The invasion of language: emergence, change and death

Research into the emergence and evolution of human language has received unprecedented attention during the past 15 years. Efforts to better understand the processes of language emergence and evolution have proceeded in two main directions: from the top-down (linguists) and from the bottom-up (cognitive scientists). Language can be viewed as an invading process that has had profound impact on the human phenotype at all levels, from the structure of the brain to modes of cultural interaction. In our view, the most effective way to form a connection between the two efforts (essential if theories for language evolution are to reflect the constraints imposed on language by the brain) lies in computational modelling, an approach that enables numerous hypotheses to be explored and tested against objective criteria and which suggest productive paths for empirical researchers to then follow. Here, with the aim of promoting the cross-fertilization of ideas across disciplines, we review some of the recent research that has made use of computational methods in three principal areas of research into language evolution: language emergence, language change, and language death.     

Neurons in area V4 of the macaque translate attended visual features into behaviorally relevant categories

Neural processing at most stages of the primate visual system is modulated by selective attention, such that behaviorally relevant information is emphasized at the expenses of irrelevant, potentially distracting information. The form of attention best understood at the cellular level is when stimuli at a given location in the visual field must be selected (space-based attention). In contrast, fewer single-unit recording studies have so far explored the cellular mechanisms of attention operating on individual stimulus features, specifically when one feature (e.g., color) of an object must guide behavioral responses while a second feature (e.g., shape) of the same object is potentially interfering and therefore must be ignored. Here we show that activity of neurons in macaque area V4 can underlie the selection of elemental object features and their "translation" into a categorical format that can directly contribute to the control of the animal's behavior.     

How hierarchical is language use?

It is generally assumed that hierarchical phrase structure plays a central role in human language. However, considerations of simplicity and evolutionary continuity suggest that hierarchical structure should not be invoked too hastily. Indeed, recent neurophysiological, behavioural and computational studies show that sequential sentence structure has considerable explanatory power and that hierarchical processing is often not involved. In this paper, we review evidence from the recent literature supporting the hypothesis that sequential structure may be fundamental to the comprehension, production and acquisition of human language. Moreover, we provide a preliminary sketch outlining a non-hierarchical model of language use and discuss its implications and testable predictions. If linguistic phenomena can be explained by sequential rather than hierarchical structure, this will have considerable impact in a wide range of fields, such as linguistics, ethology, cognitive neuroscience, psychology and computer science.     

Adaptive Communication: Languages with More Non-Native Speakers Tend to Have Fewer Word Forms

Explaining the diversity of languages across the world is one of the central aims of typological, historical, and evolutionary linguistics. We consider the effect of language contact-the number of non-native speakers a language has-on the way languages change and evolve. By analysing hundreds of languages within and across language families, regions, and text types, we show that languages with greater levels of contact typically employ fewer word forms to encode the same information content (a property we refer to as lexical diversity). Based on three types of statistical analyses, we demonstrate that this variance can in part be explained by the impact of non-native speakers on information encoding strategies. Finally, we argue that languages are information encoding systems shaped by the varying needs of their speakers. Language evolution and change should be modeled as the co-evolution of multiple intertwined adaptive systems: On one hand, the structure of human societies and human learning capabilities, and on the other, the structure of language.     

Getting the most out of Shannon information

Shannon information is commonly assumed to be the wrong way in which to conceive of information in most biological contexts. Since the theory deals only in correlations between systems, the argument goes, it can apply to any and all causal interactions that affect a biological outcome. Since informational language is generally confined to only certain kinds of biological process, such as gene expression and hormone signalling, Shannon information is thought to be unable to account for this restriction. It is often concluded that a richer, teleosemantic sense of information is needed. I argue against this view, and show that a coherent and sufficiently restrictive theory of biological information can be constructed with Shannon information at its core. This can be done by paying due attention some crucial distinctions: between information quantity and its fitness value, and between carrying information and having the function of doing so. From this I construct an account of how informational functions arise, and show that the “subject matter” of these functions can easily be seen as the natural information dealt with by Shannon’s theory.     

