Evolution Of Human Language Research Articles

Neotropical wrens learn new duet rules as adults.

Although song development in songbirds has been much studied as an analogue of language development in humans, the development of vocal interaction rules has been relatively neglected in both groups. Duetting avian species provide an ideal model to address the acquisition of interaction rules as duet structure involves time and pattern-specific relationships among the vocalizations from different individuals. In this study, we address the development of the most striking properties of duets: the specific answering rules that individuals use to link their own phrase types to those of their partners (duet codes) and precise temporal coordination. By performing two removal experiments in canebrake wrens (Cantorchilus zeledoni), we show that individuals use a fixed phrase repertoire to create new phrase pairings when they acquire a new partner. Furthermore, immediately after pairing, individuals perform duets with poor coordination and poor duet code adherence, but both aspects improve with time. These results indicate that individuals need a learning period to be able to perform well-coordinated duets that follow a consistent duet code. We conclude that both duet coordination and duet code adherence are honest indicators of pair-bond duration.

From experience to imagination: Language and its evolution as a social communication technology

Abstract In this paper, I present a new general hypothesis concerning the origin and evolutionary development of human language and its speakers. The hypothesis is based on the theory of language I develop in Dor (2015): language should be properly understood as a social communication technology of a very particular type, collectively constructed for the specific function of the instruction of imagination . The hypothesis, then, runs as follows: pre-linguistic humans (most probably Homo erectus) developed their culture and their pre-linguistic communication to the point where the collective invention of language became both necessary and possible. The moment of the origin consisted of no more than exploratory attempts to use what had already been achieved to go into the realm of the instruction of imagination. When the new function began to show its potential, a developmental process was launched that was directly driven throughout by the constant pressure to raise the levels of collective success in instructive communication. Throughout the process, individuals were selected for their ability to meet the challenges of the emerging technology, and the required capacities were (partially and variably) genetically accommodated. Homo sapiens, an imaginative species adapted for fast speech, and maybe our sisters species too, eventually emerged from the collectively-driven process with unique adaptations to language.

Speeding up chaos and limit cycles in evolutionary language and learning processes

Evolution of human language and learning processes have their foundation built on grammar that sets rules for construction of sentences and words. These forms of replicator–mutator (game dynamical with learning) dynamics remain however complex and sometime unpredictable because they involve children with some predispositions. In this paper, a system modeling evolutionary language and learning dynamics is investigated using the Crank–Nicholson numerical method together with the new differentiation with non‐singular kernel. Stability and convergence are comprehensively proven for the system. In order to seize the effects of the non‐singular kernel, an application to game dynamical with learning dynamics for a population with five languages is given together with numerical simulations. It happens that such dynamics, as functions of the learning accuracy μ, can exhibit unusual bifurcations and limit cycles followed by chaotic behaviors. This points out the existence of fickle and unpredictable variations of languages as time goes on, certainly due to the presence of learning errors. More interestingly, this chaos is shown to be dependent on the order of the non‐singular kernel derivative and speeds up as this derivative order decreases. Hence, can people use that order to control chaotic behaviors observed in game dynamical systems with learning! Copyright © 2016 John Wiley & Sons, Ltd.

Continuity and Discontinuity in Human Language Evolution: Putting an Old-fashioned Debate in its Historical Perspective

The article reconstructs the main lines of three hypotheses in the current literature concerning the evolutionary pace which characterized the natural history of human language: the “continuist” and gradualist perspective, the “discontinuist” and evolution-free perspective, and the “punctuationist” view. This current debate appears to have a long history, which starts at least from Darwin’s time. The article highlights the similarities between the old and the modern debates in terms of history of ideas, and it shows the current limits of each of these perspectives. In the final part, we present an alternative approach which considers human language not as a single trait, but as the result of a mosaic of different elements, some of which recently evolved, and some others gradually evolved and phylogenetically ancient. When matched with a tree thinking and comparative perspective, this view suggests that expressions of symbolic and linguistic behaviors in other human species could have preceded the more complex and systematic behaviors showed by Homo sapiens.

