Publications

Abstract

Last year was the 150th anniversary of Paul Broca's landmark case report on speech disorder that paved the way for subsequent studies of cortical localization of higher cognitive functions. However, many complex functions rely on the activity of distributed networks rather than single cortical areas. Hence, it is important to understand how brain regions are linked within large-scale networks and to map lesions onto connecting white matter tracts. To facilitate this network approach we provide a synopsis of classical neurological syndromes associated with frontal, parietal, occipital, temporal and limbic lesions. A review of tractography studies in a variety of neuropsychiatric disorders is also included. The synopsis is accompanied by a new atlas of the human white matter connections based on diffusion tensor tractography freely downloadable on http://www.natbrainlab.com. Clinicians can use the maps to accurately identify the tract affected by lesions visible on conventional CT or MRI. The atlas will also assist researchers to interpret their group analysis results. We hope that the synopsis and the atlas by allowing a precise localization of white matter lesions and associated symptoms will facilitate future work on the functional correlates of human neural networks as derived from the study of clinical populations. Our goal is to stimulate clinicians to develop a critical approach to clinico-anatomical correlative studies and broaden their view of clinical anatomy beyond the cortical surface in order to encompass the dysfunction related to connecting pathways.

Abstract

Lexicalized theories of syntax often assume that verb-structure regularities are mediated by lemmas, which abstract over variation in verb tense and aspect. German syntax seems to challenge this assumption, because verb position depends on tense and aspect. To examine how German speakers link these elements, a structural priming study was performed which varied syntactic structure, verb position (encoded by tense and aspect), and verb overlap. Abstract structural priming was found, both within and across verb position, but priming was larger when the verb position was the same between prime and target. Priming was boosted by verb overlap, but there was no interaction with verb position. The results can be explained by a lemma model where tense and aspect are linked to structural choices in German. Since the architecture of this lemma model is not consistent with results from English, a connectionist model was developed which could explain the cross-linguistic variation in the production system. Together, these findings support the view that language learning plays an important role in determining the nature of structural priming in different languages

Abstract

Linguistic adaptation is a phenomenon where language representations change in response to linguistic input. Adaptation can occur on multiple linguistic levels such as phonology (tuning of phonotactic constraints), words (repetition priming), and syntax (structural priming). The persistent nature of these adaptations suggests that they may be a form of implicit learning and connectionist models have been developed which instantiate this hypothesis. Research on implicit learning, however, has also produced evidence that explicit chunk knowledge is involved in the performance of these tasks. In this review, we examine how these interacting implicit and explicit processes may change our understanding of language learning and processing.

Abstract

RNAs processing other RNAs is very general in eukaryotes, but is not clear to what extent it is ancestral to eukaryotes. Here we focus on pre-mRNA splicing, one of the most important RNA-processing mechanisms in eukaryotes. In most eukaryotes splicing is predominantly catalysed by the major spliceosome complex, which consists of five uridine-rich small nuclear RNAs (U-snRNAs) and over 200 proteins in humans. Three major spliceosomal introns have been found experimentally in Giardia; one Giardia U-snRNA (U5) and a number of spliceosomal proteins have also been identified. However, because of the low sequence similarity between the Giardia ncRNAs and those of other eukaryotes, the other U-snRNAs of Giardia had not been found. Using two computational methods, candidates for Giardia U1, U2, U4 and U6 snRNAs were identified in this study and shown by RT-PCR to be expressed. We found that identifying a U2 candidate helped identify U6 and U4 based on interactions between them. Secondary structural modelling of the Giardia U-snRNA candidates revealed typical features of eukaryotic U-snRNAs. We demonstrate a successful approach to combine computational and experimental methods to identify expected ncRNAs in a highly divergent protist genome. Our findings reinforce the conclusion that spliceosomal small-nuclear RNAs existed in the last common ancestor of eukaryotes.

Abstract

Studies on children’s use of intonation in reference are few in number but are diverse in terms of theoretical frameworks and intonational parameters. In the current review, I present a re-analysis of the referents in each study, using a three-dimension approach (i.e. referential givenness-newness, relational givenness-newness, contrast), discuss the use of intonation at two levels (phonetic, phonological), and compare findings from different studies within a single framework. The patterns stemming from these studies may be limited in generalisability but can serve as initial hypotheses for future work. Furthermore, I examine the role of input as available in infant direct speech in the acquisition of intonational encoding of referents. In addition, I discuss how future research can advance our knowledge.

Abstract

Messenger ribonucleic acids (RNAs) contain a large number of cis-regulatory RNA elements that function in many types of post-transcriptional regulation. These cis-regulatory elements are often characterized by conserved structures and/or sequences. Although some classes are well known, given the wide range of RNA-interacting proteins in eukaryotes, it is likely that many new classes of cis-regulatory elements are yet to be discovered. An approach to this is to use computational methods that have the advantage of analysing genomic data, particularly comparative data on a large scale. In this study, a set of structural discovery algorithms was applied followed by support vector machine (SVM) classification. We trained a new classification model (CisRNA-SVM) on a set of known structured cis-regulatory elements from 3′-untranslated regions (UTRs) and successfully distinguished these and groups of cis-regulatory elements not been strained on from control genomic and shuffled sequences. The new method outperformed previous methods in classification of cis-regulatory RNA elements. This model was then used to predict new elements from cross-species conserved regions of human 3′-UTRs. Clustering of these elements identified new classes of potential cis-regulatory elements. The model, training and testing sets and novel human predictions are available at: http://mRNA.otago.ac.nz/CisRNA-SVM.

