The Unfolding of Language as <Emphasis Type="Italic">Hysteron Proteron</Emphasis>: Heterochrony and Extended Connectivity

In this paper it is championed that a two stages hypothesis for the evolution of language must take into account a qualified approach to heterochrony and the available information from the archaeological record. As it seems, a protracted childhood and youth was already at work in Homo erectus, but early postnatal brain growth (usually called secondary altriciality) was only available to Homo sapiens. According to these facts, the term hysteron proteron is given here to the reversal that sets off linguistic capacity during the first three years of life, upon the ancient abilities for social, natural and technological knowledge, which were already established during the last 2 Mya BP. The unfolding of linguistic capacity creates the typical effect that ontogeny reverses phylogeny: since late postnatal brain growth, quite recent in evolution, launches in ontogeny before the phylogenetically old processes of playing and learning take place during childhood and youth. Full symbolic abilities may be explained as emerging from older semiotic competences based on iconicity (figuration) and indexicality (metonymy), which would have presumably sustained human life for millennia. Furthermore, it is argued that the formation of linguistic categories follows from that overlaying of extended connectivity linked to early postnatal brain growth, inasmuch as it entangles and transforms previous iconic and referential information: i.e. the ancient semiotic capacities for proprioception, embodiment, extended mimesis and pragmatic knowledge, shaping a sort of self-organization process that provides the formal and semantic properties we find in articulated languages.     

How language <Emphasis Type="Italic">couldn’t</Emphasis> have evolved: a critical examination of Berwick and Chomsky’s theory of language evolution

This article examines some recent work by Berwick and Chomsky as presented in their book Why Only Us? Language and Evolution (2015). As I understand them, Berwick and Chomsky’s overarching purpose is to explain how human language could have arisen in so short an evolutionary period. After articulating their strategy, I argue that they fall far short of reaching this goal. A co-evolutionary scenario linking the mechanisms that realize the language system, both with one other and with cognitive mechanisms capable of exploiting linguistic expressions, is surely unavoidable. And yet this is precisely what Berwick and Chomsky in effect rule out.     

The self-organization of speech sounds

The speech code is a vehicle of language: it defines a set of forms used by a community to carry information. Such a code is necessary to support the linguistic interactions that allow humans to communicate. How then may a speech code be formed prior to the existence of linguistic interactions? Moreover, the human speech code is discrete and compositional, shared by all the individuals of a community but different across communities, and phoneme inventories are characterized by statistical regularities. How can a speech code with these properties form? We try to approach these questions in the paper, using the "methodology of the artificial". We build a society of artificial agents, and detail a mechanism that shows the formation of a discrete speech code without pre-supposing the existence of linguistic capacities or of coordinated interactions. The mechanism is based on a low-level model of sensory-motor interactions. We show that the integration of certain very simple and non-language-specific neural devices leads to the formation of a speech code that has properties similar to the human speech code. This result relies on the self-organizing properties of a generic coupling between perception and production within agents, and on the interactions between agents. The artificial system helps us to develop better intuitions on how speech might have appeared, by showing how self-organization might have helped natural selection to find speech.     

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.     

Modeling Coevolution between Language and Memory Capacity during Language Origin

Memory is essential to many cognitive tasks including language. Apart from empirical studies of memory effects on language acquisition and use, there lack sufficient evolutionary explorations on whether a high level of memory capacity is prerequisite for language and whether language origin could influence memory capacity. In line with evolutionary theories that natural selection refined language-related cognitive abilities, we advocated a coevolution scenario between language and memory capacity, which incorporated the genetic transmission of individual memory capacity, cultural transmission of idiolects, and natural and cultural selections on individual reproduction and language teaching. To illustrate the coevolution dynamics, we adopted a multi-agent computational model simulating the emergence of lexical items and simple syntax through iterated communications. Simulations showed that: along with the origin of a communal language, an initially-low memory capacity for acquired linguistic knowledge was boosted; and such coherent increase in linguistic understandability and memory capacities reflected a language-memory coevolution; and such coevolution stopped till memory capacities became sufficient for language communications. Statistical analyses revealed that the coevolution was realized mainly by natural selection based on individual communicative success in cultural transmissions. This work elaborated the biology-culture parallelism of language evolution, demonstrated the driving force of culturally-constituted factors for natural selection of individual cognitive abilities, and suggested that the degree difference in language-related cognitive abilities between humans and nonhuman animals could result from a coevolution with language.     