Self domestication and the evolution of language

We set out an account of how self-domestication plays a crucial role in the evolution of language. In doing so, we focus on the growing body of work that treats language structure as emerging from the process of cultural transmission. We argue that a full recognition of the importance of cultural transmission fundamentally changes the kind of questions we should be asking regarding the biological basis of language structure. If we think of language structure as reflecting an accumulated set of changes in our genome, then we might ask something like, “What are the genetic bases of language structure and why were they selected?” However, if cultural evolution can account for language structure, then this question no longer applies. Instead, we face the task of accounting for the origin of the traits that enabled that process of structure-creating cultural evolution to get started in the first place. In light of work on cultural evolution, then, the new question for biological evolution becomes, “How did those precursor traits evolve?” We identify two key precursor traits: (1) the transmission of the communication system through learning; and (2) the ability to infer the communicative intent associated with a signal or action. We then describe two comparative case studies—the Bengalese finch and the domestic dog—in which parallel traits can be seen emerging following domestication. Finally, we turn to the role of domestication in human evolution. We argue that the cultural evolution of language structure has its origin in an earlier process of self-domestication.     

Insights into Coupled Folding and Binding Mechanisms from Kinetic Studies

Intrinsically disordered proteins (IDPs) are characterized by a lack of persistent structure. Since their identification more than a decade ago, many questions regarding their functional relevance and interaction mechanisms remain unanswered. Although most experiments have taken equilibrium and structural perspectives, fewer studies have investigated the kinetics of their interactions. Here we review and highlight the type of information that can be gained from kinetic studies. In particular, we show how kinetic studies of coupled folding and binding reactions, an important class of signaling event, are needed to determine mechanisms.     

The transfer of information in the dance language of honeybees: progress and problems

The dance language of honeybees will always be associated with the name of Karl von Frisch, who was one of the two founders of Zeitschrift für Vergleichende Physiologie, now the Journal of Comparative Physiology. The discovery of the dance language has already led to a great number of investigations of physiological mechanisms, and more studies can be expected in the future. It therefore seems most appropriate to let this King Solomon Lecture deal with the progress and problems in our efforts to understand the transfer of information in the dance language of honeybees.     

Genetic genealogy comes of age: Perspectives on the use of deep‐rooted pedigrees in human population genetics

In this article, we promote the implementation of extensive genealogical data in population genetic studies. Genealogical records can provide valuable information on the origin of DNA donors in a population genetic study, going beyond the commonly collected data such as residence, birthplace, language, and self‐reported ethnicity. Recent studies demonstrated that extended genealogical data added to surname analysis can be crucial to detect signals of (past) population stratification and to interpret the population structure in a more objective manner. Moreover, when in‐depth pedigree data are combined with haploid markers, it is even possible to disentangle signals of temporal differentiation within a population genetic structure during the last centuries. Obtaining genealogical data for all DNA donors in a population genetic study is a labor‐intensive task but the vastly growing (genetic) genealogical databases, due to the broad interest of the public, are making this job more time‐efficient if there is a guarantee for sufficient data quality. At the end, we discuss the advantages and pitfalls of using genealogy within sampling campaigns and we provide guidelines for future population genetic studies. Am J Phys Anthropol 150:505–511, 2013. © 2013 Wiley Periodicals, Inc.     

When language breaks into pieces. A conflict between communication through isolated signals and language

Here, we study a communication model where signals associate to stimuli. The model assumes that signals follow Zipf's law and the exponent of the law depends on a balance between maximizing the information transfer and saving the cost of signal use. We study the effect of tuning that balance on the structure of signal-stimulus associations. The model starts from two recent results. First, the exponent grows as the weight of information transfer increases. Second, a rudimentary form of language is obtained when the network of signal-stimulus associations is almost connected. Here, we show the existence of a sudden destruction of language once a critical balance is crossed. The model shows that maximizing the information transfer through isolated signals and language are in conflict. The model proposes a strong reason for not finding large exponents in complex communication systems: language is in danger. Besides, the findings suggest that human words may need to be ambiguous to keep language alive. Interestingly, the model predicts that large exponents should be associated to decreased synaptic density. It is not surprising that the largest exponents correspond to schizophrenic patients since, according to the spirit of Feinberg's hypothesis, i.e. decreased synaptic density may lead to schizophrenia. Our findings suggest that the exponent of Zipf's law is intimately related to language and that it could be used to detect anomalous structure and organization of the brain.     