Abstract

This paper investigates the lexical semantics of placement verbs in Mandarin. The majority of Mandarin placement verbs are directional verb compounds (e.g., na2-xia4-lai2 ‘take-descend-come’). They are composed of two or three verbs in a fixed order, each encoding certain semantic components of placement events. The first verb usually conveys object manipulation and the second and the third verbs indicate the Path of motion, including Deixis. The first verb, typically encoding object manipulation, can be semantically general or specific: two general verbs, fang4 ‘put’ and na2 ‘take’, have large but constrained extensional categories, and a number of specific verbs are used based on the Manner of manipulation of the Figure object, the relationship between and the physical properties of Figure and Ground, intentionality of the Agent, and the type of instrument.

Abstract

While detecting genetic variations underlying brain structures helps reveal mechanisms of neural disorders, high data dimensionality poses a major challenge for imaging genomic association studies. In this work, we present the application of a recently proposed approach, parallel independent component analysis with reference (pICA-R), to investigate genomic factors potentially regulating gray matter variation in a healthy population. This approach simultaneously assesses many variables for an aggregate effect and helps to elicit particular features in the data. We applied pICA-R to analyze gray matter density (GMD) images (274,131 voxels) in conjunction with single nucleotide polymorphism (SNP) data (666,019 markers) collected from 1,256 healthy individuals of the Brain Imaging Genetics (BIG) study. Guided by a genetic reference derived from the gene GNA14, pICA-R identified a significant SNP-GMD association (r = −0.16, P = 2.34 × 10−8), implying that subjects with specific genotypes have lower localized GMD. The identified components were then projected to an independent dataset from the Mind Clinical Imaging Consortium (MCIC) including 89 healthy individuals, and the obtained loadings again yielded a significant SNP-GMD association (r = −0.25, P = 0.02). The imaging component reflected GMD variations in frontal, precuneus, and cingulate regions. The SNP component was enriched in genes with neuronal functions, including synaptic plasticity, axon guidance, molecular signal transduction via PKA and CREB, highlighting the GRM1, PRKCH, GNA12, and CAMK2B genes. Collectively, our findings suggest that GNA12 and GNA14 play a key role in the genetic architecture underlying normal GMD variation in frontal and parietal regions

Abstract

Prosodic influences on phonetic realizations of four Dutch consonants (/t d s z/) were examined. Sentences were constructed containing these consonants in word-initial position; the factors lexical stress, phrasal accent and prosodic boundary were manipulated between sentences. Eleven Dutch speakers read these sentences aloud. The patterns found in acoustic measurements of these utterances (e.g., voice onset time (VOT), consonant duration, voicing during closure, spectral center of gravity, burst energy) indicate that the low-level phonetic implementation of all four consonants is modulated by prosodic structure. Boundary effects on domain-initial segments were observed in stressed and unstressed syllables, extending previous findings which have been on stressed syllables alone. Three aspects of the data are highlighted. First, shorter VOTs were found for /t/ in prosodically stronger locations (stressed, accented and domain-initial), as opposed to longer VOTs in these positions in English. This suggests that prosodically driven phonetic realization is bounded by language-specific constraints on how phonetic features are specified with phonetic content: Shortened VOT in Dutch reflects enhancement of the phonetic feature {−spread glottis}, while lengthened VOT in English reflects enhancement of {+spread glottis}. Prosodic strengthening therefore appears to operate primarily at the phonetic level, such that prosodically driven enhancement of phonological contrast is determined by phonetic implementation of these (language-specific) phonetic features. Second, an accent effect was observed in stressed and unstressed syllables, and was independent of prosodic boundary size. The domain of accentuation in Dutch is thus larger than the foot. Third, within a prosodic category consisting of those utterances with a boundary tone but no pause, tokens with syntactically defined Phonological Phrase boundaries could be differentiated from the other tokens. This syntactic influence on prosodic phrasing implies the existence of an intermediate-level phrase in the prosodic hierarchy of Dutch.

Abstract

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

Abstract

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

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

Abstract

When solving spatial problems, people often spontaneously produce hand gestures. Recent research has shown that our knowledge is shaped by the interaction between our body and the environment. In this article, we review and discuss evidence on: 1) how spontaneous gesture can reveal the development of problem solving strategies when people solve spatial problems; 2) whether producing gestures can enhance spatial problem solving performance. We argue that when solving novel spatial problems, adults go through deagentivization and internalization processes, which are analogous to young children’s cognitive development processes. Furthermore, gesture enhances spatial problem solving performance. The beneficial effect of gesturing can be extended to non-gesturing trials and can be generalized to a different spatial task that shares similar spatial transformation processes.

Abstract

Koriat (1981) demonstrated that an association from the target to a preceding prime, in the absence of an association from the prime to the target, facilitates lexical decision and referred to this effect as "backward priming". Backward priming is of relevance, because it can provide information about the mechanism underlying semantic priming effects. Following Neely (1991), we distinguish three mechanisms of priming: spreading activation, expectancy, and semantic matching/integration. The goal was to determine which of these mechanisms causes backward priming, by assessing effects of backward priming on a language-relevant ERP component, the N400, and reaction time (RT). Based on previous work, we propose that the N400 priming effect reflects expectancy and semantic matching/integration, but in contrast with RT does not reflect spreading activation. Experiment 1 shows a backward priming effect that is qualitatively similar for the N400 and RT in a lexical decision task. This effect was not modulated by an ISI manipulation. Experiment 2 clarifies that the N400 backward priming effect reflects genuine changes in N400 amplitude and cannot be ascribed to other factors. We will argue that these backward priming effects cannot be due to expectancy but are best accounted for in terms of semantic matching/integration.