Language and Culture: Nigerian Perspective

The power of language to reflect culture and influence thinking was first proposed by an American linguist and anthropologist, Edward Sapir (1884-1939) and his student, Benjamin Whorf (1897-1941). The Saphir-Whorf hypothesis stated that the way we think and view the world is determined by our language. This theory also stated that some languages have specific words or concepts where other languages use several words to represent a specific concept. Culture is the totality of ways and manners people live their lives and be able to make sense of their existence. Every group and society has cultures that constitute the framework for their lives and behavioural patterns. Hence the linguistic, social and economic performance of nations can only be best appreciated and explained against the backdrop of the prevailing cultural domains. This paper opined that culture is a very dynamic and lethal force which should be driven to achieve human growth and language development. It explores how the development of language could lead to cultural enhancement in Nigeria. Key Words - language, culture, communication, linguistics, perception

“What gave rise to modern human behavior?”: Perspective from psychology

In celebration of the 125th anniversary of the first publication of Science magazine in the United States in 2005, the journal made a special list with 125 of the most challenging scientific questions, one of which was, “What gave rise to modern human behaviors? Did Homo sapiens acquire abstract thought, language, and art gradually or in a cultural ‘big bang’, which in Europe occurred about 40000 years ago?” Data from Africa, where our species arose, might hold the key to the answer. In the last ten years, the advances of research concerning this question from the perspective of psychology had been reviewed. Homo sapiens developed abstract thoughts, languages, and the arts during the evolution of the species. It found that human gene mutation enabled humans to grasp and use languages forty or fifty thousand years ago. As the species developed, humans began to use tools, hunted and gathered food to adapt to their changing place in nature. During this process, humans mastered languages and learned to cooperate, traded with each other, and used natural materials for decoration and artistic expressions. Humans acquired some certain thought models during the interaction with their environment. Human physiological structure and the evolution of the brain shaped their behaviors in their interaction with the environment. Based on these factors, some researchers think that modern human behaviors did not appear suddenly, but rather was the result of adaptation to the environment and the struggle for survival. The basic premise in evolutionary psychology is that people’s mental states consist of tens of thousands of modules, which are the results of adaptation to the environment. The process of evolution is accompanied by the development of human languages, which provide an important foundation for human survival and modern behaviors. In order to adapt better to the environment where people live, more advanced behaviors evolved, just as the whales, whose ancestors were land-dwellers, adapted to the environment of the sea. Examples of this are perception ability, the social roles of the genders, gender differences in spatial memory, and cultural psychological differences. Here, an evolutionary perspective is taken to explore the origin of the human minds based on the materials and methods of evolutionary biology, suggesting that modern human behavior is the result of slow evolution and adaptation to the environment. The development of culture has also had a significant impact, and has become one of the defining characteristics of human life.

Cumulative Cultural Evolution and the Origins of Language

In this article, I present a substantive proposal about the timing and nature of the final stage of the evolution of full human language, the transition from so-called “protolanguage” to language, and on the origins of a simple protolanguage with structure and displaced reference; a proposal that depends on the idea that the initial expansion of communicative powers in our lineage involved a much expanded role for gesture and mime. But though it defends a substantive proposal, the article also (perhaps more importantly) defends and illustrates a methodological proposal too. I argue that language is a special case of a more general phenomenon—cumulative cultural evolution—and while we rarely have direct information about communication, we have more direct information about the cumulative cultural evolution of technical skill, ecological strategies, and social complexity. These same factors also enable us to make a reasonable estimate of the intergenerational social learning capacities of these communities (on which rich communication depends) and of the communicative demands these communities face. For example, we can, at least tentatively, identify forms of cooperation that are stable only if third party information is transmitted widely, cheaply, and accurately. So we can use these more direct markers of information accumulation to locate, in broad terms, the period in our evolutionary history during which we became lingual.

Darwinian perspectives on the evolution of human languages

Human languages evolve by a process of descent with modification in which parent languages give rise to daughter languages over time and in a manner that mimics the evolution of biological species. Descent with modification is just one of many parallels between biological and linguistic evolution that, taken together, offer up a Darwinian perspective on how languages evolve. Combined with statistical methods borrowed from evolutionary biology, this Darwinian perspective has brought new opportunities to the study of the evolution of human languages. These include the statistical inference of phylogenetic trees of languages, the study of how linguistic traits evolve over thousands of years of language change, the reconstruction of ancestral or proto-languages, and using language change to date historical events.