Tool behavior and the origins of laterality

The cerebral cortex of modern humans is exceptional in that it is characterized by certain functional asymmetries for which no clear homologue is known in the non-human primates. These asymmetries consist at least in part in the presence in the left cerebral hemisphere of certain mechanisms which mediate language as well as skilled manual activity. Right-handedness is the most obvious overt manifestation of this cerebral asymmetry. It is argued in this paper that the lateralized representation of these mechanisms is an evolutionary consequence of the requirement for asymmetric employment of the forelimbs in the making and using of tools during hominid evolution. The adaptiveness of such an asymmetric arrangement is shown to follow from a few assumptions pertaining to brain organization and evolution. The colateralization of language mechanisms in modern humans to the left hemisphere is held to be a consequence of the coupling of these linguistic mechanisms to the motoric mechanisms already lateralized to the left hemisphere at an earlier point in hominid evolution. Finally, it is argued that this explanation of the evolution of laterality is more parsimonious in relation to known facts about human evolution than competing hypotheses.     

Soft selective sweeps: Addressing new definitions,evaluating competing models,and interpreting empirical outliers

The ability to accurately identify and quantify genetic signatures associated with soft selective sweeps based on patterns of nucleotide variation has remained controversial. We here provide counter viewpoints to recent publications in PLOS Genetics that have argued not only for the statistical identifiability of soft selective sweeps, but also for their pervasive evolutionary role in both Drosophila and HIV populations. We present evidence that these claims owe to a lack of consideration of competing evolutionary models, unjustified interpretations of empirical outliers, as well as to new definitions of the processes themselves. Our results highlight the dangers of fitting evolutionary models based on hypothesized and episodic processes without properly first considering common processes and, more generally, of the tendency in certain research areas to view pervasive positive selection as a foregone conclusion.

“We would not object so strenuously to the adaptationist programme if its invocation, in any particular case, could lead in principle to its rejection for want of evidence. We might still view it as restrictive and object to its status as an argument of first choice. But if it could be dismissed after failing some explicit test, then alternatives would get their chance. Unfortunately, a common procedure among evolutionists does not allow such definable rejection for two reasons. First, the rejection of one adaptive story usually leads to its replacement by another, rather than to a suspicion that a different kind of explanation might be required. Secondly, the criteria for acceptance of a story are so loose that many pass without proper confirmation. Often, evolutionists use consistency with natural selection as the sole criterion and consider their work done when they concoct a plausible story.” - Gould and Lewontin, 1979 [1]

     

Effects of culture on musical pitch perception

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture-to-perception influences.     

Bayesian phylogenetic analysis supports an agricultural origin of Japonic languages

Languages, like genes, evolve by a process of descent with modification. This striking similarity between biological and linguistic evolution allows us to apply phylogenetic methods to explore how languages, as well as the people who speak them, are related to one another through evolutionary history. Language phylogenies constructed with lexical data have so far revealed population expansions of Austronesian, Indo-European and Bantu speakers. However, how robustly a phylogenetic approach can chart the history of language evolution and what language phylogenies reveal about human prehistory must be investigated more thoroughly on a global scale. Here we report a phylogeny of 59 Japonic languages and dialects. We used this phylogeny to estimate time depth of its root and compared it with the time suggested by an agricultural expansion scenario for Japanese origin. In agreement with the scenario, our results indicate that Japonic languages descended from a common ancestor approximately 2182 years ago. Together with archaeological and biological evidence, our results suggest that the first farmers of Japan had a profound impact on the origins of both people and languages. On a broader level, our results are consistent with a theory that agricultural expansion is the principal factor for shaping global linguistic diversity.     