Abstract

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

Abstract

Recent game-theoretic simulation and analytical models have demonstrated that cooperative strategies mediated by indicators of cooperative potential, or “tags,” can invade, spread, and resist invasion by noncooperators across a range of population-structure and cost-benefit scenarios. The plausibility of these models is potentially relevant for human evolutionary accounts insofar as humans possess some phenotypic trait that could serve as a reliable tag. Linguistic markers, such as accent and dialect, have frequently been either cursorily defended or promptly dismissed as satisfying the criteria of a reliable and evolutionarily viable tag. This paper integrates evidence from a range of disciplines to develop and assess the claim that speech accent mediated the evolution of tag-based cooperation in humans. Existing evidence warrants the preliminary conclusion that accent markers meet the demands of an evolutionarily viable tag and potentially afforded a cost-effective solution to the challenges of maintaining viable cooperative relationships in diffuse, regional social networks.

Abstract

Common wisdom has it that Buddhism enhances compassion and self-other integration. We put this assumption to empirical test by comparing practicing Taiwanese Buddhists with well-matched atheists. Buddhists showed more evidence of self-other integration in the social Simon task, which assesses the degree to which people co-represent the actions of a coactor. This suggests that self-other integration and task co-representation vary as a function of religious practice.

Abstract

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

Abstract

The scavenger receptor C-type lectin (SRCL) is an endothelial receptor that is similar in organization to type A scavenger receptors for modified low density lipoproteins but contains a C-type carbohydrate-recognition domain (CRD). Fragments of the receptor consisting of the entire extracellular domain and the CRD have been expressed and characterized. The extracellular domain is a trimer held together by collagen-like and coiled-coil domains adjacent to the CRD. The amino acid sequence of the CRD is very similar to the CRD of the asialoglycoprotein receptor and other galactose-specific receptors, but SRCL binds selectively to asialo-orosomucoid rather than generally to asialoglycoproteins. Screening of a glycan array and further quantitative binding studies indicate that this selectivity results from high affinity binding to glycans bearing the Lewis(x) trisaccharide. Thus, SRCL shares with the dendritic cell receptor DC-SIGN the ability to bind the Lewis(x) epitope. However, it does so in a fundamentally different way, making a primary binding interaction with the galactose moiety of the glycan rather than the fucose residue. SRCL shares with the asialoglycoprotein receptor the ability to mediate endocytosis and degradation of glycoprotein ligands. These studies suggest that SRCL might be involved in selective clearance of specific desialylated glycoproteins from circulation and/or interaction of cells bearing Lewis(x)-type structures with the vascular endothelium.

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

Speech processing can often take place in adverse listening conditions that involve the mixing of speech and background noise. In this study, we investigated processing dependencies between background noise and indexical speech features, using a speeded classification paradigm (Garner, 1974; Exp. 1), and whether background noise is encoded and represented in memory for spoken words in a continuous recognition memory paradigm (Exp. 2). Whether or not the noise spectrally overlapped with the speech signal was also manipulated. The results of Experiment 1 indicated that background noise and indexical features of speech (gender, talker identity) cannot be completely segregated during processing, even when the two auditory streams are spectrally nonoverlapping. Perceptual interference was asymmetric, whereby irrelevant indexical feature variation in the speech signal slowed noise classification to a greater extent than irrelevant noise variation slowed speech classification. This asymmetry may stem from the fact that speech features have greater functional relevance to listeners, and are thus more difficult to selectively ignore than background noise. Experiment 2 revealed that a recognition cost for words embedded in different types of background noise on the first and second occurrences only emerged when the noise and the speech signal were spectrally overlapping. Together, these data suggest integral processing of speech and background noise, modulated by the level of processing and the spectral separation of the speech and noise.

Abstract

In three experiments, listeners detected vowel or consonant targets in lists of CV syllables constructed from five vowels and five consonants. Responses were faster in a predictable context (e.g., listening for a vowel target in a list of syllables all beginning with the same consonant) than in an unpredictable context (e.g., listening for a vowel target in a list of syllables beginning with different consonants). In Experiment 1, the listeners’ native language was Dutch, in which vowel and consonant repertoires are similar in size. The difference between predictable and unpredictable contexts was comparable for vowel and consonant targets. In Experiments 2 and 3, the listeners’ native language was Spanish, which has four times as many consonants as vowels; here effects of an unpredictable consonant context on vowel detection were significantly greater than effects of an unpredictable vowel context on consonant detection. This finding suggests that listeners’ processing of phonemes takes into account the constitution of their language’s phonemic repertoire and the implications that this has for contextual variability.

Abstract

As the creation of signed language resources is gaining speed world-wide, the need for standards in this field becomes more acute. This paper discusses the state of the field of signed language resources, their metadata descriptions, and annotations that are typically made. It then describes the role that ISOcat may play in this process and how it can stimulate standardisation without imposing standards. Finally, it makes some initial proposals for the thematic domain ‘sign language’ that was introduced in 2011.

Abstract

In most of the world, people have regular exposure to multiple accents. Therefore, learning to quickly process accented speech is a prerequisite to successful communication. In this paper, we examine work on the perception of accented speech across the lifespan, from early infancy to late adulthood. Unfamiliar accents initially impair linguistic processing by infants, children, younger adults, and older adults, but listeners of all ages come to adapt to accented speech. Emergent research also goes beyond these perceptual abilities, by assessing links with production and the relative contributions of linguistic knowledge and general cognitive skills. We conclude by underlining points of convergence across ages, and the gaps left to face in future work.