What bats have to say about speech and language

Understanding the biological foundations of language is vital to gaining insight into how the capacity for language may have evolved in humans. Animal models can be exploited to learn about the biological underpinnings of shared human traits, and although no other animals display speech or language, a range of behaviors found throughout the animal kingdom are relevant to speech and spoken language. To date, such investigations have been dominated by studies of our closest primate relatives searching for shared traits, or more distantly related species that are sophisticated vocal communicators, like songbirds. Herein I make the case for turning our attention to the Chiropterans, to shed new light on the biological encoding and evolution of human language-relevant traits. Bats employ complex vocalizations to facilitate navigation as well as social interactions, and are exquisitely tuned to acoustic information. Furthermore, bats display behaviors such as vocal learning and vocal turn-taking that are directly pertinent for human spoken language. Emerging technologies are now allowing the study of bat vocal communication, from the behavioral to the neurobiological and molecular level. Although it is clear that no single animal model can reflect the complexity of human language, by comparing such findings across diverse species we can identify the shared biological mechanisms likely to have influenced the evolution of human language.

A multifactorial investigation of captive chimpanzees' intraspecific gestural laterality

Social laterality is the core of two major theories: one concerns the evolution of laterality at the population level and the other the evolution of human language. However, few studies have investigated gestural laterality in communication between conspecifics. To our knowledge, the present study is the first to investigate the production of intraspecific gestures taking into account the influence of multiple factors on gestural laterality: first, gestural characteristics (sensory modality, use of a communication tool, sharing degree in the population and duration); second, the interactional context (visual field and body sides of signaller and recipient, and emotional context); and third, individual sociodemographic characteristics of signaller and recipient (age, sex, group, hierarchy, affiliation and kinship). We questioned, first, whether gestural laterality differed with gesture at the population level and second, whether some factors influenced gestural laterality. To do so, we evaluated social laterality in dyadic interactions in 39 chimpanzees, Pan troglodytes, living in three groups in captivity. We found that, at the population level, 13 of the 21 gestures we observed were performed predominantly with the right hand. Gestural laterality of signallers was influenced mainly by interactional context, gesture characteristics (except gesture duration) and signallers' hierarchical rank and age. Signallers used their hand ipsilateral to recipients for tactile and visual gestures and their contralateral hand for gestures involving auditory communication and a communication tool. Moreover, signallers' use of their right hand was more important for subordinates. This was also true in negative contexts for gestures common to most of the subjects. Our results further support the hypothesis that laterality in gestural communication might represent a precursor of the left-hemispheric lateralization of language. We discuss our results in relation to theories concerning the origins of cerebral hemispheric lateralization and their consistency with previous studies.

Early postnatal testosterone predicts sex-related differences in early expressive vocabulary

During the first few years of life, girls typically have a larger expressive vocabulary than boys. This sex difference is important since a small vocabulary may predict subsequent language difficulties, which are more prevalent in boys than girls. The masculinizing effects of early androgen exposure on neurobehavioral development are well-documented in nonhuman mammals. The present study conducted the first test of whether early postnatal testosterone concentrations influence sex differences in expressive vocabulary in toddlers. It was found that testosterone measured in saliva samples collected at 1–3 months of age, i.e., during the period called mini-puberty, negatively predicted parent-report expressive vocabulary size at 18–30 months of age in boys and in girls. Testosterone concentrations during mini-puberty also accounted for additional variance in expressive vocabulary after other predictors such as sex, child’s age at vocabulary assessment, and paternal education, were taken into account. Furthermore, testosterone concentrations during mini-puberty mediated the sex difference in expressive vocabulary. These results suggest that testosterone during the early postnatal period contributes to early language development and neurobehavioral sexual differentiation in humans.

Accommodating ‘unaccustomed pragmatic spaces’ in Arbib's model Comment on “Towards a Computational Comparative Neuroprimatology: Framing the language-ready brain” by Michael A. Arbib

Arbib's article [1] offers a sophisticated and convincing account of the evolution of human language that does not shy away from nailing together neurophysiology and the forms and functions of language. The core recognition of what language does, rather than just what language looks like or how its forms are generated, gives the model a high level of explanatory significance. This commentary explores interaction in the context of his account of comprehension, section 4.3.2, offering some observations that potentially test and support the model. They expand Arbib's existing consideration of agrammatism, where he suggests that difficulties with managing the linguistic system (Grammatical Route, G, including Light Semantics, LS) are compensated for using world knowledge (Heavy Semantics, HS). That is, if, in comprehension, one is not sure how the words go together, one increases attention to the pragmatics generated by the observable context and general memory to fill in the gaps. I introduce the opposite situation, where, in dementia of the Alzheimer's type, compromises to world knowledge and pragmatics create unstable HS, and may generate ambiguity in the linguistic input. I consider how Arbib's model sheds light on the typical fixes for this eventuality, and also venture a link back to the protolanguage account.

Neuronal factors determining high intelligence.

