partially activated, resulting in stable but transient conjunctive blend states. In the context of the preamble completion task, memory constraints reduce the strength of the target structure, allowing for co-activation of non-target parses where the local noun controls the verb (notional agreement and locally agreeing relative clauses) and non-target parses that include structural constituents with contrasting number specifications (e.g., plural instead of singular local noun). Simulations of the preamble completion task reveal that these partially activated non-target parses, as well the need to balance accurate encoding of lexical and syntactic aspects of the prompt, result in errors. In other words: Because sentence processing is embedded in a processor with finite memory and prior experience with production, interference from non-target production plans causes errors.

Abstract

Contrast coding in regression models, including mixed-effect models, changes what the terms in the model mean.
In particular, it determines whether or not model terms should be interpreted as main effects. This paper
highlights how opaque descriptions of contrast coding have affected the field of psycholinguistics. We begin with
a reproducible example in R using simulated data to demonstrate how incorrect conclusions can be made from
mixed models; this also serves as a primer on contrast coding for statistical novices. We then present an analysis
of 3384 papers from the field of psycholinguistics that we coded based upon whether a clear description of
contrast coding was present. This analysis demonstrates that the majority of the psycholinguistic literature does
not transparently describe contrast coding choices, posing an important challenge to reproducibility and replicability in our field.

Abstract

Writing is an important way to communicate in everyday life because it can convey information over time and space, but its neural substrates remain poorly known. Although the neural basis of written language production has been investigated in alphabetic scripts, it has rarely been examined in nonalphabetic languages such as Chinese. The present functional magnetic resonance imaging study explored the neural substrates of handwritten word production in Chinese and identified the brain regions sensitive to the psycholinguistic factors of word frequency and syllable frequency. To capture this, we contrasted neural activation in “writing” with “speaking plus drawing” and “watching plus drawing.” Word frequency (high, low) and syllable frequency (high, low) of the picture names were manipulated. Contrasts between the tasks showed that writing Chinese characters was mainly associated with brain activation in the left frontal and parietal cortex, whereas orthographic processing and the motor procedures necessary for handwritten production were also related to activation in the right frontal and parietal cortex as well as right putamen/thalamus. These results demonstrate that writing Chinese characters requires activation in bilateral cortical regions and the right putamen/thalamus. Our results also revealed no brain activation associated with the main effects of word frequency and syllable frequency as well as their interaction, which implies that word frequency and syllable frequency may not affect the writing of Chinese characters on a neural level.

Abstract

The current work uses memory errors to examine the mental representation of verb-particle constructions (VPCs; e.g., make up the story, cut up the meat). Some evidence suggests that VPCs are represented by a cline in which the relationship between the VPC and its component elements ranges from highly transparent (cut up) to highly idiosyncratic (make up). Other evidence supports a multiple class representation, characterizing VPCs as belonging to discretely separated classes differing in semantic and syntactic structure. We outline a novel paradigm to investigate the representation of VPCs in which we elicit illusory conjunctions, or memory errors sensitive to syntactic structure. We then use a novel application of piecewise regression to demonstrate that the resulting error pattern follows a cline rather than discrete classes. A preregistered replication verifies these findings, and a final preregistered study verifies that these errors reflect syntactic structure. This provides evidence for gradient rather than discrete representations across levels of representation in language processing.

Abstract

Interference in picture naming occurs from representing a partner's preparations to speak (Gambi, van de Cavey, & Pickering, 2015). We tested the origins of this interference using a simple non-communicative joint naming task based on Gambi et al. (2015), where response latencies indexed interference from partner task and partner speech content, and eye fixations to partner objects indexed overt attention. Experiment 1 contrasted a partner-present condition with a control partner-absent condition to establish the role of the partner in eliciting interference. For latencies, we observed interference from the partner's task and speech content, with interference increasing due to partner task in the partner-present condition. Eye-tracking measures showed that interference in naming was not due to overt attention to partner stimuli but to broad expectations about likely utterances. Experiment 2 examined whether an equivalent non-verbal task also elicited interference, as predicted from a language as joint action framework. We replicated the finding of interference due to partner task and again found no relationship between overt attention and interference. These results support Gambi et al. (2015). Individuals co-represent a partner's task while speaking, and doing so does not require overt attention to partner stimuli.

Abstract

In work on grammatical agreement in sentence production, there are accounts of verb number formulation that emphasise the role of whole-structure properties and accounts that emphasise the role of word-driven properties. To evaluate these alternatives, we carried out two experiments that examined a referential (wholistic) contributor to agreement along with two lexical-semantic (local) factors. Both experiments gauged the accuracy and latency of inflected-verb production in order to assess how variations in grammatical number interacted with the other factors. The accuracy of verb production was modulated both by the referential effect of notional number and by the lexical-semantic effects of relatedness and category membership. As an index of agreement difficulty, latencies were little affected by either factor. The findings suggest that agreement is sensitive to referential as well as lexical forces and highlight the importance of lexical-structural integration in the process of sentence production.

Abstract

Existing work shows that readers often interpret grammatical errors (e.g., The key to the cabinets *were shiny) and sentence-level blends (“without-blend”: Claudia left without her headphones *off) in a non-literal fashion, inferring that a more frequent or more canonical utterance was intended instead. This work examines how interlocutor identity affects the processing and interpretation of anomalous sentences. We presented anomalies in the context of “emails” attributed to various writers in a self-paced reading paradigm and used comprehension questions to probe how sentence interpretation changed based upon properties of the item and properties of the “speaker.” Experiment 1 compared standardised American English speakers to L2 English speakers; Experiment 2 compared the same standardised English speakers to speakers of a non-Standardised American English dialect. Agreement errors and without-blends both led to more non-literal responses than comparable canonical items. For agreement errors, more non-literal interpretations also occurred when sentences were attributed to speakers of Standardised American English than either non-Standardised group. These data suggest that understanding sentences relies on expectations and heuristics about which utterances are likely. These are based upon experience with language, with speaker-specific differences, and upon more general cognitive biases.

Abstract

Computation in neuronal assemblies is putatively reflected in the excitatory and inhibitory cycles of activation distributed throughout the brain. In speech and language processing, coordination of these cycles resulting in phase synchronization has been argued to reflect the integration of information on different timescales (e.g. segmenting acoustics signals to phonemic and syllabic representations; (Giraud and Poeppel 2012 Nat. Neurosci.15, 511 (doi:10.1038/nn.3063)). A natural extension of this claim is that phase synchronization functions similarly to support the inference of more abstract higher-level linguistic structures (Martin 2016 Front. Psychol.7, 120; Martin and Doumas 2017 PLoS Biol. 15, e2000663 (doi:10.1371/journal.pbio.2000663); Martin and Doumas. 2019 Curr. Opin. Behav. Sci.29, 77–83 (doi:10.1016/j.cobeha.2019.04.008)). Hale et al. (Hale et al. 2018 Finding syntax in human encephalography with beam search. arXiv 1806.04127 (http://arxiv.org/abs/1806.04127)) showed that syntactically driven parsing decisions predict electroencephalography (EEG) responses in the time domain; here we ask whether phase synchronization in the form of either inter-trial phrase coherence or cross-frequency coupling (CFC) between high-frequency (i.e. gamma) bursts and lower-frequency carrier signals (i.e. delta, theta), changes as the linguistic structures of compositional meaning (viz., bracket completions, as denoted by the onset of words that complete phrases) accrue. We use a naturalistic story-listening EEG dataset from Hale et al. to assess the relationship between linguistic structure and phase alignment. We observe increased phase synchronization as a function of phrase counts in the delta, theta, and gamma bands, especially for function words. A more complex pattern emerged for CFC as phrase count changed, possibly related to the lack of a one-to-one mapping between ‘size’ of linguistic structure and frequency band—an assumption that is tacit in recent frameworks. These results emphasize the important role that phase synchronization, desynchronization, and thus, inhibition, play in the construction of compositional meaning by distributed neural networks in the brain.

Abstract

Within the ISLE Metadata Initiative (IMDI) project a user-friendly editor to enter metadata descriptions and a browser operating on the linked metadata descriptions were developed. Both tools support the usage of Controlled Vocabulary (CV) repositories by means of the specification of an URL where the formal CV definition data is available.

Abstract

The recent increase in the number and complexity of the language resources available on the Internet is followed by a similar increase of available tools for linguistic analysis. Ideally the user does not need to be confronted with the question in how to match tools with resources. If resource repositories and tool repositories offer adequate metadata information and a suitable exchange protocol is developed this matching process could be performed (semi-) automatically.