Abstract

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

Abstract

Social tolerance is a core aspect of primate social relationships with implications for the evolution of cooperation, prosociality and social learning. We measured the social tolerance of bonobos in an experiment recently validated with chimpanzees to allow for a comparative assessment of group-level tolerance, and found that the bonobo group studied here exhibited lower social tolerance on average than chimpanzees. Furthermore, following the Relational Model [de Waal, 1996], we investigated whether bonobos responded to an increased potential for social conflict with tolerance, conflict avoidance or conflict escalation, and found that only behaviours indicative of conflict escalation differed across conditions. Taken together, these findings contribute to the current debate over the level of social tolerance of bonobos and lend support to the position that the social tolerance of bonobos may not be notably high compared with other primates.

Abstract

We investigated cooperative problem solving in unrelated pairs of the cooperatively breeding cottontop tamarin, Saguinus oedipus, to assess the cognitive basis of cooperative behaviour in this species and to compare abilities with other apes and monkeys. A transparent apparatus was used that required extension of two handles at opposite ends of the apparatus for access to rewards. Resistance was applied to both handles so that two tamarins had to act simultaneously in order to receive rewards. In contrast to several previous studies of cooperation, both tamarins received rewards as a result of simultaneous pulling. The results from two experiments indicated that the cottontop tamarins (1) had a much higher success rate and efficiency of pulling than many of the other species previously studied, (2) adjusted pulling behaviour to the presence or absence of a partner, and (3) spontaneously developed sustained pulling techniques to solve the task. These findings suggest that cottontop tamarins understand the role of the partner in this cooperative task, a cognitive ability widely ascribed only to great apes. The cooperative social system of tamarins, the intuitive design of the apparatus, and the provision of rewards to both participants may explain the performance of the tamarins.

Abstract

Definition Prosocial behavior is any behavior performed by one individual that results in a benefit for another individual. Prosocial motivations, prosocial preferences, or other-regarding preferences refer to the psychological predisposition to behave in the best interest of another individual. A behavior need not be costly to the actor to be considered prosocial, thus the concept is distinct from altruistic behavior which requires that the actor incurs some cost when providing a benefit to another.

Abstract

Studies of animal behavior consistently demonstrate that the social environment impacts cooperation, yet the effect of social dynamics has been largely excluded from studies of human cooperation. Here, we introduce a novel approach inspired by nonhuman primate research to address how social hierarchies impact human cooperation. Participants competed to earn hierarchy positions and then could cooperate with another individual in the hierarchy by investing in a common effort. Cooperation was achieved if the combined investments exceeded a threshold, and the higher ranked individual distributed the spoils unless control was contested by the partner. Compared to a condition lacking hierarchy, cooperation declined in the presence of a hierarchy due to a decrease in investment by lower ranked individuals. Furthermore, hierarchy was detrimental to cooperation regardless of whether it was earned or arbitrary. These findings mirror results from nonhuman primates and demonstrate that hierarchies are detrimental to cooperation. However, these results deviate from nonhuman primate findings by demonstrating that human behavior is responsive to changing hierarchical structures and suggests partnership dynamics that may improve cooperation. This work introduces a controlled way to investigate the social influences on human behavior, and demonstrates the evolutionary continuity of human behavior with other primate species.

Abstract

Researchers have struggled to obtain a clear account of the evolution of prosocial behaviour despite a great deal of recent effort. The aim of this review is to take a brief step back from addressing the question of evolutionary origins of prosocial behaviour in order to identify contextual factors that are contributing to variation in the expression of prosocial behaviour and hindering progress towards identifying phylogenetic patterns. Most available data come from the Primate Order, and the choice of contextual factors to consider was informed by theory and practice, including the nature of the relationship between the potential donor and recipient, the communicative behaviour of the recipients, and features of the prosocial task including whether rewards are visible and whether the prosocial choice creates an inequity between actors. Conclusions are drawn about the facilitating or inhibiting impact of each of these factors on the expression of prosocial behaviour, and areas for future research are highlighted. Acknowledging the impact of these contextual features on the expression of prosocial behaviours should stimulate new research into the proximate mechanisms that drive these effects, yield experimental designs that better control for potential influences on prosocial expression, and ultimately allow progress towards reconstructing the evolutionary origins of prosocial behaviour.

Abstract

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

Abstract

The social factors that influence cooperation have remained largely uninvestigated but have the potential to explain much of the variation in cooperative behavior observed in the natural world. We show here that certain dimensions of the social environment, namely the size of the social group, the degree of social tolerance expressed, the structure of the dominance hierarchy, and the patterns of dispersal, may influence the emergence and stability of cooperation in predictable ways. Furthermore, the social environment experienced by a species over evolutionary time will have shaped their cognition to provide certain strengths and strategies that are beneficial in their species‟ social world. These cognitive adaptations will in turn impact the likelihood of cooperating in a given social environment. Experiments with one primate species, the cottontop tamarin, illustrate how social dynamics may influence emergence and stability of cooperative behavior in this species. We then take a more general viewpoint and argue that the hypotheses presented here require further experimental work and the addition of quantitative modeling to obtain a better understanding of how social dynamics influence the emergence and stability of cooperative behavior in complex systems. We conclude by pointing out subsequent specific directions for models and experiments that will allow relevant advances in the understanding of the emergence of cooperation.