Many attempts have been made to correlate degrees of both animal and human intelligence with brain properties. With respect to mammals, a much-discussed trait concerns absolute and relative brain size, either uncorrected or corrected for body size. However, the correlation of both with degrees of intelligence yields large inconsistencies, because although they are regarded as the most intelligent mammals, monkeys and apes, including humans, have neither the absolutely nor the relatively largest brains. The best fit between brain traits and degrees of intelligence among mammals is reached by a combination of the number of cortical neurons, neuron packing density, interneuronal distance and axonal conduction velocity--factors that determine general information processing capacity (IPC), as reflected by general intelligence. The highest IPC is found in humans, followed by the great apes, Old World and New World monkeys. The IPC of cetaceans and elephants is much lower because of a thin cortex, low neuron packing density and low axonal conduction velocity. By contrast, corvid and psittacid birds have very small and densely packed pallial neurons and relatively many neurons, which, despite very small brain volumes, might explain their high intelligence. The evolution of a syntactical and grammatical language in humans most probably has served as an additional intelligence amplifier, which may have happened in songbirds and psittacids in a convergent manner.

Embodied Language Learning and Cognitive Bootstrapping: Methods and Design Principles

Co-development of action, conceptualization and social interaction mutually scaffold and support each other within a virtuous feedback cycle in the development of human language in children. Within this framework, the purpose of this article is to bring together diverse but complementary accounts of research methods that jointly contribute to our understanding of cognitive development and in particular, language acquisition in robots. Thus, we include research pertaining to developmental robotics, cognitive science, psychology, linguistics and neuroscience, as well as practical computer science and engineering. The different studies are not at this stage all connected into a cohesive whole; rather, they are presented to illuminate the need for multiple different approaches that complement each other in the pursuit of understanding cognitive development in robots. Extensive experiments involving the humanoid robot iCub are reported, while human learning relevant to developmental robotics has also contributed useful results.Disparate approaches are brought together via common underlying design principles. Without claiming to model human language acquisition directly, we are nonetheless inspired by analogous development in humans and consequently, our investigations include the parallel co-development of action, conceptualization and social interaction. Though these different approaches need to ultimately be integrated into a coherent, unified body of knowledge, progress is currently also being made by pursuing individual methods.

Animal Communication and Human Language: An overview

Comparative research has proven to be a fruitful field of study on the ontogenetic and phylogenetic evolution of language, and on the cognitive capacities unique to humans or shared with other animals. The degree of continuity between components of human language and non-human animal communication systems, as well as the existence of a core factor of language, are polemic subjects at present. In this article, we offer an overview of the research on animal communication, comparing the resulting data with the current knowledge on human language development. We try to summarize what is currently known about “language abilities” in multiple animals, and compare those facts to what is known about human language. The aim of the article is to provide an introduction to this particular topic, presenting the different sides of the arguments when possible. A special reference is made to the question of syntactic recursion as the main component of language, allegedly absent among non-human animals. We conclude that the current state of knowledge supports the existence of a certain degree of continuity between different aspects of animal communication and human language, including the syntactic domain.

Human-specific increase of dopaminergic innervation in a striatal region associated with speech and language: A comparative analysis of the primate basal ganglia.

The dopaminergic innervation of the striatum has been implicated in learning processes and in the development of human speech and language. Several lines of evidence suggest that evolutionary changes in dopaminergic afferents of the striatum may be associated with uniquely human cognitive and behavioral abilities, including the association of the human-specific sequence of the FOXP2 gene with decreased dopamine in the dorsomedial striatum of mice. To examine this possibility, we quantified the density of tyrosine hydroxylase-immunoreactive axons as a measure of dopaminergic innervation within five basal ganglia regions in humans, great apes, and New and Old World monkeys. Our results indicate that humans differ from nonhuman primate species in having a significant increase in dopaminergic innervation selectively localized to the medial caudate nucleus. This region of the striatum is highly interconnected, receiving afferents from multiple neocortical regions, and supports behavioral and cognitive flexibility. The medial caudate nucleus also shows hyperactivity in humans lacking a functional FOXP2 allele and exhibits altered dopamine concentrations in humanized Foxp2 mice. Additionally, striatal dopaminergic input was not altered in chimpanzees that used socially learned attention-getting sounds versus those that did not. This evidence indicates that the increase in dopamine innervation of the medial caudate nucleus in humans is a species-typical characteristic not associated with experience-dependent plasticity. The specificity of this increase may be related to the degree of convergence from cortical areas within this region of the striatum and may also be involved in human speech and language. J. Comp. Neurol. 524:2117-2129, 2016. © 2015 Wiley Periodicals, Inc.