Abstract

Native speakers of Dutch with English as a second language and native speakers of English participated in an English lexical decision experiment. Phonemes in real words were replaced by others from which they are hard to distinguish for Dutch listeners. Non-native listeners judged the resulting near-words more often as a word than native listeners. This not only happened when the phonemes that were exchanged did not exist as separate phonemes in the native language Dutch, but also when phoneme pairs that do exist in Dutch were used in word-final position, where they are not distinctive in Dutch. In an English bimodal priming experiment with similar groups of participants, word pairs were used which differed in one phoneme. These phonemes were hard to distinguish for the non-native listeners. Whereas in native listening both words inhibited each other, in non-native listening presentation of one word led to unresolved competition between both words. The results suggest that inaccurate phoneme processing by non-native listeners leads to the activation of spurious lexical competitors.

Abstract

Human brain structure changes throughout the lifespan. Altered brain growth or rates of decline are implicated in a vast range of psychiatric, developmental and neurodegenerative diseases. In this study, we identified common genetic variants that affect rates of brain growth or atrophy in what is, to our knowledge, the first genome-wide association meta-analysis of changes in brain morphology across the lifespan. Longitudinal magnetic resonance imaging data from 15,640 individuals were used to compute rates of change for 15 brain structures. The most robustly identified genes GPR139, DACH1 and APOE are associated with metabolic processes. We demonstrate global genetic overlap with depression, schizophrenia, cognitive functioning, insomnia, height, body mass index and smoking. Gene set findings implicate both early brain development and neurodegenerative processes in the rates of brain changes. Identifying variants involved in structural brain changes may help to determine biological pathways underlying optimal and dysfunctional brain development and aging.

Abstract

This study examined whether song lyrics and their semantic meaning interfere with speech intelligibility. In three experiments, a total of 108 native Dutch participants listened to Dutch target sentences in the presence of three versions of the pop songs Last Friday Night (T.G.I.F.) (Experiment 1) or Hot N Cold (Experiment 2a and 2b) by singer Katy Perry at different signal-to-noise ratios. The versions consisted of the original English songs, the karaoke versions of the songs without lyrics, and anomalous versions of the songs in the fictional language Simlish, which was created for the video game The Sims. The songs were played in chronological (Experiments 1 and 2a) or in random order (Experiment 2b). Participants’ task was to type the target sentence they had heard. In all experiments, speech intelligibility was better in nonlyrical (karaoke) than lyrical music (English and Simlish). In addition, listeners performed better in lyrics without semantic meaning (Simlish) than with semantic meaning (English). Finally, speech intelligibility was better when the song in the background was played in chronological rather than in random order. These findings aid in understanding the mechanisms involved during speech-in-music intelligibility.

Abstract

In this paper presents evidence of the disputed existence of an electrophysiological marker for the lexical-categorical distinction between open- and closed-class words. Event-related brain potentials were recorded from the scalp while subjects read a story. Separate waveforms were computed for open- and closed-class words. Two aspects of the waveforms could be reliably related to vocabulary class. The first was an early negativity in the 230- to 350-msec epoch, with a bilateral anterior predominance. This negativity was elicited by open- and closed-class words alike, was not affected by word frequency or word length, and had an earlier peak latency for closed-class words. The second was a frontal slow negative shift in the 350- to 500-msec epoch, largest over the left side of the scalp. This late negativity was only elicited by closed-class words. Although the early negativity cannot serve as a qualitative marker of the open- and closed-class distinction, it does reflect the earliest electrophysiological manifestation of the availability of categorical information from the mental lexicon. These results suggest that the brain honors the distinction between open- and closed-class words, in relation to the different roles that they play in on-line sentence processing.

Abstract

In reaction to the dominance of universalism in the 1970s and '80s, there have recently been a number of reappraisals of the relation between language and cognition, and the field of cognitive anthropology is flourishing in several new directions in both America and Europe. This is partly due to a renewal and re-evaluation of approaches to the question of linguistic relativity associated with Whorf, and partly to the inspiration of modern developments in cognitive science. This review briefly sketches the history of cognitive anthropology and surveys current research on both sides of the Atlantic. The focus is on assessing current directions, considering in particular, by way of illustration, recent work in cultural models and on spatial language and cognition. The review concludes with an assessment of how cognitive anthropology could contribute directly both to the broader project of cognitive science and to the anthropological study of how cultural ideas and practices relate to structures and processes of human cognition.

Abstract

In a famous paper Harvey Sacks (1974) argued that the sequential properties of greeting conventions, as well as those governing the flow of information, mean that 'everyone has to lie'. In this paper I show this dictum to be equally true in the Tzeltal Mayan community of Tenejapa, in southern Mexico, but for somewhat different reasons. The phenomenon of interest is the practice of routine fearsome threats to small children. Based on a longitudinal corpus of videotaped and tape-recorded naturally-occurring interaction between caregivers and children in five Tzeltal families, the study examines sequences of Tzeltal caregivers' speech aimed at controlling the children's behaviour and analyzes the children's developing pragmatic skills in handling such controlling utterances, from prelinguistic infants to age five and over. Infants in this society are considered to be vulnerable, easily scared or shocked into losing their 'souls', and therefore at all costs to be protected and hidden from outsiders and other dangers. Nonetheless, the chief form of control (aside from physically removing a child from danger) is to threaten, saying things like "Don't do that, or I'll take you to the clinic for an injection," These overt scare-threats - rarely actually realized - lead Tzeltal children by the age of 2;6 to 3;0 to the understanding that speech does not necessarily convey true propositions, and to a sensitivity to the underlying motivations for utterances distinct from their literal meaning. By age 4;0 children perform the same role to their younger siblings;they also begin to use more subtle non-true (e.g. ironic) utterances. The caretaker practice described here is related to adult norms of social lying, to the sociocultural context of constraints on information flow, social control through gossip, and the different notion of 'truth' that arises in the context of non-verifiability characteristic of a small-scale nonliterate society.

Abstract

This paper surveys the concept of culture as used in recent work in cognitive science, assessing the very different (and sometimes minimal) role 'culture' plays in different branches and schools of linguistics: generative approaches, descriptive/comparative linguistics, typology, cognitive linguistics, semantics, pragmatics, psycholinguistics, linguistic and cognitive anthropology. The paper then describes research on one specific topic, spatial language and conceptualization, describes a methodology for studying it cross-linguistically and cross-culturally. Finally, it considers the implications of results in this area for how we can fruitfully conceptualize 'culture', arguing for an approach which shifts back and forth between individual mind and collective representations, between universals and particulars, and ties 'culture' to our biological roots.

Abstract

This is an encyclopedia entry describing conversational and interactional uses of linguistic repetition.

Abstract

This article selectively reviews the literature on politeness across different disciplines—linguistics, anthropology, communications, conversation analysis, social psychology, and sociology—and critically assesses how both theoretical approaches to politeness and research on linguistic politeness phenomena have evolved over the past forty years. Major new developments include a shift from predominantly linguistic approaches to those examining politeness and impoliteness as processes that are embedded and negotiated in interactional and cultural contexts, as well as a greater focus on how both politeness and interactional confrontation and conflict fit into our developing understanding of human cooperation and universal aspects of human social interaction.

Abstract

This article is a reprint of chapter 1, the introduction to Brown and Levinson, 1987, Politeness: Some universals in language usage (Cambridge University Press).

Abstract

Speech input causes listeners to activate multiple
candidate words which then compete with one
another. These include onset competitors, that share a
beginning (bumper, butter), but also, counterintuitively,
rhyme competitors, sharing an ending
(bumper, jumper). In L1, competition is typically
stronger for onset than for rhyme. In L2, onset
competition has been attested but rhyme competition
has heretofore remained largely unexamined. We
assessed L1 (Dutch) and L2 (English) word
recognition by the same late-bilingual individuals. In
each language, eye gaze was recorded as listeners
heard sentences and viewed sets of drawings: three
unrelated, one depicting an onset or rhyme competitor
of a word in the input. Activation patterns revealed
substantial onset competition but no significant
rhyme competition in either L1 or L2. Rhyme
competition may thus be a “luxury” feature of
maximally efficient listening, to be abandoned when
resources are scarcer, as in listening by late
bilinguals, in either language.

Abstract

In lexical stress languages, phonemically identical syllables can differ suprasegmentally (in duration, amplitude, F0). Such stress
cues allow listeners to speed spoken-word recognition by rejecting mismatching competitors (e.g., unstressed set- in settee
rules out stressed set- in setting, setter, settle). Such processing effects have indeed been observed in Spanish, Dutch and German, but English listeners are known to largely ignore stress cues. Dutch and German listeners even outdo English listeners in distinguishing stressed versus unstressed English syllables. This has been attributed to the relative frequency across the stress languages of unstressed syllables with full vowels; in English most unstressed syllables contain schwa, instead, and stress cues on full vowels are thus least often informative in this language. If only informativeness matters, would English listeners who encounter situations where such cues would pay off for them (e.g., learning one of those other stress languages) then shift to using stress cues? Likewise, would stress cue users with English as L2, if mainly using English, shift away from
using the cues in English? Here we report tests of these two questions, with each receiving a yes answer. We propose that
English listeners’ disregard of stress cues is purely pragmatic.