The structural changes in the ribosome during the elongation cycle

The plenty of data about structural changes in the ribosome during its functioning has been accumulated. The most interesting information on such changes was obtained by cryo-EM of various ribosomal complexes with the ligands and by combination of rRNA site-directed mutagenesis with the analysis of structural changes in ribosome by chemical modification technique (chemical probing). The most studied structural transformations of the ribosome interacting with tRNAs and elongation factors are considered in this review. The structural rearrangements are discussed in the context of interactions between the functional centers of the ribosome. We also describe the system of tertiary contacts between the rRNA helices and proteins which forms the universal structure in the ribosome. We pay attention that by means of such system the allosteric conformational signal can be transmitted between the functional centers. Besides the discussion of different biochemical data in the scope of structural data we also consider the hypothesis that the position of GTPase associated center (GAC) in the ribosome regulates the binding of elongation factors.     

Exploring the Complex Pattern of Information Spreading in Online Blog Communities

Information spreading in online social communities has attracted tremendous attention due to its utmost practical values in applications. Despite that several individual-level diffusion data have been investigated, we still lack the detailed understanding of the spreading pattern of information. Here, by comparing information flows and social links in a blog community, we find that the diffusion processes are induced by three different spreading mechanisms: social spreading, self-promotion and broadcast. Although numerous previous studies have employed epidemic spreading models to simulate information diffusion, we observe that such models fail to reproduce the realistic diffusion pattern. In respect to users behaviors, strikingly, we find that most users would stick to one specific diffusion mechanism. Moreover, our observations indicate that the social spreading is not only crucial for the structure of diffusion trees, but also capable of inducing more subsequent individuals to acquire the information. Our findings suggest new directions for modeling of information diffusion in social systems, and could inform design of efficient propagation strategies based on users behaviors.     

A Representational Similarity Analysis of the Dynamics of Object Processing Using Single-Trial EEG Classification

The recognition of object categories is effortlessly accomplished in everyday life, yet its neural underpinnings remain not fully understood. In this electroencephalography (EEG) study, we used single-trial classification to perform a Representational Similarity Analysis (RSA) of categorical representation of objects in human visual cortex. Brain responses were recorded while participants viewed a set of 72 photographs of objects with a planned category structure. The Representational Dissimilarity Matrix (RDM) used for RSA was derived from confusions of a linear classifier operating on single EEG trials. In contrast to past studies, which used pairwise correlation or classification to derive the RDM, we used confusion matrices from multi-class classifications, which provided novel self-similarity measures that were used to derive the overall size of the representational space. We additionally performed classifications on subsets of the brain response in order to identify spatial and temporal EEG components that best discriminated object categories and exemplars. Results from category-level classifications revealed that brain responses to images of human faces formed the most distinct category, while responses to images from the two inanimate categories formed a single category cluster. Exemplar-level classifications produced a broadly similar category structure, as well as sub-clusters corresponding to natural language categories. Spatiotemporal components of the brain response that differentiated exemplars within a category were found to differ from those implicated in differentiating between categories. Our results show that a classification approach can be successfully applied to single-trial scalp-recorded EEG to recover fine-grained object category structure, as well as to identify interpretable spatiotemporal components underlying object processing. Finally, object category can be decoded from purely temporal information recorded at single electrodes.     

Why is joint attention a pivotal skill in autism?