Abstract

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

Abstract

Rhythmic categories such as morae in Japanese or stress units in English play a role in the perception of spoken
language. We examined this role in Japanese, since recent evidence suggests that morae may intervene as
structural units in word recognition. First, we found that traditional puns more often substituted part of a mora
than a whole mora. Second, when listeners reconstructed distorted words, e.g. panorama from panozema, responses
were faster and more accurate when only a phoneme was distorted (panozama, panorema) than when a
whole CV mora was distorted (panozema). Third, lexical decisions on the same nonwords were better predicted
by duration and number of phonemes from nonword uniqueness point to word end than by number of morae. Our
results indicate no role for morae in early spoken-word processing; we propose that rhythmic categories constrain
not initial lexical activation but subsequent processes of speech segmentation and selection among word candidates.

Abstract

Speech segmentation procedures may differ in speakers of different languages. Earlier work based on French speakers listening to French words suggested that the syllable functions as a segmentation unit in speech processing. However, while French has relatively regular and clearly bounded syllables, other languages, such as English, do not. No trace of syllabifying segmentation was found in English listeners listening to English words, French words, or nonsense words. French listeners, however, showed evidence of syllabification even when they were listening to English words. We conclude that alternative segmentation routines are available to the human language processor. In some cases speech segmentation may involve the operation of more than one procedure.

Abstract

Recognizing spoken language involves automatic activation of multiple candidate words. The process of selection between candidates is made more efficient by inhibition of embedded words (like egg in beg) that leave a portion of the input stranded (here, b). Results from European languages suggest that this inhibition occurs when consonants are stranded but not when syllables are stranded. The reason why leftover syllables do not lead to inhibition could be that in principle they might themselves be words; in European languages, a syllable can be a word. In Sesotho (a Bantu language), however, a single syllable cannot be a word. We report that in Sesotho, word recognition is inhibited by stranded consonants, but stranded monosyllables produce no more difficulty than stranded bisyllables (which could be Sesotho words). This finding suggests that the viability constraint which inhibits spurious embedded word candidates is not sensitive to language-specific word structure, but is universal.

Abstract

Three groups of listeners identified the vowel in CV and VC syllables produced by an American English talker. The listeners were (a) native speakers of American English, (b) native speakers of Australian English (different dialect), and (c) native speakers of Dutch (different language). The syllables were embedded in multispeaker babble at three signal-to-noise ratios (0 dB, 8 dB, and 16 dB). The identification performance of native listeners was significantly better than that of listeners with another language but did not significantly differ from the performance of listeners with another dialect. Dialect differences did however affect the type of perceptual confusions which listeners made; in particular, the Australian listeners’ judgements of vowel tenseness were more variable than the American listeners’ judgements, which may be ascribed to cross-dialectal differences in this vocalic feature. Although listening difficulty can result when speech input mismatches the native dialect in terms of the precise cues for and boundaries of phonetic categories, the difficulty is very much less than that which arises when speech input mismatches the native language in terms of the repertoire of phonemic categories available.

Abstract

To examine whether lexically stored knowledge about spelling influences phoneme evaluation, we conducted three experiments with a low-level phonetic judgement task: phoneme goodness rating. In each experiment, listeners heard phonetic tokens varying along a continuum centred on /s/, occurring finally in isolated word or nonword tokens. An effect of spelling appeared in Experiment 1: Native English speakers’ goodness ratings for the best /s/ tokens were significantly higher in words spelled with S (e.g., bless) than in words spelled with C (e.g., voice). No such difference appeared when nonnative speakers rated the same materials in Experiment 2, indicating that the difference could not be due to acoustic characteristics of the S- versus C-words. In Experiment 3, nonwords with lexical neighbours consistently spelled with S (e.g., pless) versus with C (e.g., floice) failed to elicit orthographic neighbourhood effects; no significant difference appeared in native English speakers’ ratings for the S-consistent versus the C-consistent sets. Obligatory influence of lexical knowledge on phonemic processing would have predicted such neighbourhood effects; the findings are thus better accommodated by models in which phonemic decisions draw strategically upon lexical information.

Abstract

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

Abstract

Becoming a native listener is the necessary precursor to becoming a native speaker. Babies in the first year of life undertake a remarkable amount of work; by the time they begin to speak, they have perceptually mastered the phonological repertoire and phoneme co-occurrence probabilities of the native language, and they can locate familiar word-forms in novel continuous-speech contexts. The skills acquired at this early stage form a necessary part of adult listening. However, the same native listening skills also underlie problems in listening to a late-acquired non-native language, accounting for why in such a case listening (an innate ability) is sometimes paradoxically more difficult than, for instance, reading (a learned ability).

Abstract

The way we listen to spoken language is tailored to the specific benefit of native-language speech input. Listening to speech in non-native languages can be significantly hindered by this native bias. Is it possible to determine the degree to which a listener is listening in a native-like manner? Promising indications of how this question may be tackled are provided by new research findings concerning the great flexibility that characterises listening to the L1, in online adjustment of phonetic category boundaries for adaptation across talkers, and in modulation of lexical dynamics for adjustment across listening conditions. This flexibility pays off in many dimensions, including listening in noise, adaptation across dialects, and identification of voices. These findings further illuminate the robustness and flexibility of native listening, and potentially point to ways in which we might begin to assess degrees of ‘native-likeness’ in this skill.

Abstract

Evidence is presented that (a) the open and the closed word classes in English have different phonological characteristics, (b) the phonological dimension on which they differ is one to which listeners are highly sensitive, and (c) spoken open- and closed-class words produce different patterns of results in some auditory recognition tasks. What implications might link these findings? Two recent lines of evidence from disparate paradigms—the learning of an artificial language, and natural and experimentally induced misperception of juncture—are summarized, both of which suggest that listeners are sensitive to the phonological reflections of open- vs. closed-class word status. Although these correlates cannot be strictly necessary for efficient processing, if they are present listeners exploit them in making word class assignments. That such a use of phonological information is of value to listeners could be indirect evidence that open- vs. closed-class words undergo different processing operations. Parts of the research reported in this paper were carried out in collaboration with Sally Butterfield and David Carter, and supported by the Alvey Directorate (United Kingdom). Jonathan Stankler's master's research was supported by the Science and Engineering Research Council (United Kingdom). Thanks to all of the above, and to Merrill Garrett, Mike Kelly, James McQueen, and Dennis Norris for further assistance.