Abstract

For multimodal annotations an exhaustive encoding system for gestures was developed to facilitate research. The structural requirements of multimodal annotations were analyzed to develop an Abstract Corpus Model which is the basis for a powerful annotation and exploitation tool for multimedia recordings and the definition of the XML-based EUDICO Annotation Format. Finally, a metadata-based data management environment has been setup to facilitate resource discovery and especially corpus management. Bt means of an appropriate digitization policy and their online availability researchers have been able to build up a large corpus covering gesture and sign language data.

Abstract

Producing lexical stress leads to visible changes on the face, such as longer duration and greater size of the opening of the mouth. Research suggests that these visual cues alone can inform participants about which syllable carries stress (i.e., lip-reading silent videos). This study aims to determine the influence of visual articulatory cues on lexical stress perception in more naturalistic audiovisual settings. Participants were presented with seven disyllabic, Dutch minimal stress pairs (e.g., VOORnaam [first name] & voorNAAM [respectable]) in audio-only (phonetic lexical stress continua without video), video-only (lip-reading silent videos), and audiovisual trials (e.g., phonetic lexical stress continua with video of talker saying VOORnaam or voorNAAM). Categorization data from video-only trials revealed that participants could distinguish the minimal pairs above chance from seeing the silent videos alone. However, responses in the audiovisual condition did not differ from the audio-only condition. We thus conclude that visual lexical stress information on the face, while clearly perceivable, does not play a major role in audiovisual speech perception. This study demonstrates that clear unimodal effects do not always generalize to more naturalistic multimodal communication, advocating that speech prosody is best considered in multimodal settings.

Abstract

Background

Neurocognitive models of language processing highlight the role of the left inferior frontal gyrus (IFG) in the functional network underlying language. Furthermore, neuroscience research has shown that IFG is not a uniform region anatomically, cytoarchitectonically or functionally. However, no previous study explored the language-related functional connectivity patterns of IFG subdivisions using a meta-analytic connectivity modeling (MACM) approach.
Purpose

The present MACM study aimed to identify language-related coactivation patterns of the left and right IFG subdivisions.
Method

Six regions of interest (ROIs) were defined using a probabilistic brain atlas corresponding to pars opercularis, pars triangularis and pars orbitalis of IFG in both hemispheres. The ROIs were used to search the BrainMap functional database to identify neuroimaging experiments with healthy, right-handed participants reporting language-related activations in each ROI. Activation likelihood estimation analyses were then performed on the foci extracted from the identified studies to compute functional convergence for each ROI, which was also contrasted with the other ROIs within the same hemisphere.
Results

A primarily left-lateralized functional network was revealed for the left and right IFG subdivisions. The left-hemispheric ROIs exhibited more robust coactivation than the right-hemispheric ROIs. Particularly, the left pars opercularis was associated with the most extensive coactivation pattern involving bilateral frontal, bilateral parietal, left temporal, left subcortical, and right cerebellar regions, while the left pars triangularis and orbitalis revealed a predominantly left-lateralized involvement of frontotemporal regions.
Conclusion

The findings align with the neurocognitive models of language processing that propose a division of labor among the left IFG subdivisions and their respective functional networks. Also, the opercular part of left IFG stands out as a major hub in the language network with connections to diverse cortical, subcortical and cerebellar structures.

Abstract

Background

Morphemes are the smallest building blocks of language that convey meaning or function. A controversial issue in psycho- and neurolinguistics is whether morphologically complex words consisting of multiple morphemes are processed in a combinatorial manner and, if so, which brain regions underlie this process. Relatively less is known about the neural underpinnings of morphological processing compared to other aspects of grammatical competence such as syntax.

Purpose
The present study aimed to shed light on the neural correlates of morphological processing by examining functional convergence for inflectional morphology reported in previous neuroimaging studies.

Method
A systematic literature search was performed on PubMed with search terms related to morphological complexity and neuroimaging. 16 studies (279 subjects) comparing regular inflection with stems or irregular inflection met the inclusion and exclusion criteria and were subjected to a series of activation likelihood estimation meta-analyses.

Results
Significant functional convergence was found in several mainly left frontal regions for processing inflectional morphology. Specifically, the left inferior frontal gyrus (LIFG) was found to be consistently involved in morphological complexity. Diagnostic analyses revealed that involvement of posterior LIFG was robust against potential publication bias and over-influence of individual studies. Furthermore, LIFG involvement was maintained in meta-analyses of subsets of experiments that matched phonological complexity between conditions, although diagnostic analyses suggested that this conclusion may be premature.

Conclusion
The findings provide evidence for combinatorial processing of morphologically complex words and inform psycholinguistic accounts of complex word processing. Furthermore, they highlight the role of LIFG in processing inflectional morphology, in addition to syntactic processing as has been emphasized in previous research. In particular, posterior LIFG seems to underlie grammatical functions encompassing inflectional morphology and syntax.

Abstract

Lexically guided perceptual learni ng refers to the use of lexical knowledge to retune sp eech categories and thereby adapt to a novel talker’s pronunciation. This adaptation has been extensively documented, but primarily for segmental-based learning in English and Dutch. In languages with lexical tone, such as Mandarin Chinese, tonal categories can also be retuned in this way, but segmental category retuning had not been studied. We report two experiment s in which Mandarin Chinese listeners were exposed to an ambiguous mixture of [f] and [s] in lexical contexts favoring an interpretation as either [f] or [s]. Listeners were subsequently more likely to identify sounds along a continuum between [f] and [s], and to interpret minimal word pairs, in a manner consistent with this exposure. Thus lexically guided perceptual learning of segmental categories had indeed taken place, consistent with suggestions that such learning may be a universally available adaptation process

Abstract

Do all humans perceive, think, and talk about tree cover ("forests") in more or less the same way? International forestry programs frequently seem to operate on the assumption that they do. However, recent advances in the language sciences show that languages vary greatly as to how the landscape domain is lexicalized and grammaticalized. Different languages segment and label the large-scale environment and its features according to astonishingly different semantic principles, often in tandem with highly culture-specific practices and ideologies. Presumed basic concepts like mountain, valley, and river cannot in fact be straightforwardly translated across languages. In this paper we describe, compare, and evaluate some of the semantic diversity observed in relation to forests. We do so on the basis of first-hand linguistic field data from a global sample of indigenous categorization systems as they are manifested in the following languages: Avatime (Ghana), Duna (Papua New Guinea), Jahai (Malay Peninsula), Lokono (the Guianas), Makalero (East Timor), and Umpila/Kuuku Ya'u (Cape York Peninsula). We show that basic linguistic categories relating to tree cover vary considerably in their principles of semantic encoding across languages, and that forest is a challenging category from the point of view of intercultural translatability. This has consequences for current global policies and programs aimed at standardizing forest definitions and measurements. It calls for greater attention to categorial diversity in designing and implementing such agendas, and for receptiveness to and understanding of local indigenous classification systems in communicating those agendas on the ground.

Abstract

The human brain can process facial expressions of emotions rapidly and without awareness. Several studies in patients with damage to their primary visual cortices have shown that they may be able to guess the emotional expression on a face despite their cortical blindness. This non-conscious processing, called affective blindsight, may arise through an intact subcortical visual route that leads from the superior colliculus to the pulvinar, and thence to the amygdala. This pathway is thought to process the crude visual information conveyed by the low spatial frequencies of the stimuli.

In order to investigate whether this is the case, we studied a patient (TN) with bilateral cortical blindness and affective blindsight. An fMRI paradigm was performed in which fearful and neutral expressions were presented using faces that were either unfiltered, or filtered to remove high or low spatial frequencies. Unfiltered fearful faces produced right amygdala activation although the patient was unaware of the presence of the stimuli. More importantly, the low spatial frequency components of fearful faces continued to produce right amygdala activity while the high spatial frequency components did not. Our findings thus confirm that the visual information present in the low spatial frequencies is sufficient to produce affective blindsight, further suggesting that its existence could rely on the subcortical colliculo-pulvino-amygdalar pathway.

Abstract

Infant research is often underpowered, undermining the robustness and replicability of our findings. Improving the reliability of infant studies offers a solution for increasing statistical power independent of sample size. Here, we discuss two senses of the term reliability in the context of infant research: reliable (large) effects and reliable measures. We examine the circumstances under which effects are strongest and measures are most reliable and use synthetic datasets to illustrate the relationship between effect size, measurement reliability, and statistical power. We then present six concrete solutions for more reliable infant research: (a) routinely estimating and reporting the effect size and measurement reliability of infant tasks, (b) selecting the best measurement tool, (c) developing better infant paradigms, (d) collecting more data points per infant, (e) excluding unreliable data from the analysis, and (f) conducting more sophisticated data analyses. Deeper consideration of measurement in infant research will improve our ability to study infant development.