Animal linguistics: a primer

The evolution of language has been investigated by several research communities, including biologists and linguists, striving to highlight similar linguistic capacities across species. To date, however, no consensus exists on the linguistic capacities of non-human species. Major controversies remain on the use of linguistic terminology, analysis methods and behavioural data collection. The field of ‘animal linguistics’ has emerged to overcome these difficulties and attempt to reach uniform methods and terminology. This primer is a tutorial review of ‘animal linguistics’. It describes the linguistic concepts of semantics, pragmatics and syntax, and proposes minimal criteria to be fulfilled to claim that a given species displays a particular linguistic capacity. Second, it reviews relevant methods successfully applied to the study of communication in animals and proposes a list of useful references to detect and overcome major pitfalls commonly observed in the collection of animal behaviour data. This primer represents a step towards mutual understanding and fruitful collaborations between linguists and biologists.     

Unity and diversity in human language

Human language is both highly diverse-different languages have different ways of achieving the same functional goals-and easily learnable. Any language allows its users to express virtually any thought they can conceptualize. These traits render human language unique in the biological world. Understanding the biological basis of language is thus both extremely challenging and fundamentally interesting. I review the literature on linguistic diversity and language universals, suggesting that an adequate notion of 'formal universals' provides a promising way to understand the facts of language acquisition, offering order in the face of the diversity of human languages. Formal universals are cross-linguistic generalizations, often of an abstract or implicational nature. They derive from cognitive capacities to perceive and process particular types of structures and biological constraints upon integration of the multiple systems involved in language. Such formal universals can be understood on the model of a general solution to a set of differential equations; each language is one particular solution. An explicit formal conception of human language that embraces both considerable diversity and underlying biological unity is possible, and fully compatible with modern evolutionary theory.     

Curious parallels and curious connections--phylogenetic thinking in biology and historical linguistics

In The Descent of Man (1871), Darwin observed "curious parallels" between the processes of biological and linguistic evolution. These parallels mean that evolutionary biologists and historical linguists seek answers to similar questions and face similar problems. As a result, the theory and methodology of the two disciplines have evolved in remarkably similar ways. In addition to Darwin's curious parallels of process, there are a number of equally curious parallels and connections between the development of methods in biology and historical linguistics. Here we briefly review the parallels between biological and linguistic evolution and contrast the historical development of phylogenetic methods in the two disciplines. We then look at a number of recent studies that have applied phylogenetic methods to language data and outline some current problems shared by the two fields.     

Ethnobiology and the evolution of the human mind

An evolutionary perspective on human thought and behaviour indicates that we should expect to find universal systems of perception, classification, and decision-making regarding the natural world. It is the interaction between these evolved aspects of the human mind, the biodiversity of the natural world, and unique historical, social, and economic contexts within which individuals develop and act that gives rise to cultural diversity. The palaeoanthropological record also indicates that language is a recently evolved phenomenon. This suggests that linguistic approaches in ethnobiology are likely to provide only a partial understanding of how humans perceive, classify, and engage with the natural world.     

Linguistic Relativity: Does Language Help or Hinder Perception?

A recent study has explored the interplay between language and perception through the brain's visual pathways. The results suggest an influence of linguistic categories on the speed of colour discrimination.     

Teleology, function, design and the evolution of animal behaviour

Concerns about teleological language in evolutionary biology focus on the notions of function, design and adaptation. Accounts that naturalize these ideas are currently popular. In keeping with recent developments in evolutionary theory and philosophy of biology, three naturalistic analyses of function - current utility, historical function, and functions as capacities - should be differentiated. All have roles to play in biology, although the historical conception seems the most central to evolutionary theory. While rarely distinguished from function, design should be regarded as an extension of historical function. We consider the utility of this distinction for the study of behaviour.     