Abstract

Studies of spoken-word recognition have revealed that competition from embedded words differs in strength as a function of where in the carrier word the embedded word is found and have further shown embedding patterns to be skewed such that embeddings in initial position in carriers outnumber embeddings in final position. Lexico-statistical analyses show that this skew is highly attenuated in Japanese, a noninflectional language. Comparison of the extent of the asymmetry in the three Germanic languages English, Dutch, and German allows the source to be traced to a combination of suffixal morphology and vowel reduction in unstressed syllables.

Abstract

Cross-linguistic comparisons may shed light on the levels of processing involved in the performance of psycholinguistic tasks. For instance, if the same pattern of results appears whether or not subjects understand the experimental materials, it may be concluded that the results do not reflect higher-level linguistic processing. In the present study, English and French listeners performed two tasks - click location and speeded click detection - with both English and French sentences, closely matched for syntactic and phonological structure. Clicks were located more accurately in open- than in closed-class words in both English and French; they were detected more rapidly in open- than in closed-class words in English, but not in French. The two listener groups produced the same pattern of responses, suggesting that higher-level linguistic processing was not involved in the listeners' responses. It is concluded that click detection tasks are primarily sensitive to low-level (e.g. acoustic) effects, and hence are not well suited to the investigation of linguistic processing.

Abstract

Orthographies encode phonological information only at the level of words (chiefly, the information encoded concerns phonetic segments; in some cases, tonal information or default stress may be encoded). Of primary interest to second language (L2) learners is whether orthography can assist in clarifying L2 phonological distinctions that are particularly difficult to perceive (e.g., where one native-language phonemic category captures two L2 categories). A review of spoken-word recognition evidence suggests that orthographic information can install knowledge of such a distinction in lexical representations but that this does not affect learners’ ability to perceive the phonemic distinction in speech. Words containing the difficult phonemes become even harder for L2 listeners to recognize, because perception maps less accurately to lexical content.

Abstract

The lexicon contains discrete entries, which must be located in speech input in order for speech to be understood; but the continuity of speech signals means that lexical access from spoken input involves a segmentation problem for listeners. The speech environment of prelinguistic infants may not provide special information to assist the infant listeners in solving this problem. Mature language users in possession of a lexicon might be thought to be able to avoid explicit segmentation of speech by relying on information from successful lexical access; however, evidence from adult perceptual studies indicates that listeners do use explicit segmentation procedures. These procedures differ across languages and seem to exploit language-specific rhythmic structure. Efficient as these procedures are, they may not have been developed in response to statistical properties of the input, because bilinguals, equally competent in two languages, apparently only possess one rhythmic segmentation procedure. The origin of rhythmic segmentation may therefore lie in the infant's exploitation of rhythm to solve the segmentation problem and gain a first toehold on lexical acquisition. Recent evidence from speech production and perception studies with prelinguistic infants supports the claim that infants are sensitive to rhythmic structure and its relationship to lexical segmentation.

Abstract

We show that Atkinson’s (Reports, 15 April 2011, p. 346) intriguing proposal—that global
linguistic diversity supports a single language origin in Africa—is an artifact of using suboptimal
data, biased methodology, and unjustified assumptions. We criticize his approach using more
suitable data, and we additionally provide new results suggesting a more complex scenario for the
emergence of global linguistic diversity.

Abstract

Evidence from certain geographical areas links lymphomas of the ocular adnexa marginal zone B-cell lymphomas (OAMZL) with Chlamydophila psittaci (Cp) infection, suggesting that lymphoma development is dependent upon chronic stimulation by persistent infections. Notwithstanding that, the actual immunopathogenetical mechanisms have not yet been elucidated. As in other B-cell lymphomas, insight into this issue, especially with regard to potential selecting ligands, could be provided by analysis of the immunoglobulin (IG) receptors of the malignant clones. To this end, we studied the molecular features of IGs in 44 patients with OAMZL (40% Cp-positive), identifying features suggestive of a pathogenic mechanism of autoreactivity. Herein, we show that lymphoma cells express a distinctive IG repertoire, with electropositive antigen (Ag)-binding sites, reminiscent of autoantibodies (auto-Abs) recognizing DNA. Additionally, five (11%) cases of OAMZL expressed IGs homologous with autoreactive Abs or IGs of patients with chronic lymphocytic leukemia, a disease known for the expression of autoreactive IGs by neoplastic cells. In contrast, no similarity with known anti-Chlamydophila Abs was found. Taken together, these results strongly indicate that OAMZL may originate from B cells selected for their capability to bind Ags and, in particular, auto-Ags. In OAMZL associated with Cp infection, the pathogen likely acts indirectly on the malignant B cells, promoting the development of an inflammatory milieu, where auto-Ags could be exposed and presented, driving proliferation and expansion of self-reactive B cells.