Abstract

Cross-signing—the emergence of an interlanguage between users of different sign languages—offers a rare chance to examine the evolution of a natural communication system in real time. To provide an insight into this process, we analyse an annotated video corpus of 340 minutes of interaction between signers of different language backgrounds on their first meeting and after living with each other for several weeks. We focus on the evolution of shared color terms and examine the role of different selectional pressures, including frequency, content, coordination and interactional context. We show that attentional factors in interaction play a crucial role. This suggests that understanding meta-communication is critical for explaining the cultural evolution of linguistic systems.

Abstract

Background: Identifying age-related changes in cognition that contribute towards reduced driving performance is important for the development of interventions to improve older adults' driving and prolong the time that they can continue to drive. While driving, one is often required to switch from attending to events changing in time, to distribute attention spatially. Although there is extensive research into both spatial attention and temporal attention and how these change with age, the literature on switching between these modalities of attention is limited within any age group. Methods: Age groups (21-30, 40-49, 50-59, 60-69 and 70+ years) were compared on their ability to switch between detecting a target in a rapid serial visual presentation (RSVP) stream and detecting a target in a visual search display. To manipulate the cost of switching, the target in the RSVP stream was either the first item in the stream (Target 1st), towards the end of the stream (Target Mid), or absent from the stream (Distractor Only). Visual search response times and accuracy were recorded. Target 1st trials behaved as no-switch trials, as attending to the remaining stream was not necessary. Target Mid and Distractor Only trials behaved as switch trials, as attending to the stream to the end was required. Results: Visual search response times (RTs) were longer on "Target Mid" and "Distractor Only" trials in comparison to "Target 1st" trials, reflecting switch-costs. Larger switch-costs were found in both the 40-49 and 60-69 years group in comparison to the 21-30 years group when switching from the Target Mid condition. Discussion: Findings warrant further exploration as to whether there are age-related changes in the ability to switch between these modalities of attention while driving. If older adults display poor performance when switching between temporal and spatial attention while driving, then the development of an intervention to preserve and improve this ability would be beneficial. © 2017 Callaghan, Holland and Kessler.

Abstract

Decreases in oscillatory alpha- and beta-band power have been consistently found in spoken-word production. These have been linked to both motor preparation and conceptual-lexical retrieval processes. However, the observed power decreases have a broad frequency range that spans two “classic” (sensorimotor) bands: alpha and beta. It remains unclear whether alpha- and beta-band power decreases contribute independently when a spoken word is planned. Using a re-analysis of existing magnetoencephalography data, we probed whether the effects in alpha and beta bands are spatially distinct. Participants read a sentence that was either constraining or non-constraining toward the final word, which was presented as a picture. In separate blocks participants had to name the picture or score its predictability via button press. Irregular-resampling auto-spectral analysis (IRASA) was used to isolate the oscillatory activity in the alpha and beta bands from the background 1-over-f spectrum. The sources of alpha- and beta-band oscillations were localized based on the participants’ individualized peak frequencies. For both tasks, alpha- and beta-power decreases overlapped in left posterior temporal and inferior parietal cortex, regions that have previously been associated with conceptual and lexical processes. The spatial distributions of the alpha and beta power effects were spatially similar in these regions to the extent we could assess it. By contrast, for left frontal regions, the spatial distributions differed between alpha and beta effects. Our results suggest that for conceptual-lexical retrieval, alpha and beta oscillations do not dissociate spatially and, thus, are distinct from the classical sensorimotor alpha and beta oscillations.

Abstract

Language production involves a complex set of computations, from conceptualization to articulation, which are thought to engage cascading neural events in the language network. However, recent neuromagnetic evidence suggests simultaneous meaning-to-speech mapping in picture naming tasks, as indexed by early parallel activation of frontotemporal regions to lexical semantic, phonological, and articulatory information. Here we investigate the time course of word production, asking to what extent such “earliness” is a distinctive property of the associated spatiotemporal dynamics. Using MEG, we recorded the neural signals of 34 human subjects (26 males) overtly naming 134 images from four semantic object categories (animals, foods, tools, clothes). Within each category, we covaried word length, as quantified by the number of syllables contained in a word, and phonological neighborhood density to target lexical and post-lexical phonological/phonetic processes. Multivariate pattern analyses searchlights in sensor space distinguished the stimulus-locked spatiotemporal responses to object categories early on, from 150 to 250 ms after picture onset, whereas word length was decoded in left frontotemporal sensors at 250-350 ms, followed by the latency of phonological neighborhood density (350-450 ms). Our results suggest a progression of neural activity from posterior to anterior language regions for the semantic and phonological/phonetic computations preparing overt speech, thus supporting serial cascading models of word production

Abstract

Language comprehension engages a distributed network of frontotemporal, parietal, and sensorimotor regions, but it is still unclear how meaning of words and their semantic relationships are represented and processed within these regions and to which degrees lexico-semantic representations differ between regions and semantic types. We used fMRI and representational similarity analysis to relate word-elicited multivoxel patterns to semantic similarity between action and object words. In left inferior frontal (BA 44-45-47), left posterior middle temporal and left precentral cortex, the similarity of brain response patterns reflected semantic similarity among action-related verbs, as well as across lexical classes-between action verbs and tool-related nouns and, to a degree, between action verbs and food nouns, but not between action verbs and animal nouns. Instead, posterior inferior temporal cortex exhibited a reverse response pattern, which reflected the semantic similarity among object-related nouns, but not action-related words. These results show that semantic similarity is encoded by a range of cortical areas, including multimodal association (e.g., anterior inferior frontal, posterior middle temporal) and modality-preferential (premotor) cortex and that the representational geometries in these regions are partly dependent on semantic type, with semantic similarity among action-related words crossing lexical-semantic category boundaries.

Abstract

Dyslexia is a common specific learning disability with a substantive genetic component. Several candidate genes have been proposed to be implicated in dyslexia susceptibility, such as DYX1C1, ROBO1, KIAA0319, and DCDC2. Associations with variants in these genes have also been reported with a variety of psychometric measures tapping into the underlying processes that might be impaired in dyslexic people. In this study, we first conducted a literature review to select single nucleotide polymorphisms (SNPs) in dyslexia candidate genes that had been repeatedly implicated across studies. We then assessed the SNPs for association in the richly phenotyped longitudinal data set from the Dutch Dyslexia Program. We tested for association with several quantitative traits, including word and nonword reading fluency, rapid naming, phoneme deletion, and nonword repetition. In this, we took advantage of the longitudinal nature of the sample to examine if associations were stable across four educational time-points (from 7 to 12 years). Two SNPs in the KIAA0319 gene were nominally associated with rapid naming, and these associations were stable across different ages. Genetic association analysis with complex cognitive traits can be enriched through the use of longitudinal information on trait development.

Abstract

Most people have left‐hemisphere dominance for various aspects of language processing, but only roughly 1% of the adult population has atypically reversed, rightward hemispheric language dominance (RHLD). The genetic‐developmental program that underlies leftward language laterality is unknown, as are the causes of atypical variation. We performed an exploratory whole‐genome‐sequencing study, with the hypothesis that strongly penetrant, rare genetic mutations might sometimes be involved in RHLD. This was by analogy with situs inversus of the visceral organs (left‐right mirror reversal of the heart, lungs and so on), which is sometimes due to monogenic mutations. The genomes of 33 subjects with RHLD were sequenced and analyzed with reference to large population‐genetic data sets, as well as 34 subjects (14 left‐handed) with typical language laterality. The sample was powered to detect rare, highly penetrant, monogenic effects if they would be present in at least 10 of the 33 RHLD cases and no controls, but no individual genes had mutations in more than five RHLD cases while being un‐mutated in controls. A hypothesis derived from invertebrate mechanisms of left‐right axis formation led to the detection of an increased mutation load, in RHLD subjects, within genes involved with the actin cytoskeleton. The latter finding offers a first, tentative insight into molecular genetic influences on hemispheric language dominance.