New perspectives on taste and primate evolution: the dichotomy in gustatory coding for perception of beneficent versus noxious substances as supported by correlations among human thresholds

In various environments where primates are presently observed, as well as in forests and savannas which have been inhabited by australopithecines and early hominids, there are (or there have been presumably) categories of substances eliciting taste signals associated with stereotyped responses. Such is the case for various soluble sugars of fruits and nectars, attracting consumers, and for several plant compounds in which bitter or strongly astringent properties have a repulsive effect. The occurrence of such classes of tasty substances among natural products appears to be related to the evolutionary trends that shaped primate sensory perception (for detecting either beneficent or potentially noxious substances) in the context of a long history of coevolution between animals and plants. Here, we present original psychophysical data on humans (412 individuals aged 17-59 years) as an analogy with which to test recent evidence from electrophysiology in nonhuman primates (Hellekant et al. [1997] J. Neurophysiol. 77:978-993; Danilova et al. [1998] Ann. N.Y. Acad. Sci. 855:160-164) that taste fibers can be grouped into clusters of "best-responding fibers" with two more specific clusters, one for sugars and one for quinine and tannins. The collinearity found between human taste responses (recognition thresholds) for fructose and sucrose, as well as for quinine and tannins, is presented and discussed as another evidence of the two-direction evolutionary trend determining taste sensitivity. Salt perception appears to be totally independent of these trends. Accordingly, the appreciation of a salty taste seems to be a recent culturally learned response, and not a primary taste perception. The very existence of primary tastes is discussed in the context of evolutionary trends, past and present.     

Why bodies? Twelve reasons for including bodily expressions in affective neuroscience

Why bodies? It is rather puzzling that given the massive interest in affective neuroscience in the last decade, it still seems to make sense to raise the question ‘Why bodies’ and to try to provide an answer to it, as is the goal of this article. There are now hundreds of articles on human emotion perception ranging from behavioural studies to brain imaging experiments. These experimental studies complement decades of reports on affective disorders in neurological patients and clinical studies of psychiatric populations. The most cursory glance at the literature on emotion in humans, now referred to by the umbrella term of social and affective neuroscience, shows that over 95 per cent of them have used faces as stimuli. Of the remaining 5 per cent, a few have used scenes or auditory information including human voices, music or environmental sounds. But by far the smallest number has looked into whole-body expressions. As a rough estimate, a search on PubMed today, 1 May 2009, yields 3521 hits for emotion × faces, 1003 hits for emotion × music and 339 hits for emotion × bodies. When looking in more detail, the body × emotion category in fact yields a majority of papers on well-being, nursing, sexual violence or organ donation. But the number of cognitive and affective neuroscience studies of emotional body perception as of today is lower than 20.Why then have whole bodies and bodily expressions not attracted the attention of researchers so far? The goal of this article is to contribute some elements for an answer to this question. I believe that there is something to learn from the historical neglect of bodies and bodily expressions. I will next address some historical misconceptions about whole-body perception, and in the process I intend not only to provide an impetus for this kind of work but also to contribute to a better understanding of the significance of the affective dimension of behaviour, mind and brain as seen from the vantage point of bodily communication. Subsequent sections discuss available evidence for the neurofunctional basis of facial and bodily expressions as well as neuropsychological and clinical studies of bodily expressions.     

On the fundamental nature of perception

The process of recognition or isolation of one or several entities from among many possible entities is termed intellego perception. It is shown that not only are many of our everyday percepts of this type, but perception of microscopic events using the methods of quantum mechanics are also intellego in nature. Information theory seems to be a natural language in which to express perceptual activity of this type. It is argued that the biological organism quantifies its sensations using an information theoretical measure. This, in turn, sets the stage for a mathematical theory of sensory perception.