Abstract

The role of accent in reference resolution was investigated by monitoring eye fixations to lexical competitors (e.g., candy and candle ) as participants followed prerecorded instructions to move objects above or below fixed geometric shapes using a computer mouse. In Experiment 1, the first utterance instructed participants to move one object above or below a shape (e.g., “Put the candle/candy below the triangle”) and the second utterance contained an accented or deaccented definite noun phrase which referred to the same object or introduced a new entity (e.g., “Now put the CANDLE above the square” vs. “Now put the candle ABOVE THE SQUARE”). Fixations to the competitor (e.g., candy ) demonstrated a bias to interpret deaccented nouns as anaphoric and accented nouns as nonanaphoric. Experiment 2 used only accented nouns in the second instruction, varying whether the referent of this second instruction was the Theme of the first instruction (e.g., “Put the candle below the triangle”) or the Goal of the first instruction (e.g., “Put the necklace below the candle”). Participants preferred to interpret accented noun phrases as referring to a previously mentioned nonfocused entity (the Goal) rather than as introducing a new unmentioned entity.

Abstract

Participants' eye movements to four objects displayed on a computer screen were monitored as the participants clicked on the object named in a spoken instruction. The display contained pictures of the referent (e.g., a snake), a competitor that shared features with the visual representation associated with the referent's concept (e.g., a rope), and two distractor objects (e.g., a couch and an umbrella). As the first sounds of the referent's name were heard, the participants were more likely to fixate the visual competitor than to fixate either of the distractor objects. Moreover, this effect was not modulated by the visual similarity between the referent and competitor pictures, independently estimated in a visual similarity rating task. Because the name of the visual competitor did not overlap with the phonetic input, eye movements reflected word-object matching at the level of lexically activated perceptual features and not merely at the level of preactivated sound forms.

Abstract

We can describe the position of one item with respect to another using a number of different ‘frames of reference’. For example, I can use a ‘deictic’ frame that involves the speaker’s viewpoint (The chair is on the far side of the room), or an ‘intrinsic’ frame that involves a feature of one of the items (The chair is at the back of the room). Where more than one frame of reference is available in a language, what motivates the speaker’s choice? This elicitation task is designed to explore when and why people select intrinsic frames of reference, and how these choices interact with non-linguistic problem-solving strategies.

Abstract

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

Abstract

The morphosyntactic paradigm of an inflected word can influence isolated word recognition, but its role in multiple-word phrasal integration is less clear. We examined the electrophysiological response to adjectives in short German prepositional phrases to evaluate whether strong and weak forms of the adjective show a differential response, and whether paradigm variables are related to this response. Twenty native German speakers classified serially presented phrases as grammatically correct or not while the electroencephalogram (EEG) was recorded. A functional mixed effects model of the response to grammatically correct trials revealed a differential response to strong and weak forms of the adjectives. This response difference depended on whether the preceding preposition imposed accusative or dative case. The lexically conditioned information content of the adjectives modulated a later interval of the response. The results indicate that grammatical context modulates the response to morphosyntactic information content, and lends support to the role of paradigm structure in integrative phrasal processing.

Abstract

Speech comprehension is resistant to acoustic distortion in the input, reflecting listeners' ability to adjust perceptual processes to match the speech input. For noise-vocoded sentences, a manipulation that removes spectral detail from speech, listeners' reporting improved from near 0% to 70% correct over 30 sentences (Experiment 1). Learning was enhanced if listeners heard distorted sentences while they knew the identity of the undistorted target (Experiments 2 and 3). Learning was absent when listeners were trained with nonword sentences (Experiments 4 and 5), although the meaning of the training sentences did not affect learning (Experiment 5). Perceptual learning of noise-vocoded speech depends on higher level information, consistent with top-down, lexically driven learning. Similar processes may facilitate comprehension of speech in an unfamiliar accent or following cochlear implantation.

Abstract

Language is the best example of a cultural evolutionary system, able to retain a phylogenetic signal over many thousands of years. The temporal stability (conservatism) of basic vocabulary is relatively well understood, but the stability of the structural properties of language (phonology, morphology, syntax) is still unclear. Here we report an extensive Bayesian phylogenetic investigation of the structural stability of numerous features across many language families and we introduce a novel method for analyzing the relationships between the “stability profiles” of language families. We found that there is a strong universal component across language families, suggesting the existence of universal linguistic, cognitive and genetic constraints. Against this background, however, each language family has a distinct stability profile, and these profiles cluster by geographic area and likely deep genealogical relationships. These stability profiles reveal, for example, the ancient historical relationships between the Siberian and American language families, presumed to be separated by at least 12,000 years. Thus, such higher-level properties of language seen as an evolutionary system might allow the investigation of ancient connections between languages and shed light on the peopling of the world.

Abstract

Commentary on Cohen, E. (2012). The evolution of tag-based cooperation in humans: The case for accent. Current Anthropology, 53, 588-616. doi:10.1086/667654.

Abstract

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

Abstract

Speakers choose a particular expression based on many factors, including availability of the referent in the perceptual context. We examined whether, when expressing referents, monolingual English- and Turkish-speaking children: (1) are sensitive to perceptual context, (2) express this sensitivity in language-specific ways, and (3) use co-speech gestures to specify referents that are underspecified. We also explored the mechanisms underlying children's sensitivity to perceptual context. Children described short vignettes to an experimenter under two conditions: The characters in the vignettes were present in the perceptual context (perceptual context); the characters were absent (no perceptual context). Children routinely used nouns in the no perceptual context condition, but shifted to pronouns (English-speaking children) or omitted arguments (Turkish-speaking children) in the perceptual context condition. Turkish-speaking children used underspecified referents more frequently than English-speaking children in the perceptual context condition; however, they compensated for the difference by using gesture to specify the forms. Gesture thus gives children learning structurally different languages a way to achieve comparable levels of specification while at the same time adhering to the referential expressions dictated by their language.