Abstract

Linguistic predictions may be generated from and evaluated against a representation of events and referents described in the discourse. Compatible with this idea, recent work shows that predictions about novel noun phrases include their definiteness. In the current follow-up study, we ask whether people engage similar prediction-related processes for definite and indefinite referents. This question is relevant for linguistic theories that imply a processing difference between definite and indefinite noun phrases, typically because definiteness is thought to require a uniquely identifiable referent in the discourse. We addressed this question in an event-related potential (ERP) study (N = 48) with preregistration of data acquisition, preprocessing, and Bayesian analysis. Participants read Dutch mini-stories with a definite or indefinite novel noun phrase (e.g., “het/een huis,” the/a house), wherein (in)definiteness of the article was either expected or unexpected and the noun was always strongly expected. Unexpected articles elicited enhanced N400s, but unexpectedly indefinite articles also elicited a positive ERP effect at frontal channels compared to expectedly indefinite articles. We tentatively link this effect to an antiuniqueness violation, which may force people to introduce a new referent over and above the already anticipated one. Interestingly, expectedly definite nouns elicited larger N400s than unexpectedly definite nouns (replicating a previous surprising finding) and indefinite nouns. Although the exact nature of these noun effects remains unknown, expectedly definite nouns may have triggered the strongest semantic activation because they alone refer to specific and concrete referents. In sum, results from both the articles and nouns clearly demonstrate that definiteness marking has a rapid effect on processing, counter to recent claims regarding definiteness processing.

Abstract

Interoperable annotation formats are fundamental to the utility, expansion, and sustainability of collective data repositories.In language development research, shared annotation schemes have been critical to facilitating the transition from raw acoustic data to searchable, structured corpora. Current schemes typically require comprehensive and manual annotation of utterance boundaries and orthographic speech content, with an additional, optional range of tags of interest. These schemes have been enormously successful for datasets on the scale of dozens of recording hours but are untenable for long-format recording corpora, which routinely contain hundreds to thousands of audio hours. Long-format corpora would benefit greatly from (semi-)automated analyses, both on the earliest steps of annotation—voice activity detection, utterance segmentation, and speaker diarization—as well as later steps—e.g., classification-based codes such as child-vs-adult-directed speech, and speech recognition to produce phonetic/orthographic representations. We present an annotation workflow specifically designed for long-format corpora which can be tailored by individual researchers and which interfaces with the current dominant scheme for short-format recordings. The workflow allows semi-automated annotation and analyses at higher linguistic levels. We give one example of how the workflow has been successfully implemented in a large cross-database project.

Abstract

Recent years have seen rapid technological development of devices that can record communicative behavior as participants go about daily life. This paper is intended as an end-to-end methodological guidebook for potential users of these technologies, including researchers who want to study children’s or adults’ communicative behavior in everyday contexts. We explain how long-format speech environment (LFSE) recordings provide a unique view on language use and how they can be used to complement other measures at the individual and group level. We aim to help potential users of these technologies make informed decisions regarding research design, hardware, software, and archiving. We also provide information regarding ethics and implementation, issues that are difficult to navigate for those new to this technology, and on which little or no resources are available. This guidebook offers a concise summary of information for new users and points to sources of more detailed information for more advanced users. Links to discussion groups and community-augmented databases are also provided to help readers stay up-to-date on the latest developments.

Abstract

Odor naming is enhanced in communities where communication about odors is a central part of daily life (e.g., wine experts, flavorists, and some hunter‐gatherer groups). In this study, we investigated how expert knowledge and daily experience affect the ability to name odors in a group of experts that has not previously been investigated in this context—Iranian herbalists; also called attars—as well as cooks and laypeople. We assessed naming accuracy and consistency for 16 herb and spice odors, collected judgments of odor perception, and evaluated participants' odor meta‐awareness. Participants' responses were overall more consistent and accurate for more frequent and familiar odors. Moreover, attars were more accurate than both cooks and laypeople at naming odors, although cooks did not perform significantly better than laypeople. Attars' perceptual ratings of odors and their overall odor meta‐awareness suggest they are also more attuned to odors than the other two groups. To conclude, Iranian attars—but not cooks—are better odor namers than laypeople. They also have greater meta‐awareness and differential perceptual responses to odors. These findings further highlight the critical role that expertise and type of experience have on olfactory functions.

Abstract

Children begin developing turn-taking skills in infancy but take several years to fluidly integrate their growing knowledge of language into their turn-taking behavior. In two eye-tracking experiments, we measured children’s anticipatory gaze to upcoming responders while controlling linguistic cues to turn structure. In Experiment 1, we showed English and non-English conversations to English-speaking adults and children. In Experiment 2, we phonetically controlled lexicosyntactic and prosodic cues in English-only speech. Children spontaneously made anticipatory gaze switches by age two and continued improving through age six. In both experiments, children and adults made more anticipatory switches after hearing questions. Consistent with prior findings on adult turn prediction, prosodic information alone did not increase children’s anticipatory gaze shifts. But, unlike prior work with adults, lexical information alone was not sucient either—children’s performance was best overall with lexicosyntax and prosody together. Our findings support an account in which turn tracking and turn prediction emerge in infancy and then gradually become integrated with children’s online linguistic processing.

Abstract

Child-directed speech is argued to facilitate language development, and is found cross-linguistically and cross-culturally to varying degrees. However, previous research has generally focused on short samples of child-caregiver interaction, often in the lab or with experimenters present. We test the generalizability of this phenomenon with an initial descriptive analysis of the speech heard by young children in a large, unique collection of naturalistic, daylong home recordings. Trained annotators coded automatically-detected adult speech 'utterances' from 61 homes across 4 North American cities, gathered from children (age 2-24 months) wearing audio recorders during a typical day. Coders marked the speaker gender (male/female) and intended addressee (child/adult), yielding 10,886 addressee and gender tags from 2,523 minutes of audio (cf. HB-CHAAC Interspeech ComParE challenge; Schuller et al., in press). Automated speaker-diarization (LENA) incorrectly gender-tagged 30% of male adult utterances, compared to manually-coded consensus. Furthermore, we find effects of SES and gender on child-directed and overall speech, increasing child-directed speech with child age, and interactions of speaker gender, child gender, and child age: female caretakers increased their child-directed speech more with age than male caretakers did, but only for male infants. Implications for language acquisition and existing classification algorithms are discussed.

Abstract

FOXP proteins form a subfamily of evolutionarily conserved transcription factors involved in the development and functioning of several tissues, including the central nervous system. In humans, mutations in FOXP1 and FOXP2 have been implicated in cognitive deficits including intellectual disability and speech disorders. Drosophila exhibits a single ortholog, called FoxP, but due to a lack of characterized mutants, our understanding of the gene remains poor. Here we show that the dimerization property required for mammalian FOXP function is conserved in Drosophila. In flies, FoxP is enriched in the adult brain, showing strong expression in ~1000 neurons of cholinergic, glutamatergic and GABAergic nature. We generate Drosophila loss-of-function mutants and UAS-FoxP transgenic lines for ectopic expression, and use them to characterize FoxP function in the nervous system. At the cellular level, we demonstrate that Drosophila FoxP is required in larvae for synaptic morphogenesis at axonal terminals of the neuromuscular junction and for dendrite development of dorsal multidendritic sensory neurons. In the developing brain, we find that FoxP plays important roles in α-lobe mushroom body formation. Finally, at a behavioral level, we show that Drosophila FoxP is important for locomotion, habituation learning and social space behavior of adult flies. Our work shows that Drosophila FoxP is important for regulating several neurodevelopmental processes and behaviors that are related to human disease or vertebrate disease model phenotypes. This suggests a high degree of functional conservation with vertebrate FOXP orthologues and established flies as a model system for understanding FOXP related pathologies.

Abstract

The parietal lobe has a unique place in the human brain. Anatomically, it is at the crossroad between the frontal, occipital, and temporal lobes, thus providing a middle ground for multimodal sensory integration. Functionally, it supports higher cognitive functions that are characteristic of the human species, such as mathematical cognition, semantic and pragmatic aspects of language, and abstract thinking. Despite its importance, a comprehensive comparison of human and simian intraparietal networks is missing.

In this study, we used diffusion imaging tractography to reconstruct the major intralobar parietal tracts in twenty-one datasets acquired in vivo from healthy human subjects and eleven ex vivo datasets from five vervet and six macaque monkeys. Three regions of interest (postcentral gyrus, superior parietal lobule and inferior parietal lobule) were used to identify the tracts. Surface projections were reconstructed for both species and results compared to identify similarities or differences in tract anatomy (i.e., trajectories and cortical projections). In addition, post-mortem dissections were performed in a human brain.

The largest tract identified in both human and monkey brains is a vertical pathway between the superior and inferior parietal lobules. This tract can be divided into an anterior (supramarginal gyrus) and a posterior (angular gyrus) component in both humans and monkey brains. The second prominent intraparietal tract connects the postcentral gyrus to both supramarginal and angular gyri of the inferior parietal lobule in humans but only to the supramarginal gyrus in the monkey brain. The third tract connects the postcentral gyrus to the anterior region of the superior parietal lobule and is more prominent in monkeys compared to humans. Finally, short U-shaped fibres in the medial and lateral aspects of the parietal lobe were identified in both species. A tract connecting the medial parietal cortex to the lateral inferior parietal cortex was observed in the monkey brain only.