Iconicity and the Emergence of Combinatorial Structure in Language.

In language, recombination of a discrete set of meaningless building blocks forms an unlimited set of possible utterances. How such combinatorial structure emerged in the evolution of human language is increasingly being studied. It has been shown that it can emerge when languages culturally evolve and adapt to human cognitive biases. How the emergence of combinatorial structure interacts with the existence of holistic iconic form-meaning mappings in a language is still unknown. The experiment presented in this paper studies the role of iconicity and human cognitive learning biases in the emergence of combinatorial structure in artificial whistled languages. Participants learned and reproduced whistled words for novel objects with the use of a slide whistle. Their reproductions were used as input for the next participant, to create transmission chains and simulate cultural transmission. Two conditions were studied: one in which the persistence of iconic form-meaning mappings was possible and one in which this was experimentally made impossible. In both conditions, cultural transmission caused the whistled languages to become more learnable and more structured, but this process was slightly delayed in the first condition. Our findings help to gain insight into when and how words may lose their iconic origins when they become part of an organized linguistic system.

Zipf's Law: Balancing Signal Usage Cost and Communication Efficiency.

We propose a model that explains the reliable emergence of power laws (e.g., Zipf’s law) during the development of different human languages. The model incorporates the principle of least effort in communications, minimizing a combination of the information-theoretic communication inefficiency and direct signal cost. We prove a general relationship, for all optimal languages, between the signal cost distribution and the resulting distribution of signals. Zipf’s law then emerges for logarithmic signal cost distributions, which is the cost distribution expected for words constructed from letters or phonemes.

Pointing and pantomime in wild apes? Female bonobos use referential and iconic gestures to request genito-genital rubbing.

Referential and iconic gesturing provide a means to flexibly and intentionally share information about specific entities, locations, or goals. The extent to which nonhuman primates use such gestures is therefore of special interest for understanding the evolution of human language. Here, we describe novel observations of wild female bonobos (Pan paniscus) using referential and potentially iconic gestures to initiate genito-genital (GG) rubbing, which serves important functions in reducing social tension and facilitating cooperation. We collected data from a habituated community of bonobos at Luikotale, DRC, and analysed n = 138 independent gesture bouts made by n = 11 females. Gestures were coded in real time or from video. In addition to meeting the criteria for intentionality, in form and function these gestures resemble pointing and pantomime–two hallmarks of human communication–in the ways in which they indicated the relevant body part or action involved in the goal of GG rubbing. Moreover, the gestures led to GG rubbing in 83.3% of gesture bouts, which in turn increased tolerance in feeding contexts between the participants. We discuss how biologically relevant contexts in which individuals are motivated to cooperate may facilitate the emergence of language precursors to enhance communication in wild apes.

Brain research and the social self in a technological culture

The paper does not claim to be a novel contribution to any field. It simply opposes claims by philosophers of consciousness--I take Daniel Dennett as an example (though no more than that) that non-conscious robot-like neurons (Dennett's phrase) can, taken together, add up to an explanation of (even the illusion of) consciousness. To this I oppose G. H. Mead's so-called social behaviorism. My argument, such as it is, proceeds in well-defined stages: 1. I first introduce the history of anti-reductionism among philosophers, including those of the analytical persuasion, especially among North American philosophers; 2. the "new archaeology" of hominid prehistory is then introduced to show how some eminent archeologists oppose the reductionist view that large brains--deduced from finds of larger and larger skulls--constitute the best explanation we have for the advent of Homo sapiens; 3. the heart of my paper is then a reference to--not a proper summary of--Terence Deacon's masterful book, The Symbolic Species: The Co-Evolution of Language and the Brain--where the idea of co-evolution of human communication and brain development (along with other physiological traits such as a proper voice box) is put forward as a better--as co-evolutionary--explanation of human symbolic behavior than the standard ones (including Dennett's); 4. I then make equally brief summaries of confirming evidence of such co-evolution; 5. this is followed by similar summaries of the alleged science of historical linguistics--none of it explaining the beginning, but only the development of human languages in non-reductionist terms; 6. I then introduce Berger and Luckmann's Social Construction of Reality to make a central claim: that even reductionist science--whether genetic reductionism or brain-studies-based reductionism--is and must be socially constructed; and 7. I conclude with a preference for a Meadian (similar to a Deweyan) social responsibility activism. One note relative to item number 1: I make no claim here to discuss Merleau-Ponty or any other well-known anti-reductionist; this is in answer to one referee of the paper.