Joint attention abilities play a crucial role in the development of autism. Impairments in joint attention are among the earliest signs of the disorder and joint attention skills relate to outcome, both in the 'natural course' of autism and through being targeted in early intervention programmes. In the current study, concurrent and longitudinal associations between joint attention and other social communication abilities measured in a sample of infants with autism and related pervasive developmental disorders at age 20 months, and language and symptom severity at age 42 months, were examined. Extending the findings from previous studies, joint attention ability was positively associated with language gains and (lower) social and communication symptoms, and imitation ability was also positively associated with later language. Some specificity in the association between different aspects of joint attention behaviours and outcome was found: declarative, triadic gaze switching predicted language and symptom severity but imperative, dyadic eye contact behaviours did not. Further, although joint attention was associated with later social and language symptoms it was unrelated to repetitive and stereotyped symptoms, suggesting the latter may have a separate developmental trajectory. Possible deficits in psychological and neurological processes that might underlie the impaired development of joint attention in autism are discussed.     

Neurophysiological mechanisms involved in language learning in adults

Little is known about the brain mechanisms involved in word learning during infancy and in second language acquisition and about the way these new words become stable representations that sustain language processing. In several studies we have adopted the human simulation perspective, studying the effects of brain-lesions and combining different neuroimaging techniques such as event-related potentials and functional magnetic resonance imaging in order to examine the language learning (LL) process. In the present article, we review this evidence focusing on how different brain signatures relate to (i) the extraction of words from speech, (ii) the discovery of their embedded grammatical structure, and (iii) how meaning derived from verbal contexts can inform us about the cognitive mechanisms underlying the learning process. We compile these findings and frame them into an integrative neurophysiological model that tries to delineate the major neural networks that might be involved in the initial stages of LL. Finally, we propose that LL simulations can help us to understand natural language processing and how the recovery from language disorders in infants and adults can be accomplished.     

视觉注意与神经振荡

人脑每时每刻都要接收大量视觉信息，由于人脑加工信息的能力有限，所以在较大视野内将注意分配给相关信息，同时抑制引起注意分散的不相关信息，对执行目标导向的行为至关重要。这种对视觉信息的选择性和主动性加工以适应当前目标的过程被称作视觉注意（visual attention），且视觉注意可分为自上而下的注意与自下而上的注意两种不同功能。由于来自大脑电信号的神经振荡活动在认知加工中发挥重要作用，已有研究综述了视觉注意与神经振荡（neural oscillation）的密切关系，但并未涉及不同的注意功能与神经振荡的关系。本文系统性调查了不同注意功能与神经振荡的关系，发现额-顶区域的theta频带振荡活动反映了自上而下的认知控制，而后部脑区的theta振荡与自下而上的注意相关。顶-枕区域alpha振荡的偏侧化有助于注意分配，而alpha频带的大规模同步促成了注意对视皮层自上而下的影响。Beta振荡介导了自上而下的信息与自下而上的信息之间的互动，作为信息载体促进了视觉信息处理。Gamma振荡则可能与自上而下和自下而上的注意间整合相关。本文就视觉注意功能与神经振荡关系的研究现状展开综述，旨在揭示不同的神经振荡活动在特定的视觉注意功能中的作用。     

Some methodological issues in macroecology

Recent years have seen the emergence of "macroecology" as a distinct research program in biology. It is concerned with geographical scale patterns in assemblage structure and, as such, of necessity relies heavily on approaches that are nonexperimental and that depend on the availability of reliable information for large numbers of species. This gives rise to a particular set of analytical issues that need to be addressed when conducting studies of macroecological patterns. In this article, we draw attention to nine such issues that we consider to be of particular importance. Our aim is to aid the development of what we believe to be an important subject area by identifying some of the more common problems that may confound studies, as well as some of their solutions.     

Turkish-language ability of children of immigrants in Germany: which contexts of exposure influence preschool children's acquisition of their heritage language?

A lot of research has been devoted to explaining immigrants' acquisition of the language of the receiving country. However, less attention has been paid to explaining the acquisition of the heritage language among children of immigrants. The most important determinant for young children is exposure to the language. Language exposure can occur in various contexts, such as within the family, during preschool, through peers or via media. Our empirical analysis therefore explores which of these contexts is most statistically significant for the acquisition of the heritage language among children of Turkish immigrants. Using data from the project Preschool Education and Educational Careers among Migrant Children, we show that all contexts are important at different age levels but the acquisition of the heritage language is mainly determined by the exposure to it within the family.