Our findings suggest a consistent pattern of intralobar parietal connections between humans and monkeys with some differences for those areas that have cytoarchitectonically distinct features in humans. The overall pattern of intraparietal connectivity supports the special role of the inferior parietal lobule in cognitive functions characteristic of humans.

Abstract

Oligodendrocyte gene expression is downregulated in stress-related neuropsychiatric disorders,
including depression. In mice, chronic social stress (CSS) leads to depression-relevant changes
in brain and emotional behavior, and the present study shows the involvement of oligodendrocytes in this model. In C57BL/6 (BL/6) mice, RNA-sequencing (RNA-Seq) was conducted with
prefrontal cortex, amygdala and hippocampus from CSS and controls; a gene enrichment database for neurons, astrocytes and oligodendrocytes was used to identify cell origin of deregulated genes, and cell deconvolution was applied. To assess the potential causal contribution of
reduced oligodendrocyte gene expression to CSS effects, mice heterozygous for the oligodendrocyte gene cyclic nucleotide phosphodiesterase (Cnp1) on a BL/6 background were studied;
a 2 genotype (wildtype, Cnp1+/−
) × 2 environment (control, CSS) design was used to investigate
effects on emotional behavior and amygdala microglia. In BL/6 mice, in prefrontal cortex and
amygdala tissue comprising gray and white matter, CSS downregulated expression of multiple
oligodendroycte genes encoding myelin and myelin-axon-integrity proteins, and cell deconvolution identified a lower proportion of oligodendrocytes in amygdala. Quantification of oligodendrocyte proteins in amygdala gray matter did not yield evidence for reduced translation,
suggesting that CSS impacts primarily on white matter oligodendrocytes or the myelin transcriptome. In Cnp1 mice, social interaction was reduced by CSS in Cnp1+/− mice specifically;
using ionized calcium-binding adaptor molecule 1 (IBA1) expression, microglia activity was
increased additively by Cnp1+/− and CSS in amygdala gray and white matter. This study provides back-translational evidence that oligodendrocyte changes are relevant to the pathophysiology and potentially the treatment of stress-related neuropsychiatric disorders.

Abstract

We report on an analysis of spontaneous gesture production in 2‐year‐old children who come from three countries (Italy, United Kingdom, Australia) and who speak two languages (Italian, English), in an attempt to tease apart the influence of language and culture when comparing children from different cultural and linguistic environments. Eighty‐seven monolingual children aged 24–30 months completed an experimental task measuring their comprehension and production of nouns and predicates. The Italian children scored significantly higher than the other groups on all lexical measures. With regard to gestures, British children produced significantly fewer pointing and speech combinations compared to Italian and Australian children, who did not differ from each other. In contrast, Italian children produced significantly more representational gestures than the other two groups. We conclude that spoken language development is primarily influenced by the input language over gesture production, whereas the combination of cultural and language environments affects gesture production.

Abstract

Cognitive development is shaped by interactions between cognitive architecture and environmental experiences
of the growing brain. We examined the extent to which this interaction during development could be observed in
language processing. We focused on age of acquisition (AoA) effects in reading, where early-learned words tend
to be processed more quickly and accurately relative to later-learned words. We implemented a computational
model including representations of print, sound and meaning of words, with training based on children’s gradual
exposure to language. The model produced AoA effects in reading and lexical decision, replicating the larger
effects of AoA when semantic representations are involved. Further, the model predicted that AoA would relate
to differing use of the reading system, with words acquired before versus after literacy onset with distinctive
accessing of meaning and sound representations. An analysis of behaviour from the English Lexicon project was
consistent with the predictions: Words acquired before literacy are more likely to access meaning via sound,
showing a suppressed AoA effect, whereas words acquired after literacy rely more on direct print to meaning
mappings, showing an exaggerated AoA effect. The reading system reveals vestigial traces of acquisition reflected
in differing use of word representations during reading.

Abstract

Diversity of vocabulary knowledge and quantity of language exposure prior to literacy are key predictors of reading development. However, diversity and quantity of exposure are difficult to distinguish in behavioural studies, and so the causal relations with literacy are not well known. We tested these relations by training a connectionist triangle model of reading that learned to map between semantic; phonological; and, later, orthographic forms of words. The model first learned to map between phonology and semantics, where we manipulated the quantity and diversity of this preliterate language experience. Then the model learned to read. Both diversity and quantity of exposure had unique effects on reading performance, with larger effects for written word comprehension than for reading fluency. The results further showed that quantity of preliteracy language exposure was beneficial only when this was to a varied vocabulary and could be an impediment when exposed to a limited vocabulary.

Abstract

Bock et al. (1992) found that the binding of animacy features onto grammatical roles is susceptible to priming in sentence production. Moreover, this effect did not interact with structural priming. This finding supports an account according to which syntactic representations are insensitive to the consistency of animacy-to-structure mapping. This account has contributed greatly to the development of syntactic processing theories in language production. However, this study has never been directly replicated and the few related studies showed mixed results. A meta-analysis of these studies failed to replicate the findings of Bock et al. (1992). Therefore, we conducted a well-powered replication (n = 496) that followed the original study as closely as possible. We found an effect of structural priming and an animacy priming effect, replicating Bock et al.’s findings. In addition, we replicated Bock et al.’s (1992) observed null interaction between structural priming and animacy binding, which suggests that syntactic representations are indeed independent of semantic information about animacy.

Abstract

Two groups of listeners with Dutch and British English language backgrounds judged Dutch and British English utterances, respectively, which varied in the intonation contour on the scales EMPHATIC vs. NOT EMPHATIC and SURPRISED vs. NOT SURPRISED, two meanings derived from the Effort Code. The stimuli, which differed in sentence mode but were otherwise lexically equivalent, were varied in peak height, peak alignment, end pitch, and overall register. In both languages, there are positive correlations between peak height and degree of emphasis, between peak height and degree of surprise, between peak alignment and degree of surprise, and between pitch register and degree of surprise. However, in all these cases, Dutch stimuli lead to larger perceived meaning differences than the British English stimuli. This difference in the extent to which increased pitch height triggers increases in perceived emphasis and surprise is argued to be due to the difference in the standard pitch ranges between Dutch and British English. In addition, we found a positive correlation between pitch register and the degree of emphasis in Dutch, but a negative correlation in British English. This is an unexpected difference, which illustrates a case of ambiguity in the meaning of pitch.

Abstract

A significant proportion of children have unexplained problems acquiring proficient linguistic skills despite adequate intelligence and opportunity. Developmental language disorders are highly heritable with substantial societal impact. Molecular studies have begun to identify candidate loci, but much of the underlying genetic architecture remains undetermined. We performed whole-exome sequencing of 43 unrelated probands affected by severe specific language impairment, followed by independent validations with Sanger sequencing, and analyses of segregation patterns in parents and siblings, to shed new light on aetiology. By first focusing on a pre-defined set of known candidates from the literature, we identified potentially pathogenic variants in genes already implicated in diverse language-related syndromes, including ERC1, GRIN2A, and SRPX2. Complementary analyses suggested novel putative candidates carrying validated variants which were predicted to have functional effects, such as OXR1, SCN9A and KMT2D. We also searched for potential “multiple-hit” cases; one proband carried a rare AUTS2 variant in combination with a rare inherited haplotype affecting STARD9, while another carried a novel nonsynonymous variant in SEMA6D together with a rare stop-gain in SYNPR. On broadening scope to all rare and novel variants throughout the exomes, we identified biological themes that were enriched for such variants, including microtubule transport and cytoskeletal regulation.

Abstract

The current study presents an agent-based model which simulates the innovation and
competition among lexical items in cases of language contact. It is inspired by relatively
recent historical cases in which the linguistic ecology and sociohistorical context are highly complex. Pidgin and creole genesis offers an opportunity to obtain linguistic facts, social dynamics, and historical demography in a highly segregated society. This provides a solid ground for researching the interaction of populations with different pre-existing language systems, and how different factors contribute to the genesis of the lexicon of a newly generated mixed language. We take into consideration the population dynamics and structures, as well as a distribution of word frequencies related to language use, in order to study how social factors may affect the developmental trajectory of languages. Focusing on the case of Sranan in Suriname, our study shows that it is possible to account for the
composition of its core lexicon in relation to different social groups, contact patterns, and
large population movements.