Abstract

European cooperative effort seeks best practices architecture and procedures for international sites

Abstract

Abnormal prosody is a striking feature of the speech of those with Autism Spectrum Disorder (ASD), but previous reports suggest large variability among those with ASD. Here we show that part of this heterogeneity can be explained by level of language functioning. We recorded semi-spontaneous but controlled conversations in adults with and without Autism Spectrum Disorder and measured features related to pitch and duration to determine (1) general use of prosodic features, (2) prosodic use in relation to marking information structure, specifically, the emphasis of new information in a sentence (focus) as opposed to information already given in the conversational context (topic), and (3) the relation between prosodic use and level of language function. We found that, compared to typical adults, those with ASD with high language functioning generally used a larger pitch range than controls but did not mark information structure, whereas those with moderate language functioning generally used a smaller pitch range than controls but marked information structure appropriately to a large extent. Both impaired general prosodic use and impaired marking of information structure would be expected to seriously impact social communication and thereby lead to increased difficulty in personal domains, such as making and keeping friendships, and in professional domains, such as competing for employment opportunities.

Abstract

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

Abstract

Developmental dyslexia, a severe and persistent reading and spelling impairment, is characterized by difficulties in processing speech sounds (i.e., phonemes). Here, we test the hypothesis that these phonological difficulties are associated with a dysfunction of the auditory sensory thalamus, the medial geniculate body (MGB). By using functional MRI, we found that, in dyslexic adults, the MGB responded abnormally when the task required attending to phonemes compared with other speech features. No other structure in the auditory pathway showed distinct functional neural patterns between the two tasks for dyslexic and control participants. Furthermore, MGB activity correlated with dyslexia diagnostic scores, indicating that the task modulation of the MGB is critical for performance in dyslexics. These results suggest that deficits in dyslexia are associated with a failure of the neural mechanism that dynamically tunes MGB according to predictions from cortical areas to optimize speech processing. This view on task-related MGB dysfunction in dyslexics has the potential to reconcile influential theories of dyslexia within a predictive coding framework of brain function.

Abstract

The extent to which the phonetic system of a second language is mastered varies across individuals. The present study evaluates the pattern of individual differences in late bilinguals across different phonological processes. Fifty-five late Dutch-English bilinguals were tested on their ability to perceive a difficult L2 speech contrast (the English /æ/-/ε/ contrast) in three different tasks: A categorization task, a word identification task and a lexical decision task. As a group, L2 listeners were less accurate than native listeners. However, at the individual level, almost half of the L2 listeners scored within the native range in the categorization task whereas a small percentage scored within the native range in the identification and lexical decision tasks. These results show that L2 listeners' performance crucially depends on the nature of the task, with higher L2 listener accuracy on an acoustic-phonetic analysis task than on tasks involving lexical processes. These findings parallel previous results for early bilinguals, where the pattern of performance was consistent with the processing hierarchy proposed by different models of speech perception. The results indicate that the analysis of patterns of non-native performance can provide important insights concerning the architecture of the speech perception system and the issue of language learnability.

Abstract

Prosody, particularly accent, aids comprehension by drawing attention to important elements such as the information that answers a question. A study using ERP registration investigated how the brain deals with the interpretation of prosodic prominence. Sentences were embedded in short dialogues and contained accented elements that were congruous or incongruous with respect to a preceding question. In contrast to previous studies, no explicit prosodic judgment task was added. Robust effects of accentuation were evident in the form of an “accent positivity” (200–500 msec) for accented elements irrespective of their congruity. Our results show that incongruously accented elements, that is, superfluous accents, activate a specific set of neural systems that is inactive in case of incongruously unaccented elements, that is, missing accents. Superfluous accents triggered an early positivity around 100 msec poststimulus, followed by a right-lateralized negative effect (N400). This response suggests that redundant information is identified immediately and leads to the activation of a neural system that is associated with semantic processing (N400). No such effects were found when contextually expected accents were missing. In a later time window, both missing and superfluous accents triggered a late positivity on midline electrodes, presumably related to making sense of both kinds of mismatching stimuli. These results challenge previous findings of greater processing for missing accents and suggest that the natural processing of prosody involves a set of distinct, temporally organized neural systems.

Abstract

Current research on spoken language does not provide a consistent picture as to whether prosody, the melody and rhythm of speech, conveys a specific meaning. Perception studies show that English listeners assign meaning to prosodic patterns, and, for instance, associate some accents with contrast, whereas Dutch listeners behave more controversially. In two ERP studies we tested how Dutch listeners process words carrying two types of accents, which either provided new information (new information accents) or corrected information (corrective accents), both in single sentences (experiment 1) and after corrective and new information questions (experiment 2). In both experiments corrective accents elicited a sustained positivity as compared to new information accents, which started earlier in context than in single sentences. The positivity was not modulated by the nature of the preceding question, suggesting that the underlying neural mechanism likely reflects the construction of an interpretation to the accented word, either by identifying an alternative in context or by inferring it when no context is present. Our experimental results provide strong evidence for inferential processes related to prosodic contours in Dutch

Abstract

Empirical studies addressing the age factor in second language acquisition have mainly been concerned with a comparison of end state data (from learners before and after the closure of a putative Critical Period for language acquisition) to the native speaker norm. Based on longitudinal corpus data, this paper investigates the affect of age on end state, rate and the process of acquisition and addresses the question of whether different grammatical domains are equally affected. To this end, the paper presents summarized findings from the acquisition of word order and inflectional morphology in L2 German by Russian learners of different ages and discusses theoretical implications that can be drawn from this evidence.