Abstract

This study examines acoustic and aerodynamic characteristics of consonants in standard Korean and in Cheju, an endangered Korean language. The focus is on the well-known three-way distinction among voiceless stops (i.e., lenis, fortis, aspirated) and the two-way distinction between the voiceless fricatives /s/ and /s*/. While such a typologically unusual contrast among voiceless stops has long drawn the attention of phoneticians and phonologists, there is no single work in the literature that discusses a body of data representing a relatively large number of speakers. This study reports a variety of acoustic and aerodynamic measures obtained from 12 Korean speakers (four speakers of Seoul Korean and eight speakers of Cheju). Results show that, in addition to findings similar to those reported by others, there are three crucial points worth noting. Firstly, lenis, fortis, and aspirated stops are systematically differentiated from each other by the voice quality of the following vowel. Secondly, these stops are also differentiated by aerodynamic mechanisms. The aspirated and fortis stops are similar in supralaryngeal articulation, but employ a different relation between intraoral pressure and flow. Thirdly, our study suggests that the fricative /s/ is better categorized as “lenis” rather than “aspirated”. The paper concludes with a discussion of the implications of Korean data for theories of the voicing contrast and their phonological representations.

Abstract

Children adopted early in life into another linguistic community typically forget their birth language but retain, unaware, relevant linguistic knowledge that may facilitate (re)learning of birth-language patterns. Understanding the nature of this knowledge can shed light on how language is acquired. Here, international adoptees from Korea with Dutch as their current language, and matched Dutch-native controls, provided speech production data on a Korean consonantal distinction unlike any Dutch distinctions, at the outset and end of an intensive perceptual training. The productions, elicited in a repetition task, were identified and rated by Korean listeners. Adoptees' production scores improved significantly more across the training period than control participants' scores, and, for adoptees only, relative production success correlated significantly with the rate of learning in perception (which had, as predicted, also surpassed that of the controls). Of the adoptee group, half had been adopted at 17 months or older (when talking would have begun), while half had been prelinguistic (under six months). The former group, with production experience, showed no advantage over the group without. Thus the adoptees' retained knowledge of Korean transferred from perception to production and appears to be abstract in nature rather than dependent on the amount of experience.

Abstract

Until at least 6 mo of age, infants show good discrimination for familiar phonetic contrasts (i.e., those heard in the environmental language) and contrasts that are unfamiliar. Adult-like discrimination (significantly worse for nonnative than for native contrasts) appears only later, by 9–10 mo. This has been interpreted as indicating that infants have no knowledge of phonology until vocabulary development begins, after 6 mo of age. Recently, however, word recognition has been observed before age 6 mo, apparently decoupling the vocabulary and phonology acquisition processes. Here we show that phonological acquisition is also in progress before 6 mo of age. The evidence comes from retention of birth-language knowledge in international adoptees. In the largest ever such study, we recruited 29 adult Dutch speakers who had been adopted from Korea when young and had no conscious knowledge of Korean language at all. Half were adopted at age 3–5 mo (before native-specific discrimination develops) and half at 17 mo or older (after word learning has begun). In a short intensive training program, we observe that adoptees (compared with 29 matched controls) more rapidly learn tripartite Korean consonant distinctions without counterparts in their later-acquired Dutch, suggesting that the adoptees retained phonological knowledge about the Korean distinction. The advantage is equivalent for the younger-adopted and the older-adopted groups, and both groups not only acquire the tripartite distinction for the trained consonants but also generalize it to untrained consonants. Although infants younger than 6 mo can still discriminate unfamiliar phonetic distinctions, this finding indicates that native-language phonological knowledge is nonetheless being acquired at that age.

Abstract

This study investigates young children’s comprehension of spatial terms in two languages that categorize space strikingly differently. English makes a distinction between actions resulting in containment (put in) versus support or surface attachment (put on), while Korean makes a cross-cutting distinction between tight-fit relations (kkita) versus loose-fit or other contact relations (various verbs). In particular, the Korean verb kkita refers to actions resulting in a tight-fit relation regardless of containment or support. In a preferential looking study we assessed the comprehension of in by 20 English learners and kkita by 10 Korean learners, all between 18 and 23 months. The children viewed pairs of scenes while listening to sentences with and without the target word. The target word led children to gaze at different and language-appropriate aspects of the scenes. We conclude that children are sensitive to language-specific spatial categories by 18–23 months.

Abstract

Lateralization is a fundamental characteristic of many behaviors and the organization of the brain, and atypical lateralization has been suggested to be linked to various brain-related disorders such as autism and schizophrenia. Right-handedness is one of the most prominent markers of human behavioural lateralization, yet its neurobiological basis remains to be determined. Here, we present a large-scale analysis of handedness, as measured by self-reported direction of hand preference, and its variability related to brain structural and functional organization in the UK Biobank (N = 36,024). A multivariate machine learning approach with multi-modalities of brain imaging data was adopted, to reveal how well brain imaging features could predict individual's handedness (i.e., right-handedness vs. non-right-handedness) and further identify the top brain signatures that contributed to the prediction. Overall, the results showed a good prediction performance, with an area under the receiver operating characteristic curve (AUROC) score of up to 0.72, driven largely by resting-state functional measures. Virtual lesion analysis and large-scale decoding analysis suggested that the brain networks with the highest importance in the prediction showed functional relevance to hand movement and several higher-level cognitive functions including language, arithmetic, and social interaction. Genetic analyses of contributions of common DNA polymorphisms to the imaging-derived handedness prediction score showed a significant heritability (h2=7.55%, p <0.001) that was similar to and slightly higher than that for the behavioural measure itself (h2=6.74%, p <0.001). The genetic correlation between the two was high (rg=0.71), suggesting that the imaging-derived score could be used as a surrogate in genetic studies where the behavioural measure is not available. This large-scale study using multimodal brain imaging and multivariate machine learning has shed new light on the neural correlates of human handedness.

Abstract

Clashen proposes two distinct processing routes, for regularly and irregularly inflected forms, respectively, and thus is apparently making a psychological claim. We argue his position, which embodies a strictly linguistic perspective, does not constitute a psychological processing model.

Abstract

Speakers design communication for their audience, providing more information in both speech and gesture when their listener is naive to the topic. We test whether the hippocampal declarative memory system contributes to multimodal audience design. The hippocampus, while traditionally linked to episodic and relational memory, has also been linked to the ability to imagine the mental states of others and use language flexibly. We examined the speech and gesture use of four patients with hippocampal amnesia when describing how to complete everyday tasks (e.g., how to tie a shoe) to an imagined child listener and an adult listener. Although patients with amnesia did not increase their total number of words and instructional steps for the child listener, they did produce representational gestures at significantly higher rates for the imagined child compared to the adult listener. They also gestured at similar frequencies to neurotypical peers, suggesting that hand gesture can be a meaningful communicative resource, even in the case of severe declarative memory impairment. We discuss the contributions of multiple memory systems to multimodal audience design and the potential of gesture to act as a window into the social cognitive processes of individuals with neurologic disorders.

Abstract

Expectancy mechanisms are routinely used by the cognitive system in stimulus processing and in anticipation of appropriate responses. Electrophysiology research has documented negative shifts of brain activity when expectancies are violated within a local stimulus context (e.g., reading an implausible word in a sentence) or more globally between consecutive stimuli (e.g., a narrative of images with an incongruent end). In this EEG study, we examine the interaction between expectancies operating at the level of stimulus plausibility and at more global level of contextual congruency to provide evidence for, or against, a disassociation of the underlying processing mechanisms. We asked participants to verify the congruency of pairs of cross-modal stimuli (a sentence and a scene), which varied in plausibility. ANOVAs on ERP amplitudes in selected windows of interest show that congruency violation has longer-lasting (from 100 to 500 ms) and more widespread effects than plausibility violation (from 200 to 400 ms). We also observed critical interactions between these factors, whereby incongruent and implausible pairs elicited stronger negative shifts than their congruent counterpart, both early on (100–200 ms) and between 400–500 ms. Our results suggest that the integration mechanisms are sensitive to both global and local effects of expectancy in a modality independent manner. Overall, we provide novel insights into the interdependence of expectancy during meaning integration of cross-modal stimuli in a verification task

Abstract

Interactive effects between allelic variants of the serotonin transporter (5-HTT) promoter-linked polymorphic region (5-HTTLPR) and stressors on depression symptoms have been documented, as well as questioned, by meta-analyses. Translational models of constitutive 5-htt reduction and experimentally controlled stressors often led to inconsistent behavioral and molecular findings and often did not include females. The present study sought to investigate the effect of 5-htt genotype, maternal separation, and sex on the expression of stress-related candidate genes in the rat hippocampus and frontal cortex. The mRNA expression levels of Avp, Pomc, Crh, Crhbp, Crhr1, Bdnf, Ntrk2, Maoa, Maob, and Comt were assessed in the hippocampus and frontal cortex of 5-htt ± and 5-htt +/+ male and female adult rats exposed, or not, to daily maternal separation for 180 min during the first 2 postnatal weeks. Gene- and brain region-dependent, but sex-independent, interactions between 5-htt genotype and maternal separation were found. Gene expression levels were higher in 5-htt +/+ rats not exposed to maternal separation compared with the other experimental groups. Maternal separation and 5-htt +/− genotype did not yield additive effects on gene expression. Correlative relationships, mainly positive, were observed within, but not across, brain regions in all groups except in non-maternally separated 5-htt +/+ rats. Gene expression patterns in the hippocampus and frontal cortex of rats exposed to maternal separation resembled the ones observed in rats with reduced 5-htt expression regardless of sex. These results suggest that floor effects of 5-htt reduction and maternal separation might explain inconsistent findings in humans and rodents

Abstract

Four cross-modal priming experiments and two forced-choice identification experiments investigated the use of suprasegmental cues to stress in the recognition of spoken English words, by native (English-speaking) and non- native (Dutch) listeners. Previous results had indicated that suprasegmental information was exploited in lexical access by Dutch but not by English listeners. For both listener groups, recognition of visually presented target words was faster, in comparison to a control condition, after stress-matching spoken primes, either monosyllabic (mus- from MUsic /muSEum) or bisyl labic (admi- from ADmiral/admiRAtion). For native listeners, the effect of stress-mismatching bisyllabic primes was not different from that of control primes, but mismatching monosyllabic primes produced partial facilitation. For non-native listeners, both bisyllabic and monosyllabic stress-mismatching primes produced partial facilitation. Native English listeners thus can exploit suprasegmental information in spoken-word recognition, but information from two syllables is used more effectively than information from one syllable. Dutch listeners are less proficient at using suprasegmental information in English than in their native language, but, as in their native language, use mono- and bisyllabic information to an equal extent. In forced-choice identification, Dutch listeners outperformed native listeners at correctly assigning a monosyllabic fragment (e.g., mus-) to one of two words differing in stress.

Abstract

It has long been recognised that phrases and sentences are organised hierarchically, but many computational models of language treat them as sequences of words without computing constituent structure. Against this background, we conducted two experiments which showed that participants interpret ambiguous noun phrases, such as second blue ball, in terms of their abstract hierarchical structure rather than their linear surface order. When a neural network model was tested on this task, it could simulate such “hierarchical” behaviour. However, when we changed the training data such that they were not entirely unambiguous anymore, the model stopped generalising in a human-like way. It did not systematically generalise to novel items, and when it was trained on ambiguous trials, it strongly favoured the linear interpretation. We argue that these models should be endowed with a bias to make generalisations over hierarchical structure in order to be cognitively adequate models of human language.

Abstract

Recent research has established that cortical activity “tracks” the presentation rate of syntactic phrases in continuous speech, even though phrases are abstract units that do not have direct correlates in the acoustic signal. We investigated whether cortical tracking of phrase structures is modulated by the extent to which these structures compositionally determine meaning. To this end, we recorded electroencephalography (EEG) of 38 native speakers who listened to naturally spoken Dutch stimuli in different conditions, which parametrically modulated the degree to which syntactic structure and lexical semantics determine sentence meaning. Tracking was quantified through mutual information between the EEG data and either the speech envelopes or abstract annotations of syntax, all of which were filtered in the frequency band corresponding to the presentation rate of phrases (1.1–2.1 Hz). Overall, these mutual information analyses showed stronger tracking of phrases in regular sentences than in stimuli whose lexical-syntactic content is reduced, but no consistent differences in tracking between sentences and stimuli that contain a combination of syntactic structure and lexical content. While there were no effects of compositional meaning on the degree of phrase-structure tracking, analyses of event-related potentials elicited by sentence-final words did reveal meaning-induced differences between conditions. Our findings suggest that cortical tracking of structure in sentences indexes the internal generation of this structure, a process that is modulated by the properties of its input, but not by the compositional interpretation of its output.

Abstract

Visual narratives make use of various means to convey referential and co-referential meaning, so comprehenders
must recognize that different depictions across sequential images represent the same character(s). In this study,
we investigated how the order in which different types of panels in visual sequences are presented affects how
the unfolding narrative is comprehended. Participants viewed short comic strips while their electroencephalo-
gram (EEG) was recorded. We analyzed evoked and induced EEG activity elicited by both full panels (showing a
full character) and refiner panels (showing only a zoom of that full panel), and took into account whether they
preceded or followed the panel to which they were co-referentially related (i.e., were cataphoric or anaphoric).
We found that full panels elicited both larger N300 amplitude and increased gamma-band power compared to
refiner panels. Anaphoric panels elicited a sustained negativity compared to cataphoric panels, which appeared
to be sensitive to the referential status of the anaphoric panel. In the time-frequency domain, anaphoric panels
elicited reduced 8–12 Hz alpha power and increased 45–65 Hz gamma-band power compared to cataphoric
panels. These findings are consistent with models in which the processes involved in visual narrative compre-
hension partially overlap with those in language comprehension.

Abstract

Comprehenders often predict what they are going to hear. But do they make the best predictions possible? We addressed this question in three visual-world eye-tracking experiments by asking when comprehenders consider perspective. Male and female participants listened to male and female speakers producing sentences (e.g., I would like to wear the nice…) about stereotypically masculine (target: tie; distractor: drill) and feminine (target: dress, distractor: hairdryer) objects. In all three experiments, participants rapidly predicted semantic associates of the verb. But participants also predicted consistently – that is, consistent with their beliefs about what the speaker would ultimately say. They predicted consistently from the speaker’s perspective in Experiment 1, their own perspective in Experiment 2, and the character’s perspective in Experiment 3. This consistent effect occurred later than the associative effect. We conclude that comprehenders consider perspective when predicting, but not from the earliest moments of prediction, consistent with a two-stage account.

Abstract

Corpus analyses have shown that turn-taking in conversation is much faster than laboratory studies of speech planning would predict. To explain fast turn-taking, Levinson and Torreira (2015) proposed that speakers are highly proactive: They begin to plan a response to their interlocutor's turn as soon as they have understood its gist, and launch this planned response when the turn-end is imminent. Thus, fast turn-taking is possible because speakers use the time while their partner is talking to plan their own utterance. In the present study, we asked how much time upcoming speakers actually have to plan their utterances. Following earlier psycholinguistic work, we used transcripts of spoken conversations in Dutch, German, and English. These transcripts consisted of segments, which are continuous stretches of speech by one speaker. In the psycholinguistic and phonetic literature, such segments have often been used as proxies for turns. We found that in all three corpora, large proportions of the segments comprised of only one or two words, which on our estimate does not give the next speaker enough time to fully plan a response. Further analyses showed that speakers indeed often did not respond to the immediately preceding segment of their partner, but continued an earlier segment of their own. More generally, our findings suggest that speech segments derived from transcribed corpora do not necessarily correspond to turns, and the gaps between speech segments therefore only provide limited information about the planning and timing of turns.

Abstract

Research suggests that during conversation, interlocutors coordinate their utterances by predicting the speaker’s forthcoming utterance and its end. In two experiments, we used a button-pressing task, in which participants pressed a button when they thought a speaker reached the end of their utterance, to investigate what role the wider discourse plays in turn-end prediction. Participants heard two-utterance sequences, in which the content of the second utterance was or was not constrained by the content of the first. In both experiments, participants responded earlier, but not more precisely, when the first utterance was constraining rather than unconstraining. Response times and precision were unaffected by whether they listened to dialogues or monologues (Experiment 1) and by whether they read the first utterance out loud or silently (Experiment 2), providing no indication that activation of production mechanisms facilitates prediction. We suggest that content predictions aid comprehension but not turn-end prediction.

Abstract

Past events like fluctuations in population size and post-glacial colonization processes may influence the relative importance of genetic drift, migration and selection when determining the present day patterns of genetic variation. We disentangle how drift, selection and migration shape neutral and adaptive genetic variation in 12 moor frog populations along a 1700 km latitudinal gradient. We studied genetic differentiation and variation at a MHC exon II locus and a set of 18 microsatellites.
Results

Using outlier analyses, we identified the MHC II exon 2 (corresponding to the β-2 domain) locus and one microsatellite locus (RCO8640) to be subject to diversifying selection, while five microsatellite loci showed signals of stabilizing selection among populations. STRUCTURE and DAPC analyses on the neutral microsatellites assigned populations to a northern and a southern cluster, reflecting two different post-glacial colonization routes found in previous studies. Genetic variation overall was lower in the northern cluster. The signature of selection on MHC exon II was weaker in the northern cluster, possibly as a consequence of smaller and more fragmented populations.
Conclusion

Our results show that historical demographic processes combined with selection and drift have led to a complex pattern of differentiation along the gradient where some loci are more divergent among populations than predicted from drift expectations due to diversifying selection, while other loci are more uniform among populations due to stabilizing selection. Importantly, both overall and MHC genetic variation are lower at northern latitudes. Due to lower evolutionary potential, the low genetic variation in northern populations may increase the risk of extinction when confronted with emerging pathogens and